BMS Test A&P 2 Chapter 16

Questions and Answers

Steroid hormones exert their action by:

Activating the hypothalamic release of regulating hormones

Entering the cell and activating mitochondrial DNA

Binding cell receptors and initiating cAMP activity

Entering the nucleus of a cell and initiating or altering the expression of a gene (correct)

The second-messenger mechanism of hormone action operates by:

Binding to specific receptors and employing the services of G proteins and cAMP (correct)

Synthesizing more than one hormone at a time

Altering gene expression in the nuclear DNA

Increasing the basal metabolic rate in the target organ

The stimuli causing endocrine glands to secrete their hormones in direct response to changing blood levels of certain critical ions and nutrients are called:

Hormonal stimuli

Neural stimuli

Endocrinal stimuli

Humoral stimuli (correct)

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

Second messengers Signup and view all the answers

Which of the following is not a category of endocrine gland stimulus?

Enzyme Signup and view all the answers

Which of the following is NOT a property of endocrine glands?

They have ducts. Signup and view all the answers

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

Hormones Signup and view all the answers

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?

Synergism Signup and view all the answers

Hormones that regulate the secretory action of other endocrine glands are called:

Tropins Signup and view all the answers

Which of the following hormones stimulates the adrenal cortex to release glucocorticoids that help the body to resist stressors?

Adrenocorticotropic hormone Signup and view all the answers

Which of the following hormones mainly serves to stimulate milk production by the breasts?

Prolactin Signup and view all the answers

Which of the following is not a type of hormone interaction?

Feedback Signup and view all the answers

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 Signup and view all the answers

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:

G protein acts as the link between first and second messengers Signup and view all the answers

Thyroid hormone (a small iodinated amine) enters target cells in a manner similar to:

Steroid hormones, because both diffuse easily into target cells Signup and view all the answers

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

Up-regulation Signup and view all the answers

Thyroxine is a peptide hormone, but its mechanism is different from other peptide hormones. Which of the following statements is true concerning this difference?

It does not require a second messenger to effect a response. Signup and view all the answers

Direct gene activation involves a second-messenger system.

False Signup and view all the answers

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

Water-soluble hormones, such as insulin and epinephrine Signup and view all the answers

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

Phosphodiesterase Signup and view all the answers

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

Tyrosine kinase receptors Signup and view all the answers

Which is the correct order of events for hormones activating Gs proteins?

Activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of ATP to cAMP Signup and view all the answers

Which second messenger causes the release of calcium from the endoplasmic reticulum?

IP3 Signup and view all the answers

Which of the following hormones has intracellular receptors?

Cortisol Signup and view all the answers

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

Activation of genes, which increases protein synthesis in the cell Signup and view all the answers

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 Signup and view all the answers

Which hormone's receptor is always bound to DNA, even when the receptor is empty?

Thyroid hormone Signup and view all the answers

What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor?

Chaperone proteins (chaperonins) Signup and view all the answers

What tropic hormone stimulates cortisol from the adrenal gland?

Adrenocorticotropic hormone (ACTH) Signup and view all the answers

What is the function of the ventral hypothalamic neurons?

Control secretion of thyroid stimulating hormone (TSH) Signup and view all the answers

Insulin-like growth factors (IGFs) are intermediary hormones stimulated by which of the following hormones?

GH (growth hormone) Signup and view all the answers

Which of the following hormones is regulated by a neuroendocrine ('letdown') reflex?

Oxytocin Signup and view all the answers

Where is antidiuretic hormone (ADH), also known as vasopressin, synthesized?

Hypothalamus Signup and view all the answers

What is the most important regulatory factor controlling the circulating levels of thyroid hormone?

Negative feedback Signup and view all the answers

Hypersecretion of what hormone can produce the effects of gigantism?

Growth hormone (GH) Signup and view all the answers

What hormone released into the blood by the posterior pituitary inhibits or prevents urine formation?

Antidiuretic hormone (ADH) Signup and view all the answers

What gland secretes growth hormone?

Anterior pituitary (lobe) Signup and view all the answers

Which hypothalamic hormone stimulates the release of growth hormone from the anterior pituitary (lobe)?

Growth hormone-releasing hormone (GHRH) Signup and view all the answers

Acromegaly may be caused by all EXCEPT which of the following?

Positive feedback by GH (growth hormone) on the anterior pituitary Signup and view all the answers

Which of the following is NOT a change that may be caused by hormonal stimulus?

Direct control of the nervous system Signup and view all the answers

Which of the following is NOT a major type of stimulus that triggers endocrine glands to manufacture and release hormones?

Enzymatic Signup and view all the answers

_____ is the situation when one hormone cannot exert its full effects without another hormone being present.

Permissiveness Signup and view all the answers

What is the primary function of hormones?

Alter cell activity Signup and view all the answers

Which of the following is not a steroid-based hormone?

Epinephrine Signup and view all the answers

Which of the following is NOT a change typically produced by a hormonal stimulus?

Stimulates production of an action potential Signup and view all the answers

One of the least complicated of the endocrine control systems directly responds to changing blood levels of ions and nutrients. Which of the following describes this mechanism?

Humoral stimulation Signup and view all the answers

Study Notes

Hormone Mechanisms and Types

Steroid hormones enter the nucleus and alter gene expression.
Second-messenger mechanisms bind to specific receptors using G proteins and cAMP to initiate cellular responses.
Hormones are chemical substances that regulate metabolic functions in the body; they affect other cells by binding to their receptors.

Types of Stimulus for Hormone Secretion

Humoral stimuli trigger endocrine glands to secrete hormones in response to blood levels of ions and nutrients.
Types of endocrine gland stimuli include humoral, neural, and hormonal; enzymatic stimuli are not included.

Hormonal Interactions and Effects

Synergism occurs when multiple hormones enhance each other's effects on target cells.
Tropins are hormones that regulate the secretory actions of other endocrine glands.

Specific Hormones and Their Functions

Adrenocorticotropic hormone (ACTH) stimulates the adrenal cortex to release glucocorticoids.
Prolactin primarily stimulates milk production in the breasts.
Growth hormone (GH) plays a crucial role in growth and regulation of other hormones.

Responses of Target Cells

Target cell responsiveness to hormones depends on the presence of specific receptors.
Up-regulation occurs when more receptors are synthesized in response to prolonged hormone exposure.

Mechanisms of Lipid-Soluble and Water-Soluble Hormones

Water-soluble hormones bind to cell membrane receptors, while lipid-soluble hormones diffuse through the membrane to their intracellular receptors.
Activation of genes by lipid-soluble hormones increases protein synthesis by acting as transcription factors.

Hormonal Regulation and Feedback Mechanisms

Negative feedback is the primary regulatory mechanism for circulating thyroid hormone levels.
Oxytocin operates via a neuroendocrine reflex, impacting processes like childbirth and lactation.

Hormone Production and Synthesis

Antidiuretic hormone (ADH) is synthesized in the hypothalamus and inhibits urine formation.
Growth hormone is produced in the anterior pituitary gland and regulated by growth hormone-releasing hormone (GHRH) and growth hormone-inhibiting hormone (GHIH).

Distinctions in Hormone Types and Interactions

Cortisol is a steroid hormone with intracellular receptors, while insulin is a water-soluble hormone that binds to membrane receptors.
Feedback mechanisms include feedback interactions, but feedback itself is not categorized as a type of hormone interaction.

Hormonal Disorders and Effects

Acromegaly is linked to hypersecretion of GH; it may result from several factors except for positive feedback on the pituitary.
Gigantism is also a result of excess growth hormone.

Endocrine System Overview

The endocrine system utilizes various hormones to alter cell activity and metabolic processes.
Hormonal stimuli lead to changes in cellular activities, but they do not directly control the nervous system.

Noteworthy Hormonal Categories

Steroid hormones include cortisone, aldosterone, and estrogen; epinephrine is a non-steroid hormone.
One hormone may require the presence of another to exert its full effect, known as permissiveness.

Overview of Hormonal Functions

Hormones primarily influence metabolic activity by altering the activity of target cells rather than activating external enzymes directly.
Intracellular substances like phosphodiesterase degrade second messengers like cAMP to inactivate hormone responses.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Prepare for your Anatomy and Physiology exam with this set of flashcards focused on Chapter 16, covering the Endocrine System. Test your knowledge on key concepts such as steroid hormones and their mechanisms of action. Perfect for students looking to reinforce their understanding of endocrinology.