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blood vessels
final
| Question | Answer |
|---|---|
| blood vessels | 64 % of blood volume is in the venous blood -acts as a reservoir system -blood in liver, spleen, & skin can be shaunted to other areas -emergency, raises skeletal muscle activity |
| inner layer | endothelium/ tunica interna/ or inyama |
| arteries are ---------- than veins | thicker |
| veins inner layer folds inward to form | valves |
| arteries cannot contract instead | they fold into pleats when artery contracts |
| endothelial cells act as | sensors |
| the endothelium | regulates vascular smooth muscle tone, host-defense reactions, angiogenesis, and tissue fluid hemostasis |
| middle layer | tunica media |
| tunica media | smooth muscle layer & elastic connective tissue -thicker in arteries than veins -innervated by sympathetic fibers of autonomic nervous system -vasoconstriction -vasodilation |
| vasoconstriction | sympathetic stimulation(ANS) autoregulation- vessel wall damaged |
| vasodilation | decreased sympathetic stimulation/ parasympathetic release of nitric acid presence of lactic acid |
| outer layer | tunica externa/ or adventita |
| tunica externa | mostly elastin and collagen fibers too thick for diffusion or osmosis vasa vasorum |
| vaso vasorum | blood vessels in this layer of the large arteries & veins (28 layers of smooth muscle) provides blood flow to smooth muscle cells |
| artery lumen | small |
| vein lumen | large |
| arteries | carry oxygenated blood from the left heart to the body except pulmonary artery -high pressure system -arterial system starts at aorta as it leaves LV |
| elastic/conducting arteries | largest diameter arteries more connective tissue, less smooth muscle -helps propel blood forward while ventricles are relaxing |
| walls stretch | to accommodate blood as ventricles contract after LV/RV contraction, elastin fibers in wall recoil walls also dampen the pressure peaks and valleys caused by heartbeat |
| recoil | forces blood on toward smaller arteries |
| elastic/conducting arteries | aorta brachiocephalic subclavians common carotid vertebrals pulmonary common iliac |
| brachiocephalic | subclavian carotid |
| vertebrals | off the subclavian |
| from the left ventricle to the aortic valve to the aorta | recoil |
| muscular/ distribution arteries | distribute blood to tissue of the body medium diameter arteries more smooth muscle, less connective tissue capable of greater vasoconstriction and vasodilation greater impact on blood flow |
| brachial and radial arteries femoral and tibial arteries external carotid arteries | examples of muscular/ distribution arteries |
| aneurysm | local arterial pressure exceeds the capacity of the elastic components of the tunics |
| arterioles | several hundred million resistance vessels endothelium and only a couple layers of smooth muscle have greater influence on BP |
| resistance vessels | when BP increases which increases resistance to blood flow |
| regulates blood flow into capillary system autoregulation | arterioles |
| arterioles vasoconstriction | decreases blood flow into capillaries |
| arterioles vasodilation | increases blood flow to capillaries |
| ability of tissue to automatically regulate blood flow by adjusting vasoconstriction and vasodilation for metabolic demands | autoregulation |
| precapillary sphincters | rings of smooth muscle where capillaries branch from arterioles |
| capillaries | microscopic connect arterioles and venules close contact with most of cells of the body diameter about the size of RBC |
| 10 billion capillaries in body 25,000 miles | exchange gases, nutrients, and waste occurs here |
| high need | muscle, liver, brain, nerves, kidneys |
| lower need | tendons, ligaments,fascia |
| no capillaries | cornea , lens of eye, cartilage, all covering and lining epithelial tissue cells |
| single cell thick endothelial layer surrounded by basement membrane | vary degrees of permeability depending on how tightly cells are joined ( cell junction) |
| continuous | endothelium is a complete lining contain very tight junctions which limit permeability allows water, small solutes and lipid soluble substance through found everywhere except epithelia and cartilage many in muscles, lungs, CNS, thymus gland |
| fenestrated | 10x more permeable than continuous capillaries "leaky" intracellular junction endothelium is fenestrated-contains "pores" rapid exchange of large amount of fluid and solutes can move through the pores found in endocrine glands, renal glomeruli, inte |
| discontinuous/ sinusoid | -specialized fenestrated capillaries -wide gaps between endothelial capillaries -allows large molecules like proteins and RBCs to pass through -found in liver, spleen, bone marrow, anterior pituitary gland, adrenal glands |
| capillary bed | group of interconnected capillaries |
| collaterals | multiple arteries that feed a single capillary bed if 1 artery is blocked, the capillary bed will still receive blood flow |
| AV malformation | the capillary bed is missing high pressure arterial blood flows directly into the low pressure venous system extremely fragile, prone to bleeding, can be very painful exchange of nutrients & waste in this area a bruit may also be heard on auscultation |
| capillary pore | red arrow= pore, L= lumen, blue arrow, P= perivascular space |
| capillary exchange | small diameter-blood flow is slower than in larger vessels slow speed allows for capillary exchange substances move via diffusion, osmosis, and filtration |
| substances that move via diffusion, filtration, and osmosis | o2, co2, and anesthetic gases diffuse though quickly |
| filtration involves | capillary blood pressure/ hydrostatic pressure blood colloid osmotic pressure |
| capillary blood pressure/ hydrostatic pressure | pressure of blood against the walls of the capillary generated by LV contraction, pressure "pushes" fluid out through pores and into insterstitial fluid- filtration pressure is higher at arteriolar end than venule end |
| blood colloid osmotic pressure | an opposing pressure that "pulls" fluid back into the capillary "pressure" is due mainly to plasma proteins proteins molecules are too large to pass through the pores, they stay in the capillaries osmotic pressure created by proteins in the plasma :pul |
| osmosis | movement of a solvent/ water from an area of lower solute concentration to an area of greater concentration 1 |
| osmotic/water potential | if pure water is on both sides of a semipermeable membrane, there will be no movement-no osmotic potential |
| when you add solutes to the water , an osmotic potential is created | decreased osmotic potential= water is less likely to move to another area increased osmotic potential= water is more likely to move to another area |
| edema | abnormal accumulation of fluid in the insertital fluid space increased capillary blood pressure/ hydostatic pressure decreased plasma protein/albumin increased permeability of capillaries and proteins leak out-water follows |
| inflammatory mediators | histamins, bradykinin |
| lymph system | drains excess interstitial fluid transport dietary lipids carries out immune responses |
| LYMPH | interstitial fluid that has moved into a lymph vessel: similar to plasma |
| lymph vessels | starts as lymph cappilRIES; become larger empty into 2 main vessels- right lympathic duct and thoracic duct |
| right lymphatic duct and thoratic duct drain into | subclavian veins |
| lymph nodes | masses of lymph tissue; act as a filter contain macrophages and lymphocytes |
| spleen | contains macrophage and B a lymphocytes |
| thymus gland | located in mediastinum; makes thymosin (stimulates t lymphocyte maturation) contains large numbers of lymphocytes |
| lymphatic nodules | tonsils, Peyers patches (small intestines), also found in mucous membrane lining respiratory, urinary, GI and reproductive tracts |
| start as blind-ended vessels & found throughout the body wherever capillaries are found except parts of the spleen, red bone marrow, and tissue with no capillaries(cornea, lens of eye) | lymph capillaries |
| endothelial cells of lymph capillaries | not attached end to end they overlap one another when pressure outside the vessel exceeds the pressure inside. cells separate slightly-like swing doors and moves into the capillary |
| venules and vein | carry deoxygenated blood from body towards heart capitance vessels- 64% of total blood volume is in venous system low pressure system endothelium form valves to prevent back flow |
| venules | formed by union of several capillaries |
| veins | formed by union of several venules |
| varicose veins | insufficient/weak valves |
| venous return | volume of blood flowing back to heart |
| ventricular systole skeletal pump respirartory pump | 3 ways how venous return |
| skeletal pump | compression of veins during skeletal muscle contraction milking blood moves from 1 valve to another |
| ventricular systole | blood pressure helps push blood through venous system |
| respiratory pump | inhalation and exhalation |
| inhalation | intrathoracic pressure decreases as the diaphragm moves down & intraabdominal pressure increases abdominal veins are compressed, blood is squeezed toward the heart |
| exhalation | diaphragm moves up which increases intrathoracic pressure intraabdominal pressure decreases valves prevent backflow of blood into abdominal veins |
| autoregulation/endothelium | changes pressure locally |
| neural mechanisms | autonomic nervous system (sympathetic and parasympathetic) |
| endocrine mechanisms | hormones |
| local vasodilators | chemical released at tissue level relax smooth muscles of precapillary sphincters speed up blood flow into those tissues |
| examples | increases co2 or decreases o2 at the local tissue level lactid (not enough oxygen) nitric oxide (no) released by endothelial cells elevated K+ or H+ concentration in interstitial fluid chemical associated with inflammation(histamine) elevated local |
| lack of autoregulation | lose ability to release NO raynaulds's disease, Prinzmetal angina (vasopastic angina) |
| factors affecting tissue perfusion | cardiac output peripheral resistance blood pressure |
| active cells require more oxygen and nutrients and produce more waste= | increased circulation |
| prostaglandins | activated plateletsand wbc's |
| thromboxane a2 | activated platelets and wbc's |
| endothelins | endothelial cells |
| local vasoconstrictors | chemicals released by damaged tissue cells & platelets during formation contract smooth muscles of precapillary sphincters decrease blood flow through local tissue |
| cardiovascular center | located in the medulla oblongata regulates HR, force of contraction, SV, and BP comprised of cardiac center (HR) and vasomotor center (BP) receives info from areas of the brain and sensory receptors |
| cardiac centers contains | cardioacceleratory nerves (increases CO via sympathetic stimulation) cardioinhibitory nerves (decreases Co via parasympathetic stimulation) |
| vasomotor center contains | many neurons responsible for vasoconstriction (adrenergics, neurons, release norepinephrine) |
| small # of neurons that cause vasodilation of arterioles in brain and skeletal muscles | cholinergic neurons, release acetylcholine (ach) ach stimulates the release of NO by endothelial cells in area NO causes vasodilation some neurons release NO as their neurotransmitter |
| vasomotor tone | sympathetic nervous stimulation keeps arterioles in a state of partial vasoconstriction they can dialate 11/2 x their diameter resistance in a maximally constricted arteriole is 80x greater than fully dialted arteriole |
| sensory receptors | proprioceptors baroreceptors chemoreceptors |
| proprioceptors | message of joint and muscle movement during physical activity increases HR |
| baroreceptors reflexes | sensory dendrites that trigger a vascular reflex send continuous messages about BP and CV center(medulla) to adjust CO and peripheral resistance monitor degree of stretch in arteries |
| carotid sinuses | bases of internal carotid arteries responds 60-180 mmHg |
| aortic sinuses | wall of ascending aorta wall of right atrium |
| baroreceptors | when BP increases they are stimulated send impulse to CV center at a faster rate CV center increases parasympathetic stimulation & decreases sympathetic stimulation ach released at SA node & force of contraction decreased HR vasomotor centers inhibit |
| when BP fall below normal | decrease stretch- baroreceptors send nerve impulses to slow rate-CV center , parasympathetic stimulation decreases & sympathetic stimulation, BP, CO and vascular resistance , HR and force of contraction increases (vasomotor center stimulated vasoconstri |
| atrial baroreceptors | dendrites in wall of RA, blood should pump into the aorta at the same rate as it is returning to the RA. If BP rises in RA -blood is returning faster than it is leaving. sends impulses to CV centers to increase CO until balance returns |
| valsalva maneuver | happens when u forcefully exhale while keeping ur mouth and nostrils closed increases intrathoracic pressure aortic & carotid baroreceptors are stimulated triggering reflexive action reflexes causes increased HR & vasoconstriction increases BP glottis |
| regulation chemoreceptor reflexes | monitor blood & cerebrospinal fluid levels located in 2 carotid bodies of common carotid arteries |
| hypoxia, acidosis, & hypercapnia | stimulates chemoreceptors |
| sympathetic stimulation of arterioles & venules = | vasoconstriction = increased BP and CO |
| renin-angiotensin aldosterone (RAA) system | decrease BP, BF through kidney, is secreted by juxtaglomerular cells in kidney renin converts angiotensiogen (liver) n 2 angiotensin I |
| angiotensin I | is converted into angiotensin II by ACE in the lungs |
| angiotensin II is most potent & causes | increased BP, CO, positive inotropic effect on the heart. secretion of aldosterone and ADH, stimulates hypothalamus to initiate thirst |
| aldosterone | increases reabsorption of sodium & water in kidney |
| adh | increases reabsorption of water |
| epinephrine and norepinephrine | released by adrenal medulla in sympathetic stimulation increase HR & force of contraction which increases CO causes vasoconstriction of arterioles & veins in skin and abdominalpelvic organs increases BP |
| erythropoietin | stimulates vasoconstriction, increases rbc production, increases the volume & viscosity of blood |
| antidiuretic (adh) | produced by hypothelmus, secreted by posterior pituitary released in dehydration & decreased blood volume stimulates vasoconstriction stimulated reabsorption of water n kidney increase BP increase Blood volume |
| atrial natriuretic peptide (ANP) | released by cell in RA of heart in response to excessive stretching stimulates excretion of sodium & water in urine stimulates vasodilation, blocks release of ADH, aldosterone, epinephrine, & norepi reduces BP & blood volume |
| blood pressure | pressure exerted by blood o the walls of the blood vessel, created by LV contraction=systole starts around 100 mmHg at aorta to 35 mmHg in capillaries |
| capillary hydrostatic pressure | 35-18 mmHg |
| venous pressure | 18-1 mmHg |
| circulatory pressure | 100mmHg |
| total peripheral resistance (TPR) | resistance of the entire cardiovascular system |
| pressure gradient in arterial system | 100mmHg(aorta) to 35 mmHg (caps) =65 mmHg |
| circulation= | circulatory pressure> TPR |
| vascular resistance blood viscosity turbulence | creates TPR/SVR |
| Vascular resistance | force that opposes blood flow in blood vessels created by friction between blood & blood vessel walls most significant component determined by vessel length and vessel diameter |
| blood viscosity | thin fluids flow well at low pressures, resistance to flow created by interactions among molecule &suspended materials in a liquid thicker fluids need higher pressure to push them whole blood is 5x thicker than water due to plasma proteins & blood cells |
| changes in anemia and polycythemia | blood viscosity |
| viscosity | increases in dehydration n polycythemia & decreases in anemia, overhydration |
| turbulence | normally occurs as blood flow between atria and ventricles, in large arteries when CO & arterial flow rates are high, bifurcation areas. creates swirls of blood in the blood vessel seldom occurs in small vessels unless walls are damaged |
| maintains blood flow through capillary beds | arterial blood pressure |
| pulse pressure | difference between systolic and diastolic pressure |
| mean arterial pressure single number to represent blood pressure average is 70-110 mmHg 60mmHg =ischemia | MAP |
| blood pressures | aorta/large arteries 100-120 mmHg arterioles 60-70 mmHg capillaries 25mmHG (aterial side) 11mmHg (venous side) venules 15mmHg veins 5-6 mmHg venae cava 0 mmHg |
| the difference between systolic and diastolic pressure | recoil |
| aortic compliance helps | the aorta absorb some of the force of the blood surge as it expands during systole decreases pulse pressure as aorta gets less compliant -pulse pressure increases |
Created by:
t4achange
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