AD Lecture #2

Physiologic Adaptation

Cellular changes to normal stimuli (aging, estrus)

Pathologic Adaptation

Allows cells to modify their enviornment and minimize or escape (Disease, trauma)

Atrophy

a decrease in the size of the cell

Causes of atrophy

-Diuse (muscle atrophy)

-diminished blood supply

-lack of nutrition

What is sweeney (atrophy in the neck) in horses caused by

Damage to the suprascapular nerve

Hypertrophy

an increase in cell size

In what circumstances does hypertrophy usually occur?

Secondary to an increase in functional demand or to hormone stimulation

Hyperplasia

increase in the number of cells

What is a physiologic example of hyperplasia

wound healing (stimulation of fibroblasts and new vessels)

What is a pathologic example of hyperplasia?

Viral papillomas (excess hormones/growth factors or virus that upsets normal process of cell division)

Hypoplasia

a decrease in the number of cells

What kind of condition is hypoplasia typically?

Typically a congenital condition that can occur in any tissue or organ

What are stenotic nares

nostrils are narrow making it more difficult for the animal to breath (brachycephalic syndrome)

Metaplasia

a change in the cell type - when one type of cell is replaced by another cell

Dysplasia

abnormal development of cells in tissue, change in size, shape and organization of cells, but not cancer

What can metaplasia turn into is stimulus persists?

neoplasia - cancer!

What is inflammation

a nonspecific, rapid response to local injury, involves blood and capillaries

Exogenous

Outside stimuli

examples of exogenous causes of inflammation

bacteria, mosquito bite, bee sting, spider bite, etc

endogenous

inside stimuli

examples of endogenous causes of inflammation

arthritis, histamine

Acute inflammation

Short duration, lasting from mins to days

chronic inflammation

longer duration, days to years

what are the three main functions of inflammation

Protection, adaptation, healing

5 causes of inflammation

-Infectious agnets

-chemicals/toxins

-physiologic/mechanical damage

-immune mediated reactions

-necrotic tissue

Signs of inflammation

-redness

-heat

-pain

-swelling

-loss of function

Four outcomes of inflammation

-Resolution

-Scarring

-Abscess

-Chronic situation

What is acute inflammation characterized by?

Vascular changes, edema, and a cellular infiltrate

What is chronic inflammation characterized by?

Prolonged duration, tissue injury and healing all occuring simultaneously

What form of inflammation is Granulomatous inflammation?

Chronic inflammation

Transudate

Clear fluid - changed pressure in the vessels, size of vessel doesn't change, therefore only fluid leaks out not protein

Exudate

Yellow fluid - inflammatory process, vessels become enlarged and there is leakage of fluid and protein

4 general types of inflammation

-Serous discharge (clear/yellowish fluid)

-fibrinous (protein in discharge)

-suppurative (pus)

-ulceration (epithelial surface becomes necrotic)

Pyrexia

Fever - increase in body temperature above the normal range

what is the temperature regulatin center?

The hypothalamus