human body defenses

Question 1

fever

Answer 1

elevation of body temp above 38C
other causes-
ovulation, increase secretion of thyroid hormone, tumors, reaction to vaccines, and drugs

Question 2

benefits of fever

Answer 2

1. ) decreases viral reproduction
2. ) inhibits bacterial growth and reproduction
3. ) speeds repair

Question 3

Adaptive immunity

Answer 3

It is the ability of the human body to defend itself against specific invading agents, such as bacteria, toxins, virus and foreign tissue

Question 4

characteristic of adaptive immunity

Answer 4

Specificity:

recognizes specific foreign antigen and reacts to it

Question 5

adaptivity memory

Answer 5

second response to antigen stronger and faster

Question 6

what is an antigen

Answer 6

: any substance that causes your body to produce antibodies against it
reacts with antibody

Question 7

what is an antibody

Answer 7

protein (immunoglobulin) produced in response to an antigen

Large Y-shaped protein that identify and help remove antigens or targets like bacteria or viruses

Question 8

epitopes (antigenic determinant)

Answer 8

actual region of the antigen that reacts with the antibody (5-7 a.a)

Question 9

exogenous antigen

Answer 9

those outside cell body (bacteria, bacterial toxins, parasitic worms, inhaled pollen and dust, and viruses that have not infected cells yet.

Question 10

endogenous antigen

Answer 10

Those inside the cell body 
viral proteins produced after 
virus infects the cell, 
toxins produced by intracellular 
bacteria, or
abnormal proteins synthesized 
by a cancerous cell.

Question 11

what is MHC ?

Answer 11

MHC encodes antigens on the surface of the cell.

MHC can display both “self” peptides and foreign peptides from broken down intracellular proteins

Question 12

MHC I

Answer 12

Type 1
Present on every nucleated cell in the body
They present antigens that arise from cytoplasm. The present self Pr-, as well as viral Pr- that take over the cell in order to replicate the virus
Present to cytotoxic T-cells
Bhind CD8 adhesion molecules on cytotoxic Tcells

Question 13

MCH II

Answer 13

Type 2
Only occur on specialized antigen-presenting immune cells like macrophages or dendritic cells that engulf bacteria
They present antigen to T-cells or B-cells that produce antibodies.
Type 2’s present exogenous antigens that originate extracellularly from foreign bodies such as bacteria
Bind CD4 adhesion molecules on helper Tcells

Question 14

antigen presenting cell (APC)

Answer 14

a macrophage or dendritic cell digests an intracellular pathogen then presents the remains (small peptides or antigens) on the surface

Question 15

helper T cell

Answer 15

recognizes the presentation and helps stimulate other killing cells

Question 16

cytotoxic t cell

Answer 16

primed for killing after stimulation by message from Helper T cells

Question 17

cell mediated response

Answer 17

helper T cells and cytotoxic T cells
triggered by cytotoxic T cells recognizing antigens
effective mostly against viral-infected cells, cancer cells, fungal and protozoan infections & foreign tissue (transplants)
Inside the cell

Question 18

humoral response

Answer 18

production of antibodies

Which act against bacteria, bacteria toxins and viruses outside body cells

Question 19

characteristics of antibodies

Answer 19

ability to react with a specific antigenic determinant which stimulated its production
chemical composition: 
immunoglobulin 
protein
two heavy chains and two light chains

Question 20

when antigen and antibody bind

Answer 20

Neutralizes antigens
Immobilizing bacteria
Agglutinating (clumping together) and precipitating antigens
activates complement  cell lysis
facilitates phagocytosis

Question 21

gmade

Answer 21

IgG, IgM, IgA, IgD, IgE

Question 22

IgG

Answer 22

80 – 85 % of circulating antibodies
Long lasting
Found in blood, lymph and intestine
Protects against bacteria and viruses by:
Enhancing phagocytosis, neutralizing toxins, and triggering the complement system
Can crosses placenta

Question 23

IgM

Answer 23

5 to 10% of all antibodies in blood, also found in saliva
largest in physical size
first antibody produced in initial exposure to an antigen
activates complement, causes Agglutination and lysis of microbes
responsible for RBC ABO incompatibility reaction

Question 24

IgA

Answer 24

predominant in normal body secretions
sweat, tears, salvia, mucus, breast milk and gastrointestinal secretions
prevents bacteria and viral attachment and invasion via mucous membranes
levels decrease during stress

Question 25

IgD

Answer 25

about 0.2 % of antibodies in blood
found on the surfaces of B cells as antigen receptor
activates B cells

Question 26

IgE

Answer 26

*principle antibody in allergic response
attached to mast cells and causes histamine release resulting in inflammation
systemic release may lead to anaphylactic shock
provides protection against parasitic worms

Question 27

autoimmunity

Answer 27

Pathological response

immune system attacks its own body cells (loss of immune tolerance, or recognition of self!)

Question 28

haptens

Answer 28

is a small molecule which can elicit an immune response only when attached to a large carrier such as a protein forms a hapten carrier adduct
The hapten and the carrier alone do not elicit an immune response by itself
E.g. urushiol - the txin found in poison ivy.
absorbed through the skin - oxidation in the skin cells -quinone (hapten) - reacts with skin proteins - hapten adducts.
Some haptens can induce autoimmune diseases
Hydralazine (antihypertensive)  drug-induced lupus erythematosus in certain individuals
Halothane (anaesthetic gas)  life-threatening hepatitis