Sensory and Motor Systems 1

Question 1

Where does the spinal cord run from?

Answer 1

The foramen magnum and terminates between L1 and L2 as the conus medullaris.

Question 2

What are the vertebral enlargements and its significance?

Answer 2

Cervical enlargement is where the brachial plexus exists the spinal cord. The lumbarsacral enlargement is where the lumbarsacral plexus exits the spinal cord but this is much more inferior to the enlargement than the cervical enlargement.

Question 3

What is the cauda equina?

Answer 3

Bundle of spinal nerves continuing from the conus medullaris to the coccyx.

Question 4

Where are lumbar punctures performed?

Answer 4

Between L3 and L4-> The cauda equina ends at level L1 and L2.

Question 5

What is the subarachnoid space?

Answer 5

The space between the pia mater and the arachnoid mater. It contains cerebral spinal fluid and enlarged pockets of CSF called cisterns.

Question 6

What is the epidural space?

Answer 6

The space between the dura mater of the spinal cord and the vertebral column.

Question 7

Where are epidurals injected?

Answer 7

In the epidural space between the dura mater of the spinal cord and the vertebral column.

Question 8

Where do we obtain cerebrospinal fluid?

Answer 8

The subarachnoid space between the pia mater and the arachnoid mater.

Question 9

What is the filum terminale?

Answer 9

A fibrous non-neuronal extension of the pia mater from the conus medullaris of the spinal cord to the periosteum of the coccyx

Question 10

What is the meninges?

Answer 10

The three-layered membrane enclosing the brain and the spinal cord consisting of the pia mater, the middle arachnoid mater and both are derived from neural crest cells and the outer dura mater which is derived from the paraxial mesoderm.

Question 11

Why does the spinal cord terminate earlier than the vertebral column?

Answer 11

During development, the vertebral column grows at a faster rate.

Question 12

What are the variations of the spinal cord matter in the cervical, throacic, lumbar and sacral?

Answer 12

Sacral has the greatest proportion of white matter ; Cervical has the greatest proportion of grey matter

Question 13

What does the grey matter of the spinal cord contain?

Answer 13

Soma and ganglions for sensation

Question 14

What does the white matter of the spinal cord contain?

Answer 14

Axons for stimulation

Question 15

What is the role of the central canal of the spinal cord?

Answer 15

Transports cerebrospinal fluid from the ventricular system of the brain for nutrients.

Question 16

What is funiculi?

Answer 16

A bundle of axons in the white matter

Question 16

What is the ventral white commissure?

Answer 16

A bundle of axons which cross the midline of the spinal cord

Question 17

What is the role of the gracile faniculus?

Answer 17

Bundle of axons in the spinal cord lateral to the dorsal medial fissure where first order neurons pass through without decussating to enter the medulla oblaganta and synapsse with second order neurons in the medial leminiscus. Gracile fasiculus is important for fine touch,

Question 17

What is the role of the gracile faniculus?

Answer 17

Bundle of axons in the spinal cord lateral to the dorsal medial fissure where first order neurons pass through without decussating to enter the medulla oblaganta and synapsse with second order neurons in the medial leminiscus. Gracile fasiculus is important for fine touch, vibration and propioception.

Question 18

What is the cuneate faniculus?

Answer 18

Bundle of axons in the spinal cord lateral to the gracile fasiculus important for fine touch, vibration and propioception where first order neurons pass through ipsilaterally without decussating to enter the medulla oblaganta and synapse with second order neurons in the medial leminiscus before decussating contralaterally.

Question 19

What is the function of the fourth ventricle?

Answer 19

Cushion the brain from trauma and form the central canal to transmit cerebral spinal fluid to the spinal cord

Question 20

What are the cerebral peduncles?

Answer 20

Stalks which connect the cerebrum to the midbrain for communication with the spinal cord for sensation and inducing stimuli

Question 21

What are the colliculus?

Answer 21

Two paired structure in the rostral midbrain which receive input about environmental stimuli to co-ordinate eye and head movement. There is a superior colliculi and inferior colliculi.

Question 22

What information does the superior colliculus integrate?

Answer 22

Present on the midbrain to receive input from the retina for vision.

Question 23

What does rostral mean in the brain?

Answer 23

Front of the brain

Question 24

What information does the inferior colliculus integrate?

Answer 24

Present on the midbrain to receive input from the ear for hearing

Question 25

What is the tectum?

Answer 25

Part of the midbrain posterior to the cerebral aqueduct that contains both the superior or inferior colliculi for auditory and vision input

Question 26

Why is the midbrain important for nerves?

Answer 26

Cranial nerves arise from the brainstem

Question 26

What are the cerebellar peduncles?

Answer 26

Connect the cerebellum to the midbrain and the cerebrum

Question 27

What is the function of the brainstem?

Answer 27

Breathing, heart rate, blood pressure regulation, swallowing reflex, consciousness and wakefullness.

Question 28

What are the consequences of brainstem death?

Answer 28

Loss of ability to independently breathe, swallow, regulate blood pressure and heart rate

Question 29

What is 2-point discriminative touch?

Answer 29

Able to locate touch in both the limb and the precisely spot,

Question 30

What is superficial sensation?

Answer 30

Somatic afferent nerve from the skin which is highly localised.

Question 31

What is deep sensation?

Answer 31

Somatic afferent nerve from the muscles, connective tissue and tendons which is localised.

Question 32

What is visceral sensation?

Answer 32

Visceral afferent nerve from the organs such as hunger and nausea.

Question 33

What is special sensation?

Answer 33

Sight, smell, hearing from the cranial nerves

Question 34

What is the sensory cortex?

Answer 34

In the post-central gyrus which maps out areas of the body corresponding to the body parts in the somatosensorytropic map

Question 35

What is the spinocerebellar tract?

Answer 35

Unconscious sensation to modulate balance and propioception

Question 36

What is the spinotectal tract?

Answer 36

Unconscious sensation of vision and hearing to modulate our head and eye movement towards it

Question 37

What is the spinoreticular tract?

Answer 37

Unconscious sensation to induces or maintains wakefullness

Question 38

What is the spino-olivary tract?

Answer 38

Unconscious sensation to modulate cerebellar activity to environmental change

Question 39

Where is the medial leminiscus?

Answer 39

Medial surface of the spinal cord in the medulla where first order neurons of the dorsal column pathway decussate ipsilaterally

Question 40

How do lesions more medial in the dorsal horn of the spinal cord affect the body?

Answer 40

Pain, temperature and crude touch: Below lesion, there will be contralateral loss of these sensations in the lower limbs
Fine touch, vibration, pressure and propioception: Below lesion, there will be ipsilateral loss of these sensations in the lower limbs if below medulla

Question 41

How do lateral lesions in the dorsal horn of the spinal cord affect the body?

Answer 41

Pain, temperature and crude touch: Below lesion, there will be loss of these sensations in the upper limbs
Fine touch, vibration, pressure and propioception: Below lesion, there will be loss of these sensations in the upper limbs