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107 Cards in this Set
- Front
- Back
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what supports the differing functions of arteries, capillaries, and veins?
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anatomical differences
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the smooth muscle in arteries is BLANK compared to veins?
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thicker
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capillaries completely lack BLANK, unlike veins and arteries?
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smooth muscle
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arteries are BLANK elastic than veins?
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more
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veins are BLANK compliant than arteries?
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more
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what are three differences between arteries and veins?
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arteries have more smooth muscle, are more elastic, and less compliant than veins
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all vasculature is lined with?
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endothelium
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what is endothelium?
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squamous epithelium that provides a slick surface that induces minimal friction to blood flow
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what do arteries do?
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conduct blood from heart to peripheral tissues via sequential branching into smaller and smaller arterial vessels
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as arterials branch, what occurs to the vessels?
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change from more elastic to more muscular tissue
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why are arteries closer to the heart more elastic?
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to accommodate the pulsatile ejection of blood
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arteries closer to the heart are BLANK elastic?
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more
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the arteries closer to the heart are essentially what?
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pressure reservoirs that smooth out variations in pressure accompany the cardiac cycle
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what do pressure reservoirs do?
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smooth out variations in pressure accompanying the cardiac cycle
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what do muscular arteries do?
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distribute blood to specific organs and branches into arterioes that are 'gate keeper's in the distribution of blood flow and regulation of blood flow into tissue capillary beds.
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what controls the distribution & regulation of blood flow into capillary beds?
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muscular arteries
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what are muscular arterioles?
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the anatomical location in which the resistance component of blood pressure regulation occurs
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what is the anatomical location in which the resistance component of blood pressure regulation occurs?
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muscular arteries
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what do capillaries do?
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the circulartory location in which exchange of materials between the blood and interstitial fluid occur
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where does the exchange of materials between the blood and interstitial fluid occur?
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capillaries
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what are capillaries?
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microscopically small tubes with a diamter that barely accomodates red blood cells that travel through them
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what is a unique quality of capillaries?
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leakiness
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what determines the leakiness of capillaries?
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whether the endothelium is continuous, fenestrated (porous), or sinusoidal
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the structure of the endothelium of a capillary determines what?
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how leaky it is
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what do veins do?
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conduct blood from capillary beds by sequientially joining into larger tubes that bring the blood back to the heart
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why are veins more compliant than arteries?
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lack heavy layers of smooth muscle
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what does lymphatic circulation do?
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removes water, dissolved solutes, and celular material from interstitial fluid and returns it to the venous circulation
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how is blood volume distributed between the components of vasculature?
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the venous circulation stores 65-80% or total blood volume at any given time
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what is the venous circulation have in terms of blood volume?
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capacitance area
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what is a capacitance area?
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venous circulation a resevoir of blood volume that can be mobilized when needed as a means of increasing cardiac output by increasing preload
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what serves as a blood volume reservoir?
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venous circulation
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why does the body need a capacitance area?
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to provide blood volume to be mobilized when needed as a means of cardiac output by increasing preload
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what is preload?
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venous return
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what is another term for venous return?
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preload
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a given filling pressure produces a substantially BLANK increase in volume of veins than arteries?
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greater
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what is microcirculation?
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the network of capillaries between an arteriole and venule in any given organ
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what is the network of capillaries between an arteriole and venule in any given organ?
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microcirculation
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what are the precapillary sphincters?
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cuffs of smooth muscle surrounding the root of each capillary at the metarteriole that function as valves controlling blood flow into the capillary
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what controls blood flow into the capillary?
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precapillary sphincters
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where are precapillary sphincters?
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at the root of each capillary at the metarteriole
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are all capillary networks perfused all the time?
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No
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how is perfusion of capillary networks determined?
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metabolic demands of a tissue for oxygen and carbon dioxide exchange with the blood
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how is blood flow through a capillary regulated?
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via control of the muscle tone in the precapillary sphincters by local mediators in autoregulation
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what is autoregulation?
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regulation of blood flow through a capillary via local mediators that control the muscle tone in precapillary sphincters
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what do local mediators do?
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regulate blood flow through a capillary in autoregulation by controling the muscle tone in the precapillary sphincters
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what is blood a vehicle for?
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hemoglobin
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what is blood?
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a complex fluid that consists of erythrocytes, leukocytes, & thrombocytes suspended in plasma
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what is plasma made of?
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water, salts, gases, proteins, carbohydrates, & lipids
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what are erythrocytes?
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red blood cells
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what are leukocytes?
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white blood cells
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what are thrombocytes?
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platelets
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what is another term for red blood cells?
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erythrocytes
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what is another term for white blood cells?
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leukocytes
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what is another term for platelets?
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thrombocytes
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what is blood in?
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plasma
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what factor of blood plays an important role in determining an animal's hemodynamic health?
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amount of blood in an individual animals circulatory system
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in domestic species and humand, the amount of blood in the circulatory system accounts for what percentage of body weight?
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~7%
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what percentage of the blood is made up of plasma?
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55-65%
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what is the distribution of cells in blood?
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mostly red blood cells, few white blood cells, and a larger number (small volume) of platelets
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how much protein does plasma contain?
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7 grams per deciliter; 4 albumin and the rest globulins
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what is the main protein in red blood cells?
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hemoglobin
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what is hemoglobin?
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an iron-containing protein
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what does hemoglobin do?
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binds loosely and reversibly to oxygen to form oxyhemoglobin
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where is hemoglobin found?
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red blood cells
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how much hemoglobin is present in each deciliter of blood?
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15 grams
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what is hemoglobin responsible for?
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the bulk of the blood's capacity to pick up oxygen in the lungs and deliver it to the tissues
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what carries the bulk of oxygen in the blood?
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hemoglobin
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what affects the affinity of hemoglobin for oxygen?
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2,3-diphosphogyceric acid concentration in the red cells, temperature, pH
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what does 2,3-diphophogyceric acid concentration in the red cells do?
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influences the affinity of hemoglobin for oxygen in concert with pH and temperature
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in concert, what do 2,3-diphosphogyceric acid concentration, temperature, and pH do?
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enhance the uptake of oxygen in the lungs and facilitate the release of oxygen in the tissues
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the tissue demand for oxygen is BLANK of the blood's ability to carry it
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independent
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alterations that reduce the oxygen carrying capacity of blood causes what?
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the cardiovascular system to compensate by pumping greater volumes of blood to deliver the same amount of oxygen
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what is anemia?
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reduced numbers of red blood cells
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what does anemia do to the circulatory system?
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impair the oxygen carrying capacity of blood and reduce viscosity
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what is polycythemia?
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excess numbers of red blood cells
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what does polycythemia do to the circulatory system?
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significantly enhance oxygen carrying capacity of the blood and increase the viscosity of blood
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what regulates the number of red blood cells produced and released into circulation?
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hormone erythropoietin which is secreted by the kidney
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what does erythropoietin do?
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regulates the number of red blood cells produced and released into circulation
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where does erythropeietin come from?
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kidney
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what is hypoxemia?
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cronic low oxygen levels in the blood
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what does anemia or hypoxemia stimulate?
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production of erythropoietin
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what stimulates erythropoietin production?
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anemia or hypoxemia
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what may eliminate the source of erythropoietin?
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severe kidney disease
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what can cause anemia?
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loss of erythropoietin, blood loss, iron deficiency, disease of bone marrow that influences production or differentiation of erythrocytic stem cells
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what is hemostasis?
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arrest of bleeding
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what is the term for arrest of bleeding?
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hemostasis
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when a blood vessel is damaged, what processes act to stop bleeding?
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vasoconstriction, platelet aggregation, blood coagulation
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vasoconstriction, platelet aggregation, and blood coagulation are processes of what?
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hemostasis
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what is vasoconstriction?
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narrowing of damaged vessel by active contraction of vascular smooth muscle in walls of arterioles and arteries
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what is narrowing of damaged vessel by active contraction of vascular smooth muscle in the walls or arterioles and arteries?
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vasoconstriction
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what triggers vasoconstriction?
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vasoconstricting hormones (NE & endothelin-1) and cytokines and direct mechanical stimulation of the artery and parietal nerves
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direct mechanical stimulation of artery and pariarterial nerves and the release of vasocontricting hormones (NE & endothelin-1) and cytokines cause what?
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vasoconstriction
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what hormones affect vasoconstriction
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NE & endothelin-1
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what is platelet aggregation?
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adherence of platelets to each other and the site of vascular injury
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what is the adherence of platelets to each other and the site of vascular injury called?
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platelet aggregation
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after adhering to an injured site, platelets release what?
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ADP & thromboxane A2
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what does ADP & thromboxane A2 do?
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attracts additional platelets
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what is ADP?
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adenosien diphosphate
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what prevents platelets from aggregating in normal vessels?
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prostacyclin
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what does prostacyclin do?
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prevents platelets from aggregating in normal vessels
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where does prostacyclin originate?
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released from normal endothelial cells in uninjured vessels
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what is blood coagulation?
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sequential activation of a cascade of factors to form a clot mode up of dense fibrin strands
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what is a clot made of?
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dense firin strands in which blood cells and plasma are trapped
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what removes blood clots?
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pasmin, a fibrinolytic enzyme made from an inactive protein (plasminogen) found normally in plasma
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what is plasmin?
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a fibrinolytic enzyme made from an inactive protein (plasminogen) in plasma
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what does plasminogen make when activated?
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plasmin
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what catalyzes the activation of plaminogen to plasmin?
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endogenous tissue activators or therapeutically exogenous substances
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