Exam 1 Review

Which of the following is one of the four basic cell types in the body?

• respiratory

• epithelial

• endocrine

• integumentary

• immune

epithelial

(Remember the 4 basic cell types: epithelial, muscle, nervous, and connective.)

Which of the following is INCORRECT?

a. Equilibrium requires constant energy input.

b. Positive feedback is less common in nature than negative feedback.

c. Homeostasis does not imply that a given variable is unchanging.

d. Fever is an example of resetting a set point.

e. Efferent pathways carry information away from the integrating center of a reflex arc.

a. Equilibrium requires constant energy input.

Steady state requires constant energy input - equilibrium does not.

In a reflex arc initiated by touching a hand to a hot stove, the effector belongs to which class of tissue?

a. nervous

b. connective

c. muscle

d. epithelial

c. muscle

Muscles carry out the response (removing hand from the stove).

Which statement is correct?

a. Circadian rhythms can only free-run; they cannot be fixed to environmental cues.

b. Being able to perceive color is an example of acclimatization.

c. Eating a very salty meal will create a period of positive sodium balance in the blood.

d. Drinking an excess of water will creative a negative balance of water in the body.

e. Acclimatization requires a modification of a person’s genetic makeup.

c. Eating a very salty meal will create a period of positive sodium balance in the blood.

Consuming an excess of an ion will temporarily create a positive balance of that ion.

Most of the water in the human body is found in…

a. the interstitial fluid compartment

b. the intracellular fluid compartment

c. the plasma compartment

d. the total extracellular fluid compartment

b. the intracellular fluid compartment

Intracellular fluid volume is greater than the sum of plasma and interstitial fluid.

The type of tissue involved in many types of transport processes, and which often lines the inner surfaces of tubular structures, is called ________.

epithelial (tissue)

All the fluid found outside of cells is collectively called _______ fluid.

extracellular

Extracellular fluid consists of ________ and ________ fluid.

plasma, interstitial

Physiological changes that occur in anticipation of a future change to a homeostatic variable are called _________ processes.

feedforward

A _________ is a chemical factor released by cells that acts on neighboring cells without having to first enter the blood.

paracrine factor

When loss of a substance from the body exceeds its gain, a person is said to be in _________ balance for that substance.

negative

Which properties are characteristic of ion channels?

a. They are usually lipids.

b. They exist on one side of the plasma membrane, usually the intracellular side.

c. They can open and close depending on the presence of any three types of “gates”.

d. They permit movement of ions against electrochemical gradients.

e. They mediate facilitated diffusion.

c. They can open and close depending on the presence of any three types of “gates”.

Channels are proteins that span the membrane and are opened by ligands, voltages, or mechanical stimuli.

Which of the following does NOT directly or indirectly require an energy source?

a. primary active transport

b. operation of the Na/K-ATPase pump

c. the mechanism used by cells to produce a calcium ion gradient across the plasma membrane

d. facilitated transport of glucose across a plasma membrane

e. secondary active transport

d. facilitated transport of glucose across a plasma membrane

Facilitated diffusion does not require ATP.

Secondary active transport indirectly requires ATP because ion pumps were required to establish the electrochemical gradient for a particular ion.

If a small amount of urea were added to an isoosmotic saline solution containing cells, what would be the result?

a. The cells would shrink and remain that way.

b. The cells would first shrink but be returned to normal volume after a brief period of time.

c. The cells would swell and remain that way.

d. The cells would first swell but be returned to normal volume after a brief period of time.

e. The urea would have no effect, even transiently.

b. The cells would first shrink but be returned to normal volume after a brief period of time.

After the initial movement of water out of the cells due to osmosis, the urea concentration quickly equilibrates across each cell’s plasma membrane, removing any osmotic stimulus.

Which is/are true of epithelial cells?

a. They can only move uncharged molecules under their surfaces.

b. They may have segregated functions on apical (luminal) and basolateral surfaces.

c. They cannot form tight junctions.

d. They depend upon the activity of Na/K-ATPase pumps for much of their transport functions.

e. Both B and D

e. Both B and D

Segregation of functions on different surfaces of the cell and the ability to secrete chemicals (e.g., from the pancreas) are two of the most important features of epithelial cells.

Which is incorrect?

A. Diffusion of a solute through a membrane is considerably quicker than diffusion of the same solute through a water layer of equal thickness.

B. A single ion, such as K+, can diffuse through more than one type of channel.

C. Lipid-soluble solutes diffuse more readily through the phospholipid bilayer of a plasma membrane than do water-soluble ones.

D. The rate of facilitated diffusion of a solute is limited by the number of transporters in the membrane at any given time.

E. A common example of cotransport is that of an ion and an organic molecule.

A. Diffusion of a solute through a membrane is considerably quicker than diffusion of the same solute through a water layer of equal thickness.

Diffusion is slowed by the resistance of a membrane.

In considering the diffusion of ions through an ion channel, which driving force/forces must be considered?

A. the ion concentration gradient

B. the electrical gradient

C. osmosis

D. facilitated diffusion

E. Both A and B

E. Both A and B

Because ions are charged, both the chemical and electrical gradients determine their rate and direction of diffusion.

The difference between the fluxes of a solute moving in two opposite directions is the _______.

net flux

In the process of _________, membrane-bound vesicles in the cytosol of a cell fuse with the plasma membrane and release their contents to the extracellular fluid.

exocytosis

The channels through which water moves across the plasma membrane are called __________.

aquaporins

________ is the name of the process by which glucose moves across a plasma membrane.

Facilitated diffusion

________ defines the situation where all receptor sites are occupied by a messenger.

a. affinity

b. saturation

c. competition

d. down-regulation

e. specificity

Saturation

_______ defines the strength of receptor binding to a messenger.

a. affinity

b. saturation

c. competition

d. down-regulation

e. specificity

Affinity

__________ reflects the fact that a receptor normally binds only to a single messenger.

a. affinity

b. saturation

c. competition

d. down-regulation

e. specificity

Specificity

Which of the following intracellular or plasma membrane proteins required Ca2+ for full activity?

A. calmodulin

B. janus kinase (JAK)

C. cAMP-dependent protein kinase

D. guanylyl cyclase

A. calmodulin

Calmodulin is a calcium-binding protein that is inactive in the absence of Ca2+.

Which is correct?

A. cAMP-dependent protein kinase phosphorylates tyrosine residues.

B. Protein kinase C is activated by cAMP.

C. The subunit of Gs proteins that activates adenylyl cyclase is the beta subunit.

D. Lipid-soluble messengers typically act on receptors in the cell cytosol or nucleus.

E. The binding site of a typical plasma membrane receptor for its messenger is located on the cytosolic surface of the receptor.

D. Lipid-soluble messengers typically act on receptors in the cell cytosol or nucleus.

Lipid-soluble messengers cross the plasma membrane and act primarily on cytosolic and nuclear receptors.

Inhibition of which enzyme/enzymes would inhibit the conversion of arachidonic acid to leukotrienes?

A. cyclooxygenase

B. lipoxygenase

C. phospholipase A2

D. adenylyl cyclase

E. Both B and C

B. lipoxygenase

second messenger

a. neurotransmitter or hormone

b. cAMP-dependent protein kinase

c. calmodulin

d. Ca2+

e. alpha subunit of G proteins

d. Ca2+

example of a first messenger

a. neurotransmitter or hormone

b. cAMP-dependent protein kinase

c. calmodulin

d. Ca2+

e. alpha subunit of G proteins

a. neurotransmitter or hormone

Neurotransmitters and hormones are just two of many types of ligands that act as signaling molecules and first messengers via binding to a receptor.

part of a trimeric protein in membranes

a. neurotransmitter or hormone

b. cAMP-dependent protein kinase

c. calmodulin

d. Ca2+

e. alpha subunit of G proteins

e. alpha subunit of G proteins

enzyme

a. neurotransmitter or hormone

b. cAMP-dependent protein kinase

c. calmodulin

d. Ca2+

e. alpha subunit of G proteins

b. cAMP-dependent protein kinase

vasopressin

A. tropic for the adrenal cortex

B. controlled by an amine-derived hormone of the hypothalamus

C. antidiuresis

D. stimulation of testosterone production

E. stimulation of uterine contractions during labor

C. antidiuresis

ACTH

A. tropic for the adrenal cortex

B. controlled by an amine-derived hormone of the hypothalamus

C. antidiuresis

D. stimulation of testosterone production

E. stimulation of uterine contractions during labor

A. tropic for the adrenal cortex

oxytocin

A. tropic for the adrenal cortex

B. controlled by an amine-derived hormone of the hypothalamus

C. antidiuresis

D. stimulation of testosterone production

E. stimulation of uterine contractions during labor

E. stimulation of uterine contractions during labor

prolactin

A. tropic for the adrenal cortex

B. controlled by an amine-derived hormone of the hypothalamus

C. antidiuresis

D. stimulation of testosterone production

E. stimulation of uterine contractions during labor

B. controlled by an amine-derived hormone of the hypothalamus

luteinizing hormone (LH)

A. tropic for the adrenal cortex

B. controlled by an amine-derived hormone of the hypothalamus

C. antidiuresis

D. stimulation of testosterone production

E. stimulation of uterine contractions during labor

D. stimulation of testosterone production

In the figure, which hormone (A or B) binds to receptor X with higher affinity?

At any given concentration, more A is bound to the receptor than B.

Which is NOT a symptom of Cushing’s disease?

A. high blood pressure

B. bone loss

C. suppressed immune function

D. goiter

E. hyperglycemia (increased blood glucose)

D. goiter

Goiter results from dysfunction of the thyroid gland.

Tremors, nervousness, and increased heart rate can all be symptoms of…

A. increased activation of the sympathetic nervous system

B. excessive secretion of epinephrine from the adrenal medulla

C. hyperthyroidism

D. hypothyroidism

E. A, B, and C (all are correct)

E. A, B, and C (all are correct)

Thyroid hormone potentiates the effects of epinephrine and the sympathetic nervous system.

Which of the following could theoretically result in short stature?

A. Pituitary tumor making excess thyroid-stimulating hormone

B. Mutations that result in inactive IGF-1 receptors

C. Delayed onset of puberty

D. Decreased hypothalamic concentrations of somatostatin

E. Normal plasma GH but decreased feedback of GH on GHRH

B. Mutations that result in inactive IGF-1 receptors

Choose the correct statement.

A. During times of stress, cortisol acts as an anabolic hormone in muscle and adipose tissue.

B. A deficiency of thyroid hormone would result in increased cellular concentrations of Na/K-ATPase pumps in target tissues.

C. The posterior pituitary is connected to the hypothalamus by long portal vessels.

D. Adrenal insufficiency often results in increased blood pressure and increased plasma glucose concentrations.

E. A decrease in iodine in the diet will not have significant effect on the concentration of circulating thyroid hormone for at least several weeks.

E. A decrease in iodine in the diet will not have significant effect on the concentration of circulating thyroid hormone for at least several weeks.

There is a large store of iodinated thyroglobulin in thyroid follicles and the half-life of T4 is very long (approximately 6 days).

A lower-than-normal concentration of plasma Ca2+ causes…

A. a PTH-mediated increase in 25-OH D

B. a decrease in renal 1-hydroxylase activity

C. a decrease in urinary excretion of Ca2+

D. a decrease in bone resorption

E. an increase in vitamin D release from the skin

C. a decrease in urinary excretion of Ca2+

Low plasma Ca2+ decreases the filtered load of Ca2+. It also stimulates parathyroid hormone, which increases Ca2+ reabsorption from the distal tubule. This helps to prevent further loss of Ca2+ in urine.

Which of the following is NOT consistent with primary hyperparathyroidism?

A. hypercalcemia

B. increased plasma 1,25-(OH)2D

C. increased urinary excretion of phosphate ions

D. a decrease in Ca2+ resorption from bone

E. an increase in Ca2+ reabsorption in the kidneys

D. a decrease in Ca2+ resorption from bone

Parathyroid hormone is a potent stimulator of Ca2+ resorption from bone.

True or False: T4 is the chief circulating form of thyroid hormone but is less active than T3.

True

True or False: Acromegaly is usually associated with hypoglycemia and hypotension.

False

Acromegaly is associated with hyperglycemia and hypertension.

True or False: Thyroid hormone and cortisol are both permissive for the actions of epinephrine.

True

How is it that thyroid hormones are lipid soluble but can be stored in the thyroid gland?

They have cyclic structures packed with iodine, making them partially lipid-soluble (amphipathic).

The thyroid gland uses a specialized storage system: it covalently bonds thyroid hormones to thyroglobulin within the colloid, keeping them from dissolving.

When the body needs T3 and T4, follicular cells reabsorb the thyroglobulin, break it down with enzymes (e.g., proteases), and release the hormones into the bloodstream.

What are the effects of thyroid hormones?

What regulates the secretion of thyroid hormones?

What is a goiter?

Why is having iodine in the diet important?

How does the adrenal gland respond to stress?

Increases the release of cortisol from adrenal cortex and epinephrine from adrenal medulla

What stimulates cortisol secretion?

What are major effects of cortisol?

What stimulates epinephrine secretion?

What are major effects of epinephrine?

What factors interact to influence growth?

• Interactions of the endocrine system

• Genetics

• Environmental factors

• Nutrition

• Cell growth

• Protein synthesis

How do GH and other hormones influence growth?

What are the major organ systems involved in Ca2+ homeostasis?

What are the major hormones that effect Ca2+ levels?