Brainscape's Knowledge GenomeTM

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


See full index

MBBS - Year 1 > Physiology - Gait and Limp > Flashcards

Physiology - Gait and Limp Flashcards

1
Q

Functions of motor control system

A

Posture and balance
Goal-directed movements
Communications

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

What is the motor control system guided by

A

Sensory systems - detect changes in environments

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

Classes of movements

A

Voluntary
Reflexes
Rythmicx motor patterns

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

Classes of movements - voluntary

A

Complex actions (reading, writing)
Purposeful goal directed
Learned

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

Classes of movements - reflexes

A

Involuntary, rapid, stereotypes (knee jerk, eye blink)

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

Classes of movements - rhythmic motor patterns

A

Combines voluntary & reflexive acts (chewing, walking, running)
Initiation & termination is voluntary
Once initiated, repetitive & reflexive

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

Where are alpha-motor neurons cell bodies found

A

In clumps within ventral form of spinal cord (lower motor neuron)

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

What does each motor neuron activate

A

A motor unit (6-1500 skeletal muscle fibres)

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

Function of muscle spindles

A

Identify stretch in muscle and try to prevent over stretching

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

Examples of monosynaptic reflex arcs

A

Biceps brachii, triceps brachii and brachioradialis

Most are stretching reflexes

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

Examples of polysynaptic reflex arcs

A

Plantar and anal reflexes

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

Where are sensory neurons (afferent) located

A

In spinal ganglion

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

Where do afferent neurons conduct to

A

The ventral horn where the motor neuron (efferent) is found

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

Spinal reflex examples

A

Stretch reflex
Golgi tendon reflex
Withdrawal reflex
Crossed extensor reflex

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

Steps in spinal reflex

A 
Receptor 
Sensory fibre 
(interneuron)
Alpha motor neuron 
Muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Stretch reflex

A

A muscle contraction in response to stretching within the muscle

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

What type of synaptic reflex is a stretch reflex

A

Monosynaptic reflexes that provides automatic regulation of skeletal muscle length, with a very short latency period

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

What happens when a muscle is stretched

A

The muscle spindle is stretched as a result and increases firing of alpha motor neurons
The muscle fibres then contract synergistically and resist the stretching. Another set of inhibitory interneurons causes the opposing muscle to relax

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

Myotatic (knee jerk) reflex

A

Example of monosynaptic stretch reflex
Tap of patellar tendons stretches quads (extensors) and stimulates receptors of muscle spindle
Inc in rate of firing of Ia afferent –> contraction of quads and knee flexors inhibited

20
Q

When is the knee jerk reflex lost

A

If lower lumber dorsal roots of spinal cord are damaged

21
Q

Golgi tendon organ

A

Detect and respond to changes in muscle tension (force)

22
Q

What is the Golgi tendon organ activated by

A

A passive stretch or muscular contraction e.g. standing for too long

23
Q

Innervation of Golgi tendon organ

A

Ib afferents – wrapped around bundles of collagen fibres in the tendon

24
Q

Golgi tendon reflex as a feedback mechanism

A

Controls muscle tension by causing muscle relaxation before muscle force becomes so great that tendons might be torn – helps maintain posture

25
Q

Golgi tendon reflex

A

Tension/ force in tendons will decline and so will activity of afferent Ib fibres
Normal inhibition of motor neurones will be removed so flexor muscles contract more strongly —-> increasing tension in tendon

26
Q

Inverse myotatic reflex

A

Force in patellar tendons will decline, this activity in afferent Ib fibres will decline
Normal inhibition of motor neurons supplying quads (extensors) will be removed
Muscle will contract more strongly (flexors), so increasing force in patellar tendon

27
Q

Sensitivity of Golgi tendon reflex

A

Less sensitive than the stretch reflex but can override the stretch reflex when tension is great, which explains why we drop heavy things

28
Q

Withdrawal reflex

A

Polysynaptic reflex which is intended to protect the body from damaging stimuli
Typically motor neurons send inhibitory impulses to the extensors, so flexion is not inhibited (reciprocal innervation)

29
Q

When do we not exhibit the withdrawal reflex

A

In those trained to override it and unconscious people (incl those drugged or drunk)

30
Q

When does the withdrawal reflex occur

A

When the flexors in the withdrawing limb contract and the extensors relax but the opposite occurs in the contralateral limb

31
Q

Why is the crossed extensor reflex described as contralateral

A

Reflex occurs on the opposite side of the body from the stimulus
The interneurons excite or inhibit alpha motor neurons to the muscles of the contralateral limb

32
Q

What is the main function of the crossed extensor reflex

A

Maintain posture and balance, which explains why the opposite leg takes the weight of the whole body

33
Q

Stance phase of step cycle

A

Foot touching ground, flexion of knee and ankle

Finishes with extension about all joints for forward movement

34
Q

Swing phase of step cycle

A

Bending (flexion) of hip, knee and ankle followed by knee and ankle straightening (flexion)

35
Q

Where is the central pattern generator for locomotion found

A

Spinal cord

36
Q

Central Pattern Generators

A

2 half centres which activate flexors and extensors respectively and which mutually inhibit each other
Can be modelled using inhibitory 1a interneuron and Renshaw cells

37
Q

What does the cerebellum contribute to

A

Coordination, precision and timing of voluntary movement and motor learning

38
Q

What does the basal ganglia comprise of

A

Neostriatum – caudate nucleus, putamen
Globus pallidus
Subthalamic nucleus
Substantia nigra

39
Q

Function of cerebellum

A

Entirely motor and operates at an unconscious level

Controls the maintenance of equilibrium (balance), influences posture and muscle tone and coordinates movement.

40
Q

Afferent fibres of A-alpha sensory fibres

A

Ia

Ib

41
Q

How much of the gait cycle do we spend in double support

A

20%

42
Q

Motor pathway lesions in muscle

A

E.g. myositis or muscular dystrophy

Normal reflexes
Weakness/ wasting

43
Q

Motor pathway lesions in neuromuscular junction

A

E.g. myasthenia gravis

Fatiguable weakness
Normal reflexes
Normal muscle bulk

44
Q

Causes of motor pathway lesions in UMN

A

Cerebral vascular accident

Spinal cord trauma

45
Q

Causes of motor pathway lesions in LMN

A

Motor neurone disease

Neuropathy

46
Q

Motor pathway lesions in cerebellum

A

E.g. MS

Normal reflexes
Strength
Slight decrease in tone

47
Q

Motor pathway lesions in basal ganglia

A

E.g. Huntington’s, Parkinson’s

Changes in movement

MBBS - Year 1 (93 decks)

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