7

Question 1

Define autocrine signalling

Answer 1

Same secreting and responding cell

Question 2

Define paracrine signalling

Answer 2

Secreting cell and responding cell are different

Question 3

Define endocrine signalling

Answer 3

Endocrine organs synth + release hormones ➡️ blood stream ➡️ target organs

Question 4

What are the 4 outcomes of signalling?

Answer 4

1. Survive (resist apoptosis)
2. Divide (➡️ cell cycle)
3. Differentiate
4. Die (➡️apoptosis)

Question 5

What are Growth Factors?

Answer 5

Polypeptides that act on cell surface

Stimulate cell prolif

Question 6

Describe EGF

Answer 6

Epidermal GF
Prod by: keratinocytes / MAC / inflamm cells
Mitogenic (induces mitosis)
Acts on: epithelial cells / hepatocytes / fibroblasts
Binds to EGFR

Question 7

Describe VEGF

Answer 7

Vascular Endothelial GF
Vasculogensis inducer
Angiogenesis (in tumours)

Question 8

Define PDGF

Answer 8

Stored in platelet granules
Released @ platelet activation
Prod by: (MEST) MAC / Endothelial cells / SMC / Tumour cells
Cause migration + prolif of fibroblasts / SMC / monocytes (WBC)

Question 9

Define G-CSF

Answer 9

Granulocyte Colony Stim Factor
Stim bone marrow ➡️ prod granulocytes (esp neut) ➡️ blood stream
Used as chemo treatment to stim poorly function bone marrow

Question 10

Describe G1 Phase of cell cycle

Answer 10

Cellular contents dup

Not xsomes

Question 11

Describe the Restriction Point

Answer 11

In G1
Point of no return
p53 comes into play ➡️ apoptosis (G0) or DNA repair

Question 12

Describe G1/S Checkpoint

Answer 12

Checks DNA damage b4 DNA replication

Question 13

Describe S Phase of cell cycle

Answer 13

All 46 xsomes dup

Question 14

Describe G2 Phase of cell cycle

Answer 14

Double check dupd xsomes for error ➡️ repair

Ready to divide

Question 15

Describe the G2/M checkpoint

Answer 15

Check DNA damage after DNA dup

Then mitosis then cytokinesis

Question 16

How is the cell cycle controlled

Answer 16

Cyclin Dependant Kinases (CDK)
CDK activated by cyclin ➡️ phosphorylate prot ➡️ drive cell cycle

GF stim cyclin prod and x prod of CDK inhibitors

Question 17

Define metaplasia

Answer 17

Reversible change between differentiated cells

E.g. PSCE ➡️ SSE in bronchioles of smokers

Question 18

Define atrophy

Answer 18

Shrinkage of organ tissue bc reduced cell size / number
Physiological: Ovarian Atrophy (post-menopause)
Pathological: Muscle atrophy (disuse / denervation)

Question 19

Define hypertrophy

Answer 19

Increase in cell size ➡️ increase in organ size
Physiological: Skeletal muscle
Pathological: R Ventricle wall (compensatory)

Question 20

Define hyperplasia

Answer 20

Increase in cell number
Only stable and labile tissue
Physiological: Endometrium (oestrogen)
Pathological: Eczema

Question 21

Define aplasia

Answer 21

Complete tissue dev failure

Question 22

Define hypoplasia

Answer 22

Underdev of tissue

Question 23

Define dysplasia

Answer 23

Abn cell maturation
Pre-cancerous
Reversible

Question 24

Define involution

Answer 24

Atrophy w apoptosis

Question 25

Define atresia

Answer 25

Abn narrowing of lumen

Question 26

Whats the difference between Regen and Reconstitution

Answer 26

Regen: replacement of loss cells w identical cells
Recon: replacement of a whole body part w lots of diff cells types