Question

Mary went on a run at the park to get her mind off her busy week. When she went on her run she saw a huge bear. She was in shock and froze, feeling her muscles starting to constrict and finding herself having trouble breathing. When the bear started coming after her she panicked and ran for her life.

1. Which of the following are true of her autonomic nervous system?

A. Mary’s muscles were being innervated by the cranial and sacral region of her sympathetic nervous system.

B. Mary’s ventricle columns of her periaqueductal gray caused her immobility.

C. Cortisol and adrenaline were being released and spread through her body causing the excitation of her muscles and inhibition of her bronchioles.

D. Two are correct.

E. All are correct.

2. As Mary ran away she luckily lost the bear but she ran so fast that she tripped over a log of wood hitting her knee pretty hard and screaming “OUCH.” Which of the following correctly explain her efferent pathways which are taking the information back from her Central Nervous System to her motor neurons?

A. Her somatic motor neurons consist of several neural pathways from the Central Nervous System to innervate the skeletal muscle.

B. Her motor neurons consist of adrenergic receptors on its dendrites/ cell bodies which bind to neurotransmitters, adrenaline or noradrenaline

C. No more than ten of her muscle fibers are innervated per motor neuron.

D. All of the above.

E. None of the above.

3. As Mary was on her way home she decided to go to the doctor to make sure she didn’t get an infection from her fall. When she got there the doctor first took her vitals. He told her everything was fine with her leg but when he used a stethoscope to listen to her heartbeat he heard a lub-dub-whistle. Which of the following are correct?

A. Scar tissue has built up in her atrioventricular valve which makes opening of the valve harder.

B. The murmurs of the heart occurs during systole as the heart is ejecting blood during contraction.

C. The blood is moving by what's called turbulent flow.

D. Two are correct.

E. All are correct.

Answer 1

Answer 1:

Correct Answer : B

Explanation:

1. The periaqueductal gray matter is located around the cerebral aqueduct in the midbrain.
2. Dorsal and lateral parts of the periaqueductal gray matter is responsible for freezing immobility, tachycardia, running and jumping.

Incorrect answer

• Option A - incorrect - in fight and flight scenario, the sympathetic autonomous nervous system gets activated. This system receives it nerve supply from the thoracic and lumbar portion of the spinal cord
• Option C - incorrect - cortisol breaks down fat so that energy is available to the muscles. Adrenaline causes bronchodilation.

ANswer 2

Correct answer - c

Explanation: a motor neuron innervates not more than 10 myofibrils. This allows more finer control over muscle action.

Incorrect answer

Option A - incorrect - only motor pathways called the corticospinal tract is involved with motor innervation the skeletal muscle

Option b - incorrect- the neurotransmitters involved with skeletal muscle contractions and nerve impulse transmission is acetylcholine . They act on the nicotine receptor.

Answer 3

Correct answer - Option D

Explanation

• The murmur in this patient is diastolic murmur
• It has occurred after the second heart sound (dub)
• Diastolic murmur are always pathological unless proven otherwise.
• Mitral stenosis is a condition in which the mitral valve is narrowed due to fibrosis around the leaflets of the valves.
• the narrowed opening of the atrioventricular valve generates turbulence in the blood flow.
• This creates murmur.

Incorrect - B - incorrect- the murmur as described in the question has occured after the second heart sound, therefore it is a diastolic murmur. Plus murmur can occur in the diastolic phase of the cardiac cycle as well.