Question

Martha decided to make some delicious homemade baked mac and cheese. She placed it in the oven that was really hot and when it was ready she took it out. While she left for a second, her son Elijah came in the kitchen and immediately went to grab the hot dish and yelled “OOWWW I BURNT MY HAND” his pain receptors screamed.

1. Which of the following correctly described the afferent pathway?

a) Transduction of the pain occurred outside the peripheral axons of the primary afferent neuron.

b) The AP travels through the cell body then the peripheral axons then the central axon

c) The AP travels through the peripheral axons then the cell body then the central axon.

d) Two of the above

e) None of the above

2. Elijah immediately took his hand off the dish by contracting his biceps. How did he accomplish this?

a) Shortened the sarcomere by shortening the thin and thick filaments

b) While shortening the sarcomere, he lost his H zone and the A band.

c) The troponin left the tropomyosin to do its job in covering up the actin binding site so cross bridges can’t form.

d) Two of above

e) None of the above

3. Elijah was so scared and frightened that he started having trouble breathing and became really anxious. As a patient with COPD, he was having a really hard time breathing so his mom ran to get his inhaler. What did the albuterol inhaler do?

a) Albuterol binds to cholinergic receptors in the bronchioles to move more air.

b) Caused his bronchioles to constrict.

c) Risked the possibility of the albuterol binding to adrenergic receptors in the heart and cause an EPSP

d) Two of the above

e) All of the above

Answer 1

1) d. Two of the above

Boe the options a) and b) are correct. The pain signal is first transformed into a different form of receivable energy by the help of transducers known as receptors. This transduced signals are then received by primary peripheral afferent neuron cell body. This is transmitted to the ventral afferent neuron and finally to the brain & spinal cord for final processes of the information.

2) e. None of the above

The immediate withdrawal of hands when touching the hot dish is mediated by the reflex arch. This arch directly sends the signals to the effector organs through spinal cord, so as to decrease the time required in transmitting it to brains and processing the information.

Now the effector organ undergoes contraction via decreasing the length of each sarcomere. Here no option correctly explains it because during contraction:

• The A band stays the same width and, at full contraction. The H zone, the central region of the A zone, contains only thick filaments and is shortened during contraction.
• The length of thick and thin filaments always remain the same. They only slide across each other.
• The tropomyosin doesn't cover the binding site and hence cross bridges do form.

Hope this helps. Please let me know if you have any query.

Best wishes!!