Term
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Definition
| The tendency of a cell or organism to maintain a state of equilibrium in its internal environment by adjusting physiological and biochemical processes. |
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Term
| What are some functions of the circulatory system? |
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Definition
-Facilitate the exchange of respiratory gases, nutrients, metabolic wastes, water, and electrolytes between the external environments and the cells
-means for endocrine signals to reach target cells
-aids in thermoregulation by transporting heat generated by metabolic activity to the surface of the body to be dissipated.
-role in inflammatory response-allows movement of proteins and cells from the blood into an injured tissue |
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Term
| What are three characteristics of the principle vascular response in the inflammatory response? |
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Definition
-vasodilation-allows for increased blood flow
-increased permeability of the microvasculature
-extravasation of leukocytes through endothelium |
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Term
| What does the increased permeability of the microvaculature result in? |
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Definition
-proteins to pass from plasma to interstitial space
-Edema-increase in capillary pressure and increase in protein concentration in interstitial fluid results in fluid retention
-blood becomes more visous and stasis (slows down) allowing leukocytes to accumulate along the vascular endothelium |
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Term
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Definition
| Pericardium is the sack that surround the heart. It has two layers a fibrous outer layer and a serous inner layer. |
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Term
| List the functions of the pericardium. |
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Definition
-prevents the heart from becoming distended if there is a sudden increase in venous return
-prevents excessive movement of the heart
-serous membrane lubricates |
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Term
| What is pericardial effusion and what might cause it? |
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Definition
| Pericardial effusion is the abnormal accumulation of excessive fluid in the pericardial cavity. It can be casued by pericarditis (inflammation of the pericardium) or intrapericardial hemorrhage. |
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Term
| Define cardiac tamponade? |
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Definition
| Cardiac tamponade occurs when fluid builds in the pericardium putting pressure on the chambers of the heart. This decreases cardiac output and lowers BP (hypotension). |
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Term
| Why can the pericardium handle slow increases in pressure better than fast increases? |
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Definition
| Slow increases in pericardial fluid will stretch the pericardium allowing the pressure volume relationship to be maintained. If the fluid increase is sudden however the pericardium will be unable to stretch and pressure will increase substantially. |
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Term
| Describe the characteristics of the atria. |
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Definition
| Atria are thin walled reservoirs for blood returning from the venous system. |
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Term
| Which chambers of the heart are under greater pressure--the atria or the ventricles? Which chamber is under the greatest amount of pressure? |
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Definition
| The ventricles. The left ventricle is the high pressure pump--pushes blood into the aorta. |
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Term
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Definition
| The ventricles have thick walls and contraction of the ventricles provides the pressure needed to circulate the blood through the body. |
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Term
| What chamber of the heart pushes blood into the lungs? |
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Definition
| The right ventricle pumps blood in the pulmonary artery. |
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Term
| What does systole refer to? |
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Definition
| Systole refers to contraction. |
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Term
| What does diastole refer to? |
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Definition
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Term
| Trace the flow of blood through the heart beginning with the entrance of deoxygenated blood from the body. |
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Definition
| Deoxygenated blood comes into the right atrium. It then passes through the right AV valve (tricuspid) and into the right ventricle which pumps the blood into the pulmonary circuit. Blood reenters the heart from the pulmonary veins flowing into the left atrium and then through the left AV (mitral) valve into the left ventricle which pushes it out into the body. |
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Term
| What are chordate tendinae and what is their purpose? |
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Definition
| Chordate tendinae are ligaments that attach to the free surface of the AV vales and keep them from stretching too far into the atria during ventricular contraction. |
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Term
| What prevents the backflow of blood from the aorta and pulmonary arteries into the ventricles during diastole? |
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Definition
The semilunar valves
-aortic valve-separates the left ventricle from the aorta
-pulmonary valve-separates the right ventricle from the pulmonary artery |
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Term
| Which valves does blood flow through at a greater velocity? |
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Definition
| The semilunar valves- because they have a smaller openings than the AV valeves |
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Term
| What causes heart murmors? |
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Definition
| Turbulant blood flow through a defective valve |
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Term
| What are two possible causes of heart murmors? |
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Definition
Stenosis- narrowing a a valve-causes blood to flow through at a higher velocity
Regurgitation (insufficiency)- when blood flows backwards through a valve b/c it does not close completely |
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Term
| How is the rhythm of the heart maintained? |
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Definition
| Pacemaker cells spontaneously generate action potential which is then spread through the heart via the SA node and AV node. |
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Term
| Which chambers of the heart depolarize first? |
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Definition
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Term
| How are the ventricles signaled to contract? |
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Definition
| Pacemaker cells depolarize and their signal is carried through the SA node to depolarize the atria. The signal then encounters the AV node which slows the signal slightly allowing the atria to contract prior to contraction of the ventricles. |
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Term
| How can cardiac output be calculated? |
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Definition
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Term
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Definition
| Stroke volume is the amount of blood ejected by the left ventricle per beat. |
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Term
| What properties do arteries have? |
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Definition
| Arteries carry blood that is under pressure, so they have strong walls, with low compliance. |
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Term
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Definition
| The difference between systolic (high) pressure and diastolic (low) pressure. |
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Term
| What is MAP and how is it calculated? |
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Definition
| Mean arterial pressure is calculated by MAP=P diastolic + 1/3 pulse pressure |
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Term
| How is blood pressure and flow maintained in the absence of ventricular pressure? |
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Definition
| Elastic recoil of the arteries. |
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Term
| Where is the greatest decrease in blood pressure? |
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Definition
| When blood enters the arterioles. |
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Term
| What are resistance vessels and why are they called this? |
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Definition
| Resistance vessels are small arteries and arteriols that are able to change the size of their lumen and thereby determine vascular resistance. |
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Term
| Where is the principle resistance to blood flow and what does this allow control of? |
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Definition
Principle resistance to blood flow is provided by the arterioles and allows:
-flow into specific capillary beds to be controlled
-mean arterial pressure can be regulated |
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Term
| Why is it important that blood flow be slowed by the time it reaches the capillaries? |
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Definition
| Allows time for diffusion between blood and tissue |
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Term
| How can blood bypass capillaries and flow directly from arterioles to venules? |
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Definition
| Through vessels called metarterioles. |
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Term
| Why are veins known as capacitance vessels? |
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Definition
| B/c they hold %65 of blood. |
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Term
| Describe series arrangement of vasculature. |
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Definition
| When blood passes through two capillary beds before returning to the heart. |
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Term
| Describe parallel arrangement of vasculature. |
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Definition
| Allows for the distribution of cardiac output bases on the needs of individual tissues. |
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Term
| How can the relationship between flow, resistance, and pressure of blood be calculated. |
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Definition
Ohm's law
Q=deltaP/R
Where
Q=blood flow
P=the difference between MAP in the aorta and blood pressure at the entrance of the right atrium
R=resistance to blood flow through the vasculature |
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Term
| How is velocity of blood flow calculated? |
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Definition
V=Q/A
where
V=velocity
Q=flow
A=cross sectional area |
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Term
| HOw are velocity and cross sectional area of area related? |
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Definition
| They are inversely related. |
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Term
| What is whole blood composed of? |
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Definition
Plasma
Red blood cells
White blood cells
Platelets |
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Term
| What is the function of each of the components of blood? |
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Definition
Plasma-protein rrich fluid-contains albumin, fibrinogen and other clotting proteins, binding proteins, etc
Red blood cells- exchange O2 and CO2
White blood cells- immune defense
Platelets-Hemostasis |
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