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29 Cards in this Set
- Front
- Back
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Microcirculation involves ____, ____ and _____
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arterioles, capillaries and venules
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Pericytes
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cells that surround capillaries, they determine the capillary permeability. They secret growth factors that also maintain structure. Loss = diabetes.
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You can regulate blood flow by limiting blood flow to the ______ bypass
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arteriovenous
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Metarterioles
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act as bypass channel and regulate flow into capillary beds
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Angiogenesis
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new blood vessel formation, can occur from many reasons. Development, exercise, pathology, myocardial infarction, tumorogenesis.
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Angiostatin & Endostatin
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help prevent angiogenesis
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Growth factors that help angiogenesis?
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Vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF)
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Mean Arteriole Pressure?
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MAP = diastolic - 1/3 (systolic - diastolic)
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Factors affecting MAP?
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cardiac output (CO) and peripheral resistance
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Blood Pressure control: Slow response?
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controlled by kidneys, excretion of fluid = decrease in blood volume = decrease in blood pressure
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Blood Pressure control: Fast response?
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controlled by cardiovascular system
1) vasodilation 2) decrease in cardiac output results in decrease of blood pressure |
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Myogenic autoregulation?
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regulated by vascular smooth muscles, they control vasoconstriction and vasodilation. Facilitated by stretch-activated calcium channels.
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Paracrine regulation?
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release of paracrine substances (gases) into tissues with increased metabolism, causing vasodilation.
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Active vs Reactive hyperemia?
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Active: Release of CO2 into tissue, causing vasodilation.
Reactive: blood flow to tissue is stopped COMPLETELY, release of H+ and CO2, requires removal of occlusion (blockage). |
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Adenosine?
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form of paracrine regulation. A vasodilator released when O2 consumption exceeds O2 supply. Contains nitrogenous base + ribose, NO PHOSPHATE! Is the cause of ischemic pre-conditioning and causes dilation EVERYWHERE.
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Sympathetic regulation?
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catecholamines can bind onto ALPHA-adrenergic receptors on vascular smooth mucles --> vasoconstriction --> increase in BP.
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Angiotensin II?
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A pressor (increases BP), vasoactive peptide that causes vasoconstriction
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______ is produced in the liver, which gets cleaved by ______, which is released by the liver when BP drops, turning it into _____. This precursor peptide is then cleaved by _____ enzyme, which is located inside the blood vessel endothelium, turning it into the active peptide ______, causing vasoconstriction in the arterioles.
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1) Angiotensinogen
2) Renin 3) Angiotension I (Ang1) 4) ACE 5) Angiotensin II (Ang2) |
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Where is Angiotensin made?
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Everywhere, but brain and body is made seperately and differently due to BBB (blood-brain barrier).
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____ is a vasoactive peptide made in the cardial myocytes that acts as a _____ to decrease blood pressure.
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1) Atral Natriuretic Peptide (ANP)
2) vasodilator |
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Precapillary Sphincters?
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smooth muscles that adjust the blood flow to the capillaries.
Relaxed state = blood flow in all capillaries Constricted state = blood flow directed ONLY to metarterioles |
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Capillary exchange is controlled by ______ and by _____ of substances between endothelial cells
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1) transcytosis
2) diffusion |
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_____ is the bulk flow out of a capillary and is regulated by _____ pressure gradient. ______ is the bulk flow in a capillary and is regulated by ______ pressure gradient.
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1) Filtration
2) hydrostatic 3) Absorption 4) osmotic |
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Filtration occurs near the ____ of a capillary, whereas absorption occurs near the ____ of a capillary. Capillary pressure gets ____ as it travels down the artery.
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1) artery
2) venous 3) lower |
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Ultimately, filtration always ____ absorption, resulting in a bulk flow of fluid ____ of the capillaries.
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1) exceeds
2) out |
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Baroreceptor reflex?
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primary homeostatic control for blood pressure.
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Baroreceptor reflex responds when there is a ___ in blood pressure, causing a decrease in ______ output and a increase in ______ output. This ultimately causes a _____ in blood pressure, causing a _______ feedback which inhibits the baroreceptor reflex.
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1) increase
2) sympathetic 3) parasympathetic 4) decrease 5) negative |
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Hypertension?
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chronically elevated blood pressure, systolic > 130, diastolic > 85. 90% is described as primary hypertension (no known cause). Cardiac ouput = normal, but peripheral resistance is elevated.
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Hypertension is a risk factor for ______, a disease that thickens the artery walls due to accumulation of fatty materials.
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1) atherosclerosis
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