CTL Week 8 Flashcards

(41 cards)

1
Q

what does conduction velocity of neurons depend on

A

axon diameter (larger = faster)
degree of myelination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is another function of myelination apart from making the conduction faster?

A

Myelin insulates and prevents leakage of charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

where are voltage gated Na channels located

A

areas that are unmyelinated

Nodes of Ranvier for myelinated axons, jumping from gap to gap (saltatory conduction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

where does the AP start on the neuron

A

axon hillock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

when does voltage decay occur while travelling

A

on dendrites (no voltage gated channels located here)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

when does voltage not decay

A

nonmyelinated axons - continuous conduction

myelinated axons - saltatory conduction

voltage gated channels are present along the axon = no decay in voltage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

explain the process of neurotransmission

A
  1. Nerve impulse: AP arrives at axon terminal of presynaptic neuron, depolarising terminal causing…
  2. Voltage gated Ca2+ channels open – Ca2+ influx into cell
  3. Calcium triggers synaptic vesicles containing neurotransmitters to fuse with axon membrane
  4. Neurotransmitters diffuse across the synaptic cleft
  5. Binds to receptor on ligand gated (channel closed) on postsynaptic neuron
  6. Ligand gated channels open; Receptors are chemically gated ion channels or GPCRs
  7. Causes excitatory or inhibitory graded potential in neurons
  8. Post synaptic potential occurs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

where is ACh neurotransmitter released and used?

A

Released at neuromuscular junction

synapses at: autonomic nervous system/CNS synapses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are some catecholamine neurotransmitters and where are they released

A

o Include dopamine, norepinephrine and epinephrine

o Released at ANS and CNS synapses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are some indolamine neurotransmitters

A

o Include serotonin and histamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are some amino acid neurotransmitters and where are they mainly used

A

o Include glutamate, GABA

o Major neurotransmitters in CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are some other neurotransmitters

A

o Peptides, ATP, nitric oxide, endocannabinoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the 2 effects a neurotransmitter has on receptors

A

excitatory - depolarizing

inhibitory - hyperpolarising

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

neurotransmitter action can be fast or slow depending on these 2 receptors it binds to

A

fast: ligand gated ion channel (ionotropic - fast); skeletal muscle

slow: GPCR (metabotropic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are some inhibitory neurotransmitters and where do they act

A

GABA, glycine, ACh
in cardiac muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are some excitatory neurotransmitters and where are they used

A

Glutamate, ACh

at neuromuscular junction in skeletal muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

which two hormones bind to at least two receptors with opposite effects

A

acetylcholine and norepinephrine

18
Q

what causes more neurotransmitter to be released

A

more frequent AP’s at axon terminal

19
Q

what are PSPs

A

in neurons, neurotransmitter receptors activate graded potentials (post-synaptic potential, PSPs)

20
Q

what is the strength of PSP dependent on

A

Depends on amount of neurotransmitter released and time neurotransmitter stays in the area

21
Q

what are excitatory and inhibitory PSPs and what do they cause

A

EPSPs – causes depolarization

IPSPs – causes hyperpolarisation

22
Q

can a single EPSP induce an AP

23
Q

how can a EPSP or IPSP influence a postsynaptic neurons response

24
Q

what are the two types of summation

A

Temporal and spatial

25
describe temporal summation
same excitatory presynapse: 2 excitatory stimuli in the same location, close in time, add up in the EPSP
26
describe spatial summation
2 excitatory presynapse: 2 simultaneous stimuli at different locations on the postsynaptic neuron cause EPSPs to add together
27
what is the effect of one EPSP and one IPSP
they cancel each other out
28
what determines if the AP occurs
the net summation of the EPSPs and IPSPs
29
what are some characteristics of Group A peripheral nerve fibres
Large diameter, myelinated High velocity
30
what are some characteristics of Group B peripheral nerve fibres
o Intermediate diameter, lightly myelinated fibres o Low velocity
31
what are some characteristics of Group C peripheral nerve fibres
o Smallest diameter, unmyelinated fibres o Low velocity
32
what are nerve fibres classified based on and what is the order
based on speed A - alpha A - beta A - gamma A - delta B C, dorsal root C, autonomic
33
what is proprioception and how does it affect gait
proprioception is the sense of position poor proprioception = poor gait
34
what is the relationship between knee-jerk reflex and proprioception
the knee-jerk reflex, is a proprioceptive reflex. It relies on sensory feedback from the muscle spindle, a type of proprioceptor
35
explain the stretch reflex pathway
1. Sensory receptor: mechano-gated (stretching stimulus) 2. Sensory neuron 3. Integration centre 4. Motor neuron 5. Effector: same muscle contracts, relieving the stretching
36
organization of nervous system
CNS: brain and spinal cord PNS: cranial and spinal nerves
37
how is the PNS further divided
sensory (afferent) motor (efferent) - somatic: skeletal (voluntary) - autonomic: smooth muscle, glands and cardiac (involuntary) - sympathetic and parasympathetic
38
what is the relationship between sympathetic and parasympathetic
opposite effects, both are always on, one dominates the other depending on the situation
39
explain the neurotransmitters and receptors associates with: sympathetic innervation to skeletal muscle
Preganglionic neuron transmits ACh --> nicotinic receptor (ganglion) transmits norepinephrine --> adrenergic receptor on the effector cell
40
explain the neurotransmitters and receptors associates with: sympathetic innervation to sweat glands
Preganglionic neuron transmits ACh --> nicotinic receptor (ganglion) transmits ACh --> muscarinic receptor on the effector sweat gland
41
explain the neurotransmitters and receptors associates with: parasympathetic
Preganglionic neuron ACh --> nicotinic receptor (ganglion) transmits ACh --> muscarinic receptor on the effector cell