Neurochem

Question 1

What is EPSP?

ACT POT

Answer 1

Excitatory Post Synaptic Potentials

(EPSPs) increase likelihood of ACT POT by elevating mV at the axon hillock

Question 2

What is the function of dendrites ?

bring +ve IONS into cell

Answer 2

brings +ve ions into cell.
+ ve ions > small depolarisation – EPSP ( not enough for Act .Pot.)

Question 3

What is IPSP ?

-95mVs

Answer 3

Inhibitory Post Synaptic Potential : Norm= -95mVs

-ve ions into cell > small hyperpolarization – IPSP: won’t produce Act. Pot ( pot. Goes down more !)

• (IPSPs) reduce the likelihood of ACT POT by lowering the mV at the axon hillock

Question 4

Do IPSP and EPSP cancel each other?

Answer 4

Yes

Question 5

Do Large EPSP PRODUCE at potentials?

Answer 5

Yes! Sum of EPSPs+ IPSPs determine if Act pot will occur: neural integration at axon Hillock

Question 5

Do Big IPSPs INHIBIT Act .pot?

Answer 5

Yes! Large IPSP due to many -ve ions entering cell : integration of charge at hillock can’t reach excitation – NO act.pot

Question 6

Where does integrations of polarities occur?

Hillock!

Answer 6

AXON HILLOCK: neuron will only fire if the hillock has an overall increase in positive charge (that exceeds the excitability threshold )

• Neural integration: sum of the EPSP and IPSPs where increases in mV above the excitability threshold result in an action potential

Question 7

If a neuron depolarises will it cause an act.pot.?

Answer 7

Yes!
See diagnosis P.5

Question 8

Name the 2 types of information from presynaptic neutrons?

T + S

Answer 8

Temporal and Spatial

Question 9

What are the 2 types of cell communication?

Elec + Chem

Answer 9

Electrical : gap junctions
Chemical: synaptic cleft

• GAP Junctions: seen btw glial cells – ions transferred btw plasma wall via connexons . Junction apx 3.5nm btw cells (20nm gap)

see diagnosis. p5

Question 10

What is the role of neurotransmitters?

MSGs!

Answer 10

NT packed in synaptic vesicles: convey msg’s.

Diag p 6

Question 11

Name 3 different synaptic arrangements?

A- D- A

Answer 11

Axodendritic
Axosomatic
Axoaxonic

Question 12

What is EXOCYTOSIS?

NT release

Answer 12

Process whereby vesicle are emptied into synapse

NT released upon action potential by exocytosis: * Neurotransmitters may then bind to receptor to produce a biological effect

Diag p 7

Question 13

What is ENDOCYTOSIS?

NT Recycle

Answer 13

recycling of NT

• Once unbound: neurotransmitters cleared from the synapse by endocytosis through use of transporters in cell membrane
  Diag p - 9

Question 14

what is role of action potential?

Answer 14

• enable sophisticated transfer of information from one neuron to another through chemical release