Laboratory - Frogheart

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NERVE AND MUSCLE EXPERIMENTS

The autonomic nervous system Responsible for control of involuntary or :visceral bodily functions cardiovascular system-1 respiratory-2 digestive-3 urinary-4 reproductive-5 key role in the body’s response-6 to stress

.The A.N.S :Sympathetic system .Flight or fright system :Parasympathetic system Feed or breed or rest response

A.N.S

Effect of A.N.S. on the heart :Sympathetic stimulation Increase chronotropic and the inotropic . effects on the heart Receptors are: alpha and beta adrenergic receptors :Parasympathetic stimulation .Negative inotropics

Remember :ve chronotropic+ Means increase in heart rate :ve inotropic+ .Means increase in contractility

Idea of the experiments: To analyze the effect of different autonomic

.drugs on the frog’s heart contraction

Preparation :The frog chest is open

The heart is connected to the kymograph to record the events

Imp. Defintions :Sympathomimtics Meds the stimulation of the sympathetic system e.g. adrenaline

:Sympatholytics .Inhibits the sympathetic system :Parathympatholyics Blocks the action of the parasympathetic system e.g. atropine sulfate

Effect of autonomic drugs on the frog’s heart Effect ofadrenaline: on frog’s heart .record the normal beats of the heart.pour adrenaline and record the effect:Comment Adrenaline a sympathomimetic drug increases heart rate and force of contract .as it activates beta adrenoceptors

Acetylcholine :B) Effect of acetylcholine on frog’s heart .record the normal beats of the heart .Pour acetylcholine and record the effect :Comment Acetylcholine a parasympathetic drug,decreases the heart rate as it stimulates .the muscarinic receptors

Effect of Atropine :C) Effect of atropine record the normal beats of the heart .pour atropine and record the effect pour acetylcholine and record the effect .wash with ringer .pour acetylcholine, observe pour atropine then record the effect :Comment Atropine applied before acetylcholine blocks the inhibitory effect of .the acetylcholine thus the heart continues to beat normally Atropine applied after acetylcholine does not block the inhibitory.action of the acetylcholine

Curves

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