Question

1. Predict the effect of hypothermia and dehydration (low blood flow) on release of neurotransmitter (ACh) on the muscle fiber?

(Think about the relationship of aerobic mechanism, ATP, mitochondria, exocytosis, active and transport)

a. more ACh releases

b. less ACh release

c. same amount of ACh releaes

d. none of the choices

2. Acetylcholine is released from a neuron /

a. Through exocytosis when a vesicle fuses with the membrane.

b. by rapid diffusion when a voltage-gated ion channel opens for it.

c. by conduction through a gap junction from nerve to muscle.

d. by a primary active transport pump.

3. Predict what will happen if most of the ACh-esterase were removed from synaptic cleft: less Ach will be available

a. More ACh will be available

b. Less ACh will be available

c. There will be more Na/K pump activity

d. There will be less Na/K pump activity

4. The sodium-potassium pump moves/

a. sodium into the cell and potassium out of the cell

b.sodium out of the cell and potassium into the cell

c. sodium and potassium into the cell

d. sodium and potassium out of the cell

Answer 1

1. More ACH is produced.

As we are facing hypothermia and dehydration body is facing a stress situation. Now the homeostasis mechanism becomes activated as a complementary machnism and ATP is utilised for the production of heat and as a result the ACH is produced in excess. ACH can be injected iv to produce hyperthermia.

2. Through exocytosis when a vesicle fuses with the membrane.

When the neuronal impulse is transmitted bthw acetylcholine vesicles are transported to the presynaptic membrane by exocytosis and then it fuses with the membrane and then they are released to the synaptic cleft.

3. More Na+/k+ pump activity.

As Ach is not degraded by the ACH esterase ACH action increases and the Na+/k+ pump activity continue to function and thus it becomes the most suitable answer.

4. Sodium into the cell and potassium out of the cell.

In this pump it works aginast the concentration gradient band needs energy utilisation. So it uses ATP to pump sodium inwards and potassium outwards.