L10. Central Nervous System

Question 1

Brain and Spinal Cord consists of:

Answer 1

> Grey matter: cell bodies, dendrites, unmyelinated axons

> White matter: mylinated axons

Question 2

4 major components of the brain:

Answer 2

• CEREBRUM
• DIENCEPHALON: thalamus and hypothalamus
• BRAINSTEM: medulla, pons, midbrain
• CEREBELLUM

Question 3

Cerebrum

Answer 3

Left and right hemisphere:

• separated by longitudinal fissure
• connected by corpus callosum
• each has 4 lobes (frontal, temporal, parietal, occipital)
• grey matter outside (gyri=folds)
• white matter inside

Question 4

Frontal Lobe

Answer 4

• Intellect
• Cognition
• Personality
• Conscience
• motor function (voluntary)
• Broca’s area (producing speech)

Question 5

Temporal Lobe

Answer 5

• Auditory (hearing)
• Olfactory (smelling)
• Wernicke’s area (understanding speech)

Question 6

Parietal Lobe

Answer 6

• Touch
• Pressure
• Pain
• Temperature
• Taste

Question 7

Occipital Lobe

Answer 7

• Visual processing

Question 8

Diencephalon

Answer 8

THALAMUS

• receiving and relay to cortex
• crossing over (any sensory info from the top of the brain crosses over at the thalamus to the other side)

HYPOTHALAMUS
- control gland

Question 9

Cerebellum

Answer 9

• control of posture
• proprioception
• balance; motor coordination

Question 10

Brain stem

Answer 10

Regulates essential functions:

• heart rate, blood pressure
• resperation
• vomiting, coughing

MIDBRAIN: reflex centre for head and eye movements
PONS: control of respiration
MEDULLA: pathway between higher and lower centres
- crossing over (motor fibres coming out of the brain crosses over in the medulla)

Question 11

Cranial nerves

Answer 11

• direct connection between brain and PNS
• 12 pairs
• cranial nerves I-XII
• most work locally (head and neck)
• sensory and motor function

Question 12

What’s special about vagus nerve (X)?

Answer 12

• only nerve that does not work locally (head/ neck)

- vagus nerve (X) extends from he head down to supply thorax and abdomen

Question 13

Spinal nerves

Answer 13

• each side of spine (dorsal and ventral roots join to form a spinal nerve)
• 31 pairs
• carry both sensory and motor function

Question 14

Spinal cord functions

Answer 14

• transmit information up and down CNS
• info from messages to peripheries
• reflex action to protect body

Question 15

Spinal cord structure

Answer 15

• flattened cylinder, about 45 cm
• medulla oblongata to L2 vertebrae
• Cervical enlargement- upper limbs
• Lumber enlargement- lower limbs

Question 16

Cross section of spinal cord

Answer 16

• grey matter inside (H-shape) and white matter outside
• Central canal for CSF
• nerve root where spinal nerve connects to spinal cord

Question 17

Spinal root branches

Answer 17

• ANTERIOR/ VENTRAL ROOT: contains axons of motor (efferent) neurons
• POSTERIOR/ DORSAL ROOT: contains axons of sensory (afferent) neurons

Question 18

5 components of a spinal reflex:

Answer 18

1. receptor (arrival of stimulus and activation of receptor)
2. sensory neuron (activation of sensory neuron)
3. integrating centre (information processing in the CNS)
4. motor neuron (activation of a motor neuron)
5. effector (response by effector)