Pathology - Cellular Adaptations Flashcards Preview

CJ: UoL Medicine Semester Two (ESA2) > Pathology - Cellular Adaptations > Flashcards

Flashcards in Pathology - Cellular Adaptations Deck (31):
1

How is cell proliferation controlled?

- chemical signals from the microenvironment can simulate/inhibit cell proliferation
- signalling molecules bind to a receptor, causing modulation of gene expression
- receptors usually in cell membrane, but can be in cytoplasm/nucleus

2

How can a cell population be increased?

- shorten the cell cycle
- convert quiescent cells to proliferating cells by making them enter the cell cycle

3

How does the body determine whether a cell is able to replicate?

It has checkpoints in mitosis, where it checks that the DNA has replicated successfully and the cell is big enough

4

What is the restriction point?

Most critical checkpoint - the majority of cells which pass this will complete the cell cycle. Checkpoint activation delays cell cycle and triggers DNA repair mechanisms/apoptosis via p53

5

What are cyclins?

Cyclins and cyclin dependent kinases (CDKs) are active during different phases of the cell cycle. Cyclin activates CDK, which phosphorylates the target protein (which is bound to cyclin)

6

What is hyperplasia?

Increase in tissue or organ size due to increased cell numbers

7

What is hypertrophy?

Increase in tissue or organ size due to increased cell size

8

What is atrophy?

Shrinkage of a tissue or organ due to an acquired decrease in size and/or number of cells.

9

What is metaplasia?

Reversible change of one differentiated cell type to another

10

What types of tissue does hyperplasia occur in?

Labile/stable tissues

11

What causes hyperplasia?

- increased functional demand/hormonal stimulation
- can occur secondary to a pathological cause but proliferation is normal response

12

Is hyperplasia reversible?

Yah

13

In which types of tissue does hypertrophy occur?

Labile, stable but especially permanent

14

Does hypertrophy usually occur alone in tissue?

No, it usually occurs along with hyperplasia

15

Why don't athletes get cardiac muscle hypertrophy despite their muscle being under more strain?

They have a rest between exercises, so the strain on their heart goes back to normal. Obese people cannot 'rest' their heart, so they always have stress on it

16

What is compensatory hypertrophy?

If one of a pair of organs is damaged/removed, the other will enlarge, eg kidneys

17

What happens to a cell in atrophy?

The cell shrinks to a size at which survival is still possible. There are reduced structural components, which may eventually result in cell death.

18

What is the relationship between cell atrophy and tissue atrophy?

Organ/tissue atrophy is typically due to combination of cellular atrophy and apoptosis, which is reversible up to a point

19

What are 'residual bodies'?

These break off from cells undergoing atrophy, and contain unnecessary organelles

20

Give an example of atrophy due to reduced functional demand/workload

Muscle atrophy after disuse - this is reversible with activity

21

Why may the hand muscles become wasted in just one part of the hand?

Median nerve damage leads to atrophy

22

Give an example of atrophy due to inadequate blood supply

Thinning of skin on legs with peripheral vascular disease

23

What is atrophy of the extracellular matrix called in older people?

Osteoporosis

24

Which cell types have metaplasia?

Labile or stable tissues

25

Is there a link between metaplasia and cancer?

Epithelial metaplasia can be a prelude to to dysplasia and cancer

26

What is aplasia?

Complete failure of a specific tissue/organ to develop - this is an embryonic developmental disorder eg. Aplasia of a kidney

27

What is hypoplasia?

Underdevelopment or incomplete development of a tissue or organ at embryonic stage due to an inadequate number of cells

28

What is involution?

Normal programmed shrinkage of an organ which overlaps with atrophy. Eg. Occurs in uterus after childbirth

29

What is reconstitution?

Replacement of a lost part of the body. Angiogenesis is the only mechanism for this in humans

30

What is atresia?

Congenital imperforation of an opening, eg lack of an anus, vagina or small bowel

31

What is dysplasia?

Abnormal maturation of cells within a tissue. This is potential reversible and an often pre-cancerous condition

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