Unit 8- Immune system

Question 1

what is the role of cells in the immune system?

Answer 1

in continuous search for pathogens, so they circulate using the blood and the lymphatic system

Question 2

what is the role of the primary tissues?

Answer 2

formation and maturation of cells
-Thymus and red bone marrow

Question 3

what is the role of secondary tissues?

Answer 3

Interaction with pathogens and triggering immune response

Encapsulate: Spleen, lymph notes
Diffuse: Tonsils, GLAT

Question 4

what is the role of the immune system?

Answer 4

1. To protect against external invaders: pathogens (bacteria, viruses, fungi, parasites).
2. To remove cell debris (erythrocytes, dead cells).
3. To target and eliminate cells showing an abnormal growth

Question 5

what are some errors that the immune system can cause?

Answer 5

1.Incorrect responses. Autoimmune diseases, the immune system target
something endogenous as exogenous. Eg. Type 1 diabetes.

2. Hyperactive response. The immune system provides an over-reaction to an exogenous (and potentially harmless) agent. Eg. Allergies.
3. Lack of response. Immunodeficiency

Question 6

what is the best way to prevent an immune response?

Answer 6

to avoid pathogens from entering our body

Question 7

what happens once a pathogen is detected in the body?

Answer 7

1. Targeting and identification of the pathogen.
2. Communicating the invasion to other cells of the immune system
3. Response Coordination
4. Destruction or, at least, deactivation of the pathogen

Question 8

what is the first line of defense?

Answer 8

Physical barriers: Skin:

-Keratinocytes. Isolate and protect.
-Langerhans cells. Recruit the
immune cells over an external
agent.

Other cells: melanocytes (protect
from UV light), macrophages.
- Mucus.

Chemical barriers: gastric secretion, secretions with lysozyme (saliva).

Question 9

what is the second line of defense?

Answer 9

Antimicrobial substances. They block the growth of some pathogens.
Interferons (for viral infections), complement proteins, antimicrobial peptides.

-Natural killer (NK) cells. Unspecific destruction of infected and tumor cells.
-Phagocytes (neutrophils and macrophages). Ingest and destroy pathogens.

Fever. Abnormally high body temperature due to a reset of the inner

hypothalamic regulator. It helps with the interferon effect, avoids the growth of some pathogens,and accelerates the recovery process.

-Inflammation. Key nonspecific response in damaged tissue. Prevents the spreading of the infection to other tissues and preparing the damage for the
healing process

Question 10

what are the 3 stages of inflammation?

Answer 10

1)Heat and redness: produced by vasodilation and increase of vessel permeability

2)Swelling: loss of fluid from the blood, produced edema and accumulation of cells

3)Pain: cytokines and other proinflammatory substances that help attract immune cells to the site also alter the threshold of the nociceptors present at the site, inducing peripheral sensitization, and thus pain

Question 11

How is immunity acquired?

Answer 11

after first exposure to a specific pathogen, either as an infection or as a vaccination, that allows the body to respond faster to previously known pathogens using lymphocytes

Question 12

how can antigens be recognized by?

Answer 12

1)Antibodies. When pathogens are circulating in the blood (humoral
immunity). They are used by B lymphocytes

2)Specific receptors in the membrane of cells. When pathogens are
inside a cell, infecting it (cellular immunity). They are used by T
lymphocytes.