Anatomy And Phisiology Flashcards
Anatomy and Physiology
The cardiovascular (CV) system is composed of the heart and blood vessels. The heart is a hollow, muscular organ lying in the mediastinum, the center of the thoracic cavity between the lungs. The pumping action of the heart propels blood that contains oxygen (O2), nutrients, and other vital products from the heart to body cells through a vast network of blood vessels called arteries. Arteries branch into smaller vessels until they become microscopic vessels called____. At this level, an exchange of products occurs between body cells and blood. Capillaries merge to form larger blood vessels called _____, which then combine to form veins, the vessels that return blood to the heart to begin the cycle again. Millions of body cells rely on the CV system for their survival. When it fails, life at the cellular level is not possible and, ultimately, death occurs.
capillaries
Venules
Flat, leaf-shaped structures that comprise the valves of the heart and prevent the backflow of blood
Leaflets
Tubular space or channel within an organ or structure of the body; space within an artery, vein, intestine, or tube
lumen
LŪ-mĕn □
Backflow or ejecting of contents through an opening
Circular muscles found in a tubular structure or hollow organ that constrict or dilate to regulate passage of substances through its opening
regurgitation
rē-gŭr-jĭ-TĀ-shŭn □
sphincters
SFĬNGK-tĕr □
Narrowing of the lumen of a blood vessel that limits blood flow, usually as a result of diseases, medications, or_____ processes
vasoconstriction
Physiological
văs-ō-kŏn-STRĬK-shŭn □
Widening of the lumen of a blood vessel caused by the relaxing of the muscles of the vascular walls
Thickness or a measure of how resistant a liquid is to flowing
A solution that has a high ____ is relatively thick and flows slowly.
vasodilation
văs-ō-dī-LĀ-shŭn □
viscosity
vĭs-KŎS-ĭ-tē □
Vascular System
Three major types of vessels—(1) artery, (2) capillary, and (3) ____—carry blood throughout the body. Each type of vessel differs in structure, depending on its function.
Arteries carry blood from the heart to all cells of the body. Because the pumping action of the heart propels blood through the arteries, the _____ of the arteries must be strong and flexible enough to withstand the surge of blood that results from each contraction.
Veins
Walls
The walls of -LArGe- arteries have three layers to provide toughness and elasticity. The (4) _____ externa is the outer coat, composed of_____ tissue that provides strength and flexibility. The (5) tunica media is the middle layer, composed of ____ muscle. Depending on the needs of the body, this muscle can alter the size of the (7) lumen of the vessel. When it contracts, the tunica -MeDiA- causes vasoconstriction, resulting in decreased blood flow. When it relaxes, it causes vasodilation, resulting in increased blood flow. The (6) tunica_____ is the thin, inner lining of the lumen of the vessel, composed of_____ cells that provide a smooth surface on the inside of the vessel.
Tunica
Connective
Smooth
Intima
Endothelial
The surge of blood felt in the arteries when blood is pumped from the heart is referred to as a pulse. Because of the pressure against arterial walls associated with the pumping action of the heart, a cut or severed artery may lead to profuse bleeding.
Arterial blood (except for that found in the_____ artery) contains a high concentration of oxygen (O2) and appears bright red in color. Oxygenated blood travels to smaller arteries called (8) arterioles and, finally, to the smallest vessels, the______.
Pulmonary
Capillaries
Capillaries are microscopic vessels that join the arterial system with the venous system. they are actually the most important because of their function. capillary walls are composed of only a single layer of endothelial cells, they are very thin. This thinness enables the exchange of water, respiratory____, ____molecules, _____ites, and wastes between the blood and the cells adjacent to the capillary bed. The vast number of capillaries branching from arterioles causes blood to flow very slowly, providing sufficient time for exchange of essential substances.
Gases
Macro
Metabol
Blood flow through the capillary networks is slow and______: (irregular intervals), rather than steady, and is regulated by the _____ sphincters. When tissues require more blood, these sphincters open; when less blood is required, they close. Once the exchange of products is complete, blood enters the____ system for its return to the heart.
Intermittent
(Pre-capillary)
Venous
Veins return blood to the heart. They are formed from smaller vessels called (9) venules that develop from the union of capillaries. Because the extensive network of capillaries absorbs the propelling pressure exerted by the heart, veins use other methods to return blood to the heart, including the following:
•____ muscle contraction
• gravity
• _____tory activity
•_____s
Skeletal
Respira
Valve
______are small structures within veins that prevent the backflow of blood. Valves are found mainly in the extremities and are especially important for returning blood from the legs to the heart because blood must travel a long distance against the force of gravity to reach the heart from the legs. Large veins, especially in the abdomen, contain____ muscle that provides____is and helps propel blood toward the heart.
Valves
Smooth
Peristalsis
Blood carried in veins (except for the blood in the______ veins) contains a low concentration of O2 and a correspondingly high concentration of carbon dioxide (CO2). This blood takes on a characteristic____ color and is said to be deoxygenated. It continuously circulates from the heart to the lungs so that CO2 can be exchanged for O2.
Pulmonary
Purple
The heart is a muscular pump that propels blood to the entire body through a closed vascular network. It allows a dual circulatory system:______ circulation provided by the right side of the heart and_____ circulation provided by the left side of the heart. Pulmonary circulation delivers blood to the lungs, where CO2 is exchanged for O2. Systemic circulation delivers blood to body tissues, where O2 is exchanged for CO2, a waste product that will be expelled by the lungs. Both systemic and pulmonary circulatory activities occur simultaneously.
Pulmonary
Systemic
The heart is enclosed in a sac called the ____cardium and is composed of three distinct layers:
• _____cardium, a serous membrane that lines the four chambers of the heart and its valves and is continuous with the______ of the arteries and veins
• _____cardium, the muscular layer of the heart
• _____cardium, the outermost layer of the heart.
Peri
Endo
Endothelium
Myo
Epi
The heart is divided into four chambers. The two upper chambers, the (1) right atrium (RA) and (2) left atrium (LA), ____ blood. The two lower chambers, the (3) right ventricle (RV) and (4) left ventricle (LV),_____ blood from the heart. The_____ ventricle pumps blood to the lungs (pulmonary circulation) for oxygenation, and the left ventricle pumps oxygenated blood to the entire body (_____circulation).
Collect
pump
Right
Systemic
Deoxygenated blood from the body returns to the right atrium by way of two large veins: the (5) superior vena cava, which collects and carries blood from the upper body, and the (6) inferior vena cava, which collects and carries blood from the lower body. From the right atrium, blood passes through the (7)_____ valve, consisting of three____, to the right ventricle. When the heart contracts, blood leaves the right ventricle by way of the (8) left_____ artery and (9) right pulmonary artery and travels to the lungs.
tricuspid
Leaflets
Pulmonary
During contraction of the ventricle, the_____ valve closes to prevent a backflow of blood to the right atrium. The (10) pulmonic valve (or pulmonary semilunar valve) prevents regurgitation of blood into the right ventricle from the____. In the lungs, the pulmonary artery branches into millions of capillaries, each lying close to an_____. Here, carbon dioxide in the blood is exchanged for oxygen that has been drawn into the lungs during inhalation.
tricuspid
pulmonary artery
alveolus
Pulmonary
_________ unite to form four pulmonary veins—two (11) right pulmonary veins and two (12) left pulmonary veins. These vessels carry____ back to the heart. They deposit blood in the left atrium. From there, blood passes to the left ventricle through the (13) mitral (____) valve, a structure consisting of two leaflets. Upon contraction of the____, the oxygenated blood leaves the heart through the largest artery of the body, the (14) aorta. The aorta contains the (15) aortic______ valve (aortic valve) that permits blood to flow in only one direction—from the left_____ to the aorta. The aorta branches into many smaller arteries that carry blood to all parts of the body.
-Capillaries
-oxygenated
blood
-bicuspid
-ventricles
-semilunar
the myocardium cannot use the blood it passes through the chambers of the heart as a source of oxygen and nutrients. Instead, an arterial system composed of the coronary arteries branches from the____ and provides the myocardium with its own blood supply. The artery vascularizing the right side of the heart is the (1) right coronary artery. The artery vascularizing the left side of the heart is the (2) left coronary artery. The left coronary artery divides into two branches, the (3) left_____ descending artery and the (4)______ artery. If blood flow in the coronary arteries is diminished, damage to the heart muscle may result. When severe damage occurs, part of the heart muscle may die.
Aorta
anterior
circumflex
Conduction System of the Heart
Within the heart, specialized cardiac tissue known as conduction tissue has the sole function of initiating and spreading contraction impulses. This tissue consists of the following four masses of highly specialized cells that possess characteristics of both nervous and cardiac tissue:
• ____atrial (SA) node
• ____ventricular (AV) node
• bundle of ____ (AV bundle)
• ____inje fibers
Sino
Atrio
His
Purk
The (1) sinoatrial (SA) node is located in the upper portion of the right atrium and possesses its own___ rhythm. Without being stimulated by external nerves, it has the ability to initiate and propagate each heartbeat, thereby setting the basic pace for the cardiac rate. For this reason, the SA node is commonly known as the____ of the heart. The cardiac rate may be altered by impulses from the__ nervous system. Such an arrangement allows outside influences to accelerate or decelerate heart rate. For example, the heart beats more quickly during physical exertion and more slowly during rest. Each electrical impulse discharged by the SA node is transmitted to the (2)___ node, causing the____ to contract.
Intrinsic
pacemaker
autonomic
atrioventricular (AV)
atria
The AV node is located at the base of the right atrium. From this point, a tract of____ fibers called the (3) bundle of His (or AV bundle), composed of a ___branch, relays the impulse to the (4) Purkinje fibers. These fibers extend up the ventricle walls. The Purkinje fibers transmit the impulse to the right and left ventricles, causing them to contract. Blood is now forced from the heart through the pulmonary artery and aorta. Thus, the sequence of the four structures responsible for conduction of a contraction impulse is as follows: SA node → AV node → bundle of His → Purkinje fibers
conduction
Left and right
