Tissues 8

Question 1

4 reasons why cells need to communicate.

Answer 1

1. Process Information
2. Self preservation
3. Voluntary movement
4. Homeostasis

Question 2

What is endocrine signalling?

Answer 2

When a hormone acts on a distant target cell via the bloodstream

Question 3

Give examples of endocrine signalling.

Answer 3

1. Glucagon
2. Insulin
3. Adrenaline action on trachea and bronchi

Question 4

How does insulin have paracrine effects?

Answer 4

Inhibits glucagon cells in nearby alpha cells

Question 5

Give an example of signalling between membrane attached proteins.

Answer 5

1. Virus detected in blood by APC.
2. APC digests pathogen and expresses MHC Class II on surface.
3. T - lymphocyte engages MHC Class II molecule through TCR interaction

Question 6

What is autocrine signalling?

Answer 6

Having an effect on itself.

Question 7

Give an example of autocrine signalling.

Answer 7

1. Activated T-lymphocyte initiates cascade of reactions within cell.
2. Activated T-Lymphocyte has IL-2 receptor on surface.
3. Activated T-lymphocyte secretes IL-2, which binds to the IL-2 receptor on its own surface.

Question 8

Describe neuromuscular junction signalling.

Answer 8

1. VGSC opens - depolarisation.
2. VGKC opens - repolarisation.
3. Ca influx through VGCC. Vesicle exocytosis.
4. ACh binds to Sarcolemmal Nicotinic Receptors (nAChR)
5. ACh metabolised by cholinesterase (ChE)
6. Ca = second messenger

Question 9

What are the different types of Signal receivers?

Answer 9

1. Ionotropic receptor
2. G-protein coupled receptor
3. Enzyme linked receptor
4. Intracellular receptor

Question 10

What is paracrine signalling?

Answer 10

Hormone acting on an adjacent cell