chapter 13 Word Scramble
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Term | Definition |
arterioles | smaller arteries |
tunica intima | innermost layer of the artery, only part of vessel that is in contact with blood. |
endothelium | simple squamous epithelium that makes the tunica intima. |
endothelin | a peptide that stimulates the smooth muscle; vasoconstrictor. |
vasoconstriction | a decrease in the diameter of a blood vessel caused by contraction of the smooth muscle in the wall of the vessel. |
venules | smaller veins |
valves | formed by the smooth endothelium, prevents backflow of blood and are mostly in veins of legs. |
tunica media | middle layer of the artery, made of smooth muscle and elastic connective tissue. maintains diastolic blood pressure. |
tunica externa | outer layer of the artery, made of fibrous connective tissue, prevents the rupture or bursting of the larger arteries that carry blood under high pressure. |
anastomosis | connection of vessels that is, artery to artery or veins to veins. |
arterial anastomosis | helps blood get to the capillaries of an organ to deliver oxygen and nutrients and to remove waste products. ex: between some of the coronary arteries that supply blood to the myocardium. |
venous anastomosis | helps blood return to the heart so it can be pumped again. mostly in veins of the legs. |
capillaries | carry blood from arterioles to venules; extension of the endothelium. |
precapillary sphincters | smooth muscle that regulates blood flow into capillary networks. not regulated by the nervous system. constricts or dilates(to increase blood flow)depending on needs of the tissues. |
sinusoids | capillary; larger and more permeable(allows liquids or gases to pass through)than are other capillaries. permits large substances(proteins, blood cells)to enter or leave the blood. found in the RBM and spleen and in organs(liver, pituitary glands). |
diffusion | gases move by this, that is, from their area of greater concentration to their area of lesser concentration. |
diffusion example: | ex: oxygen diffuses from the blood in systemic capillaries to the tissue fluid. carbon dioxide diffuses from tissue fluid to the blood to be brought to the lungs and exhaled. |
filtration | occurs when capillary blood pressure is higher, forces plasma and dissolved nutrients out of the capillaries and into tissue fluid. this is how nutrients(glucose, amino acids, and vitamins) are brought to cells. |
colloid osmotic pressure(COP) | albumin contributes to the COP of blood. COP is an "attracting" pressure, a "pulling" rather than a "pushing" pressure. |
circle of Willis(or cerebral arterial circle) | is a "circle" of arteries around the pituitary gland. formed by the right and left internal carotid arteries and the basilar artery, union of the right and left vertebral arteries(branches of the subclavian arteries). |
hepatic portal circulation | subdivision of systemic circulation in which blood from the abdominal digestive organs and spleen circulates through the liver before returning to the heart. |
placenta | the site of exchange between fetal blood and maternal blood. |
umbilical arteries | (two) carry blood from the fetus to the placenta, where CO2 and waste products enter maternal circulation. |
umbilical vein | carries blood with O2 and nutrients from the placenta to the fetus. |
ductus venosus | a short fetal blood vessel that takes blood from the umbilical vein to the inferior vena cava. |
foramen ovale | an opening in the interatrial septum of the fetal heart that permits blood to flow from the right atrium to the left atrium, bypassing the fetal lungs. |
ductus arteriosus | a short fetal blood vessel that takes most blood in the pulmonary artery to the aorta, bypassing the fetal lungs. |
blood pressure | the force exerted by the blood against the walls of the blood vessels; measured in mmHg(millimeters of mercury). |
systolic(pressure) | is always the higher number, represents the blood pressure when the left ventricle is contracting. |
diastolic(pressure) | is the lower number, when the left ventricle is relaxed is relaxed and does not exert force. maintained by the arteries and arterioles. |
systemic blood pressure | highest in the aorta, which receives all of the blood pumped by the left ventricle. |
hypertension | a systemic blood pressure consistently higher than the normal range. |
hypotension | a lower than normal blood pressure. |
venous return | the amount of blood that returns to the heart by way of the veins. |
skeletal muscle pump | a mechanism that increases venous return; contractions of the skeletal muscles compress the deep veins, especially those of the legs. |
respiratoy pump | a mechanism that increases venous return; pressure changes during breathing compress the veins that pass through the thoracic cavity. |
Created by:
cramacher
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