Chapter 22: The Hematologic System

Question 1

Erythropoietin

Answer 1

released from the kidney is response to hypoxia

Question 2

Reticulocyte

Answer 2

precursor cells (immature RBCs)
an increased # indicates RBC acceleration

Question 3

Hematocrit

Answer 3

measures volume of RBCs/100 ml of blood

expressed as percentage

Question 4

Hemoglobin

Answer 4

major component of RBCs

carries O2

Question 5

Hemoglobin molecule

Answer 5

adult (HbA): 2 alpha and 2 beta chains
fetal (HbF): beta and gamma chains
surrounds an iron atom

Question 6

The rate of Hgb synthesized depends on…

Answer 6

iron availability

Question 7

HbF

Answer 7

beta and gamma chains provide higher affinity to transfer O2 across placenta
replaced with HbA within 6 months of birth

Question 8

Mean Corpuscular Volume (MCV)

Answer 8

measures average size of RBCs

microcytic - normocytic - macrocytic

Question 9

Mean Corpuscular Hemoglobin Concentration (MCHC)

Answer 9

measures Hgb content within 1 RBC

hypochromic - normochromic - hyperchromic

Question 10

RBC Distribution Width (RDW)

Answer 10

measures the size differences of RBCs

useful in predicting anemias; changes before the MCV

Question 11

Blood Smear

Answer 11

provides actual visualization of the RBC morphology

sizes, color, and shape of red cells

Question 12

Pluripotent Stem Cell

Answer 12

blood-forming stem cell in bone marrow
not committed to any particular cell type
indispensable source of reserve cells

Question 13

Progenitor (Parent) Cells

Answer 13

Differentiate along a single pathway
Lymphoid stem cells
Myeloid stem cells

Question 14

Lymphoid stem cells

Answer 14

T and B cell progenitors

Question 15

Myeloid Stem Cells

Answer 15

progenitor of monocytes, granulocytes, megakaryocytes, and erythrocytes

Question 16

Leukocytes (WBCs)

Answer 16

protect against harmful bacteria and infection
Granular Leukocytes: neutrophils, eosinophils, basophils
Nongranular Leukocytes: monocytes, lymphocytes

Question 17

Neutrophils

Answer 17

most abundant
arrive first at site of infection (last 1-3 days)
phagocytic

Question 18

Eosinophils

Answer 18

increase during allergic response and parasitic infections

Question 19

Basophils

Answer 19

help with initiating inflammation

releases histamine and heparin

Question 20

Monocytes/Macrophages

Answer 20

participates in immunity, can act as APCs
phagocytic
can survive months to years

Question 21

Lymphocytes

Answer 21

B lymphocytes
T lymphocytes
Natural Killer (NK) cells

Question 22

B-Lymphocytes

Answer 22

produce antibodies (humoral immunity)
memory cells

Question 23

T-Lymphocytes

Answer 23

regulates cell-mediated immunity

T-helper and T-cytotoxic

Question 24

NK Cells

Answer 24

destroy foreign cells

Question 25

Thrombocytes

Answer 25

Platelets
cell fragments of megakaryocytes
assist to minimize blood loss

Question 26

Primary Hemostasis

Answer 26

platelet plug

Question 27

Secondary Hemostasis

Answer 27

activation of the coagulation cascade (clot)

Question 28

Hemostasis: 1 Vessel Constriction

Answer 28

mediators contribute to constriction: thromboxane A2, serotonin, endothelin-1

Question 29

Hemostasis: 2 Formation of Platelet Plug

Answer 29

adhesion and aggregation of platelets
requires vWF for adhesion
release of ADP for aggregation
linked plt and binding = GPIIb/IIIa

Question 30

_____ is required for the coagulation cascade of hemostasis

Answer 30

Calcium

Question 31

Hemostasis: 3 Coagulation Cascade

Answer 31

factors begin activating each other in sequence to convert fibrinogen to fibrin = clot
X activates prothrombin to thrombin
thrombin activates fibrinogen to fibrin
fibrin forms a meshwork

Question 32

Intrinsic Pathway

Answer 32

initiated by Factor XII - XI - IX - VIII - X
slower and longer pathway
clinically measured as PTT

Question 33

Extrinsic Pathway

Answer 33

begins with trauma to blood vessel
much faster than intrinsic
begins with Factor VII - III - X

Question 34

Procoagulation Factors

Answer 34

platelet activation

clotting factors

Question 35

Anticoagulation Factors

Answer 35

heparin on endothelial cells (inactivates thrombin and Factor Xa)
antithrombin-III (neutralizes thrombin)

Question 36

Hemostasis: 4 Clot Retraction

Answer 36

platelets use actin and myosin filaments to pull edges of broken blood vessels together
requires large #s of platelets

Question 37

Hemostasis: 5 Clot Dissolution

Answer 37

fibrinolysis = clot dissolves

Tissue Plasminogen Activator (tPA) activates plasminogen which activates plasmin (digests fibrin)