LYMPHATIC SYSTEM AND IMMUNITY

Question 1

state the three functions of the lymphatic system

Answer 1

1. drain excess interstitial fluid
2. transport lipids
3. immune system support

Question 2

name the cells of lymph nodes

Answer 2

B cells (lymphocytes)
T cells (lymphocytes) 
macrophages (phagocytes)

Question 3

describe the role of B cells

Answer 3

B cells (lymphocytes) mature in the bone marrow hence “b cells”, their function of lymphocytes in the nodes is to stimulate immune response

Question 4

describe the role of T cells

Answer 4

T cells (lymphocytes) mature in the thymus hence “t cells” function of lymphocytes in the nodes is to stimulate immune response

Question 5

describe the role of macrophages

Answer 5

macrophages (phagocytes) in the nodes is to destroy foreign substances through phagocytosis

Question 6

discuss the implications of treating a fever

Answer 6

because fever has benefits of helping the infection or inflammation routine use of these drugs should be avoided unless

• temp reaches 40 degrees
• there is known heart disease or implants
• fluid and electrolyte imbalance
• danger of febrile convulsions in children
• persons at risk of infection due to low immune system

Question 7

describe the role of fever in the inflammatory process

Answer 7

raises the temp above the optimal temp for growth of many pathogens so slows rate of bacterial growth
increases the rate of chemical reactions in the body
- the body’s defence mechanisms are faster and duration of the infection shorter

Question 8

name the 3 lines of defence and classify each as either innate or adaptive

Answer 8

fist line: innate/non-specific
second line: innate/ non-specific
third line: acquired/adaptive

Question 9

name the cells involved in phagocytosis and briefly describe the function of it

Answer 9

neutrophils: fastest of all white blood cells to respond to tissue damage by bacteria, their numbers increase explosively during bacterial infections, release chemicals (oxidants and bleach) to destroy bacteria
monocytes: leave bloodstream and develop into macrophages, they devour bacteria, fungi, spores, dust, dead body cells and cell debris

Question 10

state the overall function of inflammation

Answer 10

1. destroy the microbe
2. prevent the spread
3. clear the site
4. repair the damaged tissue

Question 11

name and describe the 3 stages of inflammation

Answer 11

1. vasodilation and increased blood vessel permeability
2. phagocyte migration to the damaged tissue and phagocytosis of bacteria and cellular debris
3. tissue repair

Question 12

describe cell-mediated immunity

Answer 12

T cells destroy cells that harbor viruses or bacteria and cancer cells and parasites
occurs inside cells

Question 13

define immunity

Answer 13

immunity is the capacity of the immune system to successfully defend the body against a potentially infectious agent

Question 14

name the cells involved in adaptive immunity

Answer 14

lymphocytes play an essential role. in adaptive immunity
T lymphocytes
B lymphocytes

Question 15

name the 2 categories of adaptive immunity

Answer 15

1. antibody- mediated immunity

2. cell-mediated immunity

Question 16

describe antibody-mediated immunity

Answer 16

this response activates B cells that then proliferate and produce
plasma cells which make antibodies that target bacteria and their toxins and prepare them for destruction. Antibodies also target viruses before they enter the body cells
memory cells which persist in the body for months to years and can react with the same antigen again if it enters the body at a later time.

Question 17

describe the primary and secondary immune response and the importance of the secondary response

Answer 17

primary immune response: is the response of the immune system the first time it is exposed to a particular antigen
the secondary immune response: is due to increased numbers of specific memory cells which are more easily stimulated to produce plasma cells which produce antibodies.

Question 18

describe an antibody

Answer 18

Y-shaped, globular protein molecules. also known as immunoglobulin (ig)
found in the blood and body fluids like lymph, CSF, urine and mucous secretions.
produced by plasma cells which arose from activated B cells
recognize and bind to specific antigen.
once bound being about removal of the antigen from the body in several different ways and prepare them for destruction.

Question 19

describe igG antibodies

Answer 19

comprise about 80% of the antibodies in serum
protect against bacteria, neutralise toxins and viruses, trigger complement, make phagocytosis more effective.
(ggeee most of them)

Question 20

describe igA antibodies

Answer 20

10-15% of antibodies in blood
most common antibody in secretions and on mucus membranes is found in:
mucus, saliva, tears, breast milk
it binds to antigen before they invade tissues and prevent microbes adhering to mucus membranes especially the respiratory system.

Question 21

describe igM antibodies

Answer 21

5-10% of antibodies
first type to be produced when antigen is encountered
lasts only a short time
very good at clumping antigen, and triggering complement

Question 22

describe the igE antibodies

Answer 22

time amount only
binds to mast cells and basophils which release histamine when antigens binds to to igE
involved in allergic reactions
play a role in immunity to parasitic infection in gut

Question 23

briefly describe the 4 functions of antibodies

Answer 23

1. enhance phagocytosis: antibodies coat the microbe making it easier for the phagocyte to regonside and ingest the microbe
2. activates complement: when the antibody connects to the antigen it changes shape exposing a section of the antibody were complement proteins can bind (complement is activation)
3. neutralisation:antibodies bind to and black the attachment sites on the microbe to stop it binding to a host cell
4. agglutination: into a large complexes so reduces the number of infectious unit phagocytes have to deal with.

Question 24

describe the role of major histocompatibility complex (MHC)

Answer 24

to prevent the immune system from attacking our own cells we have proteins on the surface of our cells which identify us as self.
they are unique to a specific individual
these proteins are the major histocompatibility complex (MHC)
all our cells (except RBC) have thousands of MHC protein surface makers built into the cell membrane