Brainscape's Knowledge GenomeTM

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


See full index

BMA1901-Module 5 > Mod5-Obj6+7: Somatic motor pathways > Flashcards

Mod5-Obj6+7: Somatic motor pathways Flashcards

1
Q

Somatic motor pathways

A

Conveys motor output from the primary motor cortex to skeletal muscles via a chain of two successive neurones

  1. ) Upper motor neuron (pyramidal neuron)
  2. ) Lower motor neuron
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Upper motor neurons (interneurons)

A

Conduct motor output from the primary motor cortex to the spinal cord

  • Cell body located in primary motor cortex
  • Axon descends in the spinal cord in a corticospinal tract to a motor nucleus within the anterior gray horn and synapses with a lower motor neuron
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Lower motor neurons

A

Conduct motor output from the spinal cord to skeletal muscles

  • Cell body is located in a motor nucleus of an anterior gray horn
  • Axon exits the spinal cord via the ventral root and travel to skeletal muscles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Two main somatic motor pathways are:

A
  1. ) Lateral corticospinal pathway

2. ) Anterior corticospinal pathway

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

Lateral corticospinal pathway

A

Begins in the primary motor cortex

  • Ends at the skeletal muscles of the limbs
  • Axons or upper motor neurons travel in a lateral corticospinal tract
  • Relays motor output that controls voluntary skeletal muscle contractions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Anterior corticospinal pathway

A

Begins in the primary motor cortex

  • Ends at the skeletal muscles of the axial skeleton, pectoral and pelvic girdles
  • Axons of upper motor neurons travel in an anterior corticospinal tract
  • Relays motor output that controls voluntary skeletal muscle contractions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Neural pathway: Posterior column pathway

A 
Spinal tract: 
Fasciculus gracilis tracts Fasciculus cuneatus tracts
Information relayed:
-Fine touch
-Vibration
-Pressure
-Proprioception
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Neural pathway: Spinothalamic (anterolateral) pathway

A 
Spinal tract:
Lateral spinothalamic tracts
Information relayed:
-Pain 
-Temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Neural pathway: Spinothalamic (anterolateral) pathway

A 
Spinal tract:
Anterior spinothalamic tracts
Information relayed: 
-Crude touch
-Pressure
-Tickle and itch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Neural pathway: Spinocerebellar pathway

A

Spinal tract:
Spinocerebellar tracts (anterior & posterior)
Information relayed:
Proprioception

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

Neural pathway: Lateral corticospinal pathway

A

Spinal tract:
Lateral corticospinal tracts
Information relayed:
Motor commands to skeletal muscles (limbs)

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

Neural pathway: Anterior corticospinal pathway

A

Spinal tract:
Anterior corticospinal tracts
Information relayed:
Motor commands to skeletal muscles (trunk, neck, pectoral & pelvic girdles)

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

Somatic reflex pathways

A

Rapid, involuntary activation of skeletal muscles in response to a stimulus

  • Spinal cord processes incoming sensory information, decides on and generates a motor response (acts as an integration centre)
  • Lower motor neurons relay the motor output to the effector skeletal muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Somatic reflexes

A

Can be facilitated or inhibited by motor output issued by the primary motor cortex and relayed down the spinal cord via the corticospinal tracts

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

Somatic reflexes can be used to assess the condition of:

A
  • Lower motor neurons
  • Spinal cord
  • Primary motor cortex
  • Corticospinal tracts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Somatic reflexes

A
  • Patellar reflex
  • Biceps reflex
  • Triceps reflex
  • Abdominal reflex
  • Plantar reflex
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Patellar reflex

A 
Stimulus 
-Tap to patellar tendon
Normal response 
-Extension at the knees (kick)
Spinal segment assessed 
-L2-L4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Biceps reflex

A 
Stimulus
-Tap to biceps brachii tendon
Normal response
-Flexion at elbow
Spinal segment assessed 
-C5,C6
19
Q

Triceps reflex

A 
Stimulus 
-tap to triceps brachii tendon 
Normal response
-Extension at elbow 
Spinal segment assessed 
-C6, C7
20
Q

Abdominal reflex

A 
Stimulus 
-Stroking of abdomen 
Normal response 
-Contraction of abdominal muscles 
Spinal segment assessed 
-T7-T12
21
Q

Plantar reflex

A 
Stimulus 
-Stroking of lateral side of sole of the foot 
Normal response
-Curling of toes (>1yr)
Spinal segment assessed 
-L4-S2
22
Q

Patellar (knee-jerk) reflex

A 
Sensory neuron (first order), Lumbar region, Lower motor neuron 
Normal response: Extension of the knee
23
Q

Patellar (knee-jerk) reflex: Hyporeflexia

A

Damage to lower motor neurone or spinal cord segment

Reduces or absent intensity of the reflex

24
Q

Patellar (knee-jerk) reflex: Hypereflexia

A

Damage to brain or corticospinal tract

-Series of kicks, instead of just one=inhibitory

25
Q

Plantar reflex

A

L4-S2 damage

26
Q

Plantar reflex: Normal response

A

Flexion of the toes

27
Q

Plantar reflex: Abnormal response: Babinski sign

A

Fanning of the toes

-Normal response in children (<1yr old) as corticospinal tracts are not fully developed

28
Q

“Spastic” paralysis

A

Upper motor neuron damage=loss of voluntary movements. Spinal reflex activity intact and stimulates muscles irregularly

29
Q

If compression or a spinal cord segment damages all spinal cord tract, these occur below the level of compression

A
  • A loss of voluntary skeletal muscle activity
  • A loss of sensation
  • Abnormal reflex activity
30
Q

The degeneration of lower motor neurons will result in…

A
  • A loss of voluntary skeletal muscle activity

- A loss of reflex activity

31
Q

Lower motor neurone activity will be affected if…

A
  • An anterior grey horn damage

- A ventral nerve root damage

32
Q

“Flaccid” paralysis

A

Muscles can not move voluntarily and involuntary muscles atrophy

33
Q

Transection of the spinal cord results in…

A
  • A loss of voluntary skeletal muscle activity (below lesion)
  • Sensory loss below the lesion
  • Paraplegia if it occurs between T1-L1
  • Quadraplegia if it occurs in the cervical region
34
Q

“Spinal shock”

A

A transient period of complete motor paralysis, sensory loss and loss of all reflexes (somatic and autonomic) below the level of the lesion. Reflex activity gradually returns

35
Q

Nerve structure and classification

A

The axons (fibres), blood and lymphatic vessels that comprise nerves are enclosed by three connective tissue layers

  1. ) Epineurium
  2. ) Perineurium
  3. ) Endoneurium
36
Q

Epineurium

A

Tough fibrous outer layer that encloses entire nerve

37
Q

Perineurium

A

Middle layer that surrounds bundles of axons called fascicles

38
Q

Endoneurium

A

Innermost layer that surrounds each individual axon

39
Q

Nerves can be classified as: sensory nerves

A

Contain the axons of sensory neurons

40
Q

Nerves can be classified as: Motor nerves

A

Contain the axons of motor neurons

41
Q

Nerves can be classified as: Mixed nerves

A

Contain both sensory and motor axons

42
Q

Nerves can be classified as: Cranial nerves (12 pairs)

A

Arise from the brain to innervate the head and neck, visceral organs

43
Q

Nerves can be classified as: Spinal nerves (31 pairs)

A

Arise from the spinal cord and branch into peripheral nerves that innervate all body areas except some head and neck regions

BMA1901-Module 5 (9 decks)

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