Cell-cell communication

Question 1

3 types of hormone signalling

Answer 1

• endocrine; secretory cell to target cell via the bloodstream
• paracrine; secretory cell to adjacent target cell directly
• autocrine; targets the same cell

Question 2

Synaptic transmission

Answer 2

Converts electrical to chemical signals to cross the gap between receptors/neurones/effectors.

Question 3

Receptors

Answer 3

Membrane proteins which first messengers (hormones, neurotransmitters etc.) bind to, generating a biological response within the target cell.

Question 4

Acetylcholine receptors (AChRs)

Answer 4

1) Nicotinic effects (nAChRs=ion channels): muscle contraction, synaptic transmission
2) Muscarinic effects (M1-5=GPCRs): bradycardia, salivation, bronchospasm, midriasis

Question 5

Dissociation constant

Answer 5

A measure of affinity at which 50% of receptors are occupied by ligands. The lower the value, the stronger the binding as less ligand is required to reach equilibrium.