L01 Intro to Endocrinology

L02 Cell-cell Communication

L02 Cell-cell Communication pt1 & pt2

Endocrine Signalling

• Autocrine: The term ‘autocrine’ is sometimes used to denote a local mediator that acts on the cell from which it is released.

• Paracrine: A ‘paracrine’ mediator acts on other neighbouring cells, without passing into systemic circulation. eg. synaptic transmission

• Endocrine: Hormone secreted from a gland, carried through circulatory system to induce an effect on a target tissue

• Neuroendocrine: Nervous system glands secrete hormone. Eg Adrenal Medulla
• Mediator necessities: Effective ****Secretion Volume/Concentration, Specific effect, Inhibition affects response

Receptors: Transduce signals from external molecules that bind to it.(definition)

First/Second messenger.

Acetylcholine receptors: 2 types

1. Nicotine - AGONIST

Curare - ANTAGONIST

Muscle contraction, synaptic transmission (Autonomic ganglia)

Nicotinic receptor: ION channel → Depolarisation of cell. ACh induces a conformational change on the ion channel, causing it to open. Na+ diffuse in.

2. Also, Muscarinic. Muscarine - AGONIST

Atropine - ANTAGONIST