A&P 2 Physiology of Heart, Blood Vessels, and Lymphatic System – Flashcards
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Blood Vessels
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form a network in our body taking the blood from the heart to the tissues of the body and returning it back to the heart
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Direction of the flow of the blood
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heart arteries arterioles capillaries venules veins heart EX: pulmonary and systemic circulation
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Arteries
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blood vessels that take the blood away from the heart and consists of 3 major layers -Tunica interna (intima) -Tunica media -Tunica externa
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Tunica interna (intima)
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-innermost layer of simple squamous epithelium known as endothelium -basement membrane -internal elastic lamina
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Tunica media
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smooth muscle capable of vasoconstriction and vasodilation
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Tunica externa
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outermost layer of elastic and collagen fibers irregular connective
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types of arteries
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elastic- large conducting muscular- medium distributing
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Elastic (conducting) arteries
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-large -found closer to the heart -have more elastic fibers and are able to receive blood under pressure -help to conduct blood from heart to the muscular arteries
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Muscular (distributing) arteries
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-medium -found closer to the organs and tissues -have more smooth muscle tissue -capable of vasoconstriction an vasodilation, control flow of blood
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Arteriosclerosis
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thickening and toughening of the arterial walls. Complications associated with this can lead to heart attack and stroke. 2 main types focal calcification atherosclerosis
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Focal Calcification
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deposition of calcium salts, replacing smooth muscle tissue of the arterial wall. Can be due to aging, or a consequence of diabetes mellitus
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Atherosclerosis
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deposition of lipids (plaques) in the tunica media
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Arterioles
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-small microscopic arteries delivering blood to capillaries -an arteriole has tunica interna, tunica media, and very thin tunica externa -through vasoconstricton and vasodilationregulate the amount of blood entering into the capillaries of an organ or tissue
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capillaries and arterioles
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have the greatest resistance together
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Capillaries
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-microscopic vessels which connect arterioles and venules -endothelial and basement layer only
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Microcirculation
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flow of blood from arterioles to capillaries to venules
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Primary Function of Capillaries -distribution of capillaries in tissues
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permit the exchange of nutrients and gases between the blood and the tissues -depends on the metabolic activity of the body
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Precapillary sphincters
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if blood flow is too high they can contract or close off
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Thoroughfare channel -Metartioles
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-closer to venule -closer to arteriole
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Vaso Vasum
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large blood vessels that have their own blood vessels
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Types of Capillaries
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-continuous -fenestrated -sinusoids
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Continuous Capillaries Ex:
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slits between endothelial cells -plasma membrane of the endothelial cells forms a continuous ring around the capillary. Have no pores Ex: skeletal and smooth muscle, and lungs
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Fenestrated Capillaries Ex:
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pores larger than slits -plasma membranes have many holes Ex: in kidneys, small intestine, choroid plexuses
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Sinusoids Ex:
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very large fenestrations (pores) -irregularly shaped and very large -some proteins can get through -incomplete basement membrane (not continuous) Ex: liver, bone marrow, and spleen
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kidneys
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filter blood to produce urine
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Capillaries are also called
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exchange vessels
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Venules
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(capacitance vessels) -blood flows in fast -formed by joining of small capillaries -collect blood from capillaries and drain it into veins
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Veins
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(capacitance vessels) -deliver blood away from tissues have the same 3 tunics as arteries but differ in the following: -contain less smooth muscle and elastic tissue -thinner walled in comparision to arteries -contain valves to prevent the backflow of blood -lumen is larger than arteries
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Varicose veins
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due to weakening of the valves in the veins of thighs and legs. Blood pools in the veins and become swollen
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What happens when we breathe in?
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pressure decreases as thoracic cavity expands
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What helps blood get back to the heart?
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skeletal muscle pump thoracic pump valves- prevent back flow
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Anastomeses -formed by what?
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most varied arrangement of blood vessels from human to human (like different finger prints) -union of branches of 2 or more arteries supplying the same region -provide alternate routes for blood to reach a tissue or organ coronary arteries
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Blood distribution
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60% of blood volume at rest is in systemic veins and venules (stored in liver and lungs) -function as blood reservoir -blood is diverted from it in times of need 15% of blood volume is in arteries and arterioles
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Types of Blood Vessels
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arterioles, arteries, venules, veins, capillaries
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Compare and Contrast Arteries and Veins *********
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-arteries are overall thicker -arteries have thicker tunica media -veins have thicker tunica externa -arteries pump blood away from heart -veins pump blood to heart -arteries are deeper -arteries have more smooth muscle -veins have more lumen -arteries usually carry oxygenated blood -veins usually carry deoxygenated blood
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How does the structure of the capillary assist in carrying out its functions
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nutrients and wastes diffuse more easily since the wall is thinner (squamous)
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blood flow
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volume of blood that flows through any tissue in a given time period -depends on pressure (P) and resistance (R) -flow is directly proportional to pressure and inversely proportional to resistance
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profusion
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how blood flows through a defined volume
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What is blood flow equal to?
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cardiac output -when cardiac output goes up the blood flow through the capillary beds increases
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What causes blood pressure -where is it highest and lowest?
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contraction of the ventricles -highest in aorta 120mmHg during systole and 80mmHg during diastole -pressure falls as we move away from heart
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Why are valves found in veins and not arteries?
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veins go against the force of gravity and do not have enough pressure
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Cardiovascular pressure is measured in terms of what values?
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-blood pressure (BP) -capillary hydrostatic pressure (CHP) -Venous pressure For circulation to happen, circulatory pressure must overcome the total peripheral resistance
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Blood pressure
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hydrostatic pressure (opposes blood flow) exerted by the blood on the walls of arteries. Ranges from 100mmHg (near the aorta) to 35 mmHg (near the capillaries)
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Capillary Hydrostatic Pressure
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pressure exerted by the fluids on the capillary walls. Ranges from 35 mmHg to 18 mmHg
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Venous pressure
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pressure within the veins. Lowes of the three pressure approximately 18mmHg
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Resistance between blood and walls of vessels
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friction between the blood and the walls of the vessels which increases BP. Depends on: -vascular resistance a) size of lumen b) total blood vessel length -blood viscosity -turbulence
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Vascular Resistance
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force that resists the flow of blood within the blood vessels and depends on: 1) size of lumen- smaller lumen, greater resistance 2) total blood vessel length- directly proportional to resistance
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Blood Viscosity
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thickness of the blood is due to ratio of RBCs to plasma and concentration of plasma proteins. Anemia, polycythemia, and other disorders change blood viscosity and thus peripheral resistance
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Turbulence
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due to high flow rates, irregular surfaces and sudden changes in vessel diameter due to blockages. It increases resistance and thereby slows the flow of blood
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pulse pressure
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systolic -diastolic pressure
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Mean arterial pressure
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diastolic pressure + 1/3 pulse pressure (heart spends more time in diastole)
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Factors affecting blood pressure
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cardiac output, blood volume, viscosity, resistance, and elasticity of arteries
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venous return
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volume of blood flowing back to the heart from the systemic veins depends on the pressure difference from venules to right atrium. Two mechanisms act to return venous blood -Skeletal muscle pump -respiratory pump
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Skeletal muscle pump
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skeletal muscles surrounding the veins contracts which exerts pressure on the walls of veins which forces the valves open and blood is pumped up. skeletal muscle is relaxed and valves close preventing the backward flow of blood
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Respiratory pump
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during inspiration the diaphragm moves inferiorly. This causes a decrease in pressure in the thoracic cavity and an increase in the pressure of the abdominopelvic cavity. As a result blood flows from the veins in the abdominopelvic region to veins in the thoracic region. During expiration, valves close preventing back flow.
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Ways that substances enter and leave capillaries
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diffusion filtration reabsorption
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diffusion
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substances like oxygen, carbon dioxide, glucose, amino acids, hormones diffuse through the capillaries down their concentration gradient. Lipid soluble molecules like gases and certain hormones, pass directly through the phospholipid layer. Water soluble compounds like glucose and amino acids pass through the intercellular clefts
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filtration
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driven by hydrostatic pressure water and small solutes forced through capillary wall and leave larger solutes in bloodstream
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Reabsorption
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result of osmotic pressure blood colloid (floating non- dissolved small particles) osmotic pressure equals pressure required to prevent osmosis Caused by suspended blood proteins that are too large to cross capillary walls
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Net hydrostatic pressure
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forces water out of solution
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Net osmotic pressure
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forces water into solution
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Net hydrostatic and osmotic pressure
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both control filtration and reabsorption through capillaries
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Net filtration pressure
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net hydrostatic - net colloid osmotic pressure outside-inside pressure
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NFP at arterial end****
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9 mmHg which means that at the arterial end there is net movement of molecules out of the capillary and at the venous end fluids move into the capillary from the surrounding tissue
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Dynamics of Capillary Exchange
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on average only 85% of the fluid that comes out of the capillaries reenters the capillaries at the venous end -the extra fluid is returned back to the circulatory system via the lymphatic system
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Edema
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an increase in the interstitial fluid volume due to filtration exceeding the reabsorption (swelling)
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Control of blood pressure and blood flow
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1) Cardiovascular center 2) Hormone Regulation 3) Local Regulation
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Cardiovascular center
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group of neurons in the medulla of the brain and it regulates heart rate, contractility, and blood vessel diameter -receives input from sensory receptors (baroreceptors and chemoreceptors) -send output via sympathetic and parasympathetic fibers -sympathetic activation results in increased heart rate and vasoconstriction, whereas parasympathetic activation causes decreased heart rate
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Baroreceptors
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aorta and carotid artery
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Hormones Regulating of Blood Pressure
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-renin-angiotensin-aldosterone system -E & NE -ADH -ANP
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Renin angiotensin aldosterone system
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dec in BP or dec in blood flow to kidney releases renin by kidney. angiotensinogen is converted to angiotensin in liver which releases aldosterone by adrenal cortex which increases water reabsorption (inc in blood volume) and vasoconstriction (inc in BP)
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E & NE
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-inc heart rate and force of contraction -causes vasoconstriction (narrowing of the blood vessels)
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ADH
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causes vasoconstriction and increased water reabsorption resulting in increase BP and blood volume
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ANP
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lowers BP and blood volume -causes vasodilation and loss of salt and water in the urine
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autoregulation
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-ability of a tissue to automatically adjust its own blood flow to match its metabolic demand for supply of oxygen and nutrients and removal of wastes
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Local Regulation of Blood Pressure
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-autoregulation -important for tissues that show major increase in activity such as brain and skeletal muscles
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Blood, heart, and cardiovascular system in response to exercise
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-work together as a unit -respond to physical and physiological changes (Exercise and Blood loss) - maintain homeostasis
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Cardiovascular Response to Light Exercise
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-Extensive vasodilation occurs increasing circulation -venous return increases with muscle contractions -cardiac output rises venous return (Frank Starling principle) -Atrial stretching
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Cardiovascular Response to Heavy Exercise
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-Activates sympathetic nervous system -cardiac output increases to maximum (about 4 times the resting level) -restricts blood flow to "nonessential" organs (digestive system) -redirects blood flow to skeletal muscles, lungs, and heart -blood supply to brain is unaffected of blood flow
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Circulatory Routes
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-pulmonary and systemic circulation -portal system -anastomeses
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portal system
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blood flows through two consecutive capillary networks before returning to the heart -hypothalamus to anterior pituitary -found in kidneys -between intestines-liver
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Anastomoses
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point where two blood vessels merge EX: coronary circulation
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Pulmonary Circulation
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Pulmonary and systemic circulation are different in several ways: -distance traveled by the blood is smaller -pulmonary arteries are larger in diameter and have thinner walls which means resistance to blood flow is low -hydrostatic pressure in pulmonary capillary is low, tends to prevent pulmonary edema
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Systemic Circulation
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-the aorta is divided into the ascending aorta, arch of the aorta, and descending aorta (thoracic and abdominal aorta). Each section gives off arteries that branch to supply the whole body -blood returns to the heart through the systemic veins. All the veins of the ystemic circulation flow into the superior or inferior vena cavae or the coronary sinus which empty into the right atrium
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First branch of aorta
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coronary arteries
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Hepatic portal system
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-detours venous blood from GI tract to sinusoids of liver on its way to the heart -this circulation enables nutrient utilization and blood detoxification by the liver
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ductus arteriosus
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becomes the ligamentum arteriosum
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foramen ovale
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becomes the fossa ovalis
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ductus venosus
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becomes the ligamentum venosum
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umbilical arteries
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become the medial umbilical ligament
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umbilical veins
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become the ligamentum teres (Round ligament)
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Fetal Circulation
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-fetus derives its oxygen and nutrients and eliminates its carbon dioxide and wastes through maternal blood supply by the placenta. -blood passes from the fetus to the placenta via two umbilical arteries and returns from the placenta via a single umbilical vein
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Age Related Changes in Blood
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-decreased hematocrit -peripheral blockage by blood clot (thrombus) -pooling of blood in legs due to venous valve deterioration
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Age Related Changes In Hearth
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-reduced maximum cardiac output -changes in nodal and conducting cells -reduced elasticity of cardiac (fibrous) skeleton -progressive atherosclerosis -replacement of damaged cardiac muscle cells by scar tissue
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Age Related Changes in Blood Vessels
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-arteries become less elastic -pressure change can cause aneurysm -calcium deposits on vessel walls can cause stroke or infarction -thrombi can form at atherosclerotic plaques
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Resistance
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the ability of the body to protect itself from damage or disease
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Types of Resistance
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-Nonspecific (innate)- provide defense mechanism against a range of pathogens in a general way -adaptive specific (immunity)- provides defense mechanism against a specific pathogen by specialized lymphocytes
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Lymphatic system
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responsible for specific resistance
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Functions of Lymphatic System
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-Fluid Balance- excess interstitial fluid enters lymphatic capillaries and becomes lymph. Finally drained into the circulatory system -Fat Absorption- lymphatic system helps to absorb fat and other substances from the digestive system with the help of specialized vessels called lacteals -Defense- lymphocytes residing the lymphatic tissue protect the body against microorganisms and foreign substances
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Lymphatic system consists of:
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-lymph -lymphatic vessels -lymphatic tissue & lymphoid organs -lymphocytes, phagocytes and other immune system cells
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lymph
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fluid similar to plasma but does not have plasma proteins - drained from interstitial spaces in all tissue of the body -returns to circulator system via lymphatic vessels and is essential for fluid balance Order it flows: blood capillaries-interstitial spaces-lymphatic capillaries-lymphatic vessels-lymph nodes-lymphatic trunk-lymphatic duct- subclavian or large veins of the body
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lymphatic vessels (lymphatics)
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carry lymph from peripheral tissue to the venous system
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Lymph capillaries
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similar to blood capillaries but are different in these ways: -have only endothelial cells which are loosely attached and are more permeable -have one way valves to prevent back flow of lymph into interstitial space
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Lymphatic vessels
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lymph capillaries merge to form these structures which have valves and are similar in structure to veins -the have all 3 layers and one way valves -lymph moves through with the help of milking action carried out by the skeletal muscles and pressure changes created by the respiration
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Lymph nodes -function
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bean shaped (or oval) clusters of B and T cells located along the lymphatic vessels; lymph flows through the nodes -superficial and deep. concentrated near mammary glands, axilla, groin -surrounded by a dense connective tissue capsule and extends into the lymph node (trabeculae) -outer part is cortex made up of lymphatic nodules containing lymphocytes and macrophages -inner medulla made up of irregular strands of lymphatic tissue (medullary cords) -filter lymph
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as lymphatic vessels exit from lymph nodes, they merge and form... -function -EX:
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lymph trunks -drains fluid from a certain area of the body EX: jugular trunks drain from the head and neck, subclavian trunks drain from the upper arms and superficial thoracic wall
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Lymphatic trunks drain into ....
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2 lymphatic ducts -Thoracic -Right lymphatic duct
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Lymphocytes -Types
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20-30% of circulating leukocytes most of them are stored T Cells B cells Nk Cells
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T cells
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thymus dependent
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Thoracic duct
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main collecting duct of the lymphatic system Receives lymph from the left side of the head, neck, and chest, the left upper extremity, and the entire body below the ribs Drains lymph into venous blood at junction of the left subclavian vein and internal jugular vein
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Right Lymphatic Duct
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- drains the right side head, arm, and chest. Empties into the venous sytem at junction of right subclavian vein and right jugular vein
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B cells
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Bone marrow derived -indirect approach humoral immunity
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Natural Killer cells
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immunological surveillance & innate nonspecific
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Formation of T cells
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make up 80% of circulating lymphocytes -stem cells in the red bone marrow divide and differentiate into blood cells. Then, lymphocyte stem cells exit bone marrow and migrate to thymus gland where they mature and differentiate in thymus to form T Cells
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Main Types of T Cells
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Cytotoxic T memory T helper T Suppressor T
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Cytotoxic T Cells
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attack cells infected by viruses and produce cell mediated immunity -also attack foreign cells
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Memory T Cells
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formed in response to foreign substance and remain in body to give immunity -respond to previously encountered antigen
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Helper T cells
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stimulate function of T cells and B cells
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Suppressor T Cells
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inhibit function of T cells and B cells
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Formation of B Cells
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make up 10-15% of circulating lymphocytes -differentiate (change) into plasma cells Formation- stem cells in the red bone marrow divide and differentiate into blood cells. Some lymphocyte cells remain in bone marrow and mature and differentiate in bone marrow to form B Cells
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plasma cells
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produce and secrete antibodies (immunoglobulin proteins)
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Another name of NK cells -function
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-aka large granular lymphocytes -5-10% of circulating lymphocytes -attack foreign cells, virus infected cells, and cancer cells
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Primary Lymphatic Organs
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where lymphocytes originate and mature to become immunocompetent Ex: red bone marrow and thymus gland
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Secondary Lymphatic Organs
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sites where the mature lymphocytes reside and carry out immune response EX: spleen, lymph nodes, nodules
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Lymphatic Nodules
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aggregates of lymphatic tissue not surrounded by a capsule EX: -MALT -peyer's patches -tonsils
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MALT
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high concen. of nodules-concen. of WBCs scattered throughout the lamina propria of mucous membranes lining the GI tract, respiratory airways, urinary tract, and reproductive tract -also in appendix- collects immune cells and collects good bacteria and houses WBCs
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Peyers Patches
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aggregates of lymphatic tissue in appendix and small intestines for protection
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Tonsils -types
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contain a lot of WBCs large groups of nodules in the mucosa of the pharynx. Provide protection against bacteria entering the body through the mouth or nasal cavities -pharyngeal tonsil(adenoids) -palatine tonsil- on each side wall -lingual tonsil-back of the tongue
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Metastasis
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characteristic of malignant tumors spread of disease from one organ to another -cancer cells travel via blood or lymphatic system -cells establish new tumors where lodge
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Secondary tumor sites
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can be predicted by direction of lymphatic flow from primary site
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Thymus
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large organ in infants but atrophied as adult 2 lobed organ located in the mediastinum -surrounded by a connective tissue capsule -trabeculae extend from capsule and divide into lobules -each lobule has a cortex and medulla -cortex- a lot of lymphocytes -medulla- few lymphocytes -site of maturation of T cells and many T cells are produced here
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Spleen
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left superior side of abdomen -destroy defective RBCs -detect and respond to foreign substances -limited reservoir for blood
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During abdominal injury what can happen to spleen?
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can rupture resulting in bleeding, shock, and death -a splenectomy may be required to prevent excessive bleeding
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Structure of Spleen
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-outer layer of connective tissue called capsule extensions of the capsule called trabeculae divide the spleen into smaller compartments -each compartment is filled with white and red pump.
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hilum
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depression on the spleen where the splenic blood vessels enter
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white pulp
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lymphatic tissue around arteries in the spleen
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red pulp
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lymphatic tissue associated with the veins of the spleen
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susceptibility
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lack of resistance
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innate or nonspecific defense mechanism
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prevent entry, limit the spread of microorganisms, or other environmental hazards. 1) physical barriers 2) phagocytes 3) immunological surveillance 4) interferons 5) complement 6) inflammatory response 7) fever
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physical barrier
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prevent entry of microbes in the body. Provided by the skin and mucous membrane -mucous membrane that lines the digestive respiratory and urogenital tract secrete a viscous mucus that prevents entry of potentially harmful microbes -many of the secretions like saliva and tear also contain proteins like lysozyme which digest cell wall of microbes and destroy it
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Examples of Phagocytes
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monocytes eosinophil neutrophil fixed macrophage free macrophage
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Phagocytes
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specialized cells that engulf pathogens and cell debris
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5 steps of phagocytosis
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chemotaxis adherence ingestion digestion killing
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Neutrophil
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60-70% of WBCs leave the blood and migrate to the infected area, attracted to the chemicals released by the damaged cells. They self destruct on destroying foreign invaders
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Monocytes
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5% of WBC leave the blood and migrate into tissues and develop into macrophages. Some macrophages are wandering and other are fixed. They extend pseudopodia and pull microbes in
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Immunological Surveillance
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carried out by NK cells. They attack cancer cells and body cells infect with viruses -nonselective- activated NK cells identify and attach to abnormal cell -Golgi apparatus in Nk cells forms perforin vesicles -vesicles release proteins called perforins (exocytosis) -perforins lyse abnormal plasma membrane
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interferons -types
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chemicals released by virus infected cells -can't save the infected cell but they diffuse to neighboring healthy cells where they stimulate the production of antiviral proteins that inhibit viral replication in these cells. Thus an infect cell helps to protect uninfected cells -alpha, beta, and gamma -most effective in controlling short term infections such as cold and influenze
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Pathways of the complement system
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-classical -alternative -lectin begins with activation of complement proteins all pathways create c3 which dissociates to c3a and c3b
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classical pathway of complement system
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antibody dependent
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alternative pathway of complement system
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antibody independent
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lectin pathway
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antibody independent
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c3a leads to...
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inflammation
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c3b leads to...
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immune clearance, phagocytosis, cytolysis
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4 mechanisms of pathogen destruction
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inflammation immune clearance phagocytiosis cytolysis
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plasma contains...
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11 special complement (C) proteins These proteins form complement system and complement antibody action. Complement proteins work together in cascades
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what pathways activate the complement system?
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classical and alternative
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effects of complement activation
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-pore formation- destruction of target plasma membranes. Five complement proteins join to form membrane attack complex (MAC) -enhancement of phagocytosis by opsonization- complements working with antibodies (opsonin) -histamine release increases the degree of local inflammation and blood flow
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Inflammation
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-triggered by a physical injury such as a cut or by entry of microorganisms -symptoms include redness, pain, heat, and swelling -an injury to basophils and mast cells causes release of histamine which triggers vasodilations -small blood vessels near the injury dilate, increasing the blood supply (redness and heat) . Fluids from the dilated vessels also move into neighboring tissues (swelling). -inflammatory response also involves the migration of phagocyte from the blood into the infected tissues which eliminate the pathogens by phagocytosis
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products of inflammation
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necrosis pus abscess
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necrosis
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local tissue destruction in area of injury
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pus
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mixture of debris and necrotic tissue
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abscess
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pus accumulated in an enclosed space
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fever
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maintained body temperature above 37C or 99F
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pyrogens
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any material that causes the hypothalamus to raise body temperature -a variety of stimuli act as pyrogens or stimulate macrophages to release pyrogens EX: circulating pathogens, toxins, or antibody complexes -active macrophages release cytokine called endogenous pyrogens or interleukin 1
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germinal center
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of a lymphoid nodule and contains dividing lymphocytes
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Retrovirus
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carries genetic info in RNA not DNA
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opsonization
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explained by the fact that phagocytes can bind more easily to antibodies than directly to bacterial membranes -process of coating an antigenic microbe with antibodies to make it more susceptible to phagocytosis
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major histocompatibility complex
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region of chromosome 6 that contains genes to encode for important immune proteins
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cytokines
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chemical messengers released by tissue cells to coordinate local activities
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trabecular
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arteries and veins that supply and drain the spleen
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interleukins
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possibly the most important diverse chemical messenger of immune system
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lymphoid system
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includes cells, tissues, and organs that defend the body from threats from the environment and from within
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pathogens
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foreign organisms that can invade and do harm to the body
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edema
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accumulation of fluid (swelling)
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occlusion
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blockage of blood vessel
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purkinje fibers
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-action potential are carried by purkinje fibers from the bundle branches to the ventricle walls at the apex of the heart whose contractions force blood towards the base
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the sympathetic and parasympathetic divisions of the ANS
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innervate the heart by means of the cardiac plexus
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Contracility
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amount of force produced by the heart at any given preload
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ECG (electrocardiogram)
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recording of the electrical events of a person's heart, measured from the surface of the body
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diastole
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relaxation phase of the cardiac cycle
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Sinoatrial node (SA)
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heart's natural pacemaker
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pulmonary circulation
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carries blood to and from the gas exchange surfaces in the lungs
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stroke volume
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amount of blood ejected from each ventricle on every heart beat
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baroreceptor
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reflexes adjust cardiac output to maintain normal arterial pressure
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brachiocehalic
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vein formed at junctions of internal and external jugular and subclavian vein
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capillaries
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exchange vessels where diffusion occurs between blood and interstitial fluid
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femoral
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on anterior medial surface of thigh
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atherosclerosis
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can lead to cardiovascular disease and stroke
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pulmonary embolism
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caused by a blood clot in the lungs
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total peripheral resistance
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resistance to blood flow over the whole cardiovascular system
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Function of arteries -function of capillaries function of veins
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conduct blood away from the heart -site of exchange of substances between the blood and tissue fluid serves as a blood reservoir
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which part of the aorta is closest to the heart?
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ascending aorta
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coronary arteries
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the first vessels to branch off of the aorta
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aortic arch
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left subclavian left common carotid brachicephalic
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sinusoids
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larger capillaries
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proteins can only pass through
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sinusoid capillaries
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medulla oblongata
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part of the brain that controls blood pressure
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deficiency in ADH can cause
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-drop in blood pressure -reduced stroke volume -decreased cardiac output
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if blood pressure is elevated the cardiovascular centers would compensate by
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causing vasodilation
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the composition of lymph is most similar to
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interstitial fluid
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primary functions of lymph
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return proteins to the bloodstream and transport foreign particles to the lymph nodes
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Sequence of fluid flow
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blood capillaries, interstitial spaces, lymphatic capillaries, lymphatic vessels, lymphatic ducts, subclavian veins
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the structure of a lymphatic vessel is most similar to
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veins
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function of the thymus
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teaches lymphocytes to recognize self from non self antigens
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major function of lymph nodes
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-produce lymphocytes -filtration of foreign particles -filtration of cellular debris
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interferons
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prevent viral replication
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activation of the complement system via the alternative pathway
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nonspecific mechanism of resistance
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example of specific body mechanism
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immunity
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injections of gammaglobulins are sometimes given to
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provide artificially acquired passive immunity
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in an autoimmune disease ...
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the immune response is directed toward self substances
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what has Class 2 MHC antigens?
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antigen presenting cells
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plasma cells
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(mature B Cells) produce antibodies
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IgG
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most common structural class of antibody molecule
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antigen binding site of an antibody molecule is contained in the...
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variable regions of the H and L chains
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major cause of heart disease -what can we do to decrease this?
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inflammation -don't irritate tissues which means less soda, less alcohol, less caffeine, reduce stress, diet, and exercise
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how much interstitial fluid goes into lymph system?
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10 to 15%
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macrophages
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go after any invader
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lymphoid nodules
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doesn't have capsule
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Tc
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specific attacks foreign invaders quickly
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what regions have more nodes?
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specialized regions like the throat, abdomen, and armpits
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cisterna chyll
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dilation where L lymphatic duct begins
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Tm
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wait and activated to attack invader
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Th
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-involved in ALL aspects of immunity help trigger immune response by recognizing invaders and can multiply to stimulate more T cells or B cells also stimulates macrophages, neutrophil non specific
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surface antigens on B cells...
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fall of and become antibodies that flow through the blood
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lymph enters through... -and leaves through...
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-afferent -efferent
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ABCD of cancer
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A-area spreading B- irregular border C- discoloration D- diameter
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septa
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trabecular in thymus
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cortex
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tests lymphocytes to make sure they attack foreign cells and not your own
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spleen
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stores RBCs and filter blood destroys nonfunctional RBCs
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lysozyme
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contained in sweat and destroys bacteria
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what does salt do to invaders?
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dehydrates bacteria
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what does acid in stomach do to invaders:
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kills bacteria
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chemotaxis
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chemicals that bring about movement
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perforins
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produced by the Golgi apparatus and come together for form pore complex
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prostaglandins
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produce pain - pressure can also push up against nerves to cause pain
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mast cells
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produce histamine and heparin which cause blood vessels to dilate
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pyrogen
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raises body temperature and causes fever
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febrile
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have a fever
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pyresis
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produce a fever
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autorhythmic cells
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generate action potential spontaneously, act as pacemaker and form conduction system for the heart
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Sinoatrial node
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generates action potential below superior vena cava -cluster of cells in the wall of the Right Atria -begins heart activity that spreads to both atria -excitation (depolarization) spreads to AV node
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AV node
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gateway to ventricles how electricity runs through pathway -in atrial septum slow the transmission of the action potential and transmit the signal to the bundle of His -atria contraction begins
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Bundle of HIs
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-superior part of interventricular septum -the av bundle divides into right and left bundle branches and action potentials descend to the apex of the heart
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tetany
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causes muscles to seize up
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action potential
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past 0 anions-inside the cells cations- outside of plasma membrane
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tetralogy of fallot
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1) pulmonary trunk is abnormally narrow (stenosis) 2) interventricular septum is incomplete 3) aorta originates where the interventricular septum normally ends 4) right ventricle is enlarged and both ventricles thicken in response to the increased workload
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Conduction system of the heart
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signals from the ANS and hormons (E ) do modify the heart beat in terms of rate and strength of contration, but they do not establish the fundamental rhythm
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auscultation
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listening to sounds within the body
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percussion
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tapping
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palpation
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feeling
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regurgitation
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blood flows back into atria or back down into ventricle causes an abnormal sound
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what is an impulse in a ventricular contractile fiber characterized by?
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-rapid depolarization, plateau, and repolarization
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depolarization
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cardiac cell resting membrane potential is -90 -voltage gates fast sodium channels open for rapid depolarization -sodium entry
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plateau
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period of maintained depolarization -slow calcium channels open and let calcium enter from outside cells and from storage in sarcoplasmic reticulum, while k channels close -Calcium binds to troponin to allow for acitin-myosin cross bridge formation and muscle contraction -Cacium entry
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repolarization
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calcium channels close and potassium channels open and -90 is restored as potassium leaves the cell
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refractory period
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the time interval when a second contraction cannot be triggered -very long so heart can fill -no contraction during this period
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sinosis
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blue skin due to lack of oxygen
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relative refractory period
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after the absolute period and an action potential can cause a contraction
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What does ECG help to determine?
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if the conduction pathway is abnormal if the heart is enlarged if certain regions are damaged
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P wave
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atrial depolarization
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P to Q
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conduction time from atrial to ventricular excitation
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QRS complex
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ventricular depolarization
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T wave
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ventricular repolarization
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ectopic focus
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AV fire before the SA node which causes a blockage
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what does calcium cause muscles to do?
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contract
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cardiac cycle
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includes all the events occurring in a single heart beat -atria and ventricles alternately contract and relax forcing blood from areas of high pressure to areas of lower pressure
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systole
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repetitive contraction of heart chambers
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Phases of Cardiac cycle
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1) atrial systole 2) ventricular systole/ atrial diastole 3) relaxation period
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Atrial Systole (cardiac cycle)
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atria contract increasing pressure forces the AV valves to open -small amount of additional blood into relaxed ventricles
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EDV
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amount of blood in the ventricle at the end of diastole
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Ventricle Systole (cardiac cycle)
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-ventricles contract -AV valves close but does not create enough pressure to open SL valves -all of the valves are closed (isovolumetric contraction) -when pressure in ventricle exceeds pressure in the arteries the SL valves open leading to ventricular ejection
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ESV
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amount of blood in the left ventricle at the end of systole
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Stroke Volume
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volume of blood ejected from the left ventricle SV= EDV-ESV
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Relaxation period of cardiac cycle
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both atria and ventricles are relaxed. pressure in the ventricles fall and the SL valves close. Brief time all four valves are closed is the isovolumetric relaxation. Pressure in the ventricles continues to fall, the AV valves open and ventricular filling begins
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ventricle diastole (cardiac cycle)
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as ventricles relax the pressure in ventricles drops; blood flows back against cusps of SL valves and forces them close. Blood flows into the relaxed atria
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fibrilation
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heart twitches, spudders, and quivers
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sound of a heartbeat
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comes primarily from the turbulence in blood flow caused by the closure of the valves
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S1
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Lubb- closing of the AV valves soon after ventricular systole begins
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S2
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Dupp- closing of the SL vales at the end of ventricular systole
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heart murmur
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abnormal sound that consists of a flow noise that is heard before, between, or after the lubb dupp or that may mask the normal sounds entirely -not all are abnormal or symptomatic but most indicate a valve disorder
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Cardiodynamics
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refers to movements and forces generated during muscle contractions
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Cardiac output
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volume of blood ejected from the left ventricle (or right) into the aorta (or pulmonary trunk) each minute CO= SV X HR
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Cardiac Reserve
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ratio between the maximum cardiac output a person can achieve and the cardiac output at rest -average is 4-5 X while athlete's is 7-8X
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Factors that affect HR
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autonomic innervation hormones -intrinsic and extrinsic stimulation -cations Na K Ca -age, gender, physical fitness, temp., emotional excitement, stress
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Intrinsic Regulation of Heart
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results from normal functional characteristics, not on neural or hormonal regulation
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Extrinsic Regulation of Heart -types of stimulation
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involves neural and hormonal control -parasympathetic and sympathetic stimulation
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Parasympathetic Stimulation
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supplied by vagus nerve, decreases heart rate (20-30 bpm), acetylcholine is secreted and hyperpolarizes the heart
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Sympathetic Stimulation
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supplied by cardiac nerves. Innervate the SA and AV nodes, coronary vessels and the atrial and ventricular myocardium. Increases hart rate (250-300bpm) and force of contraction. E and NE released
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Factors Affecting EDV
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-filling time -venous return -preload
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Frank Starling law of the heart
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greater the preload on fibers just before they contract greater is the force of contraction
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Filling time
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duration of the ventricular diastole which is entirely dependent on heart rate
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Venous Return
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- varies in response to changes in cardiac output, blood volume, patterns of peripheral circulation
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Preload
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- the degree of stretch in the heart before it contracts.
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Factors affecting ESV
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-preload -contractility -afterload
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contractility -subsances that inc contractility -substances that Dec contractility
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forcefulness of myocardial contraction. - positive inotropic agents EX: E NE stimulation of sympathetic nervous system and -negative inotropic agents EX: inhibition of sympathetic division, acidosis, and anesthetics
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Afterload
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pressure that must be overcome before a SL valve can open. An inc in afterload causes the SV to dec
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Risk Factors For Heart Disease
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-high blood cholesterol -high blood pressure -smoking -obesity & lack of regular exercise -diabetes mellitus -genetic predisposition -male gender -high blood levels of fibrinogen -left ventricular hypertrophy
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myocardial infarction
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(heart attack) -death of area of heart muscle from lack of oxygen -replaced with scar tissue -results depend on size and location of damage -usually can be diagnosed with an ECG and blood studies
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angina pectoris
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heart pain from ischemia of cardiac muscle
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Coronary Artery Disease ----treatment
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-heart muscle receiving insufficient blood supply -narrowing of vessels-arteriosclerosis, artery spasm, or clot -atherosclerosis- smooth muscle and fatty deposits on walls of arteries ----drugs, bypass graft, angioplasty, stent
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congenital heart defect
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exists at birth and usually before birth -include coarctation of the aorta, patent (open) ductus arteriosus, septal defects (interatrial or interventricular), valvular stenosis, and tetralogy of fallot -arrhythmia (dysrhythmia) irregularity in heart rhytm resulting from a defect in the conduction system of the heart -bradycardia, tachycardia, and fibrilation
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congestive heart failure -causes
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chronic or acute state that results when the heart is not capable of supplying the oxygen demands of the body -coronary artery disease, hypertension, MI, valve disorders, congenital defects
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Left Side Heart Failure
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-less effective pump so more blood remains in ventricle -heart is overstretched and even more blood remains -blood backs up into lungs as pulmonary edema -suffocation and lack of oxygen to the tissues
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Right Side Failure
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fluid builds up in tissues as peripheral edema
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if the cells of the SA node failed to function how would the heart rate be affected?
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decrease
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why is it important for impulses to be delayed at the AV node before they pass into the ventricles?
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slow down to give the ventricles time to fill
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hormones affecting blood pressure
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E & NE, melatonin, growth hormone, ADH -retain water inc BP renin, and aldosterone
