Endocrine and Nervous System

Question 1

Which hormone stimulates hormone production by the ovaries and testes?

Answer 1

luteinizing hormone (LH)

Question 2

Which of these glands secretes releasing hormones?

Answer 2

hypothalamusThe hypothalamus secretes both releasing and inhibiting hormones.

Question 3

Which of these hormones are responsible for the “fight or flight” response to danger?

Answer 3

epinephrine and norepinephrine

These hormones, secreted by the adrenal medulla, are responsible for the “fight or flight” response.

Question 4

Adrenocorticotropic hormone (ACTH) triggers the release of _____ in response to stress.

Answer 4

glucocorticoids

In response to stress, ACTH stimulates the adrenal cortex to secrete glucocorticoids.

Question 5

_____ are the main male hormones.

Answer 5

Androgens.

Androgens, such as testosterone, are the main male hormones.

Question 6

What hormone promotes water retention by the kidneys?

Answer 6

antidiuretic hormone (ADH)

A diuretic promotes water loss; thus it makes sense that ADH (secreted by the anterior pituitary) promotes water conservation.

Question 7

Which hormone opposes the action of parathyroid hormone?

Answer 7

calcitonin

Parathyroid hormone increases blood calcium levels; calcitonin lowers blood calcium levels.

Question 8

Which hormone stimulates milk production?

Answer 8

Prolactin, secreted by the anterior pituitary, stimulates milk production by the mammary glands.

Question 9

What are the two most common types of gated channels?

Answer 9

Ligand and voltage gated

Question 10

What are voltage gated channels?

Answer 10

Voltage-gated channels open and close in response to changes in the membrane potential, or voltage across the axon membrane. Voltage-gated channels function in the conduction of action potentials along axons.

Question 11

What are ligand gated channels?

Answer 11

Ligand-gated channels open and close in response to the binding of specific compounds to the channel protein. Ligand-gated channels function at the synapses, where information is passed from one cell to another.

Question 12

What is a resting potential?

Answer 12

The membrane potential of a neuron that is not sending signals is called the resting potential. Recall that membrane potential is the difference in charge (measured as voltage) across a membrane, which is caused by the uneven distribution of ions between the two sides of the membrane. Under most conditions, there is an excess of negative charge inside the cell relative to outside, so the membrane potential is represented by a negative number. This is the case at resting potential, where the membrane potential is about -70 mV.

Question 13

Describe the Na/K pump

Answer 13

The sodium-potassium pump operates continuously in the plasma membrane of a neuron, including at resting potential. The hydrolysis of one ATP provides the energy for three Na+ ions to be pumped out of the cell and two K+ ions to be pumped into the cell; the ions are pumped against their respective concentration gradients. This animation shows how the sodium-potassium pump operates.

Question 14

What can you infer about the movement of ions at resting potential?

Answer 14

For every Na+ or K+ transported by the sodium-potassium pump, a corresponding Na+ or K+ crosses the membrane in the opposite direction through a channel.

At resting potential, the membrane potential remains constant because the movement of Na+ and K+ ions driven by the sodium-potassium pump is balanced by an equal and opposite movement of Na+ and K+ ions through non-gated channels. Thus there is no net movement of charge, even though many charges are moving.

Question 15

Which term describes the difference in electrical charge across a membrane?

Answer 15

Membrane potentail

Question 16

True or false? The potential energy of a membrane potential comes solely from the difference in electrical charge across the membran

Answer 16

False.
The potential energy of a membrane potential comes both from the difference in electrical charge and from the concentration gradient of ions across a membrane.