Week 5 Atrophy Module

Question 1

what are the clinical settings of atrophy? 5

Answer 1

decreased functional demand, decreased oxygen supply, starvation, decreased trophic factors (denervation), persistent cell injury (pressure, inflammation, chronic disease)

Question 2

what is atrophy

Answer 2

decrease in organ/cell size with decrease in cell/organ fxn

Question 3

how can you discern a normal cell from an atrophic cell?

Answer 3

atrophic cells are surrounded by my ECM than normal cells

Question 4

decreased oxygen supply to a tissue results from….

Answer 4

decreased blood flow to tissue

Question 5

ischemia is often the result of ….

Answer 5

atherosclerosis

Question 6

how do you discern a normal brain from an atrophic brain?

Answer 6

a normal brain will have an “angry cat” appearance and appear full. an atrophied brain has a “jowly appearance” and have enlarged venticles, and shrunken frontal lobe

Question 7

how do skeletal muscles become atrophied from starvation?

Answer 7

carbs are utilized first, then fat, then muscle protein is degraded. w/o proper nutrition the muscle are degraded

Question 8

when do we typically see decreased trophic stimulation in skeletal muscle?

Answer 8

when a nerve to a skeletal muscle is lost (denervation)

Question 9

what is a theme seen in atrophy regarding surrounding tissues/cells?

Answer 9

when one cell type is atrophied, surrounding cell types will hypertrophy to compensate (seen in a hypoxic kidney [other kidney will hypertrophy] and muscle cells that are denervated [muscle cells that are still attached to nerves will hypertrophy])

Question 10

what results in the endometrium during menopause?

Answer 10

loss of insulin (trophic) causes atrophy and apoptosis of endometrial cells

Question 11

what is Hydrocephalus?

Answer 11

increase cerebral spinal fluid and increased pressure within the brain

Question 12

what results in the brain as a result of hydrocephalus?

Answer 12

brain atrophy (unhappy looking CT)

Question 13

What are Decubitus ulcers? what causes them?

Answer 13

bedsores caused by chronic pressure that induces atrophy and apoptosis of the skin

Question 14

what is gastritits? what is it an ideal example of?

Answer 14

inflammation of the stomach lining. ideal example of how chronic inflammation causes atrophy (and apoptosis).

Question 15

Cachexia is an ideal example of what?

Answer 15

how chronic disease (TB, AIDS, cancer) can lead to atrophy. results in a negative protein balance due to HIGH protein turnover

Question 16

what causes cancer cachexia?

Answer 16

elevated cytokines that induce protein degradation (proteasome and autophagy)

Question 17

give an example of a protein that may be increased in atrophic cells?

Answer 17

proteasomes

Question 18

what are the two broad ways in which protein (and other cell components) are degraded?

Answer 18

autophagy and ub-proteasome pathway