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Anatomy
Blood
27
Anatomy
Not Applicable
02/05/2004

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Term
What is blood?
Definition
a specialized connective tissue that contains living cells surrounded by a non-living matrix
Term
Formed elements?
Definition
blood cells (red or white) & cell fragments (platelets) that are suspended in the plasma
Term
Blood consists of what?
Definition
A matrix called plasma & formed elements
Term
What is plasma?
Definition
composed of water & dissolved substances
-gases: oxygen & CO2
-proteins: hormones, clotting factors, antibodies
-glucose
-ions: Na+, K+, Ca++
Term
What's hematocrit?
Definition
the volume of blood occupied by cells; normal vaule is 45%
Term
What are the two types of blood cells?
Definition
Red blood cells
White blood cells
Term
What's red blood cells?
-name
-shape
-contains what
Definition
Erythrocytes
-not a true cell b/c nucleus & organelles are lost as cell matures
-shape is a biconcave disc
-very flexible to squeeze through capillaries
-large surface area to volume ratio, efficient for O2 movement in & out of cell
Packed w/ hemoglobin protein which contains an iron molecule that binds O2
Term
What is anemia?
Definition
blood has low O2 capacity
-fewer RBCs(hemorrhage, bone marrow destruction)
-abnormal hemoglobin(lack of iron, genetic defect)
Term
What's polycythemia?
Definition
an excess of RBCs
-slight inc. is normal in people living at higher altitudes
-large excess is abnormal(can be life-threatening)(bone marrow cancer) blood thickens & impairs circulation
-blood doping
Term
What is erythropoiesis?
Definition
the formation of RBCs in red bone marrow(adult sternum, pelvic girdle, femur)
-stimulated by kidney hormone erythropoietin(EPO) via negative feedback
-not stored, made when needed
-requires iron & B vitamins
Term
What is the lifespan of RBCs?
Definition
~120 days
-destroyed in spleen
-the iron is recycled
-the hemoglobin degraded to bilirubin(usually metabolized by liver & intestine, excess causes jaundice)
Term
What are White blood cells?
-found
-function
-contain
Definition
Leukocytes
-they travel in the bloodstream, and in tissue
-primary function is to fight infection & disease
-formed in red bone marrow
-stored in large #s, so blood levels can rise rapidly
-released in response to immune system signal
-has nucleus, lacks hemoglobin
Term
What are the types of leukocytes?
Definition
Neutrophils
Eosinophils
Basophils
Monocytes
Lymphocytes
Term
What is the primary role/function of
neutrophils?
Definition
-usually the first of the WBCs to arrive at an injury site
-very active phagocytes, specializing in attacking & digesting bacteria
Term
What is the primary role/function of Eosinophils?
Definition
-generally ignore bacteria & cellular debris
-attracted to foreigh compounds that react w/ circulating antibodies
-#s inc. during allergic reaction or parasitic worm infection
Term
What is the primary role/function of Basophils?
Definition
-migrate to sites of injury & cross the capillary wall to accumulate w/in the damaged tissues, where they discharge their granules into the interstitial fluids
-releases histamine that enhances local inflammation initiated by mast cells
Term
What is the primary role/function of Monocytes?
Definition
-release chemicals that attract & stimulate neutrophils, additional monocytes & other phagocytes & lure fibroblasts to the region
Term
What is the primary role/function of Lymphocytes?
Definition
-attack both foreign cells & abnormal cells of the body & secrete antibodies into the circulation
-act to protect the body & its tissues
Term
What is the lifespan of WBCs?
Definition
varies from a day(neutrophils) to decades(lymphocytes)
Term
What is leukemia?
Definition
cancer of WBCs
-excess WBCs crowd out RBCs in the marrow, producing anemia
-WBCs are abnormal & patient is susceptible to infection
Term
What are platelets?
Definition
fragments of cells that are important in the clotting process
Term
What is hemostasis?
Definition
process that stops bleeding
Term
What are the processes of hemostasis?
Definition
Smooth muscle contraction
-damaged area constricts to slow bleeding
Platelet plug(phase)
-edge of cut becomes sticky attracting platelets. release chemicals to attract more platelets (+ feedback) to clot cut
Clot formation(Coagulation)
-plasma proteins converted into fibrin that trap RBCs & form clot
-clot remains until vessel wall repaired
Term
What is hemophilia?
Definition
the absence of clotting factor, results in uncontrollable bleeding
Term
What does the liver need for clotting?
Definition
Vitamin K is required to synthesize clotting factors
Term
What's thrombus?
Definition
A blood clot attached to the internal surface of a blood vessel
Term
What's embolus?
Definition
A drifting blood clot in circulation
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