Lecture 9: Lymphatic System

Question 1

What are central lymphoid organs (2)? What is their primary function?

Answer 1

1. Bone marrow
2. Thymus
3. GALT (tonsils, adenoids, appendix, peyer’s patches)
   Generation of lymphocytes

Question 2

What are peripheral lymphoid organs? What is their function?

Answer 2

lymph nodes, spleen, mucosal lymphoid tissues

initiation of adaptive immune responses and maintenance of lymphocytes

Question 3

What are characteristics and examples of Innate immune response?

Answer 3

• non specific
• responds to patterns
• no memory
  -immediate
  (physical barriers, chemical defens, secretory substance, phgocytic cells, NK cells)

Question 4

What are characteristics and examples of adaptive immunity?

Answer 4

-specific
-memory
-delay response
-B or T cell mediated
(humoral (antibody mediated) or cellular (viral infected cells))

Question 5

What are T-cells?

Answer 5

T-lymphocytes- cell mediated immunity
CD4+ (Helper cells- product antibodies and phagocytes)
CD8+ (destroy infector cells)

Question 6

What are B-cells?

Answer 6

B-lymphocytes - humoral immunity

• mature in bone marrow
• plasma cells
• extracellular pathogens

Question 7

Where are T-cells produced?

Answer 7

bone marrow –> mature in thymus

Question 8

What is the structure of a B-lymphocyte?

Answer 8

2 heavy and 2 light chains
Fab- antigen binding
Fc- effector functions

Question 9

NK cells

Answer 9

• innate immunity

- release perforins and granzymes

Question 10

What are charactristics of inflammation?

Answer 10

• innate immunity
• redness, heat, pain, swelling
• neutrophils, monocytes, macrophages
• presentation of antigen –> lymphocytes

Question 11

What are characteristics of specific immune response?

Answer 11

• adaptive immunity

- triggered when antigens are delivered to lymph nodes and recognized by lymphocytes

Question 12

Where do antigens and lymphocytes meet?

Answer 12

peripheral lymphoid organs

**4-6 days from antigen recognition to activated lymphocytes

Question 13

What do pathogens inter the lymph nodes through?

Answer 13

afferent lymphatic vessels

Question 14

What are germinal centers?

Answer 14

dense spherical structures formed by B-cells that have recongized antigen and actively proliferating

Question 15

MALT
GALT
BALT

Answer 15

• Mucuous associated lymphatic tissue
• Gut associated lymphatic tissue
• bronchus associated lymphatic tissue

Question 16

What is the function of MALT?

Answer 16

• protect GI system, GU system, and respiratory passages

* ** LP of large intestine

Question 17

The area surrounding a germinal center is called____

Answer 17

Mantle zone

Question 18

Lymphatic nodules are found randomly dispersed and localized in what three areas?

Answer 18

1. Tonsils (crypts)
2. small intestine (Peyer’s patches)
3. Appendix (cermiform)

Question 19

What is the function of afferent lymphatic vessels?

Answer 19

bring lymph to node, convex surface of node

Question 20

What is the fuction of efferent lymphatic vessels?

Answer 20

take lymph away from node, concave surface of node (hilum)

Question 21

What are dendritic cells?

Answer 21

• antigen presenting cells

- Activate T-cells

Question 22

What are follicular dendritic cells? (FDCs)

Answer 22

• found in germinal centers

- bind antigen-antibody complex

Question 23

Describe the cortex of a lymph node

Answer 23

• outer portion
• contains lymphatic tissue and sinuses
• superficial nodular cortex
• deep cortex (no nodules)

Question 24

Describe the medulla of a lymph node

Answer 24

inner portion of lymph node

- sinuses converge near hilum and drain into efferent lymphatics

Question 25

Where is the subcapsular (cortical) sinus?

Answer 25

between capsule and cortical lymphocytes

Question 26

What are the three sinuses in a lymph node?

Answer 26

1. subcapsular (cortical) sinus 2. Trabecular sinus 3. medullary sinus (trabecular sinus drains into it)

Question 27

What are High Endothelial Venules (HEVs)

Answer 27

- Postcapillary venules in deep cortex | - concentrate lymph by tansporting fluid and electrolytes from afferent vessels --> bloodstream

Question 28

What are three cells made in the Thymus?

Answer 28

1. T-cells 2. Macrophages 3. Epithlioreticular cells

Question 29

Type I, II, and III, IV,V,VI cortical epithelioreticular cells.

Answer 29

``` I- border of cortex and capsule or tabeculae II- located in cortex III- boundary of cortex and medulla IV- between cortex and medulla V- throughout medulla VI- Form Thymic hassall's corpuscles ```

Question 30

Characteristics of spleen

Answer 30

- largest lympahtic organ - collects antigens from blood - red pulp --> RBC disposal - white pulp --> lymphocytes surrounding arterioles

Question 31

Where is red pulp found in the spleen?

Answer 31

splenic cords and splenic sinuses

Question 32

Where is white pulp found in the spleen?

Answer 32

central artery

Question 33

Two main functions of spleen.

Answer 33

1. immune function | 2. hemopoietic function