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Cardiovascular Syste
Anatomy & Physiology
Question | Answer |
---|---|
blood | fluid connective tissue that is regenerated continuously and is responsible for transporting gases, nutrients, and hormones throughout the cardiovascular system |
blood vessels | form a circuit away from and back to the heart and include arteries, veins, and capillaries |
arteries | transport blood away from the heart |
veins | transport blood toward the heart |
capillaries | permeable microscopic vessels between arteries and veins that serves as sites of exchange between blood and body tissues |
blood components | erythrocytes, leukocytes, platelets, and plasma |
erythrocytes (red blood cells) | transport respiratory gases in the blood |
leukocytes (white blood cells) | defend against pathogens |
platelets | help clot blood and prevent blood loss from damaged vessels |
plasma | fluid portion of the blood and it contains plasma protein and dissolved solutes |
how blood transports | transports formed elements and dissolved molecules and ions, carriers oxygen from from and carbon dioxide to the lungs, and transports nutrients, hormones, heat and waste products |
"delivery service" for the body | blood |
how blood regulates body temperature | absorbs heat from the body cells, released from blood at body surface as blood is transported through vessels of the skin |
how blood regulates the pH | absorbs acids and bases from body cells and contains chemical buffers that bind and release hydrogen atoms |
how blood regulates the fluid balance | water lost in the urine, skin, exchange of fluid between blood plasma and interstitial fluid, and contains proteins and ions |
what blood regulates | boy temperature, pH, and fluid balance |
blood as protection | contains leukocytes, plasma proteins and other materials that help protect the body from harmful substances and contains platelets and plasma proteins that help protect the body against blood loss |
color of the blood | depends on oxygenation status |
color of oxygen-rich blood | bright red |
color of oxygen-poor blood | dark red, appears blue in superficial veins (due to the way that blue light is reflected back to the eyes) |
volume of blood in the body | about 5 liters in an adult with males having slightly more than females, and it is important to keep this normal to maintain blood pressure |
viscosity of blood | 4 to 5 times more viscous than water (thicker), but varies depending on the amount of dissolved substances in blood (i.e. increased if erythrocytes increased and increased if amount of fluid decreases) |
plasma concentration | relative concentration of solutes in plasma, determines whether fluids move into or out of plasma by osmosis (i.e. during dehyrdration plasma hypertonic and fluid moves into the plasma from surrounding tissues) |
temperature of blood | 1 degree higher than measured body temperature (98.6) and warms area through which it travels |
centrifuged blood | separates liquid and cellular components of whole blood |
three components of centrifuged blood | erythrocytes, buffy coat, and plasma |
erythrocytes | lower layer of centrifuged blood that is 44% of the sample |
buffy coat | middle slightly gray-white layer that is composed of leukocytes and platelets and makes up less than 1% of the sample |
plasma | straw colored liquid at the top of the tube that makes up the remaining 55% of the sample |
plasma | composed of water (92%), plasma protein (7%), and dissolved molecules and ions (1%), and it is extracellular fluid that is similar in composition to interstitial fluid with the exception that the protein concentration is lower in the interstitial fluid |
formed elements | erythrocytes, leukocytes, and platelets that make up 45% of whole blood |
erythrocytes (aka red blood cells) | small, flexible, formed elements that lack a nucleus and cellular organelles, have biconcave disc structure, have a plasma membrane with enclosed hemoglobin molecules, and transport oxygen and carbon dioxide between tissues & lungs |
hemoglobin | red-pigmented protein that transports oxygen and carbon dioxide (can be termed oxygenated or deoxygenated) |
oxygenated | describes hemoglobin that is maximally loaded with oxygen |
deoxygenated | describes hemoglobin when some oxygen is lost |
surface antigens | project from plasma membrane of erythrocyte and have implications for blood transfusions and pregnancy |
blood types | A, B, AB, and O |
ABO blood group | consists of two surface antigens, A and B and presence or absence determines ABO blood type |
type A | erythrocytes with surface antigen A |
type B | erythrocytes with surface antigen B |
type AB | erythrocytes with both antigens |
type O | erythrocytes with neither antigens |
antigens are accompanied with... | specific antibodies |
anti-B antibodies react with... | surface antigen B |
anti-A antibodies react with... | surface antigen A |
Type A blood pairs with... | anti-B antibodies |
Type B blood pairs with... | anti-A antibodies |
type AB blood pairs with... | neither antibodies |
type O blood pairs with... | both antibodies |
agglutination | clumping of erythrocytes and occurs when a person is transfused with blood of an incompatible type and this can blood blood vessels and prevent normal circulation or result in hemolysis (stresses importance of pairing a recipient with a compatible donor) |
hemolysis | rupture of erythrocytes and can cause organ damage |
Rh factor (surface antigen D) | another surface erythrocyte antigen whose presence depends on Rh blood type (when present, termed Rh positive and when absent, termed Rh negative) |
antibodies to Rh factor... | appear when Rh negative person is exposed to Rh positive blood (i.e. in an inappropriate blood transfusion) |
ABO and Rh types | usually reported together (i.e. type AB and Rh+ reported as AB+ and type A and Rh- reported as A-) |
leukocyte characteristics | help defend body against pathogens, contain nucleus and cellular organelles, do not contain hemoglobin, and are motile and flexible |
platelet's characteristics | membrane-enclosed cellular fragments without nucleus, serve important role in blood clotting, normally 150,000 to 400,000 per cubic millimeter blood, circulate for 8 to 10 days, and 30% stored in spleen |
hemostasis | process of blood clotting in which the flow of blood through injured blood vessel wall is stopped and there are three overlapping phases |
three phases of hemostasis | vascular spasm, platelet plug formation, and coagulation phase |
vascular spasm | sudden constriction of blood vessels, first phase in response to blood vessel injury, limits blood able to leak from vessel, continues into the next phase, lasts from few to many minutes, and involves greater vasoconstriction with greater vessel damage |
platelet plug | example of positive feedback, formed from platelets arriving at injury site |
platelet plug under normal conditions | endothelial wall is smooth, coated with prostacyclin, and activates pathway inhibiting platelet activation (so this doesn't form because there is no wound) |
platelet plug when vessel is damaged | collagen fibers in vessel wall exposed, platelets sticking her, and closing off of injury due to this (forms because there is an injury |
blood clotting | coagulation |
blood clotting | most important and complex component of hemostasis and involves clot with an insoluble protein network composed of fibrin that traps elements of blood (erythrocytes, leukocytes, platelets, and plasma proteins) |
substances involved in coagulation | calcium, clotting factors, platelets, and vitamin K |
clotting factors | most inactive enzymes produced in the liver |
vitamin K | fat-soluble vitamin, coenzyme |
intrinsic pathway | initiated by platelets recognizing damage to inside of vessel wall and take 3 to 6 minutes |
extrinsic pathway | initiated by damage outside of vessel and usually takes about 15 seconds |
initiation of coagulation cascade | two separate pathways to initiate blood clotting (intrinsic and extrinsic pathways and they converge to the common pathway) |
coagulation cascade | positive feedback mechanism (events continue until clot is formed) and size of clot is limited (some thrombin trapped withn clot and some thrombin degraded by blood enzymes) |