general neurobiology

Question 1

what are the 5 divisions of the brain?

Answer 1

• frontal
• parietal
• temporal
• occipital
• cerebellum

Question 2

what part of the brain is involved in memory?

Answer 2

hippocampus

Question 3

what is the amygdala involved in?

Answer 3

emotions

Question 4

what are the components of the brain stem?

Answer 4

pons, medulla, midbrain, hypothalamus, thalamus.

Question 5

what is the role of the thalamus?

Answer 5

• to relay information between the spinal cord and the higher neural regions within the brain

Question 6

what makes up white and grey matter?

Answer 6

grey matter contains many cell bodies and axon terminals whereas white matter contains neurons

Question 7

what is the morphology of a neuromuscular junction?

Answer 7

there are terminal buttons that contain acetylcholine vesicles. These vesicles are released into the synapse, where they bind to acetylcholine receptors on the motor end plate.

Question 8

how are vesicles released within the synaptic terminal?

Answer 8

• an action potential reaches the presynaptic terminal of a motor neuron, which depolarises the bouton and activates voltage-dependent calcium channels to allow calcium ions to enter the neuron. Calcium ions bind to sensor proteins on synaptic vesicles, triggering vesicle fusion with the cell membrane and subsequent neurotransmitter release form the MN into the cleft. at binds to ligand gated ion channels (nicotinic receptors) on the cell membrane of the myofiber,

Question 9

what are the advantages of TaDa?

Answer 9

• cheap, doesn’t involve RNA or protein pulldown or immunoprecititaton, fast

Question 10

what is the resting membrane potential of an axon?

Answer 10

-70 to -80

Question 11

what does depolarisation of the membrane mean?

Answer 11

becoming less negative

Question 12

what is the role of the sodium potassium pump and what does this do to the membrane potential?

Answer 12

the pump transports three sodium ions out of the cell and two potassium ions in. This results in the concentration of potassium iOS being higher inside and the concentration os sodium being lower inside. It uses ATP. This results in the intracellular space having a negate charge .

Question 13

what is the role of the calcium sodium pump?

Answer 13

• keeps calcium levels low at the resting state

Question 14

what is the reversal potential?

Answer 14

• the transmembrane voltage at which diffusive and electrical forces counterbalance. the transmembrane voltage exactly oppose the force of diffusion of the ion, such that there is no net current of ions across the membrane

Question 15

how can the resting potential be calculated?

Answer 15

the goldman formula: a weighted average of the reversal potentials for the individual ion types, weighted by permeability. In most animal cells, the permeability to potassium is much higher in the resting state than the permeability to sodium. As a consequence, the resting potential is usually close to the potassium reversal potential.

Question 16

describe how an action potential occurs

Answer 16

• a stimulus is received by the dendrites of a nerve cell. This causes Na+ channels to open . If the opening is sufficient to drive the interior potential l from -70 to -55mv, the process continues.
• having reached the threshold voltage, more Na+ channels open. the Na+ influx drives the cell membrane to about +30mV. The process at this point is called depolarisation.
• The sodium channels close (inactive) and the K+ channels open (they are delayed) and K+ move out, reducing the membrane potential but overshoots, causing hyper polarisation. this prevents the neuron from receiving another signal at this time.

Question 17

what is the threshold potential?

Answer 17

around -55mV

Question 18

what is saltatory conduction?

Answer 18

caused by nodes of ranvier and results in fast conduction from the cell body body (dendrite) to the axons.

Question 19

in general what is the tripartite system ?

Answer 19

the idea that glial cells play a large role in regulating neural synapses

Question 20

what 5 things have glial been implicated in?

Answer 20

• control of brain blood flow
• control neuronal survival
• regulate repair after injury
• neuropathic pain
• epilepsy

Question 21

how are astrocytes thought to control blood flow

Answer 21

• thought they are linked to vessels and synapses, hey release glial-derived signalling molecules which constrict the vessels, or cause vasodilation to shit blood flow to the active areas.

Question 22

what are microglia?

Answer 22

related to immune cells, they are constantly moving their processes and monitoring brain tissue.
- they are also thought to cause chronic pain

Question 23

what is the neurotrophic theory?

Answer 23

• theory that initially an excess of neurons is produced but then pruned depending on how much neurotrophic factor is released from the target organ. initially glial cells support neural development

Question 24

during neuromuscular junction formation, how do achR cluster?

Answer 24

-agrin is released from the end terminus which stimulates clustering maybe through musk?

Question 25

how are temporal fibres repelled at the optic chiasm?

Answer 25

• ephrin eph1 receptor repulsion stimulation

Question 26

how many axons per neuron?

Answer 26

one

Question 27

what are the 2 types of excitatory receptors?

Answer 27

AMPA receptor/Channel and NMDA receptor channel