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blood vessel 6-11
| Question | Answer |
|---|---|
| What is the Tunica intima? | The inner layer of the blood vessel, enothelium |
| What is the Tunica media? | Smooth muscle layer, innervated by sympathetic nerve fibers |
| What is the Tunica externa? | Outer layer, in large arteries and veins contains vaso vasorum (blood vessels that feed the arterial or venous wall) |
| What are 4 features of arteries? | 1. Carry oxygenated blood away from the heart 2. Thicker smooth muscle layer than veins 3. More elastic than veins 4. Smaller lumen than veins |
| What are 3 features of arterioles? | 1. Deliver blood to capillaries 2. Have greater influence on BP than arteries 3. Precapillary sphincters |
| What are precapillary sphincters? | Rings of smooth muscle at the point where capillaries branch off arterioles. |
| What are precapillary sphincters involved in? | Auto-regulation- an automatic adjustment of blood flow to meet metabolic demands --They constrict to decrease blood flow through a capillary, relax to increase blood flow through capillary |
| What are 4 features of capillaries? | 1. Microscopic, in close contact with every cell in body 2. Exchange of gases, nutrients, and wastes occurs here 3. Single endothelial cell thin 4. Permability depends on how tight or loose the cell junctions are |
| What are continuous cappilaries? | Tight cell junctuons- limited permability, slow rate of diffusion Skin, muscles, lungs, CNS |
| What are fenestrated capillaries? | Leaky intracellular jucitions-- 10x more than continuous Large amounts of fluid and metabolites eneter of leave these caps Endocrine glands, intestinal villi, renal glomeruli |
| What are discontinuous capillaries? | Wide gaps between cells-- allow movement of proteins and blood cells Liver, bone marrow, spleen |
| What are veins? | Carry deoxygenated blood from body to heart, except pulmonary veins |
| What are venules? | Formed by the union of several capillaries |
| what are 3 characteristics of veins? | 1. Formed by the union of several venules 2. Thinner than arteries 3. Endothelial layer folds inward to form valves-- prevent backflow |
| What is the portal vein? | Vein that carries blood from one capillary network to another |
| Which blood vessels have the most influence on BP? | Arterioles |
| What is the effect of sympathetic stimulation on blood vessel walls? | Increase in sympathetic stimulation = vasoconstriction = increase in BP Decrease in sympathetic stimulation = vasodilation = decrease in BP |
| What is capillary filtration? | Movement of water and solutes into interstitial fluid at arteriolar end of capillary |
| Is hydrostatic pressure(BP) greater or less than osmotic pressure? | greater |
| What is hydrostatic pressure? | BP inside the capillary, caused by LV contraction, pressure pushes fluid out, highest at arteriolar end, decreases as the blood moves through the capillary |
| What is osmotic pressure? | plasma protein concentration-- pressure of a fluid due to its solute concentration (plasmas proteins/ albumin), when high, water and solutes move into the capillary (reabsorption) |
| What is capillary reabsorption? | Movement of water and solutes back into the capillary at venule end |
| How does capillary reabsorptions happen? | 90% is reabsorbed, rest moves into lymph capillaries |
| What is venous return? | Volume of blood flowing back to the heart |
| What 4 things affect venous return? | 1. Ventricular systole/blood pressure 2. Skeletal muscle pump 3. Respiratory pump 4. Valves |
| What is the skeletal muscle pump? | Compression of veins during movement, blood moves from valve to valve |
| What is the respiratory pump? | inhaltion( abdominal veins are compressed, blood moves toward RA), exhalation ( compression on abd veins decreases, valves prevent backflow into abdominal veins) |
| What is blood pressure? | Pressure exerted by blood on walls of blood vessels, created by LV contaction/ systole |
| What happens to BP as it moves through circulatory system? | It decreases |
| What is the BP in the aorta and large arteries? | 100-120 mmHg |
| What is the BP in arterioles? | 60-70 mmHg |
| What is the BP in capillaries? | 25-15 mmHg |
| What is the BP in Venules? | 15 mmHg |
| What is the BP in Veins? | 5-6 mmHg |
| What is the BP in the Vena Cava? | 0 mmHg |
| What is pulse pressure? | Difference between systolic and diastolic prssure |
| What is Mean arterial blood pressure? | Represents the pressure that pushes blood through the circulatory system - pressure averaged over the entire cardiac cycle |
| What is normal Mean arterial blood pressure? | 70 and above is noraml 60 and below is ischemia |
| What are 4 factors that affect blood pressure? | Resistance Size of lumen blood viscosity total blood vessel length |
| What does endothelium release? | both constricting and dilating substancces |
| What is endothelium regulation stimulated by? | substances in the blood ( histamine, bradykinin, nicotine) or shear stress associated with blood flow, trauma from catheters and guidewires, cold temps, HTN |
| What is nitric oxide? | potent vasodilator released by endothelium -- lipid solubule, diffuses through endothelium and into smooth muscle cells Uncouples actin and myosin causin smooth muscle relaxation |
| Is BP regulation a positive or negative feedback? | negative feedback-- adjusts HR, SV vascular resistance, blood volume |
| Where is the cardiac center? | medulla oblongata, controls HR |
| Wheres is the vasomotor center? | Medulla oblongata, controls BP |
| What are proprioceptors? | Detect movement of joints and muscles = increase BP |
| What are chemorecptors? | Detects changes in oxygen, carbon dioxide, and pH |
| Where are chemorceptors located? | Located in 2 carotid bodies in common carotid arteries and aortic arch |
| How are chemorecptors stiimulated? | by hypoxia, acidosis, hypercapnia |
| What do chemorecpetors cause? | increase HR and vasoconstriction = increase BP |
| What are baroreceptors? | detect pressure changes in aorta, internal carotids, and large arteries in neck and chest decrease in BP = less stretch Medulla increases sympathetic stimulation which increases HR, SV AND BP |
| What is Renin? | enzyme secreted by kidney - breaks down angiotensinogen (made in liver) into angiotensin 1 |
| What is angiotensin 1? | Travels through lungs, converted to angiotensin II by ACE |
| What is angiotensin II? | potent vasoconstrictor--stimulates the release of aldosterone |
| What is aldosterone? | Hormone made by adrenal cortex- causes kidney to increase reabsorption of sodium and water=increase blood volume = increase BP |
| What is epinephrine and norepinephrine? | released by adrenal medulla during sympathetic stimulation increase HR and force of cardiac contraction = increase CO causes vasconstriction of arterioles and venules in skin and abdominal organs |
| What is ADH? | made in hypothalamus, released by posterior pituitary gland. causes kidney to increase reabsorption of water and stimulates vasoconstriction = increase BP |
| What is Atrial Natriuretic peptide (ANP)? | Released by atrial cells in the hearts causes vasodilation and increase sodium and water excretion by kidney (decrease blood volume)= decrease BP |
| What is the circulatory route of the pulmonary? | flow of deoxygenated blood from RV to alveoli of lungs and back to LA |
| What is the circulatory route of the systemic? | All systemic arteries branch from aorta all systemic veins empty into SVC or IVC |
| What is the circulatory route of the hepatic portal? | Venous blood from GI organs and spleen enters the liver Liver processes blood before blood passes into general circulation |
| What is the circulatory route of fetal? | Placenta- organ of exchange between fetal and maternal circulation Umbilical cord- 2 umbilical arteries (takes blood from fetus to placenta where it picks up oxygen), 1 umbilical vein (takes oxygenated blood to fetus) |
Created by:
lecopple1
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