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100 Cards in this Set
- Front
- Back
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Tunica intima contains what kind of tissue?
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Endothelium which is the simple squamous epithelium
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What is the name of the layer which is arranged smooth muscle cells and sheets of elastin?
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Tunica media
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What is the term for reduction in lumen diameter as the smooth muscle contracts?
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Vasoconstriction
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What is the term for increase in lumen diameter as the smooth muscle relaxes?
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Vasodilation
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Why the activities of tunica media are so crucial in regulating circulation?
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Small changes in vessel diameter greatly influence blood flow and blood pressure.
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What is tunica extrna composed of?
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Loosely waven collagen fibers
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What is the function of arterioloes?
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Move blood from main artery into capillaries
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Arterioles form what for collateral circulation?
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Anastomoses
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Capillaries are made of only what?
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Tunica interna
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Number of capillaries per tissue depends on what?
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The activity level in that tissue
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Capillary networks increase what?
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The surface area for diffusion
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How exchange between capillaries and cells of tissues happens?
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Via simple diffusion in blood plasma
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Cells of tissues diffuse what into blood for exchange?
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CO2 and lactic acid
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Name the ring of smooth muscle which control blood flow into the capillary bed.
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Precapillary sphincters
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How do precapillary sphincters control blood flow into capillary network?
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They regulate blood flow by contracting and relaxing via ANS stimulation
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Name specialized endothelium cells with many pores.
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Fenestrated capillaries
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State 4 examples of fenestrated capillaries.
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kidney, small intestine, choroid plexus of the brain and endocrine glands
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Name specialized wider capillaries with more tortuous spaces between endothelial cells
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Sinusoidal capillaries
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State 4 examples of Sinusoidal capillaries.
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Liver, bone marrow, spleen, and adrenal medulla
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How do fenestrated capillaries contribute to the blood system?
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They act as a filtering system to move materials into or out of the blood thru secretion & absorption.
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How do sinusoidal capillaries contribute to the blood system?
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They contain phagocytic WBC which filter toxins and bacteria.
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Define the venules.
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Return vessels that take deoxygenated blood back to the heart
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What type of layers do venules contain?
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Tunica interna & tunica externa
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How do the layers of the vein differ from those of artery?
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Vein has a thinner Tunica media & a thicker Tunica externa.
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Veins have valve for what?
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To prevent backflow, especially in extermities
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Venous valves are most abundant in the veins of which part of the body?
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Limbs where the upward flow of blood is opposed by gravity
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Why are veins called blood reservoirs?
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59% of the body's blood supply is found in the veins at any time
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State two factors of influencing BP.
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Cardiac output & pressure gradient
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Explain the pressure gradient
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Blood flows from regions of high pressure to regions of lower pressure
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Arrange the blood vessels with from highest pressure to lowest pressure in order.
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aorta -> arteries -> arterioles -> capillaries -> venules -> veins -> venae cavae
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What is the relationships between blood flow and cardiac output?
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Blood flow = CO
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Blood pressure is generated by what?
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Cardiac output
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State three factors of influencing Resistance of blood flow.
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Thickness of blood (viscosity) & vessel length & radius of vessel
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Viscosity is mainly influenced by what?
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Due to cells in blood -> important to maintain the correct portion
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Dehydration increase/decrease viscosity of blood.
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Increase viscosity
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Increased RBC increase/decrease viscosity of blood.
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Increase viscosity
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Low plasma proteins increase/decrease viscosity of blood.
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Decrease viscosity
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Decreased RBC increase/decrease viscosity of blood.
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Decrease viscosity
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Increased viscosity increase/decrease blood pressure.
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Increase BP to keep blood moving
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The longer the vessel length, the more/less the pressure in blood is.
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More pressure
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Resistance increases when the radius of the vessel become wider/narrower.
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Narrower due to inverse proportion
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Peripheral arterioles has more/less resistance than arteries.
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Greater resistance
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The greater the volume in blood, the higher/lower the BP is.
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BP higher since need to pump harder
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The neural center that oversees changes in the diameter of blood vessel is what?
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Vasomotor center
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This sends a rapid impulse to the vasomotor center when stretched.
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Baroreceptors
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When arterial blood pressure rises/drops, it stretches baroceptors in carotid sinuses.
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When arterial BP rises
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Vasomotor center in medulla controls what?
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Arteriole diameter
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CIC and CAC in medulla decrease or increase what?
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CIC decrease pulse -> decrease CO
CAC increase pulse -> increase CO |
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Impulses from baroreceptors stimulate what?
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CIC and CAC
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When the blood pressure falls below normal range, vasomotor fibers stimulate what?
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Vasoconstriction to cause resistance -> raise BP
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When the blood pressure raise above normal range, vasomotor fibers do what?
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Vasomotors are inhibited, and cause vasodilation to lower resistance -> lower BP
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Define the term "peripheral resistance"?
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Resistance in the vessels in systemic circulation, well away from the heart.
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In hemorrhage, venous blood can replace lost blood. True or False.
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True
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Norepinephrine & Epinephrine decrease the sympathetic fight-or-flight response. True or False
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False: enhance sympathetic response
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What chemical acts on kidney to retain sodium and water which raises BP?
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Aldosterone
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How does ADH contribute to maintain BP?
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Acts on kidneys to retain fluid which increases blood volume.
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What chemical is produced via aldosterone-renin-pathway?
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Angiotensin II
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Angiotensin II acts how in order to raise BP?
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It stimulates intense vasoconstriction
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Angiotensin II stimulates release what?
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Intense vasoconstriction and promote a rise in blood pressure
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What is the chemical that lowers BP?
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ANP/ANF
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How does ANP contribute to lower BP?
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By reducing aldosterone and ADH -> reducing fluid volume via increase of urine output with high sodium content
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Oxygen demand of the tissues causes what regarding blood pressure?
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It opens more capillary beds -> causing immediate decrease BP ->
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How to calculate the pulse pressure?
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The difference between systolic and diastolic pressure
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Define systolic pressure?
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Pressure when the left ventricle contracts and expels blood into the aorta -> aortic pressure reaches its peak (avg. 120mm Hg)
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Define diastolic pressure?
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During diastole, aortic pressure drops to lowest level (avg. 70-80mm Hg)
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Define the mean arterial pressure (MAP).
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The pressure that propels the blood to the tissues / an average blood pressure in an individual
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How to calculate MAP?
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MAP = diastolic pressure + (pulse pressure/3)
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MAP and pulse pressure both rise with increasing distance from the heart. True or False?
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False: they decline as the distance from the heart increases.
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Why is AMP important to be considered?
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Because aortic pressure fluctuates up and down with each heartbeat.
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Average blood pressure in normal adults at rest is...?
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110-140mm Hg / 70-80 mm Hg
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Define Hypotension.
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Low BP - a systolic pressure below 100mm Hg
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Define Hypertension.
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High BP - arterial pressure of 140/90 or higher
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The amount of blood entering a capillary bed is regulated by what?
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Local chemical conditions and arteriolar vasomotor nerve fibers.
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Suppose you are sitting relaxed after meal. What is going on in terms of capillary bed?
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Most of the capillary pathways are closed.
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Name the arteries which encircle the pituitary gland and optic chiasma and unites the brain's anterior and posterior blood supply.
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cerebral arterial circle (circle of Willis)
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What is the function of cerebral arterial circle?
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It equalizes blood pressure in the two brain areas and provides alternate routes for blood to reach the brain tissue is a carotid or vertebral artery becomes close.
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Define pulmonary circulation
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It brings blood into close contact with alveoli of the lungs so that gases can be exchanged
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Define systemic circulation
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It provides the functional blood supply to all body tissues: it delivers oxygen, nutrients, and other needed substances while carrying away carbon dioxide and other metabolic wastes.
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Define Aerobic activities
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Any activity involving large body muscles which increases flow to the heart, accelerates BMR >20 mins and performed at least 3 times per week
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During aerobic activities, venous blood is coming back faster and more is being returned to the heart. This causes what?
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Increase stroke volume -> Increase CO
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Increased preload by aerobic training causes what?
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Hypertrophy (increased mass) in cardiac muscles cells -> increased force of contraction
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Any increased stroke volume allows resting pulse to what?
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Resting pulse to drop
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When baroreceptors are inhibited, what is going to happen?
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It stimulates cardioacceleratory center and stimulate vasomotor center.
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When baroreceptors are stimulated, what is going to happen?
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It stimulates cardioinhibitory center and inhibits cardioacceleratory center
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What are the thick-walled large arteries near the heart that conduct blood continuously away from the heart
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Elastic arteries
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What are the name of the areas in blood vessel which are capable of undergoing vasoconstriction or vasodilation to influence blood flow and blood pressure?
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Tunica media
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Why are muscular arteries less elastic than elastic arteries?
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They are distributing vessels and have thicker tunica media to handle high pressure.
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Veins have a thinner/thicker Tunia Media & a thinner/thicker Tunica Externa than that of arteries.
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a thinner Tunia Media & a thicker Tunica Externa
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Veins entire wall is thinner/thicker than arteries.
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Thinner
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Histamine acts as what to control BP?
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Acts as a vasodilator to drop BP
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Why consuming a lot of salts is bad for the health?
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Water always follows salt, so keeping much sodium inside the body retain lots of water -> increase blood volume -> raise BP
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For adults, what are the only factors to increase the length of vessels?
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Increase fat and muscle in the body
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When the vessel radius is doubled, the resistance drops to what?
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One-sixteenth of its original value
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The larger arteries close to the heart contribute little to peripheral resistance. True or False?
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True: large arteries do not change dramatically in diameter
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Explain the Starling's Law of Capillaries.
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Fluid out from arterial end = fluid in to venuel end + fluid absorbed by the lymphatic capillaries
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State the reason why blood flows from arteriole to venueles via capillaries?
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At the arterial end of capillary, the net force is outward to tissue spaces.
At the venuel end of capillary, the net force is inward from tissue spaces into the vessel. |
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Renal veins lead to inferior vena cava. Ture or False?
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True
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Explain the Starling's Law of Capillaries.
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Fluid out from arterial end = fluid in to venuel end + fluid absorbed by the lymphatic capillaries
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State the reason why blood flows from arteriole to venueles via capillaries?
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At the arterial end of capillary, the net force is outward to tissue spaces.
At the venuel end of capillary, the net force is inward from tissue spaces into the vessel. |
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Renal veins lead to inferior vena cava. Ture or False?
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True
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