Immunology

Question 1

Granulocytes and Agranulocytes

Answer 1

Granulocytes: neutrophils, basophils, eosinophils
Agraonulocytes: lymphocytes, monocytes

Question 2

GALT (gut-associated lymphoid tissue) organs

Answer 2

Tonsils, Adenoids, Peyer’s patches, Appendix

Question 3

Neutrophils

Answer 3

1. Phagocytic
2. Short-lived (≤5 days)
3. Target bacteria, even those that have been opsonized, by chemotaxis
4. Dead neutrophils = pus

Question 4

Eosinophils

Answer 4

1. Bright red-orange granules
2. Allergic reaction & invasive parasitic infections
3. Activation releases histamine, causing inflammation
4. Vasodilation and blood vessels more leaky, lead to more immune cells move to affected tissue

Question 5

Basophils

Answer 5

1. Allergic reactions
2. Release histamine
3. Least populated
4. Related to mast cells

Question 6

Mast cells

Answer 6

1. Smaller granules but closely related to basophils
2. In tissues, mucosa, epithelium
3. Release histamine

Question 7

Different names for macrophages in different locations

Answer 7

1. CNS: Microglia
2. Skin: Langerhans cells
3. Bone: Osteoclasts

Question 8

Defensins

Answer 8

Antibacterial enzymes on the skin

Question 9

Complement system

Answer 9

Proteins in the blood that act as a nonspecific defense against bacteria. Punches hole in cell wall of bacteria. Has two pathways of action

Question 10

Complement system pathways

Answer 10

1. Classical pathway: requires binding of an antibody to a pathogen
2. Alternative pathway: does not require antibodies

Question 11

Interferons

Answer 11

Proteins that prevent viral replication & dispersion. Upregulates MHC Class I and II molecules (to present more antigens).

Causes nearby cells to:

1. Decrease production of both viral and cellular proteins
2. Decrease permeability

Question 12

Actions of Macrophages

Answer 12

1. Phagocyte the invader via endocytosis
2. Digest the invader
3. Present a tiny bit to other cells vis MHC
4. Release cytokinesis

Question 13

NK Cells

Answer 13

Detect downregulation of MHC (that are often caused by viruses)

Question 14

Suppressor T-cells

Answer 14

1. Express Foxp3 and CD4
2. Help tone down immune response once infection is controlled
3. Self-tolerance: turn off self-reactive lymphocytes

Question 15

Helper T cells: types, actions

Answer 15

1. Th1: release IFN-𝛾, promote macrophages (common in bacterial infection)
2. Th2: activate more B-cells (more in parasitic)

Question 16

Functions of the lymphatic system

Answer 16

1. Equalize fluid distribution
2. Transport fats and fat-soluble compounds in chylomicrons
3. Provide sites for mounting immune responses

Question 17

Lacteals

Answer 17

small lymphatic vessels in center of each villus in small intestine. Fats in chylomicrons travel here for transport

Question 18

Chyle

Answer 18

milky white lymphatic fluid carrying many chylomicrons

Question 19

Germinal centers

Answer 19

collection where B-cells proliferate and mature