Somatic Control

Question 1

somatic control in general

Answer 1

control of skeletal muscle - motor control
reflex loop in and out, reflex movements
precise voluntary movements
autonomic movements, rhythmic patterns of motion
includes motor units
all via ‘final communication pathway

Question 2

reflexes

Answer 2

organised neural circuit
usually organised within spinal cord
a predictable, reproducible, autonomic response to a particular sensory stimulus

Question 3

Stretch reflex

Answer 3

when the tendon is tapped the signal is sent to the stretch receptor which is the muscle spindle.
this signal travels to the dorsal root in the spinal cord. here there is an interneuron between the sensory and the motor neuron (which makes it monosynaptic)
the signal is sent to the motor neuron that comes out of the ventral root.
the motor neuron travels to the same muscle that was stretched and the quadriceps become the effector.
this is the reflex circuit

Question 4

Withdrawal reflex

Answer 4

before the signal even reaches the brain the withdrawal reflex has occurred
we have inhibitory and excitatory interneurons in the spine which send signals back down the motor neurons to the muscles to cause movement or stop it (relax).
the goal of the reflex arc is to be able to to lift our feet from the painful stimulus and also stay standing.

Question 5

interneurons

Answer 5

short and between the sensory neuron and the motor output

Question 6

the pre frontal motor cortex

Answer 6

the goal, what movement we want to produce

Question 7

pre motor cortex

Answer 7

the motor program designed

Question 8

primary motor cortex

Answer 8

activation of specific motor units, where the signal is sent out of the pre central gyrus to the required muscles

Question 9

Corticospinal pathway (pyramidal tract)

Answer 9

efferent information (down, across down)
upper motor neuron
- from the primary motor cortex to the beginning of the spinal cord.
- crosses over at the medulla (pyramid in the medulla)
- excitatory synapse onto lower motor neuron
- sometimes an interneuron
lower motor neuron
- to the motor end plate (hands and feet)
controls precise movements of hands and feet

Question 10

Non-corticospinal pathway (extrapyramidal)

Answer 10

crosses over at the midbrain and not the pyramid in the medulla
excitatory and inhibitory
doesn’t go through the pyramid of the medulla, hence why it is called extrapyramidal

Question 11

Basal nuclei function

Answer 11

pre-planning our movement, the initial step before we do anything. deep part of the brain

• modify movement using a ‘loop’ system within the cortex
• help select an appropriate movement for given situation.

Question 12

The Cerebellum (little brain)

Answer 12

ensures the selected movement is coordinated, guided by sensory feedback
compared intention with results, compared one thing to another
maintenance of posture
compares intention with result
we can make corrections if our movement goes wrong

Question 13

procedural memory

Answer 13

development of autonomic movement/ motor programmes

Question 14

Basal Nuclei structure

Answer 14

Lentiform nucleus
Caudate nucleus
Amygdaloid nucleus
the collection of nuclei below the cortex
inhibition of inappropriate movement
reward system in the brain, positive reward signal to the muscle movements
at rest the basal nuclei inhibit the cortex
inhibition of inhibition allows us to move

Question 15

How the cerebellum works

Answer 15

motor cortex signals to the lower motor neurons via the thalamus
at the same time the motor cortex sends signals to the cerebellum
sensory signals send feedback to the cerebellum
cerebellum compares actual movement to intended movement and signals adjustment to cortex and muscle