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93 Cards in this Set
- Front
- Back
What are the 5 functions of the peripheral circulation?
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1. Carries Blood
2. Exchange nutrients, waste, gas exchange 3. Transports substances : hormones, immune sys., enzymes 4. Helps regulate blood pressure 5. Direct blood flow to tissues |
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What are large elastic arteries like?
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lots of elastic
small amounts of smooth muscle |
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What are small elastic arteries like?
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less elastic
more smooth muscles |
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What type of arteries have the thinnest walls?
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capillaries
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What are the 3 types of arteries?
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1. elastic
2. muscular 3. arterioles (then capillaries) |
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What are the differences between arteries and veins?
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veins are:
thinner less elastic less smooth muscle have valves |
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Describe smallest to largest veins
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venules
small veins medium or large veins |
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What is the endothelium lining of capillaries continuous with?
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The endocardium of the heart
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what are pericapillary cells?
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cells that are intersperced and between endothelial cells and basement membranes
(fibroblasts, macrophages, undifferentiated smooth muscle) |
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What are the 3 types of capillaries?
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1. Continuous
2. Fenestrated 3. Sinusoidal |
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Describe continuous capillaries
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no gaps
less permeable to large molecules found in muscles, nervous and many other |
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Describe fenestrated capillaries
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means 'windows'
highly permeable may or may not have diaphragm found in intestinal villi, cilliary processes of the eye, choiroid plexuses of CNS, glomeruli (kidneys) |
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Describe sinusoidal capillaries
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largest in diameter
have a lot of gaps little or no basement membrane permeable to large molecules found in the endocrine glands |
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What are sinusoids?
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large diameter sinusoidal capillaries
found in liver and bone marrow |
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How do substances diffuse through capillaries?
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1. between endothelial cells
2. through fenestrae 3. through the plasma membrane |
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What are venous sinuses?
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like sinusoidal capillaries but biggerj
found in spleen primarily |
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What type of molecules readily diffuse across the plasma membrane?
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Lipid soluable
small H2O soluable |
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What types of substances do NOT go out of the capillaries?
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RBC's,
lg H2O soluable (proteins) |
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Describe how blood flows from arteriole through a capillary network
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1. arteriole
2. metarterioles 3. thoroughfare channel 4. precapillary sphincters 5. venous capillaries 6. venules |
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What are the three layers that make up the structure of arteries and veins?
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1. Tunica intima
2. tunica media 3. tunica adventitia |
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Describe the tunica intima
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endothelium
basement membrane lamina propia (thin conn. tissue) fenestrated elastic fibers (internal elastic membrane) |
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Describe the tunica media
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smooth muscle cells arranged circularly around vessel
(controls blood flow with vasodilation or vasoconstriction) elastic / collagen fibers external elastic membrane |
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Describe the tunica advertitia
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connective tissue that varies from dense to loose and is continuous with connective tissue around the vessels
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describe large elastic arteries
what do they do best and what's the tunica media like? |
have large diameters so they are good conducting arteries
have thin walls they accomodate high pressure tunic media is more elastic with less smooth muscle |
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Describe muscular arteries and what they do best and what the tunica media is like?
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have small diameter
thick walls tunica media is a little elastic but has lots of smooth muscle |
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What are arterioles like and what is their tunica media like?
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smallest
tunica media has smooth muscle and just a few elastic fibers |
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Where are valves in the vessels?
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in large diameter veins
(medium veins and lower extremities) |
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Vaso Vasorum
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small blood vessels supplying nutrition to blood vessel tunica advertitia and tunica media
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What are arteriovenous anastomoses?
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they allow the blood to flow directly from arterioles to small veins (no capillaries)
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What are portal veins?
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They start in primary capillary network, extend and end in a secondary capillary network
hepatic portal hypothalamohypophysial portal |
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What does the hepatic portal veins do?
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carries blood from the capillaries in the gastrointestinal tract / spleen to sinusoids in the liver
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Discuss innervation of blood vessels
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unmyelinated sympathetic nerves
have plexuses in the tunica advertitia have neurotransmitters in tunica media |
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Sympathetic nerve stimulation in blood vessels causes_____________?
Parasympathetic nerve stimulation in blood vessels causes________? |
vasoconstriction
vasodilation |
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Arteriosclerosis
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hardening of the arteries with age
arteries (especially the large ones) become less elastic and the resistance increases. heart has to work harder as there is hypertrophy of the tunica intima and media |
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Atherosclerosis
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deposition of material in the walls of arteries to form distinct plaques
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Describe the pathway of pulmonary circulation starting at right ventricle
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right ventricle>>
pulmonary trunk>>j right and left pulmonary arteries>> left atrium |
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What are the 3 main parts to the aorta?
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1. ascending aorta
2. aortic arch 3. descending aorta |
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what branches off the ascending aorta?
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right and left coronary arteries
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what branches off the aortic arch?
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brachiocephalic artery
left common carotid left subclavian |
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What branches off the descending aorta?
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thoracic aorta
abdominal aorta 2 common illiac aortas |
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What are the main arteries for the head and neck?
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Right side:
brachiocephalic>>common carotid>>subclavian common carotid>>internal and external carotid subclavian>>vertebral>>basilar |
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What arteris supplies the brain with blood and helps form the circle of willis?
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internal carotid and vertebral
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describe the arteries from the heart to the fingers
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aorta>>aortic arch>>brachiocephalic>>subclavian>>axillary>>brachial>>ulnar and radial>>superficial and deep palmar arch>>digits have medial and lateral arteries
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What does the thoracic aorta supply blood flow for?
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visceral --thoracic organs, bronchi / bronchioles in lungs, pericardium, esophogus
parietal--thoracic wall, diaphragm |
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What are the branches from the thoracic aorta?
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anterior and posterior intercostal arteries
superior phrenic artery |
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What does the abdominal aorta supply blood to ?
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visceral--kidneys, adrenals, gonads
celiac, (superior mesenteric, inferior mesenteric) parietal--diaphragm and ab wall |
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Describe the arteries of the pelvis
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abdominal aorta divides into:
R & L common iliac >>external (lower limbs) >>internal (pelvic area visceral: bladder, vag, rectum uterus parietal: pelvis walls/floor, lumbar, gluteal, proximal thigh muscles, external genitalia |
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Describe the arteries of the lower limb
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external common iliac>>
femoral>> popliteal>>anterior tibial / dorsalis pedis / digital branches >>posterior tibial / fibular (peroneal) / medial /lateral plantar / digital branches |
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What are the 3 major veins returning blood to the heart?
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Superior vena cava
Inferior vena cava Coronary sinus |
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What are the 3 major types of veins?
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1. Superficial (larger, generally in limbs)
2. Deep (larger, generally in head and trunk) 3. Sinuses (cranial cavity and heart) |
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What are the veins of the head and neck?
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external jugular (posterior head and neck)
internal jugular (cranial cavity, anterior face and neck) internal jugular is a continuation of cranial sinuses that proceeds to subclavian>>brachiocephalic... |
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what are the veins of theupper limb?
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cephalic>>median cubital (elbow)
basilic brachial>>radial /ulnar they all go through axillary vein and subclavian |
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What are the veins of the thorax?
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R & L brachiocephalic
>>internal thoracic >>anterior intercostal azygos (unpaired) vein >>posterior intercostal (right side) >>hemiazygos (left side |
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What are the veins of the abdomen and pelvis?
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posterior ab wall >> ascending lumbar>> either hemiazygos (left side) or azygos (right side)
rest of ab wall, pelvis, lower limbs, gonads, kidneys and adrenal glands >>inferior vena cava pelvis >> internal iliac veins >> external iliac veins >> common iliac veins >> inferior vena cava |
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What is the hepatic portal system?
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carries blood through veins from abdominal viscera (stomach, intestines, spleen) to liver sinusoids
delivers nutrients from intestines to liver |
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What veins unite to make hepatic portal system?
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superior / inferior mesenteric
splenic pancreatic gastric |
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What is the longest vein in the body?
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Great saphenous vein (in leg)
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Describe the veins of the lower limb
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superficial:
great saphenous and small saphenous >>popliteal Deep: distal (paired with arteries proximal (unpaired) anterior / posterior tibial >> popliteal >> femoral >> external iliac anterior / posterior tibial also >> fibular (peroneal) |
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What is laminar flow?
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flows in a streamlined fashion
outer layer moves slower inner layer moves more quickly |
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What is turbulent flow?
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when the rate of flow exceeds a critical velocity, passes a constriction, a sharp turn or a rough surface.
occurs mostly in heart of where the arteries are branching |
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Describe the process of taking blood pressure in a clinical setting
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1. place cuff on arm and inflate
2. place stethoscope just above elbow on the inside part 3. gradually lower the pressure until you hear the first sounds of turbulent blood flow = systolic value 4. Continue lowering the pressure until laminar flow has been reached and there is no sound and you have = diastolic value. |
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What is the kortkoff sound?
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systolic pressure
sound of first turbulent blood flow while taking blood pressure |
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What is Poiseville's Law?
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states that a small change in radius of a vessel makes a very BIG change in flow
explains how small changes in vaso dilation and constriction make a big impact on blood pressure. |
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What is the value of the viscosity of blood compared to H20 if H2O is a 1?
What largely influences the viscosity of blood? |
3.0-4.5
hematocrit (% of total blood volume composed of RBC's) dehydration and excess production of erythrocytes |
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What is the critical closing pressure?
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the pressure below which a vessel collapses. Blood flow stops
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What is Laplace's Law state?
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As the diameter increases it also increases the force on a vessel, even in the pressure remains the same
i.e. if you have a bulge the vessels diameter is going to grow therefore more force is applied to vessels wall. And then it's thinner. Recipe for aneurysms! |
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What is vascular compliance?
Are arteries or veins more compliant? |
Tendency for blood vessels volume to increase as pressure increases
stretchy = more compliant stiffer = less compliant VEINS are more compliant |
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In the systemic circulation at any given time where is the blood distributed?
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veins 64%
arteries 16% capillaries 5% |
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What is the pulse pressure and what two factors influence this?
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systolic (@120) minus diastolic (@ 80)
1. SV 2. Vascular compliance |
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Describe capillary exchange
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movement of substances into and out of capillaries
fluids move from areas of higher concentration to areas of lower concentration fluid that remains in interstitial space eventually enters the lymphatic system |
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What is NFP?
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Net Filtration Pressure
force responsible for moving fluid across capillary walls |
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What is the formula for NFP?
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Net Hydrostatic Pressure - Net Osmotic pressure
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What is Net Hydrostatic Pressure?
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BP - Pressure in interstitial fluid
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What is Net Osmotic Pressure?
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Blood Colloid Osmotic Pressure (BCOP)
minus Interstitial Colloid Osmotic Pressure (ICOP) BCOP - ICOP |
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Describe fluid exchange across the capillary walls
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1. artery
fluid moves out of capillary because of a positive net filtration pressure 2. 9/10 of fluid goes back into venous end and 1/10 remains in interstitial fluid 3. fluid goes into venous end because the net filtration pressure is negative |
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What is the result of an imbalance in the amount of interstitial fluid?
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swelling / edema
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Where are the 10 major points where a pulse can be monitored?
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1. Facial artery
2. Superficial temporal artery 3. Common Carotid artery 4. axillary artery 5. Brachial artery 6. Radial artery 7. Femoral Artery 8. Popliteal artery 9. Dorsal Pedis artery 10. Posterior tibial artery |
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What is venous tone?
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continual state of partial contraction of the veins by sympathetic stimulation
constriction of the veins causes larger venous return to heart which causes a bigger prelod which produces a bigger CO vice versa |
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What effect does gravity have on vessels?
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Pressure at aorta is 100 mm Hg and at right atrium is 0 mm Hg.
Everything else is at the mercy of gravity. Standing for long periods of time causes edema because more fluid remains in the interstitial space |
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What are the two ways blood is controlled in the tissues?
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Local Control
Nervous / Hormonal Control |
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What substances do local control mechanisms respond to when detected in the blood?
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When increased levels of metabolic substances (CO2, lactic acid, adenosine, adenosine monoposphate /diphosphate, EDRF, K+ and H+) are detected, local tissues release vasodialators
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What is vasomotion?
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cyclical and periodic contractions as local tissues respond to tissue blood needs
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Describe how Nervous / Hormonal Regulation of tissue blood works
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1-30 secs and is sympathetic stimulation
constant waves of ap's are being sent to the vasomotor center from the vessels and creates a vasomotor tone Also, the pons, midbrain and diencephalon all send msgs to the vasomotor center release of epi or norepi in response to these messages causes vasoconstriction |
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Describe how baroreceptors regulate MAP.
Is it short term or long term? |
ap's from the aortic arch reflex go to vagus nerve (X) and ap's from the carotid sinus reflex go to the glossopharangeal nerve (IX) where they end up in the cardio regulatory and vasomotor centers respectively
centers respond accordingly with para or sympathetic stimulation Short term, adaptable |
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Explain how the adrenal medullary mechanism regulates MAP
Is it short term or long term? |
sympathetic nerve fibers stimulate the adrenal medulla (like during exercise)
to release epi and norepi Its like a boost to the sympathetic stimulation Very short term |
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Explain how the Chemoreceptor Reflex regulates MAP
Is it short term or long term? |
carotid bodies >> glosso
aortic bodies >> vagus lack of O2 (like in altitude) increases ap's to vasomotor center and Vasomotor tone increases Short term Chemoreceptors also react to increased levels of CO2 and H+ It's like an emergency detector to protect the heart and brain |
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Explain how the CNS Ischemic Response regulates MAP
Is it short term or long term? |
responds to low blood flow to medulla oblongota.
Super emergency vasoconstriction Short term |
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Explain how the Renin-Angiotensin-Aldosterone mechanism regulates MAP
Is it short term or long term? |
affects kidney function
When the blood volume / arterial pressure is high, urine output increases the kidney's release renin which makes angiotensi I and angiotensin II Angiotensin II causes: --vasoconstriction in arterioles and veins to increase BP --adrenal cortex to release aldosterone --makes you thirsty, crave salt and release ADH Long term |
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What effect does aldosterone have on the kidneys?
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Makes them take in more Na+ and Cl- ions and water and therefore decreases urine output (saves the water for more blood volume)
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Explain how the ADH (vasopresin) mechanism regulates MAP
Is it short term or long term? |
sort of like partners with the renin-angiotensin-aldosterone mechanism.
baroreceptors detect decreased BP and causes vasopresin ADH to be secreted from posterior pituitary causes vasoconstriction decreases urine output this mechanism is sensitive to ion concentration in the plasma Long term |
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Explain how the atrial natriuretic mechanism regulates MAP
Is it short term or long term? |
atrial natriuretic is a polypeptide hormone released by cells in the atria of the heart.
It is released when there is a large increase in the volume of venous return effects levels of urine output in kidneys Long term |
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Explain how the fluid shift mechanism regulates MAP
Is it short term or long term? |
plays a role in dehydration.
when BP goes up fluid goes out of the capillaries into interstitial space when BP drops fluid goes into the capillaries from the interstitial spacej Long term |
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Explain how the stress relaxation response regulates MAP
Is it short term or long term? |
more contraction by smooth muscle cells in response to decreased BP
more relaxation when BP is increased (like in a transfusion) Long term |