4 - Neurones/Synapses/Transmitters

Question 1

structute of neurones?

Answer 1

• dendrites [receive input]
• axon [conducts impulse]
• axon terminal [release nt]

Question 2

what are the different shapes of neurones?

Answer 2

• unipolar [single axonal process]
• bipolar
• multipolar
• pseudo unipolar

Question 3

what are the 4 classes of NTs?

Answer 3

monoamides [dopamine] [NA]
acetylcholine
amino acids [Glutamate/Glycine]
neuroactive peptides

Question 4

structure of receptors at synapses?

Answer 4

• membrane spanning proteins
• bind with NT to cause conform change
• specific to a NT
• many subtype receptors for one nt

Question 5

steps of how a signal is transmitted across a synapse?

Answer 5

• action pot arrives at pre-synaptic n
• na channels open and cause depolarisation
• depol causes Ca release by ca channels opening
• vesicles fuse and exocytosis of NT
• diffuses and bind to receptor on post synaptic

rapid uptake of nt by enzymatic breakdown ends signal

Question 6

what are the two receptor mechanisms at a synapse?

Answer 6

ionotropic

• ex release glutamate
• cause Na channels to open and cause depol
• inhib release GABBA[A] or Glycine
• cause Cl- channels to open to cause hyperpol

metabotropic

• use g-proteins which receptor binds to
• can open or close ion channels
• or stim/inhib enzymes