All lectures

Question 1

What is the neural tube made up of at 4 weeks?

Answer 1

1) Prosencephalon
• Telencephalon
• Diencephalon

2) Mesencephalon

3) Rhombencephalon
• Metencephalon
• Myencephalon

Question 2

When are all neurones born by?

Answer 2

12 weeks

Question 3

What is the main input and output layer for the cerebral cortex?

Answer 3

Input
• Inner granular cell layer

Output
• Inner pyramidal cell layer

Question 4

What are the types of cortex, based on layers

Answer 4

1 layer: paleocortex
3 layers: archicortex
6 layers: neocortex

Question 5

What are the types of receptor, their fibre types and what they are sensitive to?

Which are rapid-adapting and which are slow-adapting receptors?

Answer 5

Hair follicle receptor - Both
  •  Direction
  •  II, Aβ
Meissner corpuscle - Rapid-adapting
  •  5-40Hz
  •  II, Aβ
Pacinian corpuscle - Rapid-adapting
  •  60-300 Hz
  •  II, Aβ
Merkel cell - Slow-adapting
  •  Touch, pressure
  •  II, Aβ
Raffini corpuscle - Slow-adapting
  •  Stretch 
  •  II, Aβ
Free nerves
  •  Pain
  •  IV, C Aδ

Question 6

What are the signs of sensory ataxia?

Answer 6

• Loss of two-touch discrimination
  
  • Romberg’s sign
  • Broad stamping gait

Question 7

Where does the following travel?

1) Contralateral unconscious proprioception
2) Ipsilateral unconscious proprioception

Answer 7

1) Anterior spinocerebellar tract

2) Posterior spinocerebellar tract

Question 8

What are the Brodman’s areas of the postcentral gyrus all responsible for?

Answer 8

1 = Cutaneous stimulus
2 = Tactile, shape identification
3a = Proprioception
3b = Primary somatosensory cortex

Question 9

Give the receptors for each fibre type on the roman numeral system.

Answer 9

Ia - Muscle spindle primary ending
Ib - Golgi tendon organ 
II - Muscle spindle secondary ending, kinesthesia 
III - Pain, temp, crude touch
IV - Pain, temp, fine touch

Question 10

Which extrapyrimidal tracts do and do not decussate?

Answer 10

DO:
• Tectospinal
• Rubrospinal

DO NOT:
• Vestibulospinal
• Pontine reticulospinal

BOTH:
• Medullary reticulospinal

Question 11

Decerebrate posturing and decorticate posturing

Answer 11

Decerebrate
• Lesion below or at red nucleus
• Loss of red nucleus function
• Extensor dominance

Decorticate
• Lesion above red nucleus
• Disinhibition of red nucleus
• Flexor dominance

Question 12

How is acetylcholine made?

Answer 12

Acetyl-CoA + Choline —choline acetyltransferase–> Acetylcholine

Question 13

What are the three types of motor units

Answer 13

Type I - slow twitch
• Slow
• Fatigue resistant

Type IIa - Intermediate
• Fast
• Fatigue resistant

Type IIb - fast
• Fastest
• Fatiguable

Question 14

LMN damage causes…?

Answer 14

• Flaccid paralysis
  
  • Fasciculations and fibrillations
  • Complete loss of reflexesg

Question 15

For both the pontine and the medullary reticulospinal tracts, state the following:

1) Which descending pathway the fibres run in
2) If they are ipsilateral or contralateral
3) Their function

Answer 15

Pontine:

1) Medial reticulospinal tract
2) Ipsilateral
3) Control of reflexes & EXTENSOR LMNs

Medullary

1) Lateral reticulospinal pathway
2) Both ipsilateral and contralateral
3) Initiation of patterned movements & FLEXOR LMNs

NB: paramedian midbrain reticular formation contains planning INFORMATION for walking, medullary RF just initiates it.

Question 16

For the lateral and anterior corticospinal tracts state the following:

1) Does it travel ipsilaterally or contralaterally?
2) What is the function?

Answer 16

Lateral corticospinal tract

1) Contralateral
2) Distal musculature (closer to the distal side of the ventral horn)

Anterior corticospinal tract

1) Ipsilateral
2) Proximal musculature

Question 17

What is the origin of the tectospinal tract?

Answer 17

SUPERIOR colliculus

Question 18

Which reflex is monosynaptic?

Answer 18

Stretch reflex

Question 19

Which proteins are involved in Ach vesicle exocytosis?

Answer 19

Vesicle-bound:
• Synaptobrevin

Membrane-bound:
• SNAP25
• Syntaxin

Question 20

What is the role of the lateral and medial vestibulospinal tracts?

Answer 20

Lateral:
• Antigravity muscles
Medial:
• Neck movements

Question 21

What are the subunits of a nicotinic receptor? Which does acetylcholine bind to?

What ion movements does this receptor allow?

Answer 21

• 2 x α
  
  • β
  • δ
  • 𝛾 (INFANTS) OR 𝜀 (ADULTS)

Acetylcholine binds to alpha

Allows Na+ in and K+ out, but there is a net influx of charge.

Question 22

What are the two types of calcium channels seen in muscle cells and where are they?

Answer 22

Sarcolemma
• L-type DHP receptors
Sarcoplasmic reticulum
• Ryanodine receptors

Question 23

What substances inhibit ryanodine receptors?

Answer 23

• Caffeine
  
  • Ryanodine
  • Alkaloids