ant ch. 21

what are the blood vessels of the body
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are what arteriesthey carry blood away from the heartwhat are the different types of arteries1. large elastic arteries >1cm 2. medium muscular arteries (.1-10mm) 3. arterioles (<.1mm)what are capillariessite of nutrient and gas exchange...between arteries and veinswhat are veinsthey carry blood towards the heart. the venules are small veins (<0.1 mm) located between capillaries and veinswhat are the largest arteries(such as the aorta) are "eastic arteries"large elastic arteries have what kind of wallsthin walls for their size (not much smooth muscle)large elastic arteries store mechanical energy during ventricular systole and transmit that energy whyto keep blood moving after the semilunar valves close....they are very elasticmedium sized muscular (distributing) arteries have whatmore smooth muscle in their tunica mediamuscular arteries help maintain whatthe proper vascular tone to ensure efficient blood flow to the distal tissue bedwhat are examples medium sized muscular arteriesbrachial artery in the arm and radial artery in the forarm....they distribute bloodwhat are arteriolesdeliver blood to capillariesthe distal-most muscle cell forms what and does whatthe precapillary sphincter which monitors and regulates blood flow into the capillary bedwhat is the anastomosisan alternate way for the blood to get to the same body tissueif one blood vessel gets blocked, an anastomosis provides whatcollateral circulation for the blood to reach the tissuewhat are capillariesthe only sites in the entire vasculature where gases, water and other nutrients are exchangedcapillaries have only a single layer of whatendothelial cells sitting on a very thin basement membranethe minimalist nature of capillaries allows them to do whatbe freely permeable to many substanceswhat are continuous capillariesthe most common with endothelial cells forming a continuous tube, interruptes only by small intercellular clefts between the simple squamous endothelial cellswhat are fenestrated cappillaries(fenestra=windows) they are found in teh kidneys, villi of small intestines, and endocrine glands are much more porouswhat are sinusoidsthey form very porous channels through which even whole blood cells can percolatewhat are veinsthey have thinner walls, less muscle/elastic tissue, and are designed to operate at much lower pressuresintraveous pressure in venules is less than whathalf of that of arterioles, and drops to just 1-2 mmHG in some larger veinsbc intravenous pressure is so low, veins have whatvalves to keep blood flowing in onl one directionwhen exposed to higher than normal pressures, veins can become whatincompetent (varicose veins)what determines how much fluid leaves the arterial end of the capillary and how much is then reabsorbed at the venous enda combination of hydrostatic and osmotic forceswhat is filtrationthe movement of fluid through the walls of the capillary into the interstitial fluidwhat is interstitial fluidthe fluid between cells of tissueswhat is reabsorptionthe movement of fluid from the interstitial fluid back into the capillaryfiltration is promoted by which two pressures1. BHP 2. IFOPblood hydrostatic pressure (BHP) is generated by whatthey pumping action of the heart-it is greater at the arterial end of the capillaryinterstitial fluid osmotic pressure (IFOP) is constant at about what1 mmHGreabsorption is promoted by what two pressures1. BCOP 2. IFHPblood colloid osmotic pressure (BCOP) is due to whatthe presence of plasma proteins too large to cross the capillaryinterstitial fluid hydrostatic pressure (IFHP) is normally whatclose to zero and becomes a significant factor only in states of edemahydrostatic pressure is whatwhat pushes water against vessel wallosmotic pressure is whatproteins pull water toward them via principle of osmosisnormally there is early as much fluid reabsorbed as there is whatfilteredon avg., about what % of fluid filtered is reabsorbed85%leftover fluid enters whatlymphatic vessels and if eventually returned to the bloosthe exchange of gases and small articles (nutrients and wastes) is a purely whatpassive diffusion processgases and particles move howdown their conccentration gradient into or out of the capillaryveins are known as whatthe volume reservoirsif blood pressure drops then what happenssympathetic nerves cause venoconstriction and more blood flows to the skeletal musclesthe volume of blood returning through the veins to the right atrium is whatthe venous returnvenous return is aided by whatthe little pressure present, the action of breathing/skeletal muscle movement, and venous valvesthe skeletal muscle pump uses whatthe action of muscles to push blood in one direction (due to valves)the respiratory pump uses whatnegative pressures in the thoracic and abdominal cavities generated during inspiration to pull venous blood towards the heartalthough not much, there is a small pressure difference between whatveins and right atriumwhat is blood pressureit is a measure of the force exerted in the lumen of the blood vesselswhat is blood flowthe amount of blood which is actually reaching the end organs (tissues of the body)what is resistancethe sum of many factors which oppose the flow of bloodcardiovascular homeostasis is mainly dependent on whatblood flow....but blood flow is hard to maintainwhat is ohms lawthe realationship between blood flow, blood pressure, and peripheral resistance and it follows a simple formulawhat is the ohms law formulaBP= Flow x Resistancehow can we increase blood flowincreasing BP and decreasing resistance. usually our body will do both when we exerciseperipheral resistance is dependent on factors such as whatviscosity of blood, length of vessels (body size), and vessel diameterviscosity and the length of blood vessels cannot be quickly changes, but...the vessel diameter is readily adjustableperipheral resistance is inversely related to whatthe fourth power of vessel diameterif the vessel dilates even a little, the resistance does whatdrops a lotif the diameter of a blood vessel decreases by one half, its resistance to blood flow does whatincreases 16 timeshardening of the arteries (loss of elasticity) seriously does whathampers the bodys ability to increase blood flow to meet mmetabolic demandsto maintain homeostasis, the cardiovasular system must adjust whatpressure/resistance to maintain adequate blood flow to vital organs at all times- a process called autoregulationautoregulation is controlled through whatnegative feedback loopswith autoregulation there is a complex interplay between whatthe cardiovascular system the nervous system and the endocrine systemthe vascular system senses whatalterations of BP and blood flow and signals the cardiovascular centers in the brain. the heart then apppropriately modifies its rate and force of contraction. arterioles and precapillary sphincters of the metarterioles adjust resistance at specific capillary bedsduring emergencies, the autonomic nervous system will do whatvasodilate the precapillary sphincters of metarterioles in the skeletal muscles, lungs, and brain, which constricting the precapillary sphincters found in tissues such as the skin, GI tract, and kidneyswhat are two of the most important control pointsthe pressure receptors (called baroreceptors) located in the arch of the aorta and the carotid sinus. also baroreceptors in the kidneys and walls of the heartstimulation of the baroreceptors in teh carotid sinus is called the whatcarotid sinus reflex and it helps normalize blood pressure in the brainstimulation of the aortic baroreceptors helps normalize whatthe systemic BPwhen blood pressure falls, baroreceptors are stretched less, and the input is sensed in the cardiovascular centers of the brain which respond with whatdecreased parasympathetic and increased sympathetic stimulation. blood pressure increases do the oppositewhat are other important receptors for autoregulation of BPchemoreceptorswhere are chemoreceptors foundin the carotid bodies (located close to baroreceptors of cartoid sinus) and aortic bodies (located in the aortic arch)when chemoreceptors detect hypoxia, hypercapnia, or acidosis they do whatsignal the cardiovasular centerswhat do chemoreceptors dothey increase sympathetic stimulation increasing heart rate and respiratory rate, and vasoconstricting the vessels (arterioles and veins) to increase BPwhat is REnin-angiotensin-aldosterone (RAA0 system)an important endocrine component of autoregulationrenin is released by whatkidneys when blood volume falls or bloos flow decreasesrenin is converted into the active hormone angiotensin II which does whatraises BP by vasoconstriction and by stimulating secretion of aldosterone from the adrenal glandsepinephrine and norepinephrine are also released from where and what do they dothe adrenal medulla as a response to sympathetic stimulation. they increase cardiac output by increasing rate and force of heart contractionsantidiuretic hormone (ADH) is released from where and does whatthe posterior pituitary gland in response to dehydration or decreased blood volume and it triggers the thirst center of the brainAtrial Naturetic Peptide (ANP) is a natural diuretic hormone released by whatthe cells of the cardiac atriawhat does ANP dolowers blood pressure (via direct vasodilation) and reduces blood volume (by promoting loss of salt and water as urine)A measure of peripheral circulation can be done by checking whatthe pulsethe pulse is a result of whatthe alternate expansion and recoil of elastic arteries after each systolethe pulse is strongest wherein arteries closest to the heart, and becomes weaker further out. normally it is the same as the heart ratewhere can u find your pulse-on your lateral wrist -on your carotid arterywhat is blood pressurethe pressure in arteries generated by the left ventricle during systole and the pressure remaining in the arteries when the ventricle is in diastolewhat is hypertension (HTN)the most common disorder affecting the CV system and is a major cause of several diseaseshypertension defelevated systolic blood pressure (SBP), an elevated diastolic blood pressure (DBP), or both. Depending on severity, it is classified as pre-hypertension, stage 1 HTN, or stage 2 HTNwhat is hypotensionblood pressure too low to maintain homeostasishypotension leading to hypo-perfusion (pressure and flow are related) of criticla organs results in whatshockmost cases of shock call for whatadministration of extra fluids and emergency medications like epinephrine to help restore blood flow (perfusion) to the tissues. If the body is not able to do this quickly, with or without outside help, organs will fail (kidney failure, liver failure, coma) and damage may become permanentthe pulmonary circulation leaves the right heart to allow blood to do whatbe re-oxygenated and to off-load CO2the systemic circulation leaves the left side of the heart to supply whatthe coronary, cerebral, renal, digestive and hepatic circulations (among others)the bronchial circulation provides oxygenated blood whereto the lungs, not the pulmonary circulation, which oxygenates bloodthe hepatic portal system is designed to do whattake nutrient-rich venous blood from the digestive tract capillares, and transport it to the sinusoidal capillaries of the liverthe hepatocytes of the liver extract whatsugars, fats, and proteins, store them (glycogen etc) and put them back into the circulation when necessarythe fetus has whatspecial circulatory requirements bc their lungs, kidneys, and GI tract are non functionalthe fetus derives oxygen and nutrients and eliminates wastes through whatthe maternal blood supply via placentathe fetus is totally dependant on whatcapillary exchangeoxygen-rich blood bypasses the fetal lungs by doing whattraveling to the left heart through the foramen ovaleblood going into pulmonary artery meets the closed/soggy lungs with what. and this blood bypasses the lungs via whatvery high resistance. ductus arteriosusat birth, a neonates lungs open and in just a few seconds, there is a massive drop in whatpulmonary vascular resistanceblood now entering the right heart now sees loewr pressure looking into the lungs and has no what"incentive" to flow through the foremen oval or the ductus arteriosuswhat are the list of the arteries-aorta (one) -brachiocephalic (one) -common carotid -internal carotid -external carotid -subclavian -axillary -brachial -radial -ulnar -brachial (usually 3) -renal -illac (common, internal, external) -femoral -poplitealwhat are the list of veins-vena cave -barchippocephalic (two) -external jugular -internal jugular -subclavian -axillary -brachial -median cubital -liac (common, internal, amd external) -fermoral -poplieal -saphenous -hepatic portal