Lymphatic System and Immunity

Question 1

What are the functions of the Lymphatic System

Answer 1

• draining interstitial (tissue) fluid
• returning plasma proteins etc to blood about 3L per day
• transporting dietary fats (in. fat soluble vitamins)
• immune response (either cell mediated or antibody (humoral) mediated response)

Question 2

What is Lymphatic fluid similar to?

Answer 2

interstitial fluid

Question 3

How does Lymphatic circulation occur?

Answer 3

via skeletal pump and one way valves a la venous system

Question 4

What is Lymphatic tissue?

Answer 4

reticular connective tissue with many lymphocytes

Question 5

What are the types of lymphatic tissue?

Answer 5

• Diffuse (unencapsulated)
• Nodules
• lymphatic organs

Question 6

What are examples of diffuse (unencapsulated) tissue?

Answer 6

lamina propria of mucous membranes and most organs

Question 7

What are some characteristics of nodules?

Answer 7

• discrete, small, unencapsulated
• sometimes solitary or in aggregations (tonsils)
• found in clusters in GI tract, urinary tracts, airways
• found in cortex of lymph nodes

Question 8

What are the lymphatic organs?

Answer 8

• lymph nodes
• tonsils
• spleen
• thymus gland
• bone marrow

Question 9

What are the functions of lymph nodes?

Answer 9

1. filtering potentially harmful particles from lymph before returning it to the blood stream.
2. monitoring fluids immune surveillance provided by lymphocytes and macrophages

Question 10

What are characteristics of lymph nodes?

Answer 10

• encapsulated, 1-2.5 mm long
• efferent vessels in hilus, several afferent vessels on other side.
• has a cortex and a medulla
• structural units called nodules (follicles)

Question 11

Where do the blood vessels enter and leave in the lymph nodes?

Answer 11

at the hilus

Question 12

What do the nodules in the outer cortex contain?

Answer 12

B cells (primary nodules) or B cells macrophages and follicular dendritic cells, which activate B cells. (secondary follicles)

Question 13

What do B lymphocytes do during an immune response?

Answer 13

proliferate and change into plasma and memory B cells inside follicles

Question 14

What does the inner cortex contain?

Answer 14

dendritic cells which present antigens to T cells which will migrate elsewhere toward antigenic activity

Question 15

What is the difference between efferent and afferent?

Answer 15

afferent–goes in

efferent–goes out

Question 16

Which way does the lymph flow?

Answer 16

one way, efferent and afferent vessels

Question 17

How is lymph filtered?

Answer 17

• it is filtered by node, and it flows through lymph sinuses
• particles are trapped by reticular fibers
• destroyed by macrophages and lymphocytes

Question 18

Tonsils

Answer 18

• aggregations of lymph nodules
• embedded in mucous membrane
• protect against foreign substances inhaled or swallowed

Question 19

What are Peyers Patches?

Answer 19

Clumps of nodules in distal part of the small intestine

Question 20

what can lymphocytes and other immune systems do if necessary?

Answer 20

they can attack bacteria etc from GI tract

Question 21

What is the largest lymphatic organ?

Answer 21

Spleen

Question 22

Where is the spleen located?

Answer 22

between the fundus of stomach and diaphragm

Question 23

What is the spleen a site of?

Answer 23

B cell proliferation into plasma cells

Question 24

What are some functions of the spleen?

Answer 24

• phagocytosis of bacteria, worn out RBC’s and platelets
• stores blood and platelets
• prenatal blood cell formation
• very permeable capillaries

Question 25

What is the spleen similar to?

Answer 25

lymph nodes, but sinuses are filled with blood, and not lymph fluid

Question 26

What is White pulp?

Answer 26

masses of lymphocytes and macrophages | -they have immune functions

Question 27

what is red pulp?

Answer 27

lymphocyte, macrophages, red blood cells | damaged red blood cells removed, platelets stored, prenatal hemopoiesis

Question 28

Where is the thymus glad located?

Answer 28

medial and superior to lungs

Question 29

What do T cells migrate from and where do they mature?

Answer 29

they migrate from the bone marrow | they mature in the thymus

Question 30

What do dendritic cells do?

Answer 30

They aid T cells' maturation

Question 31

What does they thymus gland do?

Answer 31

produces thymic hormones and aiding in T Cell maturation

Question 32

What is the difference in the size of the thymus in a child vs. an adult?

Answer 32

- Large in infant - maximum size age 12 - very little left in elderly, but still functional

Question 33

What are the pathologies of the lymphatic system?

Answer 33

lymphangitis and lymphedema

Question 34

what is lymphangitis?

Answer 34

lymph vessel inflammation, red streaks origination from infected area. May lead to septicemia, death

Question 35

what is lymphedema?

Answer 35

edema due to blockage of lymphatic drainage, common after surgery, especially mastectomy

Question 36

The immune system includes what?

Answer 36

- nonspecific resistance to disease (resistance, innate defense) - specific resistance to disease (immunity, adaptive defense.

Question 37

When are non-specific resistances to pathogens present?

Answer 37

at birth

Question 38

What do non-specific pathogens protect against?

Answer 38

many types of pathogens, they don't adapt according to the type of pathogens

Question 39

What is the outer defense?

Answer 39

skin and mucous membranes

Question 40

What are the mechanical (physical) forms of protection?

Answer 40

skin and mucous membranes ie: - mucous, saliva, hairs, tears (these trap bacteria etc.) - urine flow, defication and vomiting

Question 41

What are some chemical forms of protection?

Answer 41

- sebrum, low PH from fatty acids - perspiration contains lysozyme (enzyme) - gastric juices, vaginal secretions (low PH and enzymes)

Question 42

What are the internal defenses?

Answer 42

antimicrobial proteins ie: | -interferons, complement proteins, transferrins

Question 43

What are interferons?

Answer 43

- Produced by lymphocytes, macrophages, and fibroblasts infected with virus - bind on receptors of nearby cells - target cell is induced to synthesize antiviral chemicals (prevent viral replication)

Question 44

What are compliment proteins?

Answer 44

-proteins in the blood that are activated to enhance immune, allergic, and inflammatory reactions.

Question 45

What do complement proteins cause?

Answer 45

cytolysis of microbes, increase phagocytosis, contributes to inflammation

Question 46

Name an important complement protein and its function.

Answer 46

C3, activates other complement proteins

Question 47

How is c3 activated?

Answer 47

by the formation of the antigen-antibody complexes, or by the antigens directly.

Question 48

What are functions of C3

Answer 48

- activation of inflammation - aids in immune adherence (binds to microbe so phagocyte can recognize it as a foreign body) - aids in cytolysis (attack of microbial membrane- causes the microbe to rupture)