role of synapse and transmission across a Cholinergic synapse-Neuronal communication

Question 1

what is a synapse + consists of…

Answer 1

-the junction where 2 neurones meet
-presynaptic knob, synaptic cleft, post synaptic membrane

Question 2

what is a Cholinergic synapse

Answer 2

-a synapse that uses acetylcholine as a neurotransmitter

Question 3

how is an impulse transmitted across a synapse

Answer 3

-electrical impulse arrives at presynaptic membrane/synaptic knob
-neurotransmitters are released from vesicles at presynaptic membrane
-neurotransmitters diffuse across synaptic cleft and temporarily bind with receptor molecules on post synaptic membrane
-this stimulates the post synaptic membrane to generate an electrical impulse that travels down the axon of the postsynaptic neurone
-neurotransmitters then destroyed or recycled to prevent continued stimulation

Question 4

detailed transmission across a cholinergic synapse

Answer 4

-AP at presynaptic membrane=depolarisation
-stimulates voltage gated calcium channels to open
-Ca ions diffuse down electrochemical gradient from tissue fluid surrounding synapse to synaptic knob
-this stimulates acetylcholine vesicles to fuse with presynaptic membrane releases Ach molecules into synaptic cleft via exocytosis
-Ach diffuse across and temporarily bind to Ach receptors on post synaptic membrane= sodium channels open
-sodium ions diffuse into down electrochemical gradient into cytoplasm of post synaptic neurone
-sodium ions cause depolarisation
-Ach molecules broken down or recylced

Question 5

detailed transmission across a cholinergic synapse

Answer 5

-AP at presynaptic membrane=depolarisation
-stimulates voltage gated calcium channels to open
-Ca ions diffuse down electrochemical gradient from tissue fluid surrounding synapse to synaptic knob
-this stimulates acetylcholine vesicles to fuse with presynaptic membrane releases Ach molecules into synaptic cleft via exocytosis
-Ach diffuse across and temporarily bind to Ach receptors on post synaptic membrane= sodium channels open
-sodium ions diffuse into down electrochemical gradient into cytoplasm of post synaptic neurone
-sodium ions cause depolarisation
-Ach molecules broken down or recycled
-enzyme acetylcholinesterase catalyses the hydrolysis of Ach molecules into acetate and choline
-choline absorbed back into presynaptic membrane + reacts with acetyl CoA to form Ach which is packaged into vesicles ready for next AP