Ch 20 AP2 summer
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Created by:
ShaineDanielle5 on July 24, 2012
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Circulatory System
Dr. Jordan
LSCPA
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43 terms
Terms | Definitions |
|---|---|
 Blood flow around the body | Heart--> Arteries--> arterioles-->capillaries-->venules-->veins-->heart |
| Blood flows through | Usually, one capillary bed |
| Anastomoses | places where two veins or arteries merge |
| Tunic | walls of arteries or veins made up of three layers |
| Tunica Externa | the outtermost layer, made up of loose connective tissue (anchors vessel) |
| Tunica Media | middle tunic, thickest layer in of the vessel, made up of mostly smooth muscle (responsible for vasomotion) |
| Tunica Interna | consists of endothelium overlying a basement membrane and a sparse layer of fibroconnective tissue. (provides smooth surrounding for blood to pass) |
| Conducting | elastic, arteries are the larges and are subject to highest blood pressure. There tunica media consists of numerous sheets of elastic tissue. |
| Distributing | muscular, arteries distribute blood to specific organs. |
| Resistance | small, arteries that are primary means of controlling the routes of blood flow. |
| arterioles | smallest of the resistance arteries |
| metarteioles | link with arterioles and capillaries |
| Capillaries | vessels through which materials are exchanged between blood and tissue fluid. Organized into beds of 10-100 capillaries, with a thoroughfare channel that can bypass the bed when needed and carry blood directly to the venule |
| Continuous capillaries | occur in most tissues, their endothelial cells are held tightly togetherby tight junctions and form an uninterrupted tube |
| fenestrated capillaries | have endothelial cells riddled with holes pool |
| sinussoids | blood fillled spaces |
| venules | collect blood from capillaries |
| veins | have much lower blood pressure than arteries because of their distance away from the heart; prevent backflow of blood |
| Blood flow | amount of blood flowing through an organ, tissue, or vessel given in a time (ml/mm) |
| Perfusion | the rate of blood flow per given volume or mass of tissue (flow/g) |
| Sphygmomanometer | measures blood pressure |
| Systolic pressure | indicates the peak arterial presure during ventricular systole |
| Diastolic pressure | minimum arterial pressure between heartbeats |
| Hypertension | chronic resting systolic pressure of 140 mmHg or a diastolic pressure higher than 90 mmHg |
| Hypotension | chronic low resting BP, maybe due to blood loss, dehydration or anemia |
| Blood pressure is determined | by cardiac output, blood volume and peripheral resistance |
| Peripheral resistance | resistance that the blood encounters in the vessel as it travels away from the heart Proportional to three variables: blood viscosity, vessel length, and vessel radius |
| Blood viscosity | mostly due to erythrocytes and albumin |
| Pressure | and flow decline with increasing distance |
| Vessel Radius | exterts powerful influence over flow |
| Autoregulation | ability of tissues to regulate their own blood supply |
| Symphathetic fibers | sometimes induce casoconstriction while other trigger vasodilation |
| Angiotension II/ ADH | a potent vasoconstrictor |
| Atrial natriuretic factor | has a vasodilator effect |
| capillary exchange | refers to the two-way movement of substances between capillaries and tissue fluid |
| Diffusion | most important mechanism of exchange |
| Transcytosis | endothelial cells pick up droplets of fluid on one side of the plasma membrane by pinocytosis, transport the vesicles across the cell and discharge it on the other side by exocytosis |
| Venous Return | the flow back to the heart, achieved by 5 mechanisms Pressure Gradient, Thoaracic Pump, Cardiac Suction, Skeletal Muscle Pump, Gravity |
| Ciculatory Shock | state in which cadiac output is not sufficient to meet the bodys need. |
| Cardiogenic shock | occurs because heart is not beating adequetly, perhaps from an MI |
| Low Venous return shock | all other forms (other than cardiogenic) of circulatory shock |
| Cerebrovascular accident (CVA) | stroke,death of brain tissue caused by ischemia resulting from cerebral artherosclerosis, thrombosis, or ruptured aneurysm |
| Transient ischemic attack (TIA) | temporary feeling of dizziness, loss of sensations, weakness, or aphasia, which results from breif periods of cerebral ischemia (poor blood flow) |
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