Exam 2 (Lecture 3) - Hypothalamus and Pituitary

Question 1

Describe the main anatomical parts of the hypothalamic-pituitary system (slides 3-5).

Answer 1

1) Anterior pituitary (lobe); (derived from ectoderm of oral cavity called Rathke’s pouch); portal veins extend from pituitary stalk to anterior pituitary
2) Posterior pituitary (lobe); (derived from neural tissue); axons extend from pituitary stalk to posterior lobe
3) Median Eminence
4) Bottom of Third Ventricle
5) Infundibulum (pituitary stalk)
6) Pars intermedia
7) Pars tuberalis
8) Lumen of Rathke’s pouch

Question 2

Which hormones are released in the blood stream in the posterior pituitary? Where are they synthesized and how do they get to the posterior pituitary?

Answer 2

1) Oxytocin and Antidiuretic Hormone (ADH)

2) They are synthesized by neurons in the hypothalamus; they are transported via axons to the posterior pituitary.

Question 3

Which hormones are secreted by the anterior pituitary?

Answer 3

1) Follicle-stimulating hormone (FSH)
2) Luteinizing hormone (LH)
3) Thyrotropin (TSH)
4) Adrenocorticotropin (ACTH)
5) Prolactin (PRL)
6) Somatotropin (GH)
7) Melanotropin (MSH)

Question 4

How does the hypothalamus control secretion of hormones from the anterior pituitary and what is the role of portal blood vessels in this process?

Answer 4

1) Cells are controlled by hypothalamic releasing hormones (RH) and inhibiting hormones (IH). These are Brough from the hypothalamus by portal vessels.

2) In response to RH and IH, anterior lobe releases tropic hormones which regulate hormone secretion in other glands (FSH, LH, TSH, and ACTH) and other hormones that control metabolism in non-endocrine tissues (GH, PRL, MSH).

Question 5

Which pituitary hormones control activity of other endocrine glands?

Answer 5

1) Follicle-stimulating hormone (FSH)
2) Luteinizing hormone (LH)
3) Thyrotropin (TSH)
4) Adrenocorticotropin (ACTH)

Question 6

Which endocrine glands are controlled by the autonomic nervous system? (Slide 9)

Answer 6

1) Pancreas
2) Adrenal medulla of kidney

Question 7

Which part of the pituitary secretes the alpha-MSH? What is the function of this hormone? Which other pituitary hormone can also stimulate melanocytes?

Answer 7

1) Anterior pituitary (pars intermedia)

2) MSH Functions:
- acquisition of brown summer hair in animal such as short-tailed weasel
- suppresses appetite
- increases sexual arousal

3) ACTH can also stimulate melanin production