Lecture 2

Question 1

What is the F:N ratio and how is this manipulated in cell physiology?

Answer 1

Fibre to nerve ratio in muscles that perform fine and delicate movements have a lower F:N ratio compared to larger, more powerful muscle groups.

Question 2

How are the amount of motor units used regulated?

Answer 2

The amount of motor units utilized depends on the task and the requirement

Question 3

What is the difference in mitochondrial enzyme presence, capillarization, and glycogen levels in type S, FF, and FR fibers?

Answer 3

Type S fibers have high amount of mitochondrial enzymes and rich capillarization.
Type FF have low Mt enzymes and poor capillarization.
Type FR have high Mt enzymes as well as glycogen which makes them able to sustain powerful contractions.

Question 4

What fiber types are present and what sub group do they belong to?

Answer 4

FF = 2B or 2X fibers
FR = type 2A
S = type 1

Question 5

Describe Hennemenn’s size principle.

Answer 5

Slow motor units incorporated first and fast later

Question 6

Does muscle spindle involve the spinal cord?

Answer 6

Yes

Question 7

What is the function of golgi tendon organs

Answer 7

Golgi tendon organs inhibit alpha motor neurons when load is excessive.

Question 8

How does the knee jerk reflex occur if the hamstring muscle spindle reflex can act in response to the stretch caused by patellar tendon tap?

Answer 8

antagonistic muscle is reciprocally inhibited as part of the reflex

Question 9

What is a myotatic unit?

Answer 9

A collection of pathways controlling a single joint

Question 10

What is a monosynaptic stretch reflex?

Answer 10

The simplest reflex in a myotatic unit.

Question 11

How is a complex reflex like pulling a leg away from a drawing pin?

Answer 11

Divergent pathways are utilized to maintain balance while limb is drawn away from danger.