Excitable cells 6: Anatomy and function 2

Question 1

Human brain dorsal view structure

Answer 1

Precentral gyrus
Central sulcus
Post-central gyrus

Central fissure down middle

Question 2

4 major regions of spinal nerve bilateral connections in the spinal cord i.e spinal segments?

Answer 2

From head to toe:
Cervical
Thoraic
Lumbar
Sacral

Question 3

What is a dermatome?

Answer 3

a region of skin innervated by dorsal roots from one spinal segment

Question 4

What effect does diameter of nerve fibre have on speed of conduction?

Answer 4

Larger diameter = faster conduction

Smaller diameter = slower conduction

Question 5

4 types of sensory neuron and their roles

• > order from largest diameter to smallest
• > which are myleinated?

Answer 5

Aalpha -> skeletal muscle proprioceptor

Abeta -> skin mechanoceptor

Adelta -> pain, temperature

C -> pain, temperature, itch

all myleinated except C

Question 6

2 types of motor neurone?

-> order in largest diameter to smallest

Answer 6

Aalpha - a-motor (-> extrafusal)

Agamma - g-motor (-> intrafusal)

Question 7

Describe ascending pathway for ‘touch’

-> what is the full name of this pathway?

Answer 7

Dorsal Column Medial Lemniscal Pathway

1) Afferent Abeta-fibres from dorsal root ganglion enter spinal cord & ascend ipsilateral dorsal column to make
Synapse-1 at MEDULLA

2) Secondary afferents decussate, then follow medial lemniscus to make Synapse-2 at THALAMUS
3) Tertiary afferents make Synapse-3 at PRIMARY SENSORY CORTEX

Question 8

Describe ascending pathway for ‘pain’

-> what is the full name of this pathway?

Answer 8

Spinothalamic pathway

1) Afferent Adelta and C-fibres from dorsal root ganglion and make synapse-1 immediately on entering SPINAL CORD

2) Secondary afferents decussate and ascend
contralateral lateral column to make Synapse-2 at THALAMUS

3) Tertiary afferents make Synapse-3 at primary sensory cortex.

Question 9

Basic summary of the autonomic nervous system

Answer 9

parasympathetic

• (originates) preganglionic nuclei in medulla and sacral cord
• cholinergic efferents
• maintains homeostasis at rest

sympathetic

• (originates) preganglionic nuclei in thoracic and lumbar chord
• adrenergic efferents
• prepares for fight or flight

Question 10

Head ganglion of the autonomic nervous system?

Answer 10

Hypothalamus