Experimental physiology notes

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Experimental physiology lab notes

Definition

Receptor = target area where neurotransmitters will produce their effect!

Small Intestine smooth muscle has 2 types of receptors;

1. CHOLINERGIC - neurotransmitter is ACETYL CHOLINE binds with the cholinergic receptors.

2. ADRENOCEPTORS - neurotransmitter is noradrenaline - binds with the adrenoreceptors.

Acetylcholine (Ach) * AGONISTIC FOR MUSCARANIC RECEPTORS*

*This is released by parasympathetic nerve.

*Binds to cholinergic receptors

* Many choleric receptors in intestinal/smooth muscle is MUSCARINIC RECEPTOR

Parasympathetic nerve slows down the heart rate and also speeds up the gut activity, INCREASING MOTILITY AND SECRETION IN THE GUT.

NORADRENALINE (NA) Neurotransmitter is realised from the SYMPATHETIC NERVE and binds to the adrenoreceptors in the gut a-adreno receptors.

(Noradrenaline is AGNOSTIC for a adrenoreceptors)

SYMPATHETIC DIVISION

*Speeds up the heart rate

* Slows down gut motility and secretion

Accumulative dose response = keep adding drug without washing tissue out with IPS.

Drug = chemical substance on biological organisms, mimics and inhibits neurotransmitters and binds to the receptors.

Affinity = Drugs bind to the receptor, forms drug receptor complex.

Efficiency = Drugs binds to the receptor and induces a response.

Zero response = Drug doesn't induce a response but still binds!

Agonist = Affnity and efficacy

Antagonist = Affinity but no efficacy i.e. -> Competitive inhibitor

Atropine = Atropine is antagonist to muscuranic receptors, it competes with acetylcholine thereby increasing the gut motility. Atropine will bind to muscuranic receptors it won't have an effect but will decrease the gut motility.

Phentolamine = Phentolamine is antagonist to a adrenoreceptors, phentolamine competes with NORADRENALINE to decrease the gut motility, it won't have the same effect however it will result in an increase in gut motility.

QUESTIONS REGARDING THE LAB

Why was this tissue chosen?

A - Intestine tissue is especially useful as it displays spontaneously relaxation and contraction.