211 Final: Part 8 – Flashcards

Select the correct statement about the functioning of cardiac muscle tissue. A)The influx of potassium ions from extracellular sources is the initiating event in cardiac muscle contraction. B)The refractory period in skeletal muscle is much longer than that in cardiac muscle. C)The entire heart contracts as a unit or it does not contract at all. D)Each cardiac muscle cell is innervated by a sympathetic nerve ending so that the nervous system can increase heart rate.

Compared to skeletal muscle, cardiac muscle ________. A)has gap junctions that allow it to act as a functional syncytium B)lacks striations C)has more nuclei per cell D)cells are larger than skeletal muscle cells

The second heart sound (Dup) is created by the _____. A) opening of the semilunar valves B) opening of the atrioventricular valves C) closing of the semilunar valves D) closing of the atrioventricular valves

All deoxygenated blood returning from the systemic circulation flows into the _____. A) right ventricle B) left atrium C) coronary sinus D) right atrium

The role of the papillary muscles is to A) Secrete pericardial fluid into the pericardial space B) Tighten the chordae tendineae by contracting C) Hold the heart in position within the mediastinum D) transmit the action potential to the AV valves

Which of the events below does NOT occur when the semilunar valves are open? A)AV valves are closed. B)Blood enters pulmonary trunk and the aorta. C)Ventricles are in diastole. D)Ventricles are in systole.

Normal heart sounds are caused by which of the following events? A)excitation of the SA node B)closure of the heart valves C)opening and closing of the heart valves D)friction of blood against the chamber walls

The "lub" sounds of the heart are valuable in diagnosis because they provide information about the function of the heart's semi-lunar valves. A) True B) False

Select the correct statement about the structure of the heart wall. A)The fibrous skeleton forms the bulk of the heart. B)The myocardium is the layer of the heart that actually contracts. C)Connective tissue in the heart wall aids in the conduction of the action potential. D)The heart chambers are lined by the endomysium.

Cardiac muscle has more mitochondria and depends less on oxygen than does skeletal muscle. A) True B) False

During contraction of heart muscle cells _______. A) The calcium is prevented from entering cardiac fibers that have been stimulated B) The action potential is initiated by voltagegated slow calcium channels C) The action potential is prevented from spreading from cell to cell D) Some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores

If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________. A)decreased delivery of oxygen B)a decrease in the number of available mitochondria for energy production C)a lack of nutrients to feed into metabolic pathways D)an inadequate supply of lactic acid

Blood within the pulmonary veins returns to the ________. A)right ventricle B)right atrium C)left atrium D)left ventricle

Blood flows into the coronary arteries from the _____. A) superior vena cava B) coronary sinus C) descending aorta D) ascending aorta

The function of the chordae tendineae is to A) Pull the walls of the ventricles inward during contraction B) Open the AV valves C) Prevent ballooning of the AV valves into the atria during ventricular systole D) Open the semilunar valves

In autorhythmic cells, it is the influx of ______ that produces the action potential. A)Na B)Ca C)Cl D)K

Autonomic regulation of heart rate is via two reflex centers found in the pons. A) True B) False

The tricuspid valve is closed ________. A)when the ventricle is in systole B)while the ventricle is in diastole C)while the atrium is contracting D)by the movement of blood from atrium to ventricle

Once ventricular pressure falls below atrial pressure _____. A) AV valves open B) the heart is in its relaxation period C) the ventricles begin to fill D) All answers are correct

Increased stimulation of the heart by the cardiaoacceleratory center causes _____. A) sympathetic stimulation with increased rate of contraction only B) sympathetic stimulation with increased force of contraction only C) parasympathetic stimulation with decreased rate and force of contraction D) sympathetic stimulation with increased rate and force of contraction

Place the following parts in the correct sequence as blood flows from the vena cavae to the lungs: 1) pulmonary trunk; 2) tricuspid valve; 3) right atrium; 4) pulmonic semilunar valve; 5) right ventricle A) 4,1,2,5,3 B) 1,2,3,4,5 C) 3,2,5,4,1 D) 2,5,4,3,1

A longer interval between the P and QRS deflections usually indicates _____. A) enlarged ventricles B) damage to the cardiac myofibers in the ventricles C) nothing unusual or abnormal D) a delay between atrial depolarization and ventricular depolarization

Select the correct statement about the heart valves A)The AV valves are supported by chordae tendineae to prevent regurgitation of blood into the atria. B)The mitral valve separates the right atrium from the right ventricle. C)The tricuspid valve divides the left atrium from the left ventricle. D)The semilunar valves control the flow of blood into the heart.

The term afterload refers to _____. A) endsystolic volume B) enddiastolic volume C) the pressure that must be overcome before semilunar valves can open D) the pressure in blood vessels necessary to cause the semilunar valves to close

The source of blood carried to capillaries in the myocardium would be the ________. A)coronary sinus B)fossa ovalis C)coronary veins D)coronary arteries

Damage to the ________ is referred to as heart block. A)AV valves B)AV node C)SA node D)AV bundle

The P wave of a normal electrocardiogram indicates ________. A)ventricular repolarization B)ventricular depolarization C)atrial repolarization D)atrial depolarization

During the period of ventricular filling ________. A)the atria remain in diastole the entire time B) pressure in the heart is at its peak C)it is represented by the P wave on the ECG D)blood flows passively through the atria and the open AV valves into the ventricles

The reason that the resting heart rate (sinus rhythm) is lower than the intrinsic rate of the SA node is that _____. A) at rest, potassium ions are prevented from reentering the intracellular fluid. B) at rest, the AV node is the pacemaker C) norepinephrine keeps calcium ion channels closed D) acetylcholine from parasympathetic neruons slows the SA node's rate of initiation of action potentials

Match the following descriptions with the correct part of the heart: ____ bicuspid valve ____ aortic semilunar valve ____ tricuspid valve ____ pulmonic semilunar valve 1. prevents backflfow into the left ventricle 2. prevents backflow into the right atrium 3. prevents backflow into the left atrium 4. prevents backflow into the right ventricle

The diameter of blood vessels most directly affects A) Stroke volume B) Venous return C) Resistance D) Heart rate

The major regulator of regional blood flow in the brain is A) Any extrinsic form of regulation B) Autoregulation C) The carotid sinus reflex D) The aortic reflex

Aldosterone will ________. A)decrease sodium reabsorption to decrease blood pressure B)promote a decrease in blood volume to lower blood pressure C)promote an increase in blood pressure D)result in a larger output of urine to decrease blood pressure

Fenestrated capillaries ________. A)are not common in endocrine organs and in areas where capillary absorption is an important function B)do not occur in the glomerular capillaries of the kidneys C)are not found in the brain D)are not more permeable than continuous capillaries

Hormones that cause vasoconstriction are _____. A) angiotensin II B) epinephrine C) ADH (vasopressin) D) All answers are correct

Modified capillaries that may be discontinuous and lined with phagocytes are called ________. A)sinuses B)anastomoses C)thoroughfare channels D)sinusoids

Resistance varies inversely with the fourth power of the vessel radius or R = 1/r4. What would be the expected change A) resistance increases 10X B) resistance increases 15X C) resistance increases 5X D) resistance increases 2X

The function of baroreceptors is to monitor changes in A) Stroke volume B) Heart rate C) Peripheral resistance D) Blood pressure

The arteries that directly feed into the capillary beds are called ________. A)arterioles B)venules C)muscular arteries D)elastic arteries

Deoxygenated blood in the fetal circulation is carried in the A) Ductus venosus B) Umbilical vein C) Umbilical artery D) Both A and B are correct