Ch. 22 - The Lymphatic System

Question 1

Where are lacteals found and what is their function?

Answer 1

small intestine; carry dietary lipids into lymph vessels and ultimately into blood (lymph is known as chyle)

Question 2

What is the function of the thoracic duct?

Answer 2

receives lymph from L&R lumbar and intestinal trunks

Question 3

What is the function of the right lymphatic duct?

Answer 3

where lymph drains into venous blood

Question 4

Where is the thymus located and what is its function?

Answer 4

mediastinum b/t sternum and aorta; site of T cell maturation

Question 5

Where is the spleen located and what is its function?

Answer 5

b/t stomach and diaphragm; B/T cells carry out immune functions

Question 6

What are the 3 tonsils and where are they located?

Answer 6

PALATINE - post. region of oral cavity
LINGUAL - base of tongue
PHARYNGEAL - post. wall of nasopharynx

Question 7

Where can you find Peyer’s patches?

Answer 7

ileum of small intestine, appendix

Question 8

What are 3 mechanisms that cause lymph to move back toward the heart?

Answer 8

1. respiratory pump
2. skeletal muscle pump
3. valves in lymphatic vessels

Question 9

How does the respiratory pump move lymph towards the heart?

Answer 9

pressure changes during inhalation/exhalation; lymph moves from abdominal region to thoracic region

Question 10

How does the skeletal muscle pump move lymph towards the heart?

Answer 10

fores lymph to move up towards the junction of internal jugular and subclavian veins

Question 11

How do the valves in lymphatic vessels move lymph towards the heart?

Answer 11

lymph drains into venous blood via R & L lymphatic ducts

Question 12

How do lymphatic vessels differ from veins?

Answer 12

1. lymph capillaries have greater permeability and can absorb larger molec
2. one-way structure allows fluid to flow in and not out
3. larger diameter, thinner walls, more valves

Question 13

Where does hemopoiesis take place during fetal development?

Answer 13

blood cells in yolk sac; liver, spleen, lymph nodes

Question 14

Where does hemopoiesis take place in the adult?

Answer 14

bone marrow (mainly in pelvis, cranium, vertebrae, sternum)

Question 15

What does immunocompetent mean?

Answer 15

capable of producing an immune response

Question 16

What is positive selection?

Answer 16

only T-cells that can react are chosen to survive

non-functional T-cells are deleted

Question 17

What is negative selection?

Answer 17

T-cells that react against antigens in the body are deleted

Question 18

What are the primary lymphatic organs?

Answer 18

red bone marrow, thymus

Question 19

What are secondary lymphatic organs?

Answer 19

spleen, lymph nodes, MALT/nodules (mucosal-associated lymphatic tissues)

Question 20

What is white pulp in the spleen?

Answer 20

first step of filtration of blood

- lymphocytes andmacrophages

Question 21

What is red pulp in the spleen?

Answer 21

second step of blood filtration

• venous sinuses
• functions in hematopoiesis during fet dev

Question 22

What comprises of the lymphatic nodules/MALT?

Answer 22

includes tonsils, Peyer’s patches in ileum, parts of appendix

Question 23

What are some characteristics of innate immunity?

Answer 23

• immediate and non-specific response (no memory)

- physical barriers and internal defences

Question 24

What are the first line of defense in innate immunity?

Answer 24

skin and mucous membranes; discourage pathogens and foreign substances from entering body

Question 25

How does the skin act as a line of defense?

Answer 25

- impermeability and tight fit of cells prevent microbe entry - periodic shedding helps remove microbes

Question 26

How do mucous membranes act as a line of defense?

Answer 26

- mucous traps microbes - cilia sweep mucous out (to swallow or sneeze/cough out) - acids break down microbes - lysozymes are antibacterial agents

Question 27

What are the 5 second line (internal) of defenses?

Answer 27

``` antimicrobial substances NK cells phagocytes inflammation fever ```

Question 28

What is the function of antimicrobial substances? Name the 4 main types.

Answer 28

interferons, iron-binding proteins, antimicrobial proteins, complement system

Question 29

What are interferons?

Answer 29

induce synthesis of antiviral proteins that interfere viral replication

Question 30

What is the complement system?

Answer 30

proteins cause cytolysis of microbes, promote phagocytosis, contribute to inflammatioin

Question 31

How do NK cells act as an internal defense?

Answer 31

release chem. that form pores in cell membranes and trigger cytolysis

Question 32

What are the 5 characteristic signs of inflammation? fev

Answer 32

redness, pain, swelling, heat, loss of function

Question 33

What are the 3 stages of inflammation?

Answer 33

1. vasodilation, increased perm of BV 2. emigration of phagocytes via extravasation 3. tissue repair

Question 34

How does fever act as an internal defense?

Answer 34

intensifies effects of interferons, speeds up body rxns that aid repair, inhibits growth of some microbes

Question 35

What are the 2 key properties of adaptive immunity?

Answer 35

1. specificity for antigens (particular foreign molec) | 2. memory for previously encountered antigens

Question 36

What are antigens?

Answer 36

foreign substances that provoke immune responses

Question 37

What is an epitope?

Answer 37

small part of an antigen molecule that triggers an immune response

Question 38

What cells or organs are responsible for adaptive immunity?

Answer 38

B & T cells

Question 39

What are the 2 branches of adaptive immunity?

Answer 39

1. cell-mediated immunity | 2. antibody-mediated imunity

Question 40

Where do B and T cells originate and mature?

Answer 40

B - RBM | T - RBM --> thymus

Question 41

What is clonal selection?

Answer 41

cell with matching receptor was selected to clone itself

Question 42

What triggers clonal selection?

Answer 42

when an epitope binds to a receptor on the surface of a B or T cell; lymphocyte then proliferates and differentiates in response to that antigen

Question 43

What are the cells produced by clonal selection?

Answer 43

effector cells or memory cells

Question 44

What are effector cells and how do they function?

Answer 44

carry out immune responses that result in the destruction/inactivation of the antigen

Question 45

What are the types of effector cells?

Answer 45

active helper T cells active cytotoxic T ells plasma cells (B cells)

Question 46

What is the function of memory cells?

Answer 46

trigger a quicker rxn if the antigen is encountered again

Question 47

What are the types of memory cells?

Answer 47

memory helper T cells memory cytotoxic T cells memory B cells

Question 48

Where are adaptive immune responses initiated? (differs as antigens enter different parts of body?

Answer 48

enter bloodstream --> trapped as they flow through spleen penetrate skin --> lymph vessels then lymph nodes mucous membranes --> trapped by MALT

Question 49

What is the difference between helper T cells and cytotoxic T cells?

Answer 49

Helper T - release cytokines to activate other cells of immune system; help activate cytotoxic T & B cells Cytotoxic T - kill infected body cells

Question 50

What do activated B lymphocytes differentiate into?

Answer 50

plasma cells and memory B cells

Question 51

What activates B cells?

Answer 51

free antigens and co-stimulation by helper T cells via release of cytokines

Question 52

What do plasma cells do?

Answer 52

secrete antibodies into blood and lymph

Question 53

What is another word for antibody and what does it comprise of?

Answer 53

immunoglobulins; 4 pp chains

Question 54

What are the 5 classes of immunoglobulins?

Answer 54

IgG, IgA, IgM, IgD, IgE

Question 55

What is the function of IgG cells and where are they found?

Answer 55

protects against bact/viruses by enhancing phagocytosis, neutralizing toxins, and triggering complement system blood, lymph, intestines

Question 56

Which immunoglobulin crosses the placenta from mother to fetus?

Answer 56

IgG

Question 57

What is the function of IgA cells and where are they found?

Answer 57

provides localized protection of mucous membranes against bact/viruses found in sweat, tears, saliva, mucus, breast milk, GI secretions

Question 58

How is IgA related to stress?

Answer 58

when stressed, IgA levels decrease and increase susceptibility to infection

Question 59

What is the function of IgM cells and where are they found?

Answer 59

activates complement system and causes agglutination and lysis of microbes found on surface of B cells as antigen receptors

Question 60

After initial exposure to any antigen, which is the first antibody to be secreted by plasma cells?

Answer 60

IgM

Question 61

What is the function of IgD cells and where are they found?

Answer 61

activation of B cells found on surface of B cells as antigen receptors

Question 62

What is the function of IgE cells and where are they found?

Answer 62

involved in allergic rxns; provides protection against parasitic worms located on mast cells and basophils

Question 63

What is the difference between active and passive immunity?

Answer 63

ACTIVE - person's immune system actively produces antibodies against an antigen; involves lots of memory cells PASSIVE - person receives pre-made antibodies (in placenta); no memory cells

Question 64

What are some examples of autoimmune diseases?

Answer 64

type I diabetes, multiple sclerosis, rheumatoid arthritis, myasthenia gravis

Question 65

Myasthenia gravis...

Answer 65

...antibodies produced against ACh receptors, causing muscle weakness

Question 66

Type I diabetes mellitus...

Answer 66

...T cells destroy pancreatic island cells that produce insulin

Question 67

Multiple sclerosis...

Answer 67

...T cells destroy myelin sheaths around axons of neurons

Question 68

Rheumatoid arthritis...

Answer 68

...inflammatory cells destroy cartilage and synovial membranes