Exam 2: Membrane Potentials, Endocrine, SNS/ANS

Which of the following would likely result in a cell's resting membrane potential stabilizing at 0mV?

Na+/K+ pumps stopped functioning

For an action potential to occur:

-The stimulus must reach or exceed threshold

-Sodium movement into the cell must exceed potassium movement out of the cell

In a neuron, an action potential originates at the ________ and travels along the axon until it reaches the ________.

axon hillock: axon terminal

Hypokalemia will result in

Difficulty achieving threshold & Hyperpolarization at rest

Choose the most likely voltage to CLOSE the voltage-gated Na+ channels in the axon of a neuron.

30 mV

In myelinated axons, voltage-gated sodium channels would be concentrated in which area(s)?

nodes & axon hillock

What is the primary difference between graded potentials versus actions potentials?

In neurons, action potentials occur in axons, while graded potentials occur in the dendrites and cell bodies

The absolute refractory period of a neuron has primarily to do with

the status of the voltage-gated Na+ channels

Opening gated Na+ channels in a resting cell membrane would result in

-the inside and the outside of the cell membrane becoming more similar in charge

-depolarization

What type of ion channels are responsible for establishing the resting membrane potential of a cell?

leak channels

Graded potentials can be either depolarizing or hyperpolarizing. True or false?

False

If the graded potential is at or above threshold once it reaches the ________ of the neuron, an action potential will be generated.

axon hillock

The cell would be in the relative refractory period when...

-The voltage-gated K+ gates are open

-The cell is slightly hyperpolarized

A below-threshold stimulus does not generate an action potential, but a threshold or above-threshold stimulus does generate an action potential. This is a description of...

the all-or-none principle.

The posterior pituitary is also known as the __________.

neurohypophysis

Which hormone is released in response to low levels of calcium in the blood plasma?

parathyroid hormone

Which of these endocrine disorders could be described with the following symptoms: high metabolism, sleep disturbances, exophthalmos, goiter?

Grave's Disease

Which of the following hormones targets the anterior pituitary?

TRH

Which of the following hormones increases Na+ retention at the kidney?

Aldosterone

Chronic hypersecretion of a hormone can lead to __________ the receptor for that chemical messenger on the target cell.

-a change in the sensitivity of

-downregulation of

Which of these represents a hyposecretion disorder?

Diabetes Insipidus & Addison's Disease

Choose the target(s) for ADH.

Kidneys & Blood Vessels

Glycogenolysis may be stimulated by which of the following hormones?

Glucagon, cortisol, epinephrine

A person is diagnosed with hyposecretion of testosterone and his levels of testosterone, LH, and GnRH all measure lower than normal values. What is the most likely diagnosis?

tertiary hyposecretion

Which phase of the general adaptation syndrome includes elevated levels of epinephrine?

alarm phase

Prolactin releasing hormone (PRH) targets the

anterior pituitary

Choose the hormone released due to humoral feedback.

PTH

Choose the lipid-soluble hormone.

corticosterone

Choose the hormone that MUST bind to a cell membrane receptor.

Calcitonin and epinephrine

Which of the following is a hypophysiotropic hormone?

GHIH

Which is a metabolic effect of epinephrine hormone?

Lipolysis, increased skeletal muscle metabolism, glycogenolysis in skeletal muscle

Choose the hormone that is released daily due to circadian rhythms AND serves to elevate circulating blood plasma nutrient levels.

Cortisol

Which hypothalamus hormone is responsible for stimulating the release of luteinizing hormone from the anterior pituitary?

gonadotropin releasing hormone

Which pancreatic cell type secretes glucagon?

Alpha cells

What is the function of follicle stimulating hormone in males?

causes spermatogenesis

What are the chemical classes of hormones? SELECT ALL THAT APPLY!

A. Water-soluble amines

B. Peptides

C. Lipid-soluble amines

D. Steroids

All of the above

Which of these factors can reduce the negative impact of chronic cortisol secretion?

preparation

Oxytocin is produced by neurons in the hypothalamus, but oxytocin released into the bloodstream where?

neurohypophysis

The hormone that DECREASES circulating nutrient levels in the bloodstream.

Insulin

Which of the following activities is consistent with the major function of insulin?

Glycogenesis

Acromegaly is caused by hypersecretion of thyroid hormone. T or F?

False

Androgen insensitivity represents a hyporesponsiveness disorder. T or F?

True

A tumor that stimulates hypersecretion by the parathyroid gland would cause blood plasma Ca++ to increase. T or F?

True

Predict the response of the smooth muscle of the intestine to sympathetic nervous system stimulation.

inhibition and relaxation.

The neurotransmitter used between a postganglionic sympathetic neuron and a cardiac muscle cell is:

norepinephrine

The preganglionic synapses in the parasympathetic nervous system are:

excitatory & cholinergic

Students who suffer from test anxiety often have some of the following symptoms: increased heart rate, dilated pupils, and a dry mouth. Which branch of the autonomic nervous system would cause these symptoms?

sympathetic

What is the effect of parasympathetic postganglionic acetylcholine?

A specific effector must be provided to determine the answer

Choose some effects of chronic cortisol secretion.

SELECT ALL THAT APPLY.

gluconeogenesis

vasoconstriction

hyperglycemia

decreased muscle mass

All of the above

According to the concept of dual innervation by the autonomic nervous system, if parasympathetic activity stimulates pancreatic digestive secretions, then the sympathetic nervous system should

Inhibit pancreatic secretions

Which neurons in the efferent nervous system are cholinergic? SELECT ALL THAT APPLY.

Preganglionic parasympathetic neurons

Somatic motor neurons

Postganglionic parasympathetic neurons

Postganglionic sympathetic neurons

-Preganglionic parasympathetic neurons

-Somatic motor neurons

-Postganglionic parasympathetic neurons

The somatic nervous system provides both excitatory and inhibitory signals to skeletal muscle. T or F?

False

Which of these branches of the efferent nervous system has a single neuron and a single synapse between neuron and effector?

somatic motor

Name the hormone. (No abbreviating. Spelling counts.)Released from: anterior pituitary

Targets: breast

Chemical class: peptide

Effect: causes lactation

prolactin

Name the hormone. (No abbreviating. Spelling counts.)

Released from: adrenal cortex

Targets: kidney

Chemical class: steroid

Effect: causes Na+ retention

aldosterone

Name the hormone. (No abbreviating. Spelling counts.)

Released from: hypothalamus

Targets: anterior pituitary

Chemical class: peptide

Effect: causes the anterior pituitary to release gonadotropins

gonadotropin releasing hormone

Name the hormone. (No abbreviating. Spelling counts.)

Released from: thyroid gland

Targets: osteoclasts in bone

Chemical class: peptide

Effect: decreases circulating blood Ca++

calcitonin