Erythrocytes Flashcards

1
Q

What is blood and its function & avg volume in adults?

A
  • Specialized connective tissue in fluid
  • Function: thermoregulation & homeostasis, 1’ vehicle for transport of nutrients, O2, CO2, waste products, & hormones
  • ~5Liters
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2
Q

Plasma

A

extracellular matrix

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3
Q

components of blood

A
  • plasma ~55% of blood volume

- 91-92% water, 7-8% protein, 1-2% electrolytes (Na, Ca, K, HCO3)

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4
Q

serum

A

only plasma. NO clotting factors

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5
Q

what are the 3 plasma proteins?

A
  1. Fibrinogens
  2. Albumins
  3. Globulins
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6
Q

Albumins

A

bulk of plasma proteins, all synthesized in liver
•transport proteins for insoluble metabolites
•maintaining colloid osmotic pressure in blood vessels

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7
Q

Globulins

A
  • large molecules

- transport proteins for lipids & heavy metal ions

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8
Q

Globulins consists the largest fraction of what?

A

immunoglobulins—Ab’s synthesized by plasma cells

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9
Q

Fibrinogens

A
  • largest proteins; soluble, synthesized by liver

- polymerize to form insoluble fibrin during clotting

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10
Q

process of forming fibrin

A

prothrombin->thrombin catalyzes fibrinogen->fibrin

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11
Q

formed elements

A

cells in the blood, which are rbc’s, WBC’s, & platelets

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12
Q

hemopoiesis consist of what? And forms what?

A

rbc’s, WBC’s, & platelets—formed in bone marrow

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13
Q

hematocrit

A

volume of RBC

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14
Q

Polycythemia vera

A

genetic neoplasia => ^ rbc production

•> 48% in women & 52% in men => sludging of blood & variety of symptoms

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15
Q

PCV

A

packed cell volume (+/-buffy coat, depending on source)

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16
Q

buffy coat

A

WBC’s & platelets; ~1-2%

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17
Q

Blood smear

A

drop of blood smeared, air-dried, stained with modified Romanovsky method (e.g., Wright, Giemsa, Diff-Quik)

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18
Q

Hemopoiesis

A
  • Process by which mature blood cells develop from precursor cells
  • Consists of erythropoiesis and Myeolpoiesis
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19
Q

Erythropoiesis

A

red cell production

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20
Q

Myeolpoiesis

A

white cell production

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21
Q

Under control of erythropoietin, secreted by what organ?

A

kidney

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22
Q

pluripotential

A

how hemopoiesis begins which differentiates into several unipotenital stem cells

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23
Q

how does hemopoiesis occur in adult humans?

A

occurs in vascular sinuses of bone marrow of cert bones—especially flat bones of skull, ribs, sternum, vertebrae, pelvis, & some long bones

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24
Q

how does hemopoiesis occur in fetus?

A
  1. first trimester: occurs in “blood islands” in wall of yolk sac
  2. second trimester: occurs in liver & lymphatic tissue
  3. last month of pregnancy: in bone marrow
  4. At time of birth, restricted 1’ to marrow cavities—# of active sites ↓with age
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25
Q

types of bone marrow? (2)

A
  1. Red marrow

2. Yellow or fatty marrow inactive

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26
Q

Red marrow

A

active, contains large #’s of mature rbc’s

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27
Q

Yellow or fatty marrow

A

inactive

28
Q

stages of erythropoiesis

A

Stem cell colony forming units (CFU-E) -> proerythroblast ->erythroblast/ normoblast->reticulocyte->mature rbc

29
Q

overall trend of erythropoiesis

A

progressive ↓in cell size, loss of nucleus & organelles, ↑in [Hb]

30
Q

how do erthrocytes appear in mammals?

A

enucleate

31
Q

what do mature RBC consits?

A
  • outer cell membrane containing cytoplasm, Hb, & few enzymes
  • lack mitochondria have limited lifespan (~120 days)
  • only make ATP via anaerobic glycolysis
32
Q

Senescent rbc’s

A

removed from circulation by liver & spleen

33
Q

Howell-Jolly bodies

A

occasional, basophilic nuclear remnants visible within cytoplasm

34
Q

Reticulocytes

A

immature rbc’s with stippled cytoplasm; still have some rRNA

Slightly larger than mature rbc’s

35
Q

Reticulocytosis

A

↑reticulocytes in circulation associated with chronic blood loss, hemolytic anemia—aka “left shift”

36
Q

hemolytic anemia is also known as what?

A

“left shift”

37
Q

what can anemias be seen in?

A

severe or chronic infections

38
Q

what are the 2 types of anemia?

A
  1. macrocytes

2. megaloblastic

39
Q

megaloblastic anemia

A

some anemias present large numbers of erythrocyte precursors in peripheral blood

40
Q

macrocytes

A

Present in anemias, Vit B12 & B9 deficiency => large cells

41
Q

Erythrocytes diameter size

A

6-8um biconcave disc-> deformability

42
Q

Spectrin and its function

A

-primary structural protein in RBC’s
-Function: Provides both resiliency & deformability.
Binds to inner surface of plasma membrane

43
Q

significance of the biconcave shape of erythrocytes

A

increase surface area for gas exchange

44
Q

Hemoglobin structure & function

A

Structure: contains 4 polypeptide chains associated with 4 Fe-containing heme groups

Function: Involved in O2 & CO2 transport; contain large amounts of Fe containing pigment

45
Q

What is anemia

A
  • decrease in Fe or blood loss
  • RBC’s are small (microcytic) and pale staining (hypochromic)
  • being more tired
46
Q

microcytic vs. normocytic

A

microcytic: small RBCs size
normocytic: normal RBC size

47
Q

hypochromic vs. normochromic

A

hypochromic: pale staining
normochromic: normal staining

48
Q

Sickle cell anemia

A
  • alteration in Hb structure that effects RBC
  • occurs from a single amino acid substitution
  • Causes conformational change => “sickle” shape; more fragile, easily damaged
  • Cause damage to endothelial cells of capillary walls due to rough edges
49
Q

single amino acid substitution in sickle cell anemia

A

Valine changes to glutamic acid @ position 6 for B- globulin chain

50
Q

what can sickle cell anemia confer resistance to?

A

malaria

51
Q

malaria

A

caused by an intracellular blood parasite, Plasmodium spp.

52
Q

Thrombocytes structure and function

A

=platelets

  • small, non-nucleated cells contain organelles
  • Function in blood clotting—form physical plugs at site of vascular damage
  • Some drugs (e.g., aspirin) impair platelet function
53
Q

megakaryocytes

A
  • how thrombocytes are formed from large, polyploid cells in bone marrow
  • single, multilobed nucleus
54
Q

what do cells develop pleated in the cytoplasm?

A

demarcation channels–platelets “tear off”

55
Q

Coagulation

A
  • Result of cascade interaction between plasma proteins & coagulation factors
  • Occurs only if endothelial lining of vessel injured
56
Q

In coagulation, what are the 2 convergent pathways

A

extrinsic & intrinsic

57
Q

Extrinsic pathway

A

faster—Initiated by release of tissue thromboplastin a result of tissue damage

58
Q

Intrinsic pathway

A

slower—initiated by exposure of collagen

-Requires numerous clotting factors (e.g., von Willebrand’s factor, Factor VIII) & longer cascade rxn

59
Q

process of coagulation

A
  1. blood vessel wall breaks, tissue injury results
  2. Thromboplastin is released and initiates extrinsic pathway. Also exposes collagen, initiates intrinsic pathway
  3. Platelets adhere to collagen; also release serotonin (potent vasoconstrictor—constricts sm Mm in damaged vessel to minimize blood loss)
60
Q

serotonin

A

potent vasoconstrictor—constricts smooth muscle in damaged vessel to minimize blood loss

61
Q

what do extrinsic and intrinsic pathways converge to form, and what is the result?

A
  • form common pathway (at point where Factor X activated)
  • Results in conversion of prothrombin to thrombin AND soluble fibrinogen into insoluble fibrin
  • Traps platelets & rbc’s
62
Q

What stops clotting?

A
  • Exhaustion of fibrinogen & removal of thrombin from blood during conversion of fibrinogen to fibrin
  • Also anticoagulants antithrombin III& heparin
  • Inappropriate clot formation => heart attack, stroke, DIC
63
Q

Hemophilia

A
  • Deficiency in clotting factor(s), so blood can’t clot
  • defect in intrinsic pathway
  • Sex-linked, in males; present on X chromosome
64
Q

Hemophilia A

A

deficiency of clotting Factor VIII (8)

65
Q

Hemophilia B

A

Factor IX (9) deficiency

66
Q

Hemophilia C

A

Factor XI (11) deficiency

67
Q

Von Willebrand’s disease

A

blood disorder in which the blood does not clot properly