Human Anatomy and Physiology Answers

Which ion induces the synaptic vesicles to fuse with the presynaptic membrane (and eject their contents)?

a.
Ca2+

b.
Na+

c.
K+

d.
Cl-

e.
None of the above

What is the event that creates the absolute refractory period?

a.
Potassium leak channels close

b.
Calcium voltage-channels close

c.
Sodium voltage-gated channels inactivate and will not open until the membrane potential drops below threshold

d.
Localized ion concentrations become imbalanced so abnormal current flows result

e.
Potassium blocks the voltage-gated sodium channels, and continues to do so until removed by the Na+/K+ pump

During action potential repolarization, which of the following statements is correct?

a.
Sodium voltage-gated channels are open

b.
Chloride voltage-gated channels are open

c.
Potassium voltage-gated channels are open

d.
Potassium voltage-gated channels are closed

e.
Potassium leak channels are closed

At what point during an action potential do the sodium voltage-gated channels close?

a.
At the start of the hypopolarization phase

b.
At the start of the hyperpolarization phase

c.
At the end of the repolarization phase

d.
At the end of the depolarization phase

e.
The sodium voltage-gated channels are always slightly open

When a voltage-gated sodium channel opens, sodium ions rush into the cell. Why?

a.
The sodium channel pumps in sodium ions
b.
Potassium ions attract sodium ions
c.
The concentration gradient drives sodium ions into the cell
d.
There is a slight vacuum inside the axon
e.
None of the above

Which of the following is not happening during the depolarizing phase of an action potential?

a.
The cell membrane depolarizes
b.
Potassium voltage-gated channels open
c.
Sodium voltage-gated channels open
d.
The potential difference reverses (the inside of the cell actually gets slightly positive)
e.
All of the above occur during the depolarization phase of an action potential

In a resting state, which of the following best describes what is happening in the membrane of a skeletal muscle (sarcolemma) or neuron?

a.
Both the Na+ voltage-gated channels and the K+ voltage-gated channels are open
b.
Both the Na+ voltage-gated channels and the K+ voltage-gated channels are closed
c.
The Na+ voltage-gated channels are open and the K+ voltage-gated channels are closed
d.
The Na+ voltage-gated channels are closed and the K+ voltage-gated channels are open
e.
Both the Na+ and the K+ voltage-gated channels are open, and the Na+/K+ pumps are closed

How could you lower your risk of cardiovascular disease overall? What improvements do you need to make in your diet with respect to the amount and type of dietary fat to reduce your risk of heart disease? Give specific examples of foods you could add, reduce or substitute in your diet to improve the overall quantity and quality of fat in your diet.

If your diet is very low in fat (<20% of calories from fat), what dietary modifications can you make to fall within the recommended range?

Describe the gills as respiratory organs in non-chordates.
Explain the organization of nervous system in non-chordates.

2. (a)
Explain the mode of formation of coral reefs and their significance.
(b) Describe the different types of mouth parts found in insets with help of
diagrams.
(c)
3. (a)
Differentiate between Bipinnaria larva and Brachiolaria larva with the help of
diagram