Movement

Question 1

Where do reflexes occur?

Answer 1

Brainstem/spinal cord region.

Question 2

Why is recruitment quick in reflex movements.

Answer 2

The are monosynaptic.

Question 3

How many axons/neurons are present in the descending pathway?

Answer 3

2

Question 4

Explain what both the upper and the lower motor neuron do.

Answer 4

Upper: Projects from the motor cortex in the brain to the brainstem/spinal cord.
Lower innervates the muscle groups.

Question 5

What are somatic reflexes?

Answer 5

Protection mechanisms.

Question 6

What fibres are activated in the tendon-jerk reflex?

Answer 6

1A sensory fibres.

Question 7

What reflex has a conscious element?

Answer 7

Flexion withdrawal reflex. Has visual and sensory cues that make the individual aware of the consequences.

Question 8

What does the flexion withdrawal reflex have that connects the motor and sensory fibres?

Answer 8

An interneuron.

Question 9

What structure causes inhibition of neurons? What afferents does this contain and how does it operate?

Answer 9

Golgi tendon organ.
Group 1b afferents.
Projects into the spinal cord and activates the inhibitory neuron.

Question 10

Where is there no golgi tendon organ? What, in its place, performs the same function?

Answer 10

In jaw muscles. Periodontal ligament used to asses the applied forces.

Question 11

How does the gag reflex work?

Answer 11

Activation by mechanoreceptors in the soft palate/posterior part of tongue.
Activates glossopharyngeal sensory afferent fibres which terminate in the caudal part of the spinal trigeminal nucleus.
This activates second order neurons which bifurcate to allow motor neurons to supply both sides of the throat.

Question 12

What structures do reflexes also trigger? (Hint: Fluid)

Answer 12

Glands.

Question 13

Name examples of semi-automatic movements

Answer 13

Breathing, chewing, walking.

Question 14

What are semi-automatic movements directed by? What 2 types of neurons are active?

Answer 14

Central pattern generators.

Excitatory and inhibitory.

Question 15

What is the pathway for facial movement called?

Answer 15

Corticobulbar.

Question 16

What is the pathway for other movements called?

Answer 16

Corticospinal.

Question 17

What commands ensure a functioning gag?

Answer 17

Bilateral descending cortical commands. Synchronous bilateral muscle contraction.

Question 18

In relation to damage of the descending sensory pathways; What is anaesthesia?

Answer 18

Loss of sensation.

Question 19

In relation to damage of the descending sensory pathways; What is paraesthesia?

Answer 19

Altered sensations.

Question 20

In relation to damage of the descending motor pathways; What is palsy?

Answer 20

Paralysis.

Question 21

Name a difference between damage to the upper neurons and the lower neurons.

Answer 21

Damage to the lower neurones prevent voluntary movement and reflexes. However in damage to the upper neuron reflexes can become exaggerated.

Question 22

Name the two additional descending motor projections.

Answer 22

Basal Ganglia.

Cerebellum.

Question 23

What does the basal ganglia allow?

Answer 23

Sudden changes of movement.

Question 24

Name the action centres of the basal ganglia.

Answer 24

Corpus striatum: Caudate nucleus, putamen and globus pallidus.
Sub-thalamic nuclei.
Substantia.

Question 25

Name two diseases that affect the basal ganglia. Name the two classes they fall into. (Hint: Kinetic)

Answer 25

Parkinsons and huntingtons.

Question 26

What causes parkinsons?

Answer 26

Black cells of the substantial nigra don’t produce dopamine.

Question 27

What causes huntingtons?

Answer 27

Selective loss of inhibitory neurons (GABA) in the crops striatum.