chapter 14 inflammation and wound healing - week 1

Question 1

what are the various forms of cell injury and what do they do to the cell.

Answer 1

Hypoxia or ischemic injury
Compromised cell metabolism, acute or gradual cell death

Physical agents
Heat
Denaturation of protein, acceleration of metabolic reactions
Cold
Decreased blood flow from vasoconstriction, slowed metabolic reactions, thrombosis of blood vessels, freezing of cell contents that forms crystals and can cause cell to burst
Radiation
Alteration of cell structure and activity, alteration of enzyme systems, mutations
Electrothermal injury
Interruption of neural conduction, fibrillation of cardiac muscle, coagulative necrosis of skin and skeletal muscle
Mechanical trauma
Transfer of excess kinetic energy to cells, causing rupture of cells, blood vessels, tissue; examples include the following:
Abrasion: scraping of skin or mucous membrane
Laceration: severing of vessels and tissue
Contusion (bruise): crushing of tissue cells, causing hemorrhage into skin
*Puncture: *piercing of body structure or organ
Incision: surgical cutting
**Chemical injury **
Alteration of cell metabolism, interference with normal enzymatic action within cells

Microbiol injury
Viruses
Taking over of cell metabolism and synthesis of new particles that may cause cell rupture; cumulative effect may produce clinical disease
Bacteria
Destruction of cell membrane or cell nucleus, production of lethal toxins

*Immunological *
Antigen–antibody response/Autoimmune response
Release of substances (histamine, complement) that can injure and damage cells Activation of complement, which destroys normal cells and produces inflammation
Neoplastic growth
Cell destruction from abnormal and uncontrolled cell growth
Normal substances (e.g., digestive
enzymes, uric acid)
Release into abdomen, causing peritonitis and crystallization of excess accumulation in joints and renal tissue

Question 2

what are common cell adaptations that occur as normal physiological processes to injury

Answer 2

Hypertrophy, hyperplasia, atrophy, metaplasia, dysplasia, and anaplasia

Question 3

describe the three inflammatory responses

Answer 3

Acute - the healing occurs in 2 to 3 weeks and usually leaves no residual damage.
Subacute - has the features of the acute process but lastslonger.
Chronic- lasts for weeks, months, or even years. The injurious agent persists or repeatedly injured tissue.

Question 4

Describe the pathophysiology of the vascular response to injury

Answer 4

• Arterioles in area of cell injury will go through momentary vasoconstriction (simulated by sympathetic NS)
• Platelets will then adhere to vessels and aggregate to seal injured area (forming fibrin-platelet clot)
• They will then release proinflammatory mediators (ex. histamine) causing vasodilation
• This results in hyperemia (increase blood flow to area)
• Filtration pressure increases causing capillaries permeability to also increase
• This causes more movement of fluid from capillaries into tissue spaces (creating a local edema)
• When fibrinogen leaves the blood, it will become fibrin
• Fibrin will then strengthen blood clot formed from platelets
• Platelets release growth factors to begin healing process
  *

Question 5

Describe the pathophysiology of the cellular response

Answer 5

• Phagocytes produce nitric acid (whose role in inflammatory response is to inhibit vascular smooth muscle contraction and growth, platelet aggregation and leukocyte adhesion to endothelium)
• Cytokines are released by macrophages (which causes endothelial cells to squeeze out cellular adhesion molecules (selectins and integrins)
• Blood flow through capillaries in the area slows as fluid is lost and viscosity increases
• Neutrophils and monocytes move to the inner surface of the capillaries (margination) and through the capillary wall (diapedesis) into to the site of injury
• White blood cells then migrate along a concentration gradient through chemotaxis (which ensures accumulation of neutrophils and monocytes at the site of injury)

Question 6

What is exudate? How is it created and what is it consisting of?

Answer 6

Exudate consists of fluid and leukocytes. It has serous, catarrhal, fibrinous, purulent and hemorrhagic fluids. It is created when there is an injury to tissue

Question 7

What are the components of healing?

Answer 7

Regeneration and repair

Question 8

what is the purpose of wound management

Answer 8

It is a part of primary prevention to try to avoid infection or necrosis of the tissue to the injury

Question 9

adhesions

Answer 9

are bands of scar tissue that form between or around organs.

Question 10

anaplasia

Answer 10

is cell differentiation to a more immature or embryonic form.

Question 11

apoptosis

Answer 11

programmed cell death is a normal, anticipated event that occurs in some regenerating tissues to create homeostasis, such as bone marrow, skin, and gut epithelium.

Question 12

atrophy

Answer 12

is a decrease in the size of a tissue or organ as a result of a reduction in the number or size of individual cells.

Question 13

dehiscence

Answer 13

is the separation and disruption of previously joined wound edges.

Question 14

dry gangrene

Answer 14

can result from degenerative changes that occur with certain chronic diseases, such as atherosclerosis or diabetes, when the blood supply to the lower extremities is gradually reduced

Question 15

dysplasia

Answer 15

is an abnormal differentiation of dividing cells that results in changes in their size, shape, and appearance.

Question 16

evisceration

Answer 16

occurs when wound edges separate to the extent that intestines protrude through the wound.

Question 17

fibroblasts

Answer 17

are immature connective tissue cells that migrate into the healing site and secrete collagen.

Question 18

fistula

Answer 18

is an abnormal passage that forms between organs or a hollow organ and the skin.

Question 19

hyperplasia

Answer 19

is a multiplication of cells as a result of increased cellular division

Question 20

hypertrophic scar

Answer 20

is inappropriately large, red, raised, and hard. However, it remains confined to the wound edges and regresses in time.

Question 21

hypertrophy

Answer 21

is an expansion in the size of cells, which results in increased tissue mass without cell division.

Question 22

inflammatory response

Answer 22

is a biological response to cell injury caused by pathogens, irritants, or chronic health conditions.

Question 23

integrins

Answer 23

cell receptors that mediate attachment between endothelial cells and surrounding tissues, also involved in leukocyte extravasation during the immune response

Question 24

keloid

Answer 24

is a protrusion of scar tissue that extends beyond the wound edges and may form tumor-like masses of scar tissue

Question 25

lethal injury

Answer 25

is an irreversible process that causes cell death.

Question 26

metaplasia

Answer 26

s the transformation of one cell type into another in response to a change in physiological condition or an external irritant.

Question 27

necrosis

Answer 27

is tissue death that occurs as a result of a traumatic injury, infection, or exposure to a toxic chemical that causes a local inflammatory response, which results from the release of intracellular contents after the rupture of the outer membrane of the dead cells.

Question 28

pressure injury

Answer 28

is a localized injury to the skin or underlying soft tissue, usually over a bony prominence or related to a medical or other device as a result of pressure or pressure in combination with shear, friction, or both.

Question 29

pressure injury

Answer 29

is a localized injury to the skin or underlying soft tissue, usually over a bony prominence or related to a medical or other device as a result of pressure or pressure in combination with shear, friction, or both.

Question 30

regeneration

Answer 30

is the replacement of lost cells and tissues with cells of the same type.

Question 31

repair

Answer 31

is healing as a result of lost cells being replaced by connective tissue.

Question 32

selectins

Answer 32

cell surface carbohydrate-binding proteins that mediate cell adhesion, involved in leukocyte extravasation during the immune response

Question 33

shearing force

Answer 33

pressure exerted on the skin when it adheres to the bed and the underlying skin layers slide in the direction of body movement

Question 34

sublethal injury

Answer 34

alters function without causing cell destruction. The changes caused by this type of injury are potentially reversible if the harmful stimulus is removed.