Neuroanatomy

Question 1

What is the main function of upper motor neurons?

Answer 1

they are involved with initiating, maintaining and planning the sequences that are involved in voluntary movement. . The UMN with cell bodies in brain stem are involved with regulation of muscle tone, control of posture and basic “navigational movements”

Question 2

State the origin and termination of the rubrospinal tract and state it’s function:

Answer 2

originates in the red nucleus
terminates in the lateral grey matter
influences the lower motor neurons of flexor muscles

Question 3

State the origin and termination of the lateral vestibulospinal tract and state it’s function:

Answer 3

originates in the vestibular nuclei
fibres terminate on the LCN activating the LMN of trunk and limbs- functions to facilitate extensors and inhibit the flexors
functions in the maintenance of balance and posture

Question 4

State the origin and termination of the medial vestibulospinal tract and state it’s function:

Answer 4

originates in the rostral, medial, and caudal vestibular nuclei
terminates in cervical and cranial thoracic spinal cord segments
adjusts head an neck position in response to changes in posture

Question 5

State the origin and termination of the tectospinal tract and state what the function of it is:

Answer 5

originates in the visual tectum
terminates in the cervical and the upper thoracic spinal cord
control of head and eye movements in response to visual stimuli

Question 6

What is the origin and the termination of the of the reticulospinal tract (medullary lateral and pontine medial)?

Answer 6

both originate within the reticular formation
extends to all levels of the spinal cord
MRST- supreseses extensor spinal reflex activity
PRST- facilitates extensor spinal reflex activity

Question 7

What is the origin and termination of the CST (corticospinal) and the CBT (corticobulbar) tract?

Answer 7

both arise from within the cerebral cortex
CBT innervates the cranial nerve of the brainstem
The CST is associated with posture terminating on both the axial and proximal limb muscles

Question 8

What are the main signs that are associated with upper motor neuron damage?

Answer 8

• paresis- weakness and an inability to initiate gait generation
• normal to hyperreflexia
• late and mild muscle atrophy
• muscle tone will be normal to increases in nature

Question 9

What is the function of the cerebellum and what are the main functions of them?

Answer 9

• cerebrocerebellum (the lateral hemispheres) - involved in the regulation of highly skilled movements
• spinocerebellum- regulation of movements associated with posture and equilibrium
• veestibulocerebellum- regulates eye muscles and movements in response to vestibular inputs

Question 10

What are the signs that are associated with diffuse cerebellar disease?

Answer 10

• general inadequecy of motor movement
• bilateral symmetric ataxia without weakness
• ataxia is characterised by an inability to regulate rate, range and force of movement

Question 11

What is the main function of the the basal ganglia?

Answer 11

• function is poorly understood but in mammals supposed to have a role in priming the UMN circuits for initiation of movements and to suppress unwanted movements

Question 12

What is the main function of the cerebellum and where is it located?

Answer 12

• located on the dorsal surface of the pons

- only regulates upper motor neuron activity

Question 13

What are the differences in the ascending pathways to the cerebral cortex and the cerebellum?

Answer 13

• 2 different pathways to the cerebral cortex follow a similar pattern with 1st, 2nd and 3rd order neurons all of which pass through the thalamus
• pathway to the cerebellum is much more direct- only 1st and second order neurons (they do not pass through the thalamus)

Question 14

What are the names and origins of the ascending spinal tracts to the cerebral cortex?

Answer 14

• fasiculus gracilis - contains ascending fibres from limbs and trunks caudal to T6
• fasiculus cuneatus- contains fibres from thoracic limbs and trunk that is cranial to T6
• the trigeminal pathway carries information from the face

Question 15

What are the names and the origins of the ascending spinal tracts to the cerebellum?

Answer 15

• dorsal spinocerebellar tract and the ventral spinocerebellar tracts carry information from the muscle spindles, GTO’s and the joint receptors
• spinocuneocerebellar and rostral spinocerebellar tracts carry proprioceptive information from the thoracic limbs

Question 16

What are the primary clinical signs that are seen with proprioceptive deficits?

Answer 16

• ataxia is the principal signs that is seen and often toe dragging or knuckling can also be seen as a common clinical sign

Question 17

State the three main categories of pain and state what the stimulus for each is:

Answer 17

• nociceptive- occurs from brief trauma- brief pain ( the normal response to acute tissue injury)
• inflammatory pain- inflammation- persistant pain in response to peripheral or central den-sensitisation
• neuropathic- nerve or CNS damage- abnormal and can be long lasting

Question 18

State the nerve that innervates the pudundal nerve, its function and status in storage and voiding:

Answer 18

• sacral somatic nerve
• function is the contraction of the external sphincter to urethral striated muscle (nictonic cholinergic)
• active in storage, but inhibited during voiding

Question 19

State the nerve that innervates the hypogastric nerve and state it’s function and status in storage and voiding:

Answer 19

• innervated by the lumbar sympathetic nerve
• contraction of internal sphincter muscle (a-adrenergic)
• relaxation of the detrusor muscle (B-adrenergic)
• storage- active, voiding inhibited

Question 20

State the nerve that innervates the pelvic nerve, state its function and status in storage and voiding:

Answer 20

• sacral parasympathetic nerve
• contraction of detrusor muscle (mAchR) and dilation of urethral smooth muscle via parasympathetically mediated NO release
• Inhibited in storage, but is active during voiding