Bio 126 Drexel exam 1 - endocrine and digestive systems

Which type of hormone is lipid soluble?

a. Amino acid derivatives.

b. DNA.

c. Steroids.

d. Polypeptides.

b. Steroids

- Steroid hormones are lipid soluble.

Which molecules determine the tissue specificity of hormones?

a. Agonists.

b. Second messengers.

c. Hormone-response elements.

d. Receptors.

d. Receptors

- Hormones bind to receptors on target cells and trigger a cellular response.

True or false? Lipid-insoluble hormones affect their target cells by binding to receptors inside the cell.

false

- Lipid-insoluble hormones cannot cross the plasma membrane and get into the cell, so they must bind to receptors on the cell surface and transduce their signals through signal transduction pathways.

Which of the following statements about lipid-soluble hormones is true?

a. They bind to receptors on the plasma membrane.

b. They bind to DNA as soon as they enter a cell.

c. They act by affecting the transcription of genes.

d. They act by producing second messengers.

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c. They act by affecting the transcription of genes.

-Lipid-soluble hormones act by affecting the transcription of genes.

Which of the following is a structure that allows hormone-receptor complexes to bind to specific DNA sequences?

a. Enhancer.

b. Hormone-response element (HRE).

d. Promoter

c. zinc finger

c. Zinc finger.

- A zinc finger is a distinctive DNA-binding domain on some hormone receptors that is exposed when hormone-receptor complexes are formed.

What is the role of cAMP in the signal transduction pathway activated by epinephrine?

A. It binds to and activates protein kinase A, which then phosphorylates other enzymes.

B. It catalyzes the breakdown of glycogen to glucose.

C. It binds to the receptor protein on a target cell.

D. It activates adenylyl cyclase.

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A. It binds to and activates protein kinase A, which then phosphorylates other enzymes.

- cAMP binds to and activates protein kinase A, which then phosphorylates other enzymes in the signal transduction pathway.

True or false? For a signal transduction pathway to be activated, hormones must be present in the bloodstream at very high concentrations.

False

- Only low concentrations of hormones are needed in the bloodstream to activate a signal transduction pathway, which works by producing second messengers inside the cell that amplify the hormonal signal.

does the hypothalamus, anterior pituitary, or posterior pituitary integrate nervous and

endocrine systems?

The hypothalamus

which synthesizes oxytocin and ADH

a. Hypothalamus

b. Anterior pituitary

c. Posterior pituitary

a. the hypothalamus

- The hormones oxytocin and ADH are synthesized in the hypothalamus and travel along the long axons of neurosecretory cells to the posterior pituitary,

which is an extension of the hypothalamus?

a. Posterior pituitary

b. anterior pituitary

a. Posterior pituitary

which releases oxytocin and ADH?

a. the hypothalamus

b. the posterior pituitary

c. the anterior pituitary

b. the posterior pituitary

- the posterior pituitary stores and releases the hormones.

which is regulated by hormones

released into portal blood vessels

a. the hypothalamus

b. the posterior pituitary

c. the anterior pituitary

c. the anterior pituitary

which synthesizes and releases PRL (Prolactin) and TSH

a. the hypothalamus

b. the anterior pituitary

c. the posterior pituitary

b. the anterior pituitary

- The anterior pituitary produces and secretes many hormones, including PRL (prolactin) and TSH, in response to signals from the hypothalamus.

suckling by young causes a.__________ to release b.__________which stimulates PRL secreation from c._______ and then PRL in the blood reaches the d. __________ target cells, and the response is e. ________

a. the hypothalamus

b. TRH (thyrotropin-releasing hormone)

c. the anterior pituitary

​d. mammar​y glands

​e. milk production

Suppose that a woman had to have part of her thyroid gland surgically removed. She would most likely suffer from a condition known as hypothyroidism due to too little thyroid function.

Predict how this woman's hypothyroidism would affect prolactin levels in her body.

A. Thyroid hormone levels decrease, TRH levels decrease, and PRL levels decrease.

B. Thyroid hormone levels decrease, TRH levels decrease, and PRL levels increase.

C. Thyroid hormone levels decrease, TRH levels increase, and PRL levels decrease.

D. Thyroid hormones levels decrease, TRH levels increase, and PRL levels increase.

E. Thyroid hormone levels increase, TRH levels increase, and PRL levels increase.

F. Thyroid hormone levels increase, TRH levels increase, and PRL levels decrease.

G. Thyroid hormone levels increase, TRH levels decrease, and PRL levels increase.

d. Thyroid hormones levels decrease, TRH levels increase, and PRL levels increase.

- Surgical removal of all or part of the thyroid can result in hypothyroidism, or undersecretion of the thyroid hormones T3 and T4. Thyroid hormones have a negative feedback effect on the production of thyroid-releasing hormone (TRH) by the hypothalamus: When T3 and T4 levels decrease, TRH levels increase.

TRH has a stimulatory effect on the anterior pituitary's production of both thyroid-stimulating hormone (TSH) and prolactin (PRL). Therefore, when thyroid hormone levels decrease, TRH levels increase, stimulating the secretion of PRL.

Due to proximity, adrenal glands are often damaged during surgery on what organ?

kidney

Your body doesn't produce the correct amount of DHEA. Which of the following stages of development will be impacted?

a. menarche

b. thelarche

c. gonadarche

d. adrenarche

d. adrenarche

Which of the following do the adrenal glands depend on to release DHEA?

a. thalamus

b. pituitary

c. hypothalamus

d. thyroid

b. Pituitary

What is the function of endocrine glands?

a. They release hormones into the bloodstream for distribution around the body.

b. They release enzymes into the bloodstream through ducts.

c. They are the targets of hormones.

d. They release hormones into a space other than the circulatory system by means of ducts.

a. They release hormones into the bloodstream for distribution around the body.

- Endocrine glands release hormones into the bloodstream for distribution to distant cells in the body.

True or false? The homeostatic system for blood calcium concentration is maintained by the hormones calcitonin and parathyroid hormone.

True

Which of the following statements about the pituitary gland is false?

a. Neurosecretory cells produce hormones that are stored in the anterior pituitary.

b. The anterior pituitary is connected to the hypothalamus by blood vessels

c. The posterior portion is an extension of the hypothalamus.

d. It produces hormones that control the menstrual cycle.

a. Neurosecretory cells produce hormones that are stored in the anterior pituitary.

- a. Neurosecretory cells produce hormones that are stored in the anterior pituitary.

True or false? The pancreas is responsible for producing hormones that maintain the homeostatic levels of glucose in the blood.

true

- The pancreas produces two hormones, insulin and glucagon, which work together to maintain the homeostatic levels of glucose in the blood.

How is the production of hormones such as thyroxine and estrogen regulated?

A. The hypothalamus directs the anterior pituitary to produce hormones that then stimulate or inhibit the production of these hormones.

B. The hypothalamus directs the posterior pituitary to produce hormones that then stimulate or inhibit the production of these hormones.

C. The anterior pituitary directs the hypothalamus to produce hormones that then stimulate or inhibit the production of these hormones.

D. Hormones produced in the hypothalamus act on the thyroid gland and ovaries to stimulate or inhibit the production of these hormones.

A. The hypothalamus directs the anterior pituitary to produce hormones that then stimulate or inhibit the production of these hormones.

- The hypothalamus directs the anterior pituitary to produce hormones that regulate other hormones in a variety of endocrine organs, including the thyroid gland and ovaries.

Which of the following statements about endocrine glands and the hormones they produce is true?

a. Erythropoietin (EPO) produced by the kidneys increases blood calcium levels.

b. Prolactin produced by the posterior pituitary triggers contractions in the uterus during labor.

c. Aldosterone produced by the adrenal glands controls the reabsorption of sodium ions by the kidneys.

d. Antidiuretic hormone (ADH) produced by the anterior pituitary controls the body's metabolic rate.

c. Aldosterone produced by the adrenal glands controls the reabsorption of sodium ions by the kidneys.

- The adrenal glands sit atop the kidneys and secrete a variety of hormones, including aldosterone, which controls the reabsorption of sodium ions by the kidneys.

Gigantism, a condition characterized by exceptionally rapid growth, is sometimes caused by a tumor that induces the gland in which it develops to overproduce a certain hormone. Where would such a tumor be expected to grow?

a. Pancreas.

b. Pituitary gland.

c. Adrenal glands.

d. Thyroid gland.

b. Pituitary gland.

- Since the anterior pituitary produces growth hormone (GH), which has growth-stimulating effects throughout the body, a tumor of the anterior pituitary could produce gigantism.

Which of these glands secretes releasing hormones?

a. hypothalamus

b. adrenal cortex

c. thymus

d. ovaries

e. testes

a. Hypothalamus

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

a. insulin and glucagon

b. thyroxine and calcitonin

c. androgens and estrogens

d. antidiuretic hormone (ADH) and oxytocin

e. epinephrine and norepinephrine

e. epinephrine and norepinephrine

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

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

a.melatonin

b. insulin

c. glucocorticoids

d. thymosin

e. parathyroid hormone

c. glucocorticoids

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

_____ are the main male hormones.

a. Progesterones

b. Mineralocorticoids

c. Androgens

d. Luteinizing hormones

e. Estrogens

c. Androgens

What hormone promotes water retention by the kidneys?

a. follicle-stimulating hormone (FSH)

b. prolactin

c. antidiuretic hormone (ADH)

d. melatonin

e. glucagon

c. antidiuretic hormone (ADH)

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

Which hormone opposes the action of parathyroid hormone?

a. calcitonin

b. insulin

c. thyroxine

d. thymosin

e. glucagon

a. calcitonin

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

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

a. progesterone

b. testosterone

c. glucocorticoids

d. luteinizing hormone (LH)

e. estrogens

d. luteinizing hormone (LH)

Which hormone stimulates milk production?

a. parathyroid hormone

b. mineralocorticoids

c. prolactin

d. thyroid-stimulating hormone (TSH)

e. thymosin

c. prolactin

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

Receptors for nonsteroid hormones are located in _____.

a. the extracellular fluid

b. the cytoplasm

c. the nucleus

d. the cytosol

e. association with a cell's plasma membrane

e. association with a cell's plasma membrane

- Since nonsteroid hormones do not cross a cell's plasma membrane, their receptors are located in association with the plasma membrane.

Which of these is a nonsteroid hormone?

a. estrogen

b. testosterone

c. both estrogen and testosterone

d. oxytocin

e. epinephrine and oxytocin

e. epinephrine and oxytocin

How do nonsteroid hormones differ from steroid hormones?

nonsteroid hormones act via signal transduction pathways; steroid hormones do not act via signal transduction pathways

- Since they do not enter the cell, nonsteroid hormones act via signal transduction pathways.

Which of these extracellular signal molecules could diffuse through a plasma membrane and bind to an intracellular receptor?

a. estrogen

b. epinephrine

c. cellulose

d. oxytocin

e. starch

a. estrogen

- Steroid hormones such as estrogen can diffuse through the plasma membrane and bind to intracellular receptors.

The primary reason steroid hormones usually act slowly is that _____.

A. they are produced at very low concentrations

B. acting via a signal transduction pathway makes for slower responses than does directly interacting with a cell's DNA

C. they are too large to enter a cell and therefore must first bind to a plasma membrane receptor before having an effect on a cell

D. target cells tend to ignore steroid hormones in favor of nonsteroid hormones

E. they turn genes on or off and it takes time for gene products to build up or become depleted

they turn genes on or off and it takes time for gene products to build up or become depleted

Steroid hormone-receptor complexes act in _____.

a. the nucleus

b. lysosomes

c. vesicles

d. the cytoplasm

e. the plasma membrane

a. the nucleus

- Steroid hormone-receptor complexes bind to DNA, where they affect transcription.

What is the function of endocrine glands?

A. They are the targets of hormones.

B. They release hormones into a space other than the circulatory system by means of ducts.

C. They release enzymes into the bloodstream through ducts.

D. They release hormones into the bloodstream for distribution around the body.

D. They release hormones into the bloodstream for distribution around the body.

How is the production of hormones such as thyroxine and estrogen regulated?

A. Hormones produced in the hypothalamus act on the thyroid gland and ovaries to stimulate or inhibit the production of these hormones.

B. The anterior pituitary directs the hypothalamus to produce hormones that then stimulate or inhibit the production of these hormones.

C. The hypothalamus directs the anterior pituitary to produce hormones that then stimulate or inhibit the production of these hormones.

D. The hypothalamus directs the posterior pituitary to produce hormones that then stimulate or inhibit the production of these hormones.

C. The hypothalamus directs the anterior pituitary to produce hormones that then stimulate or inhibit the production of these hormones.

- The hypothalamus directs the anterior pituitary to produce hormones that regulate other hormones in a variety of endocrine organs, including the thyroid gland and ovaries.

Which of the following statements about endocrine glands and the hormones they produce is true?

A. Erythropoietin (EPO) produced by the kidneys increases blood calcium levels.

B. Prolactin produced by the posterior pituitary triggers contractions in the uterus during labor.

C. Antidiuretic hormone (ADH) produced by the anterior pituitary controls the body's metabolic rate.

D. Aldosterone produced by the adrenal glands controls the reabsorption of sodium ions by the kidneys.

D. Aldosterone produced by the adrenal glands controls the reabsorption of sodium ions by the kidneys

- The adrenal glands sit atop the kidneys and secrete a variety of hormones, including aldosterone, which controls the reabsorption of sodium ions by the kidneys.

In a physiological system operating with positive feedback, _____.

A. a stimulus will prevent a small change from becoming too large

B. a change in a variable will amplify rather than reverse the change

C. a stimulus will initiate a response that returns the system to near its initial parameters

D. only an effector/response and control center are necessary to complete the control system

E. the range of acceptable values for a given parameter will be narrower than if the system were regulated by negative feedback

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B. a change in a variable will amplify rather than reverse the change

- A good example is the contraction of the uterus during labor and delivery at the end of pregnancy.

In their mechanism of action, a difference between lipid-soluble and water-soluble hormones is that _____.

A. lipid-soluble hormones activate a "second messenger" pathway

B. water-soluble hormones cross the plasma membrane more readily than do lipid-soluble hormones

C. water-soluble hormones bind reversibly to DNA

D. lipid-soluble hormones bind to an intracellular receptor and this hormone-receptor complex binds to DNA

E. the water-soluble hormones travel only in the blood, and the lipid-soluble hormones travel only in the lymphatic fluid

D. lipid-soluble hormones bind to an intracellular receptor and this hormone-receptor complex binds to DNA

- Most water-soluble signals bind to plasma membrane proteins, initiating signal-transduction pathways. In contrast, the lipid-soluble hormones enter target cells and bind with intracellular receptors; the hormone-receptor complexes act as transcription factors, thus altering gene expression.

Jet lag occurs when a person moves rapidly from one time zone to another, causing conflict between the body's biological rhythm and the new cycle of light and dark. Some scientists suspect that jet lag may result from disruption of the daily cycle of secretion of the hormone known as _____.

a. insulin

b. epinephrine

c. prolactin

d. estrogen

e. melatonin

e. melatonin

Hormones are _____.

a. chemical signals between cells, transported in blood or hemolymph

b. are all under the control of the pituitary gland

c. produced only in response to environmental stress

d. always proteins

e. signals that must interact with DNA in order to be effective

a. chemical signals between cells, transported in blood or hemolymph

- Hormones are secreted into body fluids, usually blood, and communicate developmental and regulatory messages within the body.

The hormone epinephrine causes opposite effects in two populations of target cells because _____.

A. epinephrine can only reach target cells in adipose tissue, as it is fat-soluble

B. epinephrine crosses the membrane on one set of target cells but binds to membrane-bound receptors in the other set of target cells

C. the chemical form of epinephrine released by neurons is different from the epinephrine released by endocrine cells

D. epinephrine activates biochemical pathways in one set of target cells but works only by changing gene expression in the other set of target cells

E. each set of target cells has different receptor-transduction mechanisms

E. each set of target cells has different receptor-transduction mechanisms

- Look at the epinephrine example in your text. That hormone can trigger different responses in different target cells. Epinephrine can trigger vasodilation responses (blood vessels in skeletal muscles used for fight-or-flight) and vasoconstriction responses (gut vasculature) in an emergency that evokes its secretion.

Oxytocin secretion and milk release from the mammary glands of lactating female mammals are initiated by _____.

A. the physical sensation of the baby sucking at the nipple

the secretion of the pancreatic hormone called glucagon

B. a hormone released by the anterior pituitary gland in response to the smell of the baby

C. estrogens from the ovaries

D. the level of fullness in the breast, based on the rate of milk synthesis

A. the physical sensation of the baby sucking at the nipple

- The milk-release response system was given as an example of a neuroendocrine pathway with positive feedback leading to milk release from the nursing mother to the sucking baby. The "neuro" part includes the baby's activation of the mother's mechanoreceptor neurons in the breast.

The anterior and posterior lobes of the pituitary differ in that _____.

A. the anterior lobe of the pituitary is nervous tissue that connects directly to the brain whereas the posterior pituitary is derived from non-neural tissues

B. many anterior pituitary hormones regulate other endocrine glands whereas posterior pituitary hormones regulate nonendocrine tissues

C. the anterior lobe of the pituitary receives neuronal impulses from brain cells whereas the posterior lobe receives blood-borne hormones

D. the posterior pituitary gland synthesizes oxytocin and antidiuretic hormone whereas the anterior lobe receives all of its hormone products in the blood

E. the posterior lobe of the pituitary operates independently of the brain whereas the anterior lobe is directly dependent on brain activity

B. many anterior pituitary hormones regulate other endocrine glands whereas posterior pituitary hormones regulate nonendocrine tissues

- Anterior pituitary hormones FSH and LH (ovaries and testes), TSH (thyroid), and ACTH (adrenal cortex) stimulate endocrine glands; posterior pituitary hormones ADH (kidney tubules) and oxytocin (mammary glands, uterine tissues, brain) regulate nonendocrine tissues.

How does the adrenal gland respond to stress?

A. The adrenal medulla secretes epinephrine and norepinephrine in response to long-term stress.

B. The adrenal medulla secretes epinephrine and norepinephrine in response to short-term stress.

C. The adrenal cortex secretes mineralocorticoids and glucocorticoids in response to short-term stress.

D. The adrenal cortex secretes epinephrine and norepinephrine in response to short-term stress.

E. The adrenal medulla secretes mineralocorticoids and glucocorticoids in response to long-term stress.

B. The adrenal medulla secretes epinephrine and norepinephrine in response to short-term stress.

- A major activity of these catecholamines secreted by the adrenal medulla is to increase the amount of chemical energy available for immediate use.

Urine formed by a kidney collects in the _____ before being drained from the kidney by the _____ and transported to the _____.

a. urethra ... urinary bladder ... ureter

b. renal pelvis ... medulla ... cortex

c. renal pelvis ... ureter ...urinary bladder

d. renal pelvis ... urethra ... urinary bladder

e. ureter ... renal pelvis ... urinary bladder

c. renal pelvis ... ureter ...urinary bladder

Fluid from the glomerulus first collects in _________

Bowman's capsule.

The _____ are the major blood vessels transporting blood to the kidneys.

a. pulmonary arteries

b. glomerulus

c. renal arteries

d. renal veins

e. venae cavae

c. renal arteries

The word "renal" refers to a kidney. Recall that arteries transport blood away from the heart. Renal arteries transport blood to the kidneys.

The outer part of the kidney is the _____.

cortex

Which of these is the functional unit of a kidney?

a. neuron

b. villi

c. nephron

d. alveolus

e. osteon

c. nephron

- Nephrons perform the work required to maintain water and electrolyte balance.

Which of the following statements is true?

A. The kidneys are paired organs that regulate water and electrolyte balance in terrestrial vertebrates.

B. The kidneys regulate water and blood glucose in terrestrial vertebrates.

C. Most humans have one kidney, which regulates water and electrolyte balance, removes nitrogenous wastes from the blood, and eliminates the wastes in the urine.

D. The kidneys are paired organs that remove nitrogenous wastes from the urine.

A. The kidneys are paired organs that regulate water and electrolyte balance in terrestrial vertebrates

-The kidneys also remove nitrogenous wastes from the blood and eliminate them in the urine.

Which of the following represents the correct sequence of flow through the nephron?

A. Distal tubule > loop of Henle > collecting duct > renal corpuscle > proximal tubule

B. Renal corpuscle > proximal tubule > loop of Henle > distal tubule > collecting duct

C. Renal corpuscle > distal tubule > proximal tubule > loop of Henle > collecting duct

D. Renal corpuscle > loop of Henle > collecting duct > proximal tubule > distal tubule

B. Renal corpuscle > proximal tubule > loop of Henle > distal tubule > collecting duct

What is the driving force for the filtration of blood by the renal corpuscle?

Higher pressure in glomerular capillaries than in the surrounding Bowman's capsule.

-The blood pressure in the glomerular capillaries is higher than in the Bowman's capsule, so water and small solutes are forced out of the blood through capillary pores, leaving the larger components of the blood behind.

Which regions of the nephron function independently of hormonal control for the most part?

Renal corpuscle, proximal tubule, and loop of Henle.

- Filtration, reabsorption, and the establishment of an osmotic gradient by these regions of the nephron are largely unregulated.

In which region of the nephron is a steep osmotic gradient created?

Loop of Henle.

Which of the following statements best describes the actions of the hormone ADH on the nephron?

A. ADH causes the loop of Henle to increase urea reabsorption under conditions of dehydration.

B. ADH causes the distal tubule to increase Na+ reabsorption when Na+ levels in the blood are low.

C. ADH causes the collecting duct to increase water reabsorption by the surrounding tissue under conditions of dehydration.

D. ADH causes the proximal tubule to increase glucose reabsorption when the body's energy needs are high.

C. ADH causes the collecting duct to increase water reabsorption by the surrounding tissue under conditions of dehydration.

- ADH increases the water permeability of the distal tubule and collecting duct, increasing the amount of water reabsorbed into the surrounding tissue and decreasing the amount lost as urine.

Under the influence of antidiuretic hormone (ADH), _____ is produced.

more concentrated urine

Antidiuretic hormone (ADH) makes the _____ permeable to water.

collecting duct

Select the correct statement describing the osmolarity of mammalian urine.

A. The osmolarity of mammalian urine may vary over time.

B. The osmolarity of mammalian urine varies little between species

C. Mammalian urine is always hyperosmotic to blood.

A. The osmolarity of mammalian urine may vary over time.

What is the difference between a countercurrent multiplier system, such as the one involving the loop of Henle, and the countercurrent systems that maximize oxygen absorption by fish gills or reduce heat loss in endotherms?

Unlike the other countercurrent systems, a countercurrent multiplier system, such as the one involving the loop of Henle, expends energy in active transport

- The countercurrent multiplier system involving the loop of Henle expends energy to actively transport NaCl from the filtrate in the upper part of the ascending limb of the loop. This expended energy distinguishes a countercurrent multiplier system from the other countercurrent systems. Read about countercurrent multiplier systems.

Select the correct statement about osmolarity.

A. If two solutions are separated by a selectively permeable membrane, water flows by osmosis from a hyperosmotic solution to a hypoosmotic one.

B. The contents of an animal cell are hyperosmotic.

C. Osmolarity measures the moles of solute per liter of solution.

C. Osmolarity measures the moles of solute per liter of solution.

Select the correct statement about osmoregulation.

A. All osmoconformers are marine animals.

B. All marine invertebrates are stenohaline.

C. The less the gradient between an animal's internal osmolarity and its external osmolarity (that of its surroundings), the higher the cost of osmoregulation.

A. All osmoconformers are marine animals

Where and when does osmolarity of the filtrate increase?

As the filtrate moves down the descending limb of the loop of Henle

Which term describes a steady state in which the internal conditions of an organism are kept within a narrow range without regard to the external conditions?

a. Negative feedback.

b. Conformational homeostasis.

c. Regulatory homeostasis.

d. Thermoregulation.

c. Regulatory homeostasis.

-Regulatory homeostasis involves adjusting the internal conditions of an organism to stay within a narrow range without regard to the external conditions.

Which of the following actions is not a function of the epithelium?

a. Regulates the excretion of waste.

b. Creates an internal environment that is different from the external environment.

c. Controls the exchange of nutrients between the internal and external environments.

d. Allows the internal environment to alter its conditions to match those of the external environment.

Allows the internal environment to alter its conditions to match those of the external environment.

- The epithelium allows the internal environment to remain constant even if the external environment changes

True or false? Organisms must maintain homeostasis because optimal enzyme activity is achieved within a very narrow range of conditions.

true

Which component of a homeostatic system compares sensory information to a target value

Integrator.

Which component of a homeostatic system perceives changes in some parameter of the environment?

sensor

Which of the following actions acts to warm a homeothermic body?

a. Dilating blood vessels.

b. Shivering.

c. Sweating.

d. Panting.

b. Shivering.

Which of the following statements describes a negative feedback response?

a. A person who loses 3 pounds continues to diet to lose an additional 10 pounds.

b. After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels.

c. The onset of contractions during childbirth stimulates the release of a hormone that stimulates further contractions.

d.The arrival of platelets at a wound site stimulates the recruitment of more platelets to form a clot.

b. After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels.

Which of these is an example of negative feedback?

A. As a blood clot begins to form, the process of its formation gets faster and faster.

B. After you eat, glucagon stimulates an increase in blood sugar levels.

C. After you eat, insulin stimulates the lowering of blood sugar levels.

D. The digestive enzyme pepsinogen is converted to pepsin by the action of hydrochloric acid; pepsin itself can then convert pepsinogen into pepsin.

E. Once labor begins, contractions increase in frequency and intensity.

C. After you eat, insulin stimulates the lowering of blood sugar levels.

Homeostasis is the ____

maintenance of a relatively constant and optimal internal environment

- Homeostasis is a dynamic state of optimal conditions, maintained at great expense to the organism

Negative feedback is a method of homeostatic control that _____.

ensures that conditions in an organism do not vary too much above or below their set points

An example of a properly functioning homeostatic control system is seen when

A. the level of glucose in the blood is abnormally high whether or not a meal has been eaten.

B. a blood cell shrinks when placed in a solution of salt and water.

C. the core body temperature of a runner rises gradually from 37°C to 45°C.

D. the blood pressure increases in response to an increase in blood volume.

E. the kidneys excrete salt into the urine when dietary salt levels rise.

E. the kidneys excrete salt into the urine when dietary salt levels rise.

Positive feedback differs from negative feedback in that

The positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite to it.

Coordinating body functions via chemical signals is accomplished by

the endocrine system.

A cell with membrane-bound proteins that selectively bind a specific hormone is called that hormone's

target cell

The reason that the steroid hormone aldosterone affects only a small number of cells in the body is that

only its target cells contain aldosterone receptors.

Different body cells can respond differently to the same peptide hormones because

a target cell's response is determined by the components of its signal transduction pathways.

Most types of communication between cells utilize

the release of chemical signals by the cell sending the message.

Oxytocin and antidiuretic hormone are synthesized in the

hypothalamus.

The endocrine glands include the

parathyroid glands.

The body's reaction to PTH (parathyroid hormone), a reduction in plasma levels of calcium, can be opposed by

calcitonin.

In a positive-feedback system where hormone A alters the amount of protein X,

an increase in A always produces an increase in X, which results in an increase in A.

The hypothalamus....

A. secretes tropic hormones that act directly on the gonads.

B. does not have any hormone receptors on its cells.

C. includes neuronal cells that terminate in the posterior pituitary.

D. functions only as an endocrine target, by having lots of receptors on its cells.

E. functions only in neuronal transmission.

includes neuronal cells that terminate in the posterior pituitary.

The counter-regulatory functions of the pancreas refer to the fact that it _____.

releases one hormone that reduces glucose levels in the blood and another that increases them

The anterior and posterior lobes of the pituitary differ in that _____.

many anterior pituitary hormones regulate other endocrine glands whereas posterior pituitary hormones regulate nonendocrine tissues

Which hormone is placed into the correct chemical class?

a. Prolactin is a glycoprotein hormone.

b. Calcitonin is a peptide hormone.

c. Thyroid-stimulating hormone is an amine hormone.

b. Calcitonin is a peptide hormone.

Select the correct statement about feedback regulation in endocrine systems.

A. All hormones are regulated by negative feedback loops.

B. A hormone cascade pathway involves the hypothalamus, posterior pituitary, and endocrine gland.

D. Some homeostatic control systems rely on pairs of negatively regulated hormone pathways, each counterbalancing the other.

Some homeostatic control systems rely on pairs of negatively regulated hormone pathways, each counterbalancing the other.

- Regulation of blood glucose provides a good example

When digested, proteins are broken down into _____.

amino acids

When digested, fats are broken down into _____.

both glycerol and fatty acids

Starch is a type of _____.

polysaccharide

- Starch is a carbohydrate composed of many monomers (many monosaccharide units).

Your small intestine can absorb ____ without their being further digested.

fructoses

-Fructose is a monosaccharide, and monosaccharides can be absorbed without having to be broken down into smaller units.

What enzyme begins the breakdown of starch?

amylase

- The digestion of starches, such as amylose, begins with the amylase secreted by the salivary glands.

Starch can be broken down into the disaccharide known as _____.

maltose