Ch. 4 Tissue Repair

Question 1

External Defenses

1.

Answer 1

Mechanical
Chemical
Microbiological

Question 2

External Defense

Mechanical

Answer 2

Intact skin

Mucous membranes: line body cavities that open to the exterior.

Question 3

External Defense

Chemical

Answer 3

Fatty Acids- lower the pH on skin, to make it slightly acidic.
Enzymes
-lysosome: tears, milk, saliva, mucus, break down cell walls.
-pepsin: produced in stomach, breaks down proteins into smaller peptides in stomach
Stomach acid: Keep low pH.
Vaginal secretions
Urine

Question 4

External Defense

Microbiological

Answer 4

Good bacteria in vagina and colon.

Question 5

Internal Defenses

Answer 5

Inflammatory Response:
Nonspecific: Fights anything in general.
Develops quickly: like a scratch.

Specific Immune response:targets specific pathogens, cells fight foreign bacteria, takes longer to mount the response
Example, vaccines.

Question 6

Tissue repair

2.

Answer 6

When tissue injury occurs, external barriers are penetrated and internal defenses are therefore activated

Question 7

Tissue Repair
3. Repair occurs in two major ways:
Regeneration and Fibrosis

Answer 7

Regeneration: replacement of destroyed tissue with same kind of tissue (epithelium with epithelium)

Fibrosis: Replacement of destroyed tissue with fibrous connective tissue (called scar tissue). Replaced with different tissue.

Question 8

Steps for Tissue Repair

Answer 8

Heat, redness, pain, swelling.

1. Inflammation sets the stage
2. Organization restores the blood supply
3. Regeneration and fibrosis effect permanent repair
4. Note:*

Question 9

Step One for Tissue Repair

Answer 9

Inflammation sets the stage:
vessels bleed and inflammatory chemicals are released.
vessels are more permeable, allow white blood cells, fluid, clotting proteins and other plasma proteins to seep into the injured area.
Clotting occurs; surface dries and forms a scab.

Question 10

Step Two for Tissue Repair:

Answer 10

The clot is replaced by granulation tissue, which restores the vascular supply.
Fibroblasts produce collagen fibers that bridge the gap.
Macrophages phagocytize cell debris. Eat dead cells
Surface epithelial cells multiply and migrate over the granulation tissue.

Question 11

Step Three for Tissue Repair:

Answer 11

The fibrosed area matures and contracts; the epithelium thickens.
A fully regenerated epithelium with an underlying area of scar tissue results.

Question 12

Step Four for Tissue Repair:

Answer 12

Note: Repair process described above follows healing of a wound (cut, scrape, puncture, etc.) that breaches an epithelial barrier. In simple infections (pimple, sore throat, etc.) healing is solely be Regeneration. There is usually no clot formation or scarring. Only severe (destructive) infections lead to scarring.

Question 13

Regenerative Capacity of Different Tissue: undergo mitosis

Answer 13

Regeneration, rate of mitosis increases risk of cancers.

Extremely Well: Epithelial tissues, bones, areolar, and blood forming tissue.

Moderate: Smooth muscles and dense regular connective tissue.

Weak: Skeletal muscle and cartridge.

No regeneration: Cardiac muscle and nervous tissue in the brain and spinal cord have virtually no functional regenerative capacity and are routinely replaced by scar tissue.

Question 14

Extremely Well

Answer 14

Epithelial tissues
Bone
Areolar
Blood

Question 15

Moderately well

Answer 15

Ligaments/ Tendons

Smooth muscle and dense regular connective tissue.

Question 16

Weak Regenarative

Answer 16

Skeletal muscle, cartlidge

Question 17

No regeneration

Answer 17

Cardiac muscle, nervous tissue brain and spinal cord have

Replaced by scar tissue.