AP Biology : Endocrine System

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #1 : Understanding The Pituitary And Hypothalamus

Growth hormone (GH) stimulates the growth of bone and other tissues in the human body. The hypothalamus is very important in the release of GH through the release of growth-hormone-releasing hormone (GHRH), which causes release of GH from another endocrine gland.

From which endocrine gland is growth hormone (GH) released?

Possible Answers:

Pancreas

Posterior pituitary

Thyroid

Anterior pituitary

Correct answer:

Anterior pituitary

Explanation:

Growth-hormone-releasing hormone (GHRH) causes release of growth hormone (GH) from the anterior pituitary.

The posterior pituitary is responsible for antidiuretic hormone (ADH) and oxytocin release. The thyroid releases thyroid hormones (T3 and T4), which control metabolic rates. The pancreas releases glucagon and insulin to control blood sugar levels.

Example Question #2 : Endocrine System

Which endocrine gland in the brain regulates the release of hormones from the anterior pituitary?

Possible Answers:

Thyroid gland

Posterior pituitary

Hypothalamus

Pineal gland

Correct answer:

Hypothalamus

Explanation:

The hypothalamus releases hormones that control the release of hormones from the anterior pituitary, which in turn controls the release of hormones from other endocrine glands. The anterior pituitary is also controlled by several negative feedback systems based on hormones released throughout the body and their effects.

Example Question #3 : Endocrine System

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are both released from the anterior pituitary. The hypothalamus regulates their release through release of __________.

Possible Answers:

Gonadotropin-releasing hormone (GnRH)

Thyroid-stimulating hormone (TSH)

Growth hormone-releasing hormone (GHRH)

Corticotropin-releasing factor (CRF)

Correct answer:

Gonadotropin-releasing hormone (GnRH)

Explanation:

Gonadotropin-releasing hormone (GnRH), released from the hypothalamus, is responsible for regulating follicle-stimulating hormone and luteinizing hormone release. Growth-hormone-releasing hormone (GHRH) regulates release of growth hormone (GH), and corticotropin-releasing factor (CRF) regulates adrenocorticotropic hormone (ATCH) release from the anterior pituitary. Thyroid-stimulating hormone (TSH) is released from the anterior pituitary and stimulates release of T3 and T4 from the thyroid.

Example Question #1 : Endocrine System

Which of these hormones stimulates secretion of cortisol?

Possible Answers:

Adrenocorticotropic hormone (ACTH)

Human growth hormone (hGH)

Follicle stimulating hormone (FSH)

Thyroid stimulating hormone (TSH)

Cortisone

Correct answer:

Adrenocorticotropic hormone (ACTH)

Explanation:

Cortisol is a hormone secreted by the adrenal cortex. The adrenal cortex is first stimulated by adrenocorticotropic hormone, which is secreted from the anterior pituitary gland.

Example Question #5 : Understanding The Pituitary And Hypothalamus

The hypothalamus plays a central role in vertebrates by integrating the endocrine and nervous systems. What gland receives signals from the hypothalamus?

Possible Answers:

Pineal gland

Thyroid gland

Adrenal gland

Pituitary gland

Correct answer:

Pituitary gland

Explanation:

Signals from the hypothalamus go to the posterior pituitary gland, which is located at the base of the hypothalamus. The pituitary consists of two lobes (anterior and posterior), which function independently. The anterior and posterior pituitary produce a collection of hormones that are key to endocrine signaling throughout the body. 

The posterior pituitary stores and secretes two hormones (oxytocin and vasopressin), while the anterior pituitary produces six different hormones (growth hormone, prolactin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH) and adrenocorticotropic hormone (ACTH). The posterior pituitary will only secrete hormones when stimulated by the hypothalamus.

Example Question #2 : Endocrine System

Which of the following hormones is released from the anterior pituitary?

Possible Answers:

Insulin

Cortisol

Epinephrine

Glucagon

Prolactin

Correct answer:

Prolactin

Explanation:

The anterior pituitary gland contains endocrine cells that release hormones through the hypothalamic-hypophyseal axis. Prolactin controls milk production and contributes to regulation of the immune system. Of the listed hormones, prolactin is the only hormone released from the anterior pituitary.

Insulin and glucagon are secreted by the pancreas. Cortisol is released by the adrenal cortex; epinephrine is released by the adrenal medulla.

Example Question #4 : Endocrine System

Which of the following hormones is not secreted by the pituitary gland?

Possible Answers:

Adrenocorticotropic hormone

Prolactin

Follicle-stimulating hormone

Growth hormone

Melatonin

Correct answer:

Melatonin

Explanation:

Melatonin is secreted by the pineal gland, which is also in the brain. The function of melatonin is not yet certain, but current research hints that it plays functions in regulation of the circadian rhythm. All other hormones are indeed secreted by the pituitary gland. 

Example Question #5 : Endocrine System

Which of the following is a hormone secreted by the posterior pituitary?

Possible Answers:

Oxytocin

Growth hormone

Adrenocorticotropic hormone

Prolactin

Thyroid-stimulating hormone

Correct answer:

Oxytocin

Explanation:

The posterior pituitary only secretes oxytocin and vasopressin (antidiuretic hormone). The hypothalamus actually creates these hormones and stores them in the posterior pituitary. 

The anterior pituitary releases the growth hormone (GH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin. You can remember all of these hormones by using the acronym FLATPEG, where:

F- FSH

L- LH

A- ACTH

T- TSH

P- Prolactin

E- Endorphins

G- GH

Example Question #8 : Endocrine System

Where in the body is core temperature regulated?

Possible Answers:

Anterior pituitary

Posterior pituitary

Hypothalamus

Thalamus

Correct answer:

Hypothalamus

Explanation:

The hypothalamus is a structure in the brain responsible for homeostatic control over much of the body. It is responsible for maintaining core body temperature within normal levels. There are special neurons located within the hypothalamus that respond to changes in body temperature. The hypothalamus then sends out signals to the result of the body in response to changes in temperature.

Example Question #7 : Endocrine System

How do steroid hormones elicit a response from their target cells?

Possible Answers:

Steroid hormones attach to a membrane-bound receptor on the cell. This creates an intracellular second messenger which leads to a reaction cascade.

Steroid hormones enter the nucleus of the target cell and increase the creation of ribosomes by the nucleolus. This results in more proteins being made by the target cell.

Steroid hormones move freely throughout the bloodstream and attach to their target cells. This interaction increases ion permeability in the cell.

Steroid hormones enter the target cell and alter the products of the cell at the transcription level.

Correct answer:

Steroid hormones enter the target cell and alter the products of the cell at the transcription level.

Explanation:

Steroids are nonpolar, which means that they are able to pass easily through cell membranes, but require a transport protein through the hydrophilic blood in order to do so. The steroid hormone then enters the nucleus and attaches to the DNA in order to increase the desired product at the level of transcription.

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