MCAT Biology : Pituitary and Hypothalamus

Study concepts, example questions & explanations for MCAT Biology

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Example Questions

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Example Question #11 : Endocrine System

Which of the following hormones is not produced by the anterior pituitary gland?

Possible Answers:

Follicle-stimulating hormone

Growth hormone

Prolactin

Oxytocin

Correct answer:

Oxytocin

Explanation:

Oxytocin is produced by the hypothalamus and stored in the posterior pituitary gland. Upon stimulation, oxytocin is released from the posterior pituitary to cause lactation and uterine contractions during pregnancy, though it has also been linked to some social phenomena.

Growth hormone, follicle-stimulating hormone, and prolactin are produced and secreted from the anterior pituitary gland. Growth hormone promotes bone elongation and cell division. Follicle-stimulating hormone works to regulate the menstrual cycle. Prolactin stimulates milk production, while oxytocin stimulates the actual act of lactation.

Example Question #11 : Pituitary And Hypothalamus

A researcher is analyzing an individual with dwarfism who has a height of 4’6”. Which of the following is likely true regarding this individual?

Possible Answers:

The hGH is not synthesized properly in the anterior pituitary gland

The LH is not synthesized properly in the hypothalamus

The hGH is not synthesized properly in the hypothalamus

The LH is not synthesized properly in the anterior pituitary gland

Correct answer:

The hGH is not synthesized properly in the anterior pituitary gland

Explanation:

A major player in a growing person is the human growth hormone (hGH). hGH is a peptide hormone released from the anterior pituitary gland. Recall that the hormones secreted from the anterior pituitary gland are synthesized in the gland itself. It receives signaling hormones from the hypothalamus which tells the anterior pituitary gland to start synthesizing a particular hormone. In the case of hGH, hypothalamus releases GHRH (growth hormone releasing hormone) which signals the anterior pituitary to signal and release hGH. Since this person has a short stature, the person likely has a problem with synthesis or release of hGH from anterior pituitary gland.

Example Question #12 : Endocrine System

Which of the following is false regarding the posterior and the anterior pituitary gland?

I. Posterior pituitary gland receives hormones that are synthesized in the hypothalamus

II. Both glands release peptide and steroid hormones

III. Both glands synthesize hormones that are released after they receive a signal from the hypothalamus

Possible Answers:

I only

I and II

II only

II and III

Correct answer:

II and III

Explanation:

Posterior pituitary gland has a direct connection to the hypothalamus whereas the anterior pituitary gland does not. The hormones secreted from posterior pituitary gland (oxytocin and ADH) are synthesized in the hypothalamus. Since there is a direct connection between the hypothalamus and the posterior pituitary, the synthesized hormones are transported directly into the posterior pituitary where they are stored and secreted. 

Both glands are involved in releasing several important hormones; however, all the hormones released by both pituitary glands are peptide hormones. Steroid hormones are typically synthesized in the gonads and in the adrenal medulla. 

Posterior pituitary does not synthesize its own hormones. As mentioned earlier, it receives hormones synthesized in the hypothalamus. Posterior pituitary serves to store and secrete the hormones. Anterior pituitary, on the other hand, can synthesize hormones. It often receives a signaling hormone from hypothalamus that initiates synthesis and release of hormones. For example, growth hormone releasing hormone (GHRH) released from the hypothalamus signals the anterior pituitary to synthesize growth hormone.

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