MOD S8 - Cellular Adaptations Flashcards Preview

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Flashcards in MOD S8 - Cellular Adaptations Deck (19)
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List a and describe the phases of the cell cycle

G1
S
G2
M

1

What and when is R (the restriction point) in the cell cycle?

R is the most important checkpoint of the cell cycle where the cell decides whether to continue
It is at the end of G1

2

How is the cell cycle controlled?

By R (the restriction point) and the phosphorylation of the retinoblastoma protein (pRb)

3

When does the retinoblastoma protein become important?

pRb governs the cell cycles beyond R

4

Discuss the proliferative capacity of stem cell populations in labile tissue

Stem cells persistently divide to replenish losses

5

Discuss the proliferative capacity of stem cell populations in stable cell populations

Stem cells usually proliferate very slowly
Proliferate persistently when required

6

Discuss the proliferative capacity of stem cell populations in permanent cell populations

Stem cells present but cannot mount an effective proliferative response to significant cell loss

7

Define regeneration

Replacement of cell losses by identical cells to maintain tissue or organ size

8

Define hyperplasia

Increase in tissue or organ size due to an increase in cell numbers

9

Define hypertrophy

Increase in tissue or organ size due to increase in cell size

10

Define atrophy

Decrease in tissue or organ size due to decrease in cell number or size due to an acquired disease

11

Define metaplasia

Reversible change of one differentiated cell type to another

12

Define aplasia

Complete failure of a specific organ or tissue to develop

13

Define hypoplasia

Incomplete Development of a tissue or organ

14

Define dysplasia

Abnormal maturation of cells within a tissue

15

Where does hyperplasia occur? Give physiological and pathological examples and cell types.

In labile and stable cell populations
Physiologically occurs in bone marrow at high altitude and in the proliferative endometrium
Pathologically occurs in the thyroid goitre

16

Where does hypertrophy occur? Give physiological and pathological examples and cell types.

In permanent cell populations, occurs alone.
In more proliferative tissues, may occur with hyperplasia

17

Where does atrophy occur? Give physiological and pathological examples and cell types.

Can occur in many cell populations

18

Where does metaplasia occur? Give physiological and pathological examples and cell types.

Most clearly adaptive in epithelial tissue
Occurs as a change in epithelium to one more suited to the new environment eg smokers' pseudostratified ciliated changes to the more robust squamous
Can be a prelude to dysplasia/cancer