Neural Integration

Question 1

Answer 1

Question 2

Where is Na⁺ more concentrated?

Answer 2

ECF

(Na⁺ influx)

Question 3

Where is K⁺ more concentrated?

Answer 3

ICF

(K⁺ efflux)

Question 4

What is the determining factor of RMP?

Answer 4

Passive diffusion

Question 5

Why is the RMP negative?

Answer 5

Cell membrane is more permeable to K⁺ than Na⁺

More K⁺ moves out of the cell than Na⁺ moves in

RMP is closer to K⁺ equilibrium potential

Question 6

When does the absolute refractory period occur?

Answer 6

During the period when the K⁺ channels are open

(2ms from when Na⁺ channels first open)

Question 7

When does the relative refractory period occur?

Answer 7

when the K⁺ channel closes for _~2ms

Question 8

What affects conduction velocity of an action potential?

Answer 8

Diameter of axon

Myelin

Question 9

Where is neurotransmitter released?

Answer 9

Into the synaptic cleft

Question 10

Why is it useful to have varying speeds of AP conduction?

Answer 10

Simultaneous convergence of signals from different locations

Question 11

How do ionotropic receptors function and what do they interact with?

Answer 11

open upon contact with neurotransmitters

Allow ions to pass through

Typically excitatory receptors

Question 12

How does GABA work?

Answer 12

GABA opens Cl^- channels on the post synpatic cell

Cl^- has Eq. potential of -70mv

Movement of Cl^- into cell hyperpolarises membrane potential

Inhibitory neurotransmitter

Question 13

What kind of neurotransmitter is glycine?

Answer 13

Inhibitory

Question 14

What kind of synapse relies on Ca²⁺ to continue transmitting an AP?

Answer 14

CNS/neuron to neuron

Question 15

What interaction releases acetylcholine as a neurotransmitter?

Answer 15

Alpha motor neuron to skeletal muscle cell

Question 16

What interaction releases glutamate and GABA as a neurotransmitter?

Answer 16

Neuron to neuron

Question 17

What receptors does acetylcholine act on?

Answer 17

Nicotinic

Question 18

What allows for the massive depolarisation of skeletal muscle cells?

Answer 18

Large amount of acetylcholine released

Large number of nicotinic receptors on post synaptic neuron

Question 19

What causes the falling phase of an AP?

Answer 19

K⁺ efflux

Question 20

Answer 20

Question 21

Convergence of neurons give what level of resolution?

Answer 21

Low

Question 22

What part of the brain controls the all senses other than smell?

Answer 22

Thalamus

Question 23

How is intensity of a stimulus coded?

Answer 23

Population coding

(as intensity increases, receptors of higher threshold recruited)

Question 24

What does frequency coding encode?

Answer 24

Intensity of stimulus given by AP frequency

Duration of stimulus given by duration of AP

Question 25

Where are photoreceptors located in the eye?

Answer 25

In the pigmented epithelium at the back of the retina (Positioning and pigmentation ensures light is not bounced around)

Question 26

What kind of pathway do neurons have in the retina?

Answer 26

Convergent

Question 27

Why does the fovea have high resolution?

Answer 27

Neurons are pushed to the side Light strikes the photoreceptors directly 1:1 ratio photoreceptor to ganglion cell Only contains cones

Question 28

What functions do cones perform?

Answer 28

Daytime and colour vision

Question 29

What functions do rods perform?

Answer 29

Night/low light vision

Question 30

Why is it easier to see in low light in your peripheral vision?

Answer 30

There are no rods in the fovea Rods are in the peripheral retina

Question 31

Are cones or rods greater in number?

Answer 31

Rods (20:1)

Question 32

What kinds of cones are there?

Answer 32

red, green, blue

Question 33

What do neurotransmitter do rods release tonically?

Answer 33

Glutamate

Question 34

Glutamate is normally an excitatory neurotransmitter, where does it act as an inhibitory neurotransmitter?

Answer 34

Acts on bipolar neurons | (metabotropic glutamate receptors)

Question 35

What happens when light interacts with rhodopsin?

Answer 35

Na⁺ channel closes Glutamate release halted Bipolar cell no longer inhibited Light is reported as an AP

Question 36

What allows glutamate to inhibit a bipolar cell?

Answer 36

Metabotropic glutamate receptor (metabotropic - alters function) Receptor signals closing of cation channels Hyperpolarizes cell membrane No AP generated