Chapter 15 - blood

Question 1

describe blood plasma

Answer 1

90% water. 6-8% proteins by weight. nutrients (glucose, lipids, amino acids). wastes (urea, lactic acid).

Question 2

describe erythrocyte amount, anatomy, and primary function

Answer 2

5 million per microliter. no nucleus; no organelles; biconcave disk. transport O2 and CO2

Question 3

describe leukocytes amount, anatomy, and primary function

Answer 3

4k-10k per microliter. ? defend body against pathogens

Question 4

describe platelets amount, anatomy, and primary function

Answer 4

100k-500k per microliter. cytoplasmic fragments; granules. hemostasis

Question 5

why are erythrocytes shaped as biconcave disk

Answer 5

for a large surface-to volume ratio for efficient diffusion. the shape is flexible

Question 6

do erythrocytes have organelles

Answer 6

No nucleus or organelles: no mitochondria, no oxygen consumption, receive energy through glycolysis only. 2 ATPs per glucose molecule

Question 7

describe life cycle of erythrocytes

Answer 7

no nucleus, DNA, RNA, or protein synthesis. no division of mature RBCs. short life span = 120 days. replace 2-3 million RBCs/sec. old erythrocytes are filtered and recycled by spleen (and liver)

Question 8

how do erythrocytes develop

Answer 8

all blood cells develop from the hematopoietic stem cells in red bone marrow. erythrocyte synthesis is stimulated by erythropoietin (secreted by kidneys)

Question 9

name 3 dietary requirements for normal erythrocyte production

Answer 9

iron: component of hemoglobin (heme portion). folic acid: necessary for DNA replication and thus cell proliferation. vitamin b12: necessary for DNA replication and thus cell proliferation

Question 10

compare spleen and liver in recycling erythrocytes

Answer 10

spleen filters and removes old erythrocytes. liver metabolizes and recycle by-products from breakdown of erythrocytes

Question 11

describe steps in spleen handling of erythrocytes

Answer 11

spleen filters blood. spleen macrophages phagocytose old, worn out RBCs. globin subunits are broken into amino acids. hemoglobin is catabolized: iron is removed and recycled, heme -> bilirubin. bilirubin is released into bloodstream. travels to liver for further metabolism. products of bilirubin catabolism are (1) secreted in bile and travel to intestinal tract for elimination, and (2) released into bloodstream and excreted in urine

Question 12

what happens to iron have hemoglobin catabolization

Answer 12

efficiently recycled for synthesis of new hemoglobin. transported in blood bound to transferrin: from GI tract to bone marrow. from liver to bone marrow. Iron is stored in liver( bound to ferritin)

Question 13

what is anemia

Answer 13

any condition where capacity for carrying oxygen is reduced

Question 14

what is hemolytic anemia

Answer 14

excessive destruction of RBCs; in malaria, sickle cell anemia

Question 15

what is renal anemia

Answer 15

decreased erythropoietin production

Question 16

what do leukocytes do

Answer 16

function in defense of body: part of the immune system. defend against pathogens. identify and destroy cancer cells. perform phagocytosis of debris from dead or injured cells

Question 17

describe neutrophils

Answer 17

most numerous WBCs. represent 50-80% of leukocytes in blood. phagocytic cells. circulate for 7-10 hours. migrate to tissues, live for a few days. first line of defense during infections

Question 18

describe eosinophils

Answer 18

represent 1-4% of leukocytes. defend against parasitic invaders. granules contain toxic molecules that attack parasites

Question 19

describe monocytes

Answer 19

represents 5% of leukocytes. migrate to tissues and become macrophages (very powerful phagocytes). involved in immune surveillance: wandering macrophages and resident macrophages

Question 20

describe basophils

Answer 20

the rates WBCs representing less than 1% of all leukocytes. non-phagocytic cells. mediate inflammation and allergic reactions by releasing histamine and heparin

Question 21

describe lymphocytes

Answer 21

2nd most numerous WBC. represents 30% of leukocytes and 99% of interstitial fluid cells. there are 3 types: B cells T cells and natural killer cells

Question 22

describe B cells

Answer 22

upon contacting antigen –> activated B cells –> plasma cell. plasma cells secrete antibodies (immunoglobulins). antibodies mark invaders for destruction

Question 23

describe T cells

Answer 23

directly damage foreign cells. attack infected, mutant, or transplanted cells. develop into cytotoxic T cells that destroy target cells: this takes several days, secretory products form pores in the target cell’s membrane, lysis occurs

Question 24

describe platelets

Answer 24

not true cells. they’re cell fragments: no nucleus has organelles and granules. they break off from megakaryocytes in red bone marrow and enter circulation. they’re important in blood clotting

Question 25

name the 3 steps in hemostasis

Answer 25

1. vascular spasm 2. platelet plug 3. formation of a blood clot

Question 26

what is vascular spasm

Answer 26

damage to blood vessel: vessel constricts to minimize blood loss. this leads to intrinsic vascular responses and sympathetic discharge to the area

Question 27

what is a platelet plug

Answer 27

aggregation of platelets at site of damage. further decreases blood loss. necessary for subsequent clot production. initiated by exposure of subendothelial collagen to von willebrand factor (vWf) present in plasma

Question 28

describe formation of a blood clot

Answer 28

clotting is coagulation. blood is converted into solid gel called a clot or thrombus. occurs around a platelet plug. it is the dominant hemostatic defense mechanism. involves multiple clotting factors and a chemical reaction (coagulation cascade).

Question 29

what is end result of blood clot formation

Answer 29

fibrinogen –> fibrin (loose) –> fibrin (mesh) –> fibrin clot= blood clot

Question 30

describe clotting factors

Answer 30

they’re produced by liver and secreted in inactive form. they become activated during coagulation cascade. plasma without clotting factors = serum. hemophilia is a genetic disorder with deficiency in clotting factor. usually factor VIII

Question 31

what is Von Willebrand’s disease

Answer 31

reduced levels of vWf. decreased platelet plug formation

Question 32

what does vitamin K deficiency cause

Answer 32

decreased synthesis of clotting factors