Unit 4 - Immune System PART A

Question 1

Main function of the immune system organs/tissues/cells is to maintain homeostasis by:

Answer 1

a. recognizing and removing abnormal self-cells.
b. removing dead or damaged cells
c. preventing or limiting infections due to viruses, bacteria, fungi, parasites (protozoans and worms), allergens, etc.

Question 2

Immune cells must be able to recognize cells that…

Answer 2

belong to the body (SELF), cells that are DEFECTIVE (e.g. cancerous cells) and cells that are not part of the body (NON-SELF).

Question 3

“Self” cells

Answer 3

body’s normal cells

Question 4

Defective cells

Answer 4

e.g. cancerous cells

Question 5

Non-Self cells

Answer 5

viruses, bacteria, parasites, allergens, & other disease-causing PATHOGENS in addition to any of our own cells that have become defective & threaten to do harm, such as become cancer

Question 6

First line of defense:

Answer 6

Physical, chemical and mechanical barriers.

• such as skin, tears, mucus & stomach acid
• attempt to keep pathogens from entering the ECF but…if pathogen gets past first line of defense barriers, next steps occur

Question 7

If pathogen gets past first line of defense barriers, next steps are:

Answer 7

a. DETECTION and IDENTIFICATION of pathogen.
b. COMMUNICATION with other immune cells.
c. RECRUITMENT of assistance and COORDINATION of response.
d. DESTRUCTION or SUPPRESSION of pathogen.

Question 8

Immunogens

Answer 8

substances that trigger the body’s immune response

Question 9

Immunogens that react with products of the immune response are known as…

Answer 9

antigens

Question 10

Internal response is carried out by _______ that communicate using _______ (which act as autocrine, paracrine and in a few cases hormonal signals)

Answer 10

LEUKOCYTES

CYTOKINES

Question 11

Internal response is carried out by leukocytes that communicate using cytokines (which act as autocrine, paracrine and in a few cases hormonal signals). The internal response involves:

Answer 11

a. Macrophages (monocytes)
b. Dendritic Cells
c. Microglia (in the central nervous system)
d. Neutrophils
e. Mast Cells (from basophils)
f. Eosinophils
g. Natural Killer Cells
h. Lymphocytes (T and B Lymphocytes)

Question 12

Cytokines

Answer 12

protein signal molecules released by 1 cell that affect the growth or activity of another cell

Question 13

Immune system is also the primary user of ___________ that occurs when surface receptors on 1 cell recognize & bind to surface receptors on another cell

Answer 13

contact-dependent signaling

Question 14

There are two major divisions of immune responses:

Answer 14

a. Innate immunity

b. Adaptive Immunity

Question 15

Innate immunity

Answer 15

body’s EXISTING defenses that provide an IMMEDIATE, NON-SPECIFIC response (i.e. acts on anything identified as non-self) that is rapid acting (MINUTES to HOURS).

• Involves barriers to pathogens (physical, chemical, mechanical)
• Cellular responses that directly destroy or suppress the pathogen
• Characterized by INFLAMMATION
• Formation of antigen-presenting cells (macrophages and dendritic cells) which are required for both innate responses and adaptive responses.
• Not remembered by immune system (NO memory cells).

Question 16

Inflammation

Answer 16

visible on the skin as a red, warm, swollen area

Question 17

Cells responsible for the rapid innate response are…

Answer 17

circulating & stationary leukocytes that are genetically programmed to respond to a broad range of material that they identify as foreign

Question 18

Some types of phagocytes display bits of digested pathogen on their cell surface to attract cells involved in the adaptive immune response –>

Answer 18

antigen-presenting cells (APC’s)

Question 19

Describe this sentence in INNATE immunity: “Not remembered by immune system (NO memory cells)”

Answer 19

an innate response to a pathogen is NOT remembered by the immune system & must be triggered anew with each response

Question 20

Adaptive Immunity (AKA acquired immunity)

Answer 20

LEARNED response to a SPECIFIC PATHOGEN/ANTIGEN; is SLOWER acting (days to weeks), but provides LONG LASTING IMMUNITY (MEMORY CELLS)
- Cell-mediated immunity
- Antibody-mediated (humoral) immunity
(both overlap; interconnected parts of a single process)

Question 21

Describe this sentence ADAPTIVE immunity: “…but provides long lasting immunity (MEMORY cells)”

Answer 21

upon reexposure certain immune cells (MEMORY cells) “REMEMBER” their prior exposure to the pathogen & react more rapidly

Question 22

Cell-mediated immunity (AKA humoral immunity)

Answer 22

contact dependent signaling (cytotoxic T-cells)

- uses ANTIBODIES

Question 23

Antibody-mediated (humoral) immunity

Answer 23

production of antibodies by B lymphocytes and plasma cells

Question 24

Antibodies

Answer 24

proteins secreted by immune cells, to carry out the immune response
- bind to foreign substances to disable them or make them more visible to the cells of the immune system

Question 25

NOT all pathogens can be destroyed by the body’s immune system

Answer 25

• sometimes can just control the damage & keep the invader from spreading
  ex: bacterium that causes tuberculosis, malaria parasite & the herpes viruses

Question 26

Immunity

Answer 26

the body’s ability to protect itself