Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Semester 3 > Case 1 - intro to the nervous system > Flashcards

Case 1 - intro to the nervous system Flashcards

1
Q

what is perception

A

constructive process in the brain that depends upon both information about stimuli (sensations) and the mental structure of the perceiver.

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

what is pain derived from

A

is a perception derived from sensory input between nociceptors

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

what is nociception

A

is the sensory nervous systems process of encoding noxious stimuli. it deals with a series of events and processes required for an organism to receive a painful stimulus, convert it to a molecular signal, and recognise and characterise the signal in order to trigger an appropriate defence response

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

what are neurones

A

cells which integrate information and pass it on

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

what are glia

A

‘support cells’, maintaining the environment and ‘moping up’

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

how much of the cardiac output is directed to the brain

A

25-30% of cardiac output is directed to the brain

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

what two substances from blood can the brain only use

A

glucose and O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is there no build up of in the brain

A

lactate buildup from anaerobic metabolism

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

what is excitotoxicity

A

over exposure to glutamate with actions on NMDA receptors which allow Ca influx and can cause swelling and rupture

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

morphological features of a neurone

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

what are the three types of synaptic connection

A
  • axodendritic
  • axosomatic
  • axoaxonic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

diagram explaining the simple circuits of synapse connection

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

what do dendrites do

A

they ‘collect’ information from synaptic outputs, potentially from relatively long distances away, with the membrane at the soma summing all of the dendritic EPSPs and IPSPs both across time and location

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

what is an EPSP

A

excitatory postsynaptic potential

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

what is an IPSP

A

Inhibitory postsynaptic potential

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

what happens if the membrane depolarisation at the exon hillock reaches threshold

A

an action potential is initiated, which travels down the axon to the axon terminal which releases a neurotransmitter

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

what is the neurone used in this

A

an analoge-to-digital converter (D2A etc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what does continuously varying changes in the cell soma membrane potential do

A

gives rise to discrete ‘all or none’ action potential events

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how many synapses can there be onto any single Nerone

A

can be hundreds to thousands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the 4 reflex types

A
  • stretch reflex
  • inhibitory reflex
  • flexor reflex
  • crossed extensor reflex
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what do ligaments bind

A

ligaments bind bone to bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what do tendons bind

A

tendons bind muscle to bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is flexion

A

the closing of a joint e.g contraction of the biceps (flexor muscle) - cases the joint at the elbow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what extension

A

the opening of a joint e.g contraction of the triceps (an extensor muscle) opens the joint at the elbow

25
Q

what would contraction of both extensor and flexor cause

A

results in stiffness at the joint with no movement

26
Q

what has to happen in order to get movement

A

the antagonist muscle must relax during agonist contraction - this is an important concept to understand

27
Q

what happens during flexion of the elbow joint

A
  • the biceps are the agonist
  • the triceps are the antagonist
28
Q

what happens during extension of the elbow Joint

A
  • the triceps are the agonist
  • the biceps are the antagonist
29
Q

what is a reflex

A

uses existing neural circuits In the spinal cord - reflexes do not require learning

30
Q

the sensor, integrator and effect model

A
31
Q

stretch reflex

A

taping the tendon connecting a muscle to a bone causes that muscle to stretch slightly. this stretch is deterred by a sensor which through a reflex circuit causes the muscle to contract

32
Q

why does the muscle contract

A

to counteract the imposed stretch

33
Q

describe the ‘knee jerk’ reflex

A

stretch of the patellar tendons stretches the quadriceps. the induces reflex quadriceps contraction. as the quadriceps is an extensor muscle, contraction ‘opens’ the knee joint and straightens the leg

34
Q

what does the knee jerk reflex protect from

A

protects the muscle from damage due to over-stretching.

35
Q

what is this reflex also called

A

the myotatic reflex

36
Q

what are the two main types of muscle fibres

A
  • extrafusal: main body of the muscle
  • intrafusual: lie within the extrafusal and forms the muscle spindle
37
Q

diagram of knee jerk reflex

A
38
Q

what is the spindle response

A

a mechanoreceptor

39
Q

relationship between the main muscle fibres and the spindles

A

parallel

40
Q

what happens when muscle fibres stretch

A

the spindle also stretches increasing the sensory signal in its Group 1a afferents. these project to the spinal cord via the dorsal horn

41
Q

diagram showing spindle strech

A
42
Q

what happens when muscle fibres contract

A

the muscle length shortens, making the spindle fibres go slack, loose and stop signalling stretch

43
Q

what counteracts this

A

the gamma motor neurone excites the spindles intrafusal fibres to maintain spindle muscle tone during contraction

44
Q

spindle being slack explanation and compensation

A

when the spindle is slack, there is not information about muscle length being transmitted to the spinal cord. this is bad as the position of the joint and related muscle state of contraction are vital in order to effect controlled movement. contracting the intrafusal fibres compensates for this state by restoring spindle output. in such a case the brain can calibrate the ‘new’ value of spindle output against the amount of activity in the gamma motor neurones to estimate true length of the main muscle

45
Q

what produces muscle contraction

A

motor units are small in order to deliver fine control of movement. motor units air large for muscles involved in large powerful movements where u need a small range of simple powerful movements

46
Q

diagram of muscle contraction

A
47
Q

arrangement of motor neurones in the spinal cord diagram

A
48
Q

what are the steps underlying monosynaptic stretch reflex

A
  1. stretching of muscle stimulates muscle spindles
  2. activation of sensory neurone
  3. information processing at motor neurone
  4. activation of motor neurone
  5. contraction of the muscle
49
Q

how is the flexor muscle inhibited

A

via synapse at 2 and inhibitory interneurone

50
Q

what can abnormal oscillation of flexion and extension around the joint be often seen in

A

spasticity

51
Q

how does the Golgi tendon organ lie in relation to tendons and muscles

A

it lies in series with muscle fibres (spindles are parallel)

52
Q

what does Golgi tendon organ do

A

responds to tension developed by muscle during isometric contraction. prevents heavy loading of muscle causing damage.

53
Q

ow does the Golgi tendon organ work

A

works by activating inhibitory interneurones to relax the muscle immediately

54
Q

diagram showing lay out of Golgi tendon organ and spindle

A
55
Q

what is the inverse of a stretch reflex

A

when the agonist muscle is excited and aids in extension of the joint. at the same time the antagonist muscle is relaxed, so therefore inverse of a stretch reflex

56
Q

diagram of the flexor reflex

A
57
Q

what is the crossed extensor reflex

A

flexors in the withdrawing limb contract and the extensors reflex, while in the other limb the opposite happens.

signals travelling via the spinal cord contract the contralateral muscles of the hips and abdomen. this shifts the body centre f gravity over the extended leg

58
Q

summary: please please work.

A

Neurones combine to form simple and highly complex circuits.

simplest neuronal circuit organisation can be seen in the 4 reflex types.

Semester 3 (94 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions