A Study On Cardiovascular System Sport Essay Example
A Study On Cardiovascular System Sport Essay Example

A Study On Cardiovascular System Sport Essay Example

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  • Pages: 12 (3261 words)
  • Published: August 26, 2017
  • Type: Case Study
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The heart, which is approximately the same size as a clenched fist, is a formidable muscle that plays a crucial role in the circulatory system. It tirelessly propels blood throughout an individual's lifetime. Composed of robust cardiac muscle tissue, it has the ability to rhythmically contract and relax. The heart wall comprises three layers.

The endocardium, which lines the interior chambers of the heart, enables unrestricted blood flow. Composed mainly of cardiac muscle, the myocardium is situated between the other layers and is responsible for contraction. Acting as the outer layer of the serous pericardium, the epicardium serves its purpose. In total, there are four distinct chambers, four valves, and four vessels in the heart. Among these are two smaller chambers known as atria that receive and collect incoming blood.

The blood is transported to


the left and right ventricles, which expel it from the heart by contracting. The upper chambers on each side are referred to as the left atrium and right atrium. The lower chambers are called the right and left ventricles, which make up a significant part of the heart's volume. When the ventricles contract, they propel blood out of the heart and circulate it throughout the body. Specifically, the right ventricle pushes blood into the pulmonary artery for transportation to the lungs where gas exchange takes place. In contrast, the left ventricle pumps blood into the aorta, which then distributes oxygenated blood to all other body parts. To prevent backflow when contracting and forcing blood into circulation, there are four valves in cardiac anatomy.

The bicuspid valve, found between the left atrium and left ventricle, permits blood to flow from the former to

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the latter. Similarly, the tricuspid valve aids in blood transfer from the right atrium to the right ventricle as it is situated between them. Chordate tendineae, a type of connective tissue, prevent these valves from inverting. The semilunar valves are referred to as aortal and pneumonic valves.

The human body has valves that prevent backflow from the ventricles into larger arteria bases. Four vessels, namely the aorta, vena cava, pneumonic vena, and pneumonic arteria, serve this protective function. The aorta, which originates from the left ventricle of the heart, is the largest arteria responsible for carrying oxygenated blood to all body parts. The vena cava is divided into two: superior vein cava and inferior vein cava. The superior vein cava is a large yet short vena that transports deoxygenated blood from the upper half of the body to the right atrium.

The inferior vena cava carries deoxygenated blood from the lower half of the body to the heart, and the pulmonary vein transports oxygen-rich blood from the lungs to the left atrium of the heart. Similarly, the pulmonary artery moves deoxygenated blood from the heart to the lungs. These blood vessels all have three layers in their walls and enclose a lumen containing blood.

Reducing friction during blood flow is the main function of the inner adventitia, while the middle layer (tunica media) and outer layer (tunica externa) serve to protect and strengthen the blood vessel, ensuring its stability within the body structure. The three types of blood vessels include arteries, capillaries, and veins. Arteries are responsible for transporting oxygenated blood from the heart to various parts of the body.

The blood flows under pressure into smaller arteries, creating

arterioles which supply the capillary beds of organs, muscles, and tissues. Thick-walled arteries near the heart, like the aorta, are known as elastic arteries. They remain passive during vasoconstriction and act as flexible tubes. Elastic arteries transport blood at high pressure to the muscular arteries and larger arterioles, especially during exercise.

Arterioles are responsible for the redistribution of blood flow and blood pressure. They deliver oxygen and nutrients while removing waste products through the muscular and organ capillary system. Each capillary connects to a venous terminal, which in turn connects to a vein. The blood then enters the venules and is transported to larger veins.

The bosom is separated into two halves, specifically the right pump and left pump. The right pump receives blood from the organic structure and pumps it to the lungs for the pneumonic system. The left pump receives oxygenated blood from the lungs and pumps it throughout the organic structure's systemic circulation. The activity of the cardiac muscle tissue in the ventricle when it contracts is known as systole, while its relaxation is referred to as diastole. Cardiac end product denotes the volume of blood that is expelled from the bosom within one minute.

Stroke volume refers to the amount of blood pumped by one ventricle of the heart during a single contraction. It is influenced by three factors: preload, contractibility, and afterload. The cardiac conductivity system consists of several structures, including the sinoatrial node, atrioventricular node, atrioventricular bundle, bundle subdivisions, and purkinje fibers. The process of cardiac excitation starts in the SA node, where an action potential is triggered and spreads to both atria, causing them to contract. The action potential then reaches

the AV node and subsequently the AV bundle. After propagating along the AV bundle, the action potential enters the bundle subdivisions.

The purkinje fibers can rapidly and rhythmically conduct action potentials. Blood is made up of two main components: plasma and cells. Plasma, a viscous fluid with a straw-like color, mainly consists of water. It contains substances like glucose, cell nutrients, hormones, gases, enzymes, antibodies, and waste products. The blood cells include red blood cells (erythrocytes) and white blood cells (leukocytes).

The main functions of red blood cells are to absorb oxygen in the capillary beds of the lungs and deliver it to cells throughout the body. Red blood cells also eliminate carbon dioxide from tissues for excretion by the lungs. White blood cells, on the other hand, act as our defense mechanism against diseases through antibodies.
There are two ways to transport oxygen in the blood: dissolving it in the liquid part of the blood or binding it to hemoglobin, an iron protein molecule present in red blood cells.
Waste product removal occurs through three methods: carbon dioxide can dissolve in blood, bind to hemoglobin, or be carried as bicarbonate. Blood pressure refers to the force exerted by blood on arterial walls.

High blood pressure is influenced by several factors, such as the amount of blood pumped and resistance to blood flow. Contributing factors include high blood volume, heart rate, stroke volume, blood viscosity, and peripheral resistance. If any of these conditions decrease, blood pressure decreases as well. When at rest, arterioles narrow which leads to a decrease in blood flow to the muscles.

During exercise, autoregulation causes arterioles to dilate, which reduces vascular resistance and increases blood flow. This

is necessary because the body's energy demands increase during exercise, requiring greater blood flow throughout the entire body.

Respiratory system

The respiratory system comprises the nasal cavity, throat, voice box, windpipe, bronchial tubes, and lungs. Its primary function is to acquire oxygen for the cells of the body and remove carbon dioxide. Structurally, it can be divided into two parts: the upper respiratory system (nose, nasal cavity, structures related to larynx) and the lower respiratory system (larynx, trachea , bronchi , lungs). Functionally, it can also be divided into two parts: conducting zone (throat , voice box , windpipe , bronchial tubes , bronchioles) and respiratory zone (alveoli , alveolar ducts , alveolar sacs , bronchioles). The conducting zone filters air by warming and moisturizing it before transporting it to the lungs. Gas exchange takes place within the respiratory zone. Inhaled air circulates inside the nasal cavity.

The rhinal pit's hairs serve to filter warm air, capturing dust or pollen, while the mucous membrane contains antibacterial enzymes that catch and eliminate dust and bacteria. The throat, known as the pharynx, is divided into three parts: nasopharynx, oropharynx, and laryngopharynx. It acts as a pathway for both air and food.The larynx, which is composed of cartilage and contains tonsils, serves multiple functions. It acts as a resonant chamber for speech and provides protection against foreign invaders. The larynx includes the Adam's apple and has three main roles: facilitating open air passages, directing air and food to the correct pathways (via the epiglottis), and contributing to voice production.

The trachea, also known as the windpipe, descends from the larynx and divides into two main bronchial tubes before entering the lungs. Like

the nasal cavity and larynx, it is lined with cilia and mucus for protection. These bronchial tubes transport air to the lungs, with the right one being wider, shorter, and more vertical than its left counterpart. This makes it a common location for foreign objects getting stuck.

Within the lungs, bronchial tubes divide into lobar bronchial tubes. On the right side, there are three lobar bronchial tubes, while on the left side there are two. Lobar bronchial tubes serve as thin-walled air pouches within the lung and aid in gaseous exchange.

The oxyhemoglobin dissociation curve illustrates the relationship between oxygen and hemoglobin. This curve is influenced by factors like oxygen partial pressure, body temperature, pH concentration, and carbon dioxide partial pressure.

In the lungs, hemoglobin concentration increases because of cooler temperature and low oxygen pressure. In the tissues, a decrease in oxygen pressure prompts hemoglobin to release oxygen. A rightward shift occurs due to increased acidity or warmth, particularly during exercise. The process of inhaling is called inspiration while exhaling is termed termination. By expanding the chest cavity, air pressure within the lungs decreases, enabling more air to enter.

The lungs enlarge due to tension in the chest wall, involving the diaphragm and external intercostal muscles within the thoracic cavity. When at rest, the external intercostal muscles contract while the internal intercostal muscles relax. This motion causes the ribs and breastbone to move upwards and outwards, leading to an expansion of thorax volume.

During exercise, the pectoral muscles lift the rib cage to expand the volume of the thorax. The cowl muscle and back muscles also contract to enlarge the thorax, allowing more air to enter the lungs. When at

rest, both the thoracic and external intercostal muscles relax and return to their original position.

The interaction between the ribs and diaphragm affects the pleural fluid, causing pressure changes. As a result, lung volume decreases and air pressure in the respiratory system increases, leading to air expulsion. To assist in removing air from the lungs, the internal intercostal muscles and abdominal muscles contract. Gas exchange takes place at the alveoli, which is where the bronchioles end.

The respiratory membrane is formed by 300 million gas filled alveoli in both the alveolar and capillary walls. This membrane facilitates gaseous exchange by enabling oxygen to pass from the air sacs into the blood, while carbon dioxide exits the blood and enters the air sacs. This process, called simple diffusion, occurs readily throughout most of the lung volume. During quiet breathing, tidal volume refers to approximately 450cm3 of air being inhaled and exhaled.

In addition to tidal volume, an individual can inhale up to 3000cm3 of fresh air, known as the inspiratory reserve volume. The expiratory volume, which includes the additional air that can be exhaled after a normal breath, can reach up to 1500cm3. This is the sum of the residual volume and the expiratory reserve volume within the lungs. The vital capacity represents the total amount of air that can be forcefully exhaled from the lungs following maximum inhalation.

The lungs have a volume of around 4800cm3. After exhaling forcefully, the residual volume is the remaining air in the lungs. Total lung capacity represents the maximum amount of air inhaled. The complex process of controlling external respiration involves nerve cells in the myelin and Pons' reticulate formation.

The myelin consists of

two groups of nerve cells, namely the dorsal respiratory group and the ventral respiratory group. Both these groups are involved in regulating respiratory rhythm. Chemoreceptors play a role in detecting changes in oxygen and carbon dioxide levels, which also help regulate respiration.

Nervous system

The human nervous system is divided into two main parts: the central nervous system (which includes the brain and spinal cord) and the peripheral nervous system (composed of nerves and ganglia). The central nervous system receives information from all parts of the body and comprises five primary regions in the brain - brainstem, cerebellum, hypothalamus, cerebrum, and limbic system. Additionally, spinal cord serves as a pathway for bidirectional information flow between the skin, joints, muscles, and brain. The peripheral nervous system facilitates communication throughout the body with the help of spinal nerves.

The Peripheral Nervous System (PNS) consists of 31 pairs of spinal nerves, 12 pairs of cranial nerves, sensory nerve cells, and motor nerve cells. Sensory nerve cells carry signals from sensory receptors to the Central Nervous System (CNS), while motor nerve cells transmit signals from the CNS to muscles and glands, causing a response. Neurons, also known as nerve cells, have a cell body containing a nucleus. Dendrites are extensions of the neuron that receive incoming signals.

The transmission of the nervous urge, referred to as the unit of information, occurs via axons that are enveloped by a myelin sheath. This specialized cell membrane surrounds vertebrate axons and improves impulse conductivity by serving as an insulating layer.

The Node of Ranvier is responsible for transmitting a nerve impulse, typically occurring only at the neuromuscular junction. Nerve cells carry action potential throughout the body, resulting

in muscle contraction. The peripheral nervous system has two divisions: the sensory-somatic nervous system and autonomic nervous system. Motor nerve cells, also referred to as peripheral nerve fibers, consistently generate an excitatory response to activate muscles.

The autonomic nervous system has either an excitatory or inhibitory effect depending on the activation of specific nerve cells. It is responsible for controlling the internal environment of the body to maintain homeostasis. The autonomic nervous system is divided into sympathetic and parasympathetic components. The sympathetic nervous system releases acetylcholine, noradrenaline, and epinephrine, preparing the body for a "flight" or "fight" response during exercise. On the other hand, the parasympathetic nervous system has the opposite effect to the sympathetic nervous system, releasing acetylcholine and nitric oxide.

Reflex discharge is utilized to treat autonomic muscle activity by providing the fundamental mechanism. Peripheral receptors transmit sensory input through afferent nerve cells that enter the spinal cord via the dorsal root. Subsequently, this information is relayed to separate levels of the cord. From there, the impulse travels through the motor root tract, facilitated by anterior motor nerve cells, and reaches the effector organ. Upon stimulation, the nerve receptor transmits sensory information to the spinal cord via sensory nerve fibers.

This triggers motor motor fibers to stimulate the appropriate muscular response. Reflex actions in the spinal cord and other subconscious areas of the central nervous system (CNS) regulate many muscle functions. In order to stimulate muscle contraction, nerve impulse reaches the neuromuscular junction. Calcium enters and activates acetylcholine release. Acetylcholine then travels across the synapse and binds to acetylcholine receptors on the postsynaptic membrane located on the sarcolemma. This allows sodium ions to enter.

Myosin binds to

actin fibril, calcium binds to troponin to expose the binding sites for myosin to attach to actin. To release energy, myosin pulls actin using ATP. Muscle contraction occurs when ADP and K are released and myosin head flexes, causing actin to be pulled along with myosin. Myosin then picks up another ATP, releases actin, and reattaches to it to pull again. This process repeats until all calcium is stored and actin binding sites are covered by troponin. Endplate potential generates and a depolarization wave spreads throughout the T-tubular network. This process is known as the sliding filament theory.

Hormone system

It consists of a gland, small amounts of hormones, and target or receptor organs. Hormones are chemical substances synthesized by specific host secretory organs and enter the bloodstream for distribution throughout the body.

The major hormone organs include the pituitary, thyroid, parathyroid, adrenal, pineal, kidney, and thymus glands. Other organs such as the pancreas, sex glands, hypothalamus, and adipose cells have specific areas that produce hormones. Growth hormone stimulates the breakdown of fat and inhibits the breakdown of carbohydrates. It is thought that increasing growth hormone secretion may enhance development and preserve glycogen reserves. However, this does not occur. Adrenocorticotropic hormone is secreted by the posterior pituitary gland and stimulates the adrenal cortex, increasing mobilization of free fatty acids for energy. This hormone is released during exercise to promote fat breakdown and spare glycogen, benefitting prolonged high-intensity exercise performance.

Hormones like prolatin and oxytin have been subject to limited research. Studies have indicated that the resting prolatin levels of male smugglers are lower on average compared to sedentary nonrunners. There is no variation in the level of antidiuretic hormone

between trained and untrained individuals. During submaximal exertion, the concentration of antidiuretic hormone diminishes.

Both follicle-stimulating and luteinizing hormones have a decreased value in trained females, possibly influenced by their menstrual cycle. Male athletes have lower testosterone levels than untrained male athletes. Long-term resistance training may increase testosterone levels in males. Parathyroid hormone promotes the release of calcium from bones, and elevated blood calcium levels stimulate the synthesis of vitamin D3. Endurance training enhances exercise-related increases in this hormone in both young and older adults. The thyroid hormones are triiodothyronine (T3) and thyroxine (T4), which increase the metabolic rate for normal physical growth.

During exercise, the turnover of thyroid hormones increases, which can lead to an excess of T3 and T4 known as thyrotoxicosis. Aldosterone promotes the resorption of sodium and secretion of potassium. This system helps regulate the body's fluid volumes, electrolytes, and blood pressure to maintain homeostasis. However, exercise does not affect the resting levels of these hormones or their response to exercise.

Cortisol stimulates the breakdown of proteins and fats, leading to an increase in blood glucose levels and helping the body adapt to stress. In trained individuals, cortisol levels rise less compared to sedentary individuals, resulting in the enlargement of the adrenal gland. Epinephrine and norepinephrine increase cardiac output, regulate blood vessels, promote glycogen breakdown, and release fatty acids. These hormones decrease significantly during the first week of exercise training. As a result, they lower heart rate and blood pressure during exercise, reducing the oxygen demands of the heart and other forms of stress.

Insulin decreases blood glucose levels and stimulates the synthesis of proteins, lipids, and glycogen. On the other hand, glucagon increases blood

glucose levels and promotes the breakdown of glycogen and the production of glucose. During endurance training, the levels of insulin and glucagon in the blood are kept closer to their resting values. Homeostasis is responsible for maintaining a stable internal environment, including temperature, to ensure optimal functioning of the body. This is achieved through control systems that detect any changes in the internal environment.

Three key components include a receptor, which detects stimulation and changes the body's structure; a control center, which establishes the boundaries for maintaining a variable factor; and an effector, which takes action to adjust the environment and keep it stable.


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