Immune System

Question 1

antigen

Answer 1

protein (or protein sequence) recognized by an antibody

Question 2

antigen-presenting cell

Answer 2

large, typically dendritic cell that recognizes foreign cells/materials, internalizes and digests them, and presents the resulting antigens to effector immune cells (i.e. macrophages)

Question 3

CD marker

Answer 3

cell surface protein that acts as a marker for a class of cells; CD stands for cluster of differentiation

Question 4

B cells

Answer 4

• cells that will make antibodies

Question 5

T cells

Answer 5

• cell-mediated immune responses

- differentiate in thymus

Question 6

what is the function of the immune system?

Answer 6

to protect

Question 7

what other systems does the immune system require?

Answer 7

• bone marrow and thymus
• spleen and lymph nodes
• skin, mucosa

Question 8

what role does the bone marrow and thymus play in the immune system?

Answer 8

production & differentiation of immune cells

Question 9

what role does the spleen/lymph nodes and skin/mucosa play in the immune system?

Answer 9

exposure to antigen and response

Question 10

what is body’s first line of defense?

Answer 10

skin & mucosal layers

Question 11

what is innate immunity?

Answer 11

• recognize non-self and attack it

- can kill bacteria directly without requiring any other immune system components

Question 12

what is adaptive immunity?

Answer 12

• aka acquired immunity
• antibody or cell-mediated immunity
• T cells, B cells, antigen presenting cells

Question 13

what cells are involved with innate immunity to fight off viruses?

Answer 13

• natural killer (NK) cells

- interferons

Question 14

what is lamina propria?

Answer 14

• loose CT underneath mucosal epithelium
• typically very rich in immune cells b/c it is surveilling tissue & acts as a barrier
• tries to reduce any bacteria/viruses/etc going deeper into the body

Question 15

name the resident immune cells in the lamina propria

Answer 15

• macrophages (has indented nucleus)
• mast cells (single central nucleus & contains granules containing histamine/heparin)
• plasma cells (mature B cells, clock face nucleus, comet-like shape)

Question 16

what is a M cell?

Answer 16

• brings bacteria from lumen of gut to underlying CT
• specialized cell type found in epithelium whose job it is to actually bring bacteria thru epithelium
• occurs where there is a lymph nodule

Question 17

what is GALT and where is it found?

Answer 17

• Gut-associated lymphatic tissue

- found in oral cavity, esophagus, stomach, intestines, rectum

Question 18

what is BALT and where is it found?

Answer 18

• Bronchi-associated lymphatic tissue

- found in bronchial tree: bronchus, bronchioles, NOT in alveoli

Question 19

what is MALT?

Answer 19

• mucosa-associated lymphatic tissue

Question 20

what type of epithelium lines the respiratory tract?

Answer 20

ciliated pseudostratified columnar epithelium

Question 21

describe the filtration pathway of the lymphatic system

Answer 21

lymph draining from tissue > lymphatic vessels > lymph node > filtered in node (anything infected should get stuck there) > lymph exits node > returns to blood

Question 22

what is a high endothelial venule?

Answer 22

• blood vessel within lymph node

- used to regulate movement of immune cells into and out of cortex of lymph node

Question 23

what can be found in a medullary sinus of a lymph node?

Answer 23

• lymph
• lymphocytes
• macrophages
• APCs

Question 24

where do the precursors of mast cells mature?

Answer 24

spleen

Question 25

where can you find a Hassal’s corpuscle?

Answer 25

medulla of the thymus

Question 26

what does a Hassal’s corpuscle look like?

Answer 26

very eosinophilic cells wrapped in a concentric swirl

Question 27

describe T cell maturation & quality control

Answer 27

• differentiation begins in CORTEX of thymus = T cell receptor and CD4 and CD8 expression must occur to get out of cortex, or else they will be killed by macrophages within the cortex
• specialize in medulla = express either CD4 OR CD8 and still express T cell receptor
• tested for function = eliminate those that cannot function because not properly expressing receptors (positive selection) AND eliminate those that recognize self (negative selection)
• managed by epithelioreticular cells that tag cells that fail selection process = macrophages digest failures

Question 28

what are the majority of cells in the medulla of the thymus called?

Answer 28

thymocytes

Question 29

how do T cells kill?

Answer 29

• cells that make protein that punches holes in target cell membrane; allows granzyme B to enter & start disintegrating the cell
• T cells can also induce apoptotic cell death by secreting Fas ligand that binds to a receptor on the target cell & induces apoptotic pathways

Question 30

what is the PALS in the spleen?

Answer 30

• Periarterial lymphatic sheath = the lymphocytes immediately around an artery

Question 31

describe red pulp of the spleen

Answer 31

• remove aging RBCs (destruction, iron recycling)

- blood storage

Question 32

describe white pulp of the spleen

Answer 32

• in spleen
• T and B cell, and mast cell activation & proliferation
• monitor for blood-borne antigens

Question 33

where are B cells produced?

Answer 33

bone marrow

Question 34

where are mast cells produced?

Answer 34

their precursors mature in the spleen

Question 35

what connects cords and sinuses?

Answer 35

reticular CT

Question 36

how are antibodies produced?

Answer 36

• produced by mature B cells called plasma cells