CH 1: Cells of the Immune System

Question 1

Hematopoiesis

Answer 1

Generation of RBCs, WBCs, and platelets

Question 2

Pluripotent hematopoietic stem cells

Answer 2

Can self renew, or give rise to these different, more mature, hematopoietic cells
differentiated cells don’t self generate

Question 3

Hematopoietic cells

Answer 3

• Erythrocytes
• Leukocytes
• Megakaryocytes

Question 4

Erythrocytes

Answer 4

RBCs
- movement of oxygen

Question 5

Leukocytes

Answer 5

WBCs
- help eliminate infections

Question 6

Megakaryocytes

Answer 6

Source of platelets
- wound repair
- “cell with giant nucleus”
- platelets aren’t truly cells, but come from cells
- platelets contribute to blood clotting & secreting cytokines & growth factors

Question 7

Types of Leukocytes

Answer 7

• small lymphocytes
• dendritic cell
• plasma cell
• mast cell
• NK cell
• monocyte
• neutrophil
• macrophage
• eosinophil
• basophil

Question 8

Granulocytes: Myeloid Linage

Answer 8

Group of myeloid cells with cytoplasmic granules that kill organisms and enhance inflammation
- have irregularly shaped nuclei
- Neutrophils
- Eosinophils
- Basophils

Question 9

Neutrophils

Answer 9

Phagocytes; die at site of infection to form pus
- recruited to site of infection

Question 10

Eosinophils

Answer 10

Defend against parasites

Question 11

Basophils

Answer 11

Defend against parasites, but at very low abundance

Question 12

Large reserves of neutrophils are stored in?

Answer 12

The BONE MARROW and are released when needed to fight infection. Neutrophils travel to & enter the infected tissue, where they engulf & kill bacteria. The neutrophils die in the tissue & are engulfed & degraded by macrophages.

Question 13

Monocytes: Myeloid Linage

Answer 13

Circulate in blood; have indented nucleus, gives rise to:
- macrophages
- dendritic cells

Question 14

Macrophages

Answer 14

Sedentary, scavenger cells of tissue…wait for infection
- eliminates dead/damaged cells
“Large phagocyte”

Question 15

Dendritic cells

Answer 15

Mobile, star-shaped cellular messengers that can activate an adaptive immune response

Question 16

Mast cells: Myeloid Linage

Answer 16

Found in connective tissues; have granules
- involved in allergy response

Question 17

Bacteria and macrophage interaction:

Answer 17

1. Binding of bacteria to phagocytic receptors on macrophages induces their engulfment & degradation.
2. Binding of bacterial components to signaling receptors on macrophages induces the synthesis of inflammatory cytokines.

Question 18

Large granular lymphocytes: Lymphoid Lineage

Answer 18

Effector cells of innate immunity; granular cytoplasm
- Natual Killer (NK) cells

Question 19

Natual Killer (NK) cells

Answer 19

Enter viral-infected tissue to kill infected cells and secrete cytokines
- binds specifically, to prevent killing healthy cells

Question 20

Small lymphocytes: Lymphoid Lineage

Answer 20

Almost no cytoplasm; adaptive immune response
- circulate in quiescent & immature form
- B & T lymphocytes
- no granules, mostly made of nucleus
- very small
*imp for adaptive response

Question 21

B lymphocytes/cells

Answer 21

Have cell-surface receptors called immunoglobulins
- plasma cells

Question 22

Plasma cells

Answer 22

Effector B cells that secrete antibodies - soluble forms of immunoglobulins

Question 23

T lymphocytes/cells

Answer 23

Have T-cell receptors (never secreted)

Question 24

Diversity of immunoglobulins & T-cell receptors

Answer 24

We have millions of different immunoglobulins & T-cell receptors

Question 25

Immunoglobulins

Answer 25

Proteins - diff shape = diff function

Question 26

Antigen

Answer 26

Foreign part from a certain pathogen

Question 27

Diff pathogens have?

Answer 27

Diff antigens

Question 28

Effector functions of B cells:

Answer 28

- B cells differentiate into antibody-producing plasma cells - Humoral immunity - Opsonization

Question 29

Humoral immunity

Answer 29

Immunity due to antibodies & their actions - B & T cells - relating to body fluids

Question 30

Opsonization

Answer 30

Coating a bacterium with antibodies to enhance phagocytosis - coating w something - can activate complement sys ex: antibodies

Question 31

Effector functions of T cells

Answer 31

- Two types of effector T cells: - cytotoxic T cells - helper T cells

Question 32

Cytotoxic T cells

Answer 32

Kill cells infected with certain viruses or bacteria - CD8

Question 33

Helper T cells

Answer 33

Secrete cytokines to help other cells become effector cells (help active macrophages) - CD4 - don't do the killing themselves - Regulatory T cells

Question 34

Regulatory T cells

Answer 34

Subset of helper T cells that controls activity of other T cells to prevent tissue damage and stope immune response - shut it down - don't want immune response to continue & damage tissue - inactivating cells

Question 35

Where are lymphocytes found?

Answer 35

Most lymphocytes are found in lymphoid tissues or organs - Bone marrow, thymus, spleen, adenoids, tonsils, appendix, lymph nodes, and Peyer's patches *important for keeping us healthy

Question 36

Peyer's patches

Answer 36

Areas of lymph tissue in small intestine

Question 37

Primary/central lymphoid tissues

Answer 37

Where lymphocytes develop & mature - Bone marrow - Thymus

Question 38

Bone marrow

Answer 38

Origination site of B & T cells - maturation site of B cells

Question 39

Thymus

Answer 39

Maturation site of T cells

Question 40

Peripheral/secondary lymphoid tissues

Answer 40

Where mature lymphocytes are stimulated - activation

Question 41

Lymph nodes lie at junctions of the LYMPHATICS

Answer 41

Networks of lymphatic vessels, that originate in connective tissues and collect plasma that leaks out of blood vessels - forms lymph

Question 42

Lymph

Answer 42

Extracellular fluid, which is eventually returned to the blood

Question 43

B & T cells move through the body through what?

Answer 43

Through blood and lymph

Question 44

If a lymphocyte is activated by a pathogen...

Answer 44

It stays in lymph node - Otherwise, eventually leaves in efferent lymph & return to blood

Question 45

Lymphocyte recirculation

Answer 45

Movement between blood & lymph - allows lymphocyte population to continually survey secondary organs for infection

Question 46

Following infections

Answer 46

- Connective tissue commonly infected - Intact pathogens, pathogen fragments, & pathogen-infected DCs carried from here to nearest lymph node by the lymphatics -----draining lymph node - Pathogen-specific B cells proliferate at the germinal center, causing "swollen glands"

Question 47

Draining lymph node

Answer 47

lymph node receiving fluid collected at infected site - Closes node to certain pathogen

Question 48

Spleen

Answer 48

Lymphoid organ that serves as a filter for the blood - not connected directly, enters thru blood vessels - 2 functions: --- removes damaged or senescent red cells ---defends against blood-borne pathogens - Made up of two tissues: --- red pulp --- white pulp

Question 49

Red pulp

Answer 49

rbcs monitored and removed - short half life

Question 50

White pulp

Answer 50

wbcs gather to provide adaptive immunity

Question 51

Can humans survive without a spleen?

Answer 51

Yes

Question 52

Most microorganisms in humans found?

Answer 52

Respiratory and GI tract - vulnerable to infection --- GALT --- BALT --- MALT

Question 53

Gut-associated lymphoid tissues (GALT)

Answer 53

Tonsils, adenoids, appendix, and Peyer's patches

Question 54

Bronchial-associated lymphoid tissue (BALT)

Answer 54

Lines respiratory epithelium

Question 55

Mucosa-associated lymphoid tissue (MALT)

Answer 55

More diffuse mucosal lymphoid tissues

Question 56

M cells

Answer 56

Specialized cells of mucosal epithelium - how pathogens arrive at resp. & GI tact sites

Question 57

Lymphocytes enter mucosal lymphoid tissue from?

Answer 57

The blood & leave via lymphatics - activated lymphocytes stay & perform effector funtcions