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Physiology (Chpt 12, Body Defenses) FINAL


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What is immunity?
The body's ability to resist or eliminate potentially harmful foreign materials or abnormal cells (does not have to be foreign)
3 key functions of immune system?
1. defense against invading pathogens (bacteria, viruses, etc)

2. removes "worn-out" cells

3. identifies and destroys abnormal or mutant cells
An inappropriate immune response leads to what?
allergies or an autoimmune response
What are leukocytes?
Why are white blood cells white under a microscope?
because they lack hemoglobin
Size of a WBC verses a RBC?
WBC is slightly larger
Leukocytes (WBC) could be said to be the ? units of the body's immune system?
mobile units
3 functions of leukocytes?
1. defend against invasion by pathogens

2. identify and destroy cancer cells

3. function as "clean up crew", by phagocytizing debris of dead or injured cells
WBCs can leave circulation and go where?
to sites of invasion and tissue damage
How many kinds of leukocytes are there?
Name the two broad categories of leukocytes?
1. polymorphonuclear granulocytes

2. mononuclear agranulocytes
Describe general features of polymorphonuclear granulocytes?
- literally means "many-shaped nucleus, granule-containing"

- nucleii segmented into lobes, with abundant membrane enclosed granules in cytoplasm
Describe general features of mononuclear agranulocytes?
- literally means "single-nucleus, lacking granules"

- actually has granule, just fewer than polymorphonuclear granulocytes

- single, large, nonsegmented nucleus and few granules
Name the three different polymorphonuclear granulocytes and how you would distinguish each of them under a microscope?
1. neutrophils : granules attract neutral dye

2. eosinophils : granules attract red dye

3. basophils : granules attract blue dye
Name the two different mononuclear agranulocytes?
1. monocytes (larger)

2. lymphocytes (smallest leukocytes)
Describe the rate of production for leukocytes?
varies, depending on defense needs of body
Where are leukocytes produced?
from pluripotent cells in the bone marrow
Granulocytes and monocytes are only produced where?
in bone marrow
Where are lymphocytes produced?
originally in the bone marrow from precursor cells...then most new ones are produced from lymphocytes in lymphoid tissue
In the bone marrow undifferentiated pluripotent stem cells go on to become what two things?
1. myeloid stem cells

2. lymphoid stem cells
What do myeloid stem cells become? (4 possibilities)Where does this occur?
1. megakaryocytes

2. erythrocyte precursors

3. granulocyte precursors

4. monocyte precursors

(all occurs in the bone marrow)
What do lymphoid stem cells become? Where does this occur?
they become lymphocytes

(the lymphocytes are in lymphoid tissue or in circulation)
What are megakaryocytes precursors for?
What are the least numerous cellular elements in the body?
Normally approximately 2/3s of the leukocytes in the body are what?
The percentage of what can change depending on the defense needs of the body?
percentage of each WBC
What in general signals the changes in the percentage of WBCs needed by the body?
various hormones
Name the 5 leukocytes?
1. neutrophils

2. eosinophils

3. basophils

4. monocytes

5. lymphocytes
Far and away the highest percentage of leukocytes in the body are what?
neutrophils (60-70%)
Function of neutrophils?

-first on scene during bacterial invasion

-important during inflammation
Function of eosinophils?
-increase (eosinophilia) associated with allergic conditions and parasitic infections

-so normally to rid parasitic infections but also causes allergic conditions
Function of basophils?
-similar to mast cells

- roles poorly understood

-synthesize and store histamine and heparin (but real function not entirely clear)
Function of monocytes?
when circulating they are phagocytes

-develop into macrophages in tissues
What are the main functions of the lymphocytes?
immune defense against specific targets
The two types of lymphocytes?
1. B lymphocytes

2. T lymphocytes
What do the B lymphocytes do?
produce antibodies which mark and destroy foreign matter
What do the T lymphocytes do?
carry out cell-mediated immune response, releasing chemicals that destroy target cells
Name the 8 lymphoid tissues?
1. bone marrow

2. lymph nodes

3. spleen

4. tonsils

5. adenoids

6. appendix

7. peyer's patches (digestive tract)

8. thymus
The origin of all blood cells is where?
in the bone marrow
The spleen also removes worn out what?
blood cells
What is the thymus necessary for the maturation of?
T cells
What does the thymus secrete to mature T cells?
The thymus is absolutely essential for appropriate what?
immune response
Immune responses can be innate and ? or adaptive and ?.
innate and nonspecific....adaptive and specific
In general how do innate and nonspecific immune responses differ from adaptive and specific immune responses?
differ in timing and selectivity of defense mechanism
4 aspects of innate immunity?
1. immediate response upon exposure to threat

2. nonselective defense against foreign invaders

3. first line of defense: Rapid, but limited

4. Neutrophils, Macrophages, and Plasma Proteins
2 aspects of adaptive (acquired) immunity?
1. targets are specific: foreign matter to which the body already exposed

2. body is prepared, but takes time to respond
In adaptive immunity what is the difference between the first time you are exposed to foreign matter to subsequent times?
the first time the response takes longer then subsequent times
The adaptive immune response includes what two types of immunity?
1. antibody-mediated (humoral) immunity

2. cell-mediated immunity
Describe antibody-mediated immunity?
- Abs produced by B cell derivatives, the plasma cells (turn out lots of Ab)

-generally recognize freely existing foreign-invaders (such as bacteria, some viruses)
Describe cell-mediated immunity?
-production of activated T-cells, which attack undesirable cells

-(generally recognize body cells gone awry, such as viral infected cells, cancer cells, etc)
B and T cells recognize and selectively respond to what?
foreign agents and cancer cells

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