Neurons [Synaptic]

Question 1

Description of what happens at a chemical synapse (pre to post)

Answer 1

Depolarisation at the presynaptic terminal causes release of a neurotransmitter which diffused across the synaptic cleft and binds to receptors in the postsynaptic membrane. This initiates opening of a channel and a current therefore.

Question 2

3 key features of chemical synapses

Answer 2

Specificity of neurotransmitters
Complexity
Plasticity (learning developing)

Question 3

2 types of chemical synapses

Answer 3

Excitory: evoke depolarisations of the postsynaptic membrane called EPSPs.
Inhibitory: evoke hyperpolarisations of the postsynaptic membrane called IPSPs.

Question 4

Excitatory synapses neurotransmitter and channels

Answer 4

Glutamic acid (glutamate) and ACh. Opens channels for Na+ K+ and Ca2+

Question 5

Inhibitory synapses neurotransmitters and channels

Answer 5

GABA or glycine. Opening of K+ channels.

Question 6

Factors determining synaptic action

Answer 6

Type of neurotransmitter
Type of complex
Amount of neurotransmitter
Synaptic plasticity - LTP or LTD

Question 7

3 types of glutamate receptors + whats glutamate for? What ions do the receptors allow through?

Answer 7

Glutamate is a neurotransmitter for excitatory synapses. AMPA(K/Na), NMDA (allows everything), Kaitane (K/Na)

Question 8

What is EPP?

Answer 8

End plate potentials. Ion channels open which are non-selective cationic. Trigger AP.

Question 9

What do temporal and spatial summation enhance?

Answer 9

EPSPs amplitude

Question 10

Spatial summation

Answer 10

2 presynaptic neurons, 1 postsynaptic neuron.

Question 11

Temporal summation

Answer 11

1 presynaptic, 1 post.

More calcium released and not enough time to remove it so increase in neurotransmitter release with shorter interval.

Question 12

Direct gating - description + speed

Answer 12

Transmitter binds to receptor/channel complex, hyper/depolarising membrane. Fast and short-lasting.

Question 13

Indirect gating - description + speed

Answer 13

Transmitter binds to receptors such as metabotropic (G protein). Activates cAMP and kinases causes channels to open and changes membrane potential. Slower and longer-lasting

Question 14

Small molecule/classical neurotransmitters - speed, direct/indirect, types

Answer 14

Fast, act directly on receptors.

Amino acids, ACh, amines.

Question 15

Neuropeptides

Answer 15

Large, indirect (metabotropic), slow.

Question 16

3 types of neurotransmitter inactivation

Answer 16

Diffusion
Enzymatic degration
Reuptake (eg. Glutamate transporter)

Question 17

Glutamate types of receptors

Answer 17

4 types: 3 ion channels directly gated and one second-messenger-mediated.

Question 18

What happens when too much glutamate released?

Answer 18

Excessive activation of receptors leading to high Ca++ influx. Excitotoxity.