Question

Describe how the following would change if you were to extend your arm at the elbow (that is, stretch the biceps).
a) the length of the muscle spindles in the biceps muscle
b) the firing of muscle-spindle afferents from the biceps muscle
c) the firing of alpha motor neurons that project to biceps muscle extrafusal fibers (assume you are trying to hold your arm in place.)

Answer 1

Answer:

a. The biceps would relax causing it to increase in length

b. The firing of the muscle-spindle afferents from the biceps would decrease.

c. The alpha motor neurons would contract or decrease.

Explanation:

The skeletal joints in the human or animal body are controlled by muscles. Examples of these muscles are the biceps and triceps found in the human arm. They control the elbow joint with the biceps in front and triceps at the back of the elbow.

When the arm is extended from the elbow, the biceps relaxes or extends while the triceps contracts. This increases the length of the biceps and reduces the triceps length.

Answer 2

We have that for the Question "Describe how the following would change if you were to extend your arm at the elbow (that is, stretch the biceps)"

Answers:

• A) Muscle spindles are receptor existing in the muscle which feel the charge of exchange of size of muscle as properly as the size of muscle fibres. These are receptor existing in spiral structure around the intrafusal fibres. When muscle fibres are stretched that is stretching of extrafusal fibres motives simultaneous stretch of intrafusal fibres and so the stretch of muscle spindles due to the fact muscle spindles are current parallel to the extrafusal fibres. Therefore the spindle size enlarge when muscle size is increased.

• B) when we lengthen our arm at elbow ,the biceps size amplify which stimulate the muscle spindles . This stimulation is essential due to the fact the activation of muscle spindles initiates the afferent impulse which contains data to the brain and overstretching of the muscle is averted . To forestall overstretching ,Motor fibres are activated which contract the muscle . So firing od muscle spindles increases.

• C) the firing from the alpha motor neurones is extended due to the fact to preserve arm in region we need to observe pressure at elbow joint . There for this voluntary muscle contraction alpha motor neurones firing increases.

For more information on this visit

https://brainly.com/question/17756498