1.1 Endocrine, part 1: Key Terms, 1.1 Endocrine, Lecture Questions, Practice Quiz Lesson 1

Eicosanoids are:

--Biologically active lipids, --derived from arachidonic acid (fatty acid), --secreted by most cell membranes.

What are the functions of the endocrine system?

--Regulation of cellular metabolism and energy balance, --Growth and development, --Development and influence of behavior and emotions, --Maintenance of water, electrolyte, and nutrient balance, --Reproduction, --Immune response

Endocrine glands

--are ductless glands. --are the organs of the endocrine system. --secrete hormones directly into the bloodstream. --help maintain homeostasis.

The half-life of a hormone is:

--the time necessary to reduce the hormone concentration in the blood to half of what had been secreted.

Generally, there are two main factors that determine the levels of a hormone in the blood. Explain what those factors are and provide examples of how they might increase or decrease a hormone's level.

1. HORMONE SYNTHESIS -- is directly related to plasma hormone levels, and 2. HORMONE ELIMINATION -- (by liver, kidneys, and target cell uptake) is inversely related to plasma hormone levels.

Which hormones are synthesized from cholesterol? A. Steroids B. Modified amino acids C. Peptides D. Glycoproteins E. All of the above

A, Steroids

Which of the following is true of epinephrine? A. It is a tyrosine amine hormone B. A trytophan amine hormone C. A proline amine hormone D. A serien amine hormone

A. It is a tyrosine amine hormone

Which is the correct order of events for hormones activating Gs proteins? A. activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of ATP to cAMP B. activation of G protein, binding of GTP, activation of phospholipase C, activation of DAG and IP3 C. activation of a G protein, tyrosine kinase receptor, phosphorylation of intracellular proteins

A. activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of ATP to cAMP

The symphathetic nervous system directly stimulates which of the following amine hormones? A. Epinephrine from the adrenal medulla B. Thyroid hormones C. Insulin D. Aldosterone

A. epinephrine from the adrenal medulla

What is the mechanism of action of lipid-soluble hormones?

Activation of genes, which increases protein synthesis in the cell

After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do?

Acts as a transcription factor and binds to DNA, activating a gene

Which of the following is a mechanism of stimulating hormone release? A. Humoral regulation B. Hormonal regulation C. Neural regulation D. All of the above

All of the above

______ hormones are made from an amino acid by chemical modification, or made by joining amino acids to form a peptide (very small protein).

Amino acid-based

________signals are similar to hormones in many ways, but act only on the very cells that release them!

Autocrine

Which of the following chemical messengers is NOT derived from lipids? A. Prostaglandins B. Insulin C. Cortisol D. Aldosterone E. Estrogens

B. Insulin

Which of the following is correctly matched? A. Steroid hormones bind to an intracellular receptor. Thyroid hormones bind to a plasma membrane receptor. B. Steroid hormones bind to a cytoplasmic receptor. Thyroid hormones bind to a nuclear receptor. C. Steroid hormones bind to a nuclear receptor. Thyroid hormones bind to a cytoplasmic receptor. D. Steroid hormones bind to a plasma membrane receptor. Thyroid hormones bind to an intracellular receptor

B. Steroid hormones bind to a cytoplasmic receptor. Thyroid hormones bind to a nuclear receptor.

Why do steroid hormones have a longer half-life than other hormones?

Because they are bound to protein carriers

Eicosanoids do NOT include __________. A. Paracrines B. Leukotrienes C. Hydrocortisones D. Prostaglandins

C. Hydrocortisones

Which of the folowing general chemical categories is NOT represented by a group of hormones? A. Modified amino acids (amines) B. Polypeptides and proteins C. Nucleic acids D. Steroids

C. Nucleic acids

Which of the following adrenergic receptors increase cAMP levels? A. α1 receptors B. α2 receptors C. β receptors

C. β receptors

Steroids hormones are derivatives of _____________. .

Cholesterol

Which of the following hormones has intracellular receptors? A. Epinephrine B. Cortisol C. Insulin

Cortisol

Which of the following is NOT a change that may be caused by a hormonal stimulus? A. A change in membrane potential B. The stimulation of a genetic event resulting in protein synthesis C. An increase in enzymatic activity D. Direct control of the nervous system

Direct control of the nervous system

The thyroid hormone, thyroxin, is formed: A. from cholesterol B. from changes to carbohydrates D. from other hormones E. From changes to an amino acid

E. From changes to an amino acid

Which are some characteristic of the endocrine system?

EFFECTS: causes metabolic activity changes in target cells RESPONSE TIME: slow reaction time (seconds to hours) DURATION OF RESPONSE: long-lasting (minutes to weeks) RECOVERY: slow (hours to weeks) COMMUNICATION: hormones in the bloodstream

________ are biologically active lipids which act in an autocrine or paracrine manner. They are made from essential fatty acids and influence inflammation, ion transport, sleep and other activities.

Eicosanoids

_______ _______secrete chemical messengers that travel in the bloodstream.

Endocrine glands

Which of the following is NOT a category of endocrine gland stimulus? A. Enzyme B. Humoral C. Neural D. Hormonal

Enzyme

Direct gene activation involves a second messenger (TRUE/FALSE)

FALSE

Which of the following is NOT a type of hormone interaction? A. Permissiveness B. Synergism C. Antagonism D. Feedback

Feedback

Cells that respond to peptide hormones usually do so through a sequence of biochemical reactions involving receptor and kinase activation. In order for cells to respond, it is necessary for first and second messengers to communicate. This is possible because ________. a. peptide hormones are converted by cell membranes enzymes into second messengers b. hormones alter cellular operations through direct stimulation of a gene c. the hormone receptor complex moves into the cytoplasm as a unit d. G protein acts as the link between first and second messengers

G protein acts as the link between first and second messengers.

Growth factor hormones, such as insulin, bind to which type of receptor?

G proteins

If you had to summarize the role of the endocrine system in one word, what would it be?

Homeostasis

Chemical substances secreted by cells into the extracellular fluids and that regulate the metabolic functions of other cell in the body are called:

Hormones

What BEST describes the process of up-regulation?

Increase the number of surface receptors

Which of the following hormones are controlled by a humoral stimuli? A. Triiodothyronine B. Insulin C. Epinephrine D. Norepinephrine E. Cortisol

Insulin

Which of the following hormones are controlled by humoral stimuli? A. Triiodothyronine B. Insulin C. Epinephrine D. Norepinephrine E. Cortisol

Insulin

What happens to the protein calmodulin when hormones bind to it?

It activates enzymes

The hormones and neurotransmitters released by the endocrine and nervous systems are chemical substances referred to as _________.

Ligands

Endo-

Means "in or within."

Para-

Means "near or beside."

Exo-

Means "out of, outside, away from."

Auto-

Means "self."

-crine

Means "to secrete."

-philic

Means loving/liking/preferring/having an affinity for something.

Compared to the nervous system, the endocrine system has:

More widespread and lasting effects

Hormone secretion is primarily regulated by ___________ feedback mechanisms.

Negative

__________ tend to be localized and immediate (microseconds to seconds); _________ tend to be widespread, slow (minutes to hours) to be implemented and slow (minutes to hours) to deactivate.

Neural controls; hormonal controls

Chemical signaling that affects neighboring cells is called:

Paracrine

________signals are similar to hormones in many ways, but act only on neighboring cells, not on distant targets.

Paracrine

When a chemical messenger helps initiate an inflammatory response by causing cellular changes in neighboring cells, it is demonstrating ___________ signaling.

Paracrine (para- refers to near or beside)

Lipo-

Pertaining to fat or fatty substance.

What intracellular substance degrades cAMP, thus inactivating the response to a hormone?

Phosphodiesterase

Which of the following does NOT influence the response of the target cell? A. Number of receptors for the hormone B. Concentration of hormone in the blood C. Rate of blood flow D. Affinity for binding between hormone and receptor

Rate of blood flow

Hydro-

Relating to water

Virtually all of the protein or amino acid-based hormones exert their effects through intracellular ________.

Second messengers

Which of the following is NOT a change typically produced by a hormonal stimulus? A. activates or deactivates enzymes B. stimulates production of an action potential C. alters plasma membrane permeability D. induces secretory activity

Stimulates production of an action potential

Which of the following occurs in situations where more than one hormone produces the same effects at the target cell and their combined effects are amplified? A. Summation B. Permissiveness C. Synergism D. Antagonism

Synergism

All adenohypophyseal hormones, except growth hormone (GH), affect their target cells via a cyclic AMP (cAMP) second messenger (TRUE/FALSE).

TRUE

All peptide hormone synthesis requires gene activation that produces mRNA (TRUE/FALSE)

TRUE

Both "turn on" factors (hormonal, humoral, and neural stimuli) and "turn off" factors (feedback inhibition and others) may be modulated by the activity of the nervous system (TRUE/FALSE)

TRUE

Neurotransmitters are a special class of paracrines (TRUE/FALSE)

TRUE

Cells that respond to a particular hormone are called:

Target cells

What property prevents the hormones of cell-surface receptors from entering the cell?

The molecules are water-soluble and cannot penetrate the lipid-soluble interior of the plasma membrane.

Hormones must bind to receptors on target cells in order to affect changes. Where can these receptors be located? (select all that apply) A. The plasma membrane B. They cytoplasm C. The nucleus D. The endoplasmic reticulum E. The Golgi Body

The plasma membrane The cytoplasm The nucleus

The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on ________.

The presence of the appropriate receptors on the cells of the target tissue or organ.

Peptide hormones must bind to a plasma membrane receptor because:

They are polar

Most peptide hormones are easily transported in the blood plasma because:

They are water-soluble

A newly developed pesticide has been observed to bind to an intracellular hormone receptor. If ingested, residue from this pesticide could disrupte the levels of: A. melatonin B. thyroid hormone C. growth hormone D. insulin

Thyroid hormone

Which hormone's receptor is always bound to DNA, even when the receptor is empty? A. Insulin B. Cortisol C. Thyroid hormone

Thyroid hormone

Eicosanoids are a primary type of local hormone (true/false)

True

Which of the choices below is NOT a factor required for target cell activation by hormone receptor interaction? A. Blood levels of hormone B. Type of hormone C. Number of receptors for the hormone D. Strength of the bond between the receptor and the hormone.

Type of hormone

In circumstances where the body requires prolonged or increased levels of a hormone, the DNA of a target cell will specify the synthesis of more receptors on the surface of the cells of the target organ. This is known as ___________.

Up-regulation

What type of hormones bind to receptors located on the cell membrane?

Water-soluble hormones

If the signal for an organ to release a hormone is _____, the signal is hormonal.

a releasing hormone.

What type of response is initiated by steroid and thyroid hormones?

altered activity of genes

Amino acid-based hormones generally bind _____, but _______ is an important exception.

at the cells surface; thyroid hormone

When eicosanoids bring about cellular changes within the cell from which they were formed, the process is called _________ stimulation.

autocrine

Lipid-soluble hormones readily diffuse through capillary walls, whereas water-soluble hormones must:

be secreted through exocytosis, an active transport mechanism.

Modified amino acids that act as hormones are referred to as ________ amines.

biogenic amines

Steroid hormones are lipids, derived from:

cholesterol

Steroids, one of the two major hormone classes, are made from ______

cholesterol

Which second messenger causes the release of calcium from the endoplasmic reticulum? A. tyrosine kinase B. DAG C. cAMP dD IP3

d. IP3

Steroid hormones exert their action by _______.

entering the nucleus of a cell and initiating or altering the expression of a gene.

Damage to the liver might impair enzymatic degradation of some hormones. The levels of such hormones in the blood would therefore be expected to:

increase:

Lipophilic hormones bind to ___________ receptors of target cells.

intracellular

The receptors for steroids and thyroid hormones are ________.

intracellular

Thyroid hormone is somewhat unique in that:

it is a biogenic amine that is lipid-soluble

Concerning the half-life of hormones, lipid soluble hormones have a (longer/shorter) half-life?

longer

What amine hormone helps coordinate body activities with the light-dark cycle?

melatonin

Generally, the shorter the half-life of a hormone the _________ (more, less) frequently it must be replaced.

more

Most hormones are made of chains of amino acids and are therefore ____________.

proteins

In order for a cell to responde to a hormone, the cell must have the appropriate ________.

receptor

______ enter the cell and interact directly with DNA and nuclear factors to bring about changes in gene expression.

steroid hormones

The most common second-messenger mechanism of hormone action operates by:

synthesizing more than one hormone at a time

The binding of a hormone and a carrier protein is _______ (temporary, permanent); a very ______ (large, small) fraction of such a hormone in the blood is bound to a carrier at any one point in time.

temporary; large

Circulating hormones are released into ______ by an endocrine gland, and must travel to reach their (often distant) target

the blood

If the signal for an organ to release a hormone is _______, the signal is humoral.

the level of a chemical in the blood

If the signal for an organ to release a hormone is ______, the signal is neural

transmitted by the nervous system

Protein hormones are _________ soluble

water