Lecture 12

Question 1

What are the 6 types of blood cells?

Answer 1

Erythrocytes

Neutrophils

Basophils

Eosinophils

Monocytes

Lymphocytes

Question 2

For Erythrocytes, list their characteristics and functions.

Answer 2

classic RBC that carries oxygen

Characteristics: devoid of granules and organelles

Composed of about 50% integral membrane proteins (spectrin and actin bound to ankyrin)

Question 3

For Neutrophils, list their characteristics and functions.

Answer 3

active amoeboid phagocytes that secrete enzymes that destroy certain bacteria by the formation of free radicals (superoxide); also create lysozyme and lactoferin to destroy bacterial cell walls

Characteristics: 3-5 nuclear lobes with connecting strands

Their small, numerous granules contain lysozyme and other proteases

Their larger, less numerous granules contain elastase and myeloperoxidase

Question 4

For Basophils, list their characteristics and functions.

Answer 4

express IgE on their surface and release histamine, when activated by antigen binding, to mediate allergic reactions

Characteristics: large, membrane-bound basophilic granules with a bilobed nucleus

Question 5

For Eosinophils, list their characteristics and functions.

Answer 5

primarily go after parasites but can also lead to allergic reactions
Characteristics: larger than basophils/neutrophils
Found with basophils usually
Bilobed nucleus
Have the following specific granules:
Major basic protein (MBP): disrupts parasite membranes and causes basophils to release histamine
Peroxidase
Cationic Protein: neutralizes heparin and is anti-parasitic

Question 6

For Monocytes, list their characteristics and functions.

Answer 6

largest of the RBC’s that serves as a precursor of macrophages and osteoclasts

Characteristics: eccentrically located, kidney-shaped nucleus

Granular cytoplasm due to small lysosomes

Question 7

For Lymphocytes, list their characteristics and functions.

Answer 7

Characteristics: large and round with a slightly indented nucleus that fills most of the cell

Occur in small, medium, and large sizes

Question 8

Explain how basophils can increase vascular permeability. What other effect does this function have?

Answer 8

they can produce leukotrienes to increase vascular permeability and slow the contraction of smooth muscles

Question 9

Basophils contain vasoactive substances such as heparin and Kallikren. What do these subtances induce when released?

Answer 9

Heparin is an anticoagulant

Kallikrein: attracts eosinophils

Question 10

Basophils contain vasoactive substances such as heparin and Kallikren. What do these subtances induce when released?

Answer 10

Heparin is an anticoagulant

Kallikrein: attracts eosinophils

Question 11

How many types of monocytes are there? what do these do?

Answer 11

2 types

B Monocytes are precursors of plasma cells

T lymphocytes mature later in the thymus

Question 12

How many types of monocytes are there? what do these do?

Answer 12

2 types

B Monocytes are precursors of plasma cells

T lymphocytes mature later in the thymus

Question 13

What are platelets derived from and why do they release thromboxane?

Answer 13

cells derived from megakaryocytes that enhance aggregation by the release of thromboxane

Question 14

The adhesion of platelets involves ________

Answer 14

integrins

Question 15

What promotes clot formation, retraction, and dissolution?

Answer 15

platelets

Question 16

What promotes clot formation, retraction, and dissolution?

Answer 16

platelets

Question 17

What are the 5 stages of hemostasis?

Answer 17

Constriction of smooth muscles around cells

Constriction of vessels

Slowing of blood

Formation of platelet plug

Blood clotting (coagulation)

Question 18

List the steps involved in the formation of the platelet plug

Answer 18

underlying collagen fibers of the damaged epithelial tissue are exposed

Platelets adhere to the exposed collagen fibers and release the contents of their secretory vesicles (including ADP) and cause the conversion of arachidonic acid (in the platelet plasma membrane) to thromboxane A2 which further stimulates platelet aggregation.

ADP and other factors cause platelet aggregation in order to form the platelet plug

Question 19

Where is Von Williebrand factor released from, and what is it’s function?

Answer 19

Von Willebrand factor is released from Weibel-Palade bodies in endothelial cells

It facilitates the adherence of platelets to the walls of the damaged blood vessel

Question 20

Compare the intrinsic and extrinsic clotting pathways

Answer 20

Intrinsic Pathway: everything necessary for it to occur is already within the blood and it is triggered during injury to the epithelial tissues of the vessel being damaged, exposing their collagen fibers

Extrinsic Pathway: involves the formation of tissue factor (thrombin or Factor III)

Question 21

describe the steps that form a blood clot (include both factors, prothrombin, fibrinogen, plasminogen activator cascade, and t-PA)

Answer 21

Factor XII is activated when it contacts the exposed collagen of a damaged vessel wall

Factor XII activates prothrombin to become thrombin

Thrombin splits fibrinogen into fibrin polypeptides

A fibrin meshwork forms by the enzymatic action of Factor XIII which traps erythrocytes and other cells to become a clot

Question 22

Describe the process of the dissolution of a blood clot. What activates this process?

Answer 22

Fibrinolysis (dissolution of fibrin) occurs when plasminogen is converted to it’s enzymatic form, plasmin. (plasmin and t-PA both dissolve the clot)

Fibrin activates this process

Question 23

What are the 2 cell adhesion proteins involved in extravasation?

Answer 23

Selectin and Integrins

Question 24

Describe Selectin’s role in Extravasation.

Answer 24

P-selectin appears on the cell surface when endothelial cells are activated by inflammatory signaling

Oligosaccharide ligands on leukocytes bind to carbohydrate recognition domains (CRD’s) on the P-selectins (which are from Weibel-Palade bodies)

Binding of ligands to the P-selectins causes leukocytes to roll along the endothelium

Question 25

Describe Integrin’s role in Extravasation.

Answer 25

Integrin receptors on the leukocyte membrane are activated and bind to ICAM-1 and ICAM-2 on endothelial cells

VCAM and ICAM on endothelial cells are then bound to Integrins in the leukocyte membrane

Transendothelial migration occurs via integrins interacting with endothelial ligands

Question 26

Describe the source and role of Weibel-Palade bodies in leukocyte extravasation.

Answer 26

Weibel-Palade bodies are externalized, and present P-selectins for leukocytes to bind to, on the endothelial lining of vessels during an inflammatory response

Question 27

What is Erythroblastosis fetalis?

Answer 27

Hemolytic disease that occurs in newborns that is causes by blood group incompatibility between the mother and the fetus (usually Rh antigens)

Ex. Mother is Rh negative, baby is Rh positive

Question 28

What is the major cause of the Rh incompatibility that occurs in erythroblastosis fetalis cases?

Answer 28

While ABO and Rh blood group antigens are of particular interest, the D antigen is the major cause of Rh incompatibility

Question 29

What are the results of erythroblastosis fetalis?

Answer 29

Hemolysis, which results in

Hemolytic anemia which causes hypoxic injury to the heart and liver leading to generalized edema (hydrops fetalis)

Jaundice which causes damage to the CNS

Hyperbilirubinemia