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Question 1

How many secretory cell types does the adenohypophysis have?

Answer 1

5 secretory cell types

Question 2

How many hormones does the adenohypophysis secrete?

Answer 2

6 hormones

Question 3

What regulates the adenohypophysis’s endocrine functions?

Answer 3

The hypothalamus

Question 4

What is the hypothalamic–pituitary axis?

Answer 4

It is the functional connection between the brain and hormone regulation.

Question 5

What are the 5 cell types of the adenohypophysis?

Answer 5

Somatotropes, Lactotropes, Thyrotropes, Corticotropes, and Gonadotropes.

Question 6

What do somatotropes produce and what type of cell are they?

Answer 6

Acidophils, Produce GH

Question 7

What do Lactotropes produce and what type of cell are they?

Answer 7

Acidophils, Produce prolactin

Question 8

What do Thyrotropes produce and what type of cell are they?

Answer 8

Basophils, Produces TSH

Question 9

What do Corticotropes produce and what type of cell are they?

Answer 9

Basophils, Produce ACTH

Question 10

What do Gonadotropes produce and what type of cell are they?

Answer 10

Basophils, Produce FSH LH

Question 11

What is the most numerous cell type in the Pars distalis?

Answer 11

Somatotropes

Question 12

What cell bodies does the hypophysiotropic region of the hypothalamus contain?

Answer 12

Parvocellular cell bodies

Question 13

Where do the parvocellular cell bodies extend their axons?

Answer 13

Towards the median eminence

Question 14

How do the hormones released by the parvocellular cell bodies reach the adenohypophysis?

Answer 14

They reach it through a system of fenestrated capillaries through a main plexus then through the hypophyseal portal vessels to the secondary plexus where they reach the pars distalis of the adenohypophysis.

Question 15

What hormone does not decrease in production even if the pituitary stalk is damaged?

Answer 15

Prolactin

Question 16

How many endocrine axes are there?

Answer 16

5

Question 17

What does each endocrine axis break down into?

Answer 17

Three levels: Hypothalamic neurons, Anterior pituitary cells, Peripheral endocrine glands.

Question 18

What is primary, secondary, and tertiary endocrine disease?

Answer 18

Primary: Failure at peripheral gland. Secondary: Failure at the anterior pituitary cells. Tertiary: Failure at the hypothalamus

Question 19

What is short loop and long loop feedback?

Answer 19

Short loop: Feedback from the hormones of the anterior pituitary onto the hypothalamus. Long loop: Feedback from the peripheral hormones from the target tissue onto the anterior pituitary and hypothalamus.

Question 20

If the trophic hormone is high (e.g. TSH), but the target gland hormone is low (e.g. T4), what might be the cause?

Answer 20

The problem is caused by failure at the target gland.

Question 21

If the trophic hormone is low (e.g. TSH), and the target gland hormone is low (e.g. T4), what might be the cause?

Answer 21

Trophic hormone deficiency

Question 22

If the trophic hormone is high (e.g. TSH), and the target gland hormone is high (e.g. T4), what might be the cause?

Answer 22

Autonomous secretion of pituitary hormone or resistance to target gland hormone’s negative feedback.

Question 23

If the trophic hormone is low (e.g. TSH), but the target gland hormone is high (e.g. T4), what might be the cause?

Answer 23

Autonomous secretion of target gland hormone

Question 24

What hormone do parvocellular neurons synthesize?

Answer 24

Corticotropin Releasing hormone (CRH)

Question 25

What exactly does CRH do?

Answer 25

CRH induces corticotrope cells in the pars distalis to increase the expression of the POMC gene which increases the production of the POMC prohormone which is then cleaved into ACTH and B-LPH.

Question 26

What effects does abnormally high levels of ACTH and B-LPH have on melanin?

Answer 26

When ACTH is at supraphysiological levels (e.g. Addison disease) then ACTH can bind to the MC1R and along with β-LPH induces melanin deposition in melanocytes in the skin leading to skin darkening.

Question 27

Where and what type of receptor does ACTH bind to?

Answer 27

ACTH binds to the melanocortin-2 receptor (MC2R) on cells in the zona fasciculata of the adrenal cortex.

Question 28

What does ACTH stimulate the secretion of?

Answer 28

ACTH stimulates the adrenal cortex to synthesize the glucocorticoids, cortisol and corticosterone. The cortex also synthesizes androgens – dehydroepiandrosterone (DHEA).

Question 29

At what time of the day does the secretion of ACTH peak?

Answer 29

Early in the morning.

Question 30

What can severe chronic depression lead to?

Answer 30

Hyper secretion of CRH is a factor in the development of tertiary hypercortisolism.

Question 31

What hormone does the parvocellular neurons synthesize that is related to the thyroid?

Answer 31

Thyroid releasing hormone (TRH)

Question 32

What does TRH stimulate the secretion of?

Answer 32

It stimulates the secretion of TSH from the anterior pituitary.

Question 33

What type of peptide is TRH?

Answer 33

It is a tripeptide.

Question 34

What is TRH synthesized from?

Answer 34

TRH is synthesized as a larger prohormone that contains six copies of TRH within its sequence.

Question 35

What are the three glycoprotein hormones of the anterior pituitary?

Answer 35

TSH, LH, FSH

Question 36

What is the composition of TSH?

Answer 36

TSH is a heterodimer of α-glycoprotein subunit (α-GSU), and a β-subunit (β-TSH).

Question 37

How do the subunits of TSH differ from those of FSH and LH?

Answer 37

The α-GSU is common to TSH, FSH, and LH, whereas the β subunit is hormone specific.

Question 38

What does glycosylation of the subunits found in TSH do?

Answer 38

Glycosylation of the subunits increases their stability in circulation and enhances the affinity and specificity of the TSH.

Question 39

Where is GnRH produced?

Answer 39

GnRH is produced by a subset of parvocellular hypothalamic GnRH neurons.

Question 40

What is the hormone that FSH increases the secretion of in both genders?

Answer 40

Inhibin

Question 41

What is kallman syndrome?

Answer 41

A syndrome that causes hypogonadotropic hypogondasim due to lack of secretion of GnRH and therefore a lack of FSH and LH Patients also usually don't have a sense of smell

Question 42

What are the symptoms of Kallman syndrome?

Answer 42

Small penis/undescended testicles at birth lack of sexual development at puberty No sense of smell

Question 43

What does GH stimulate the secretion of in the liver?

Answer 43

insulin like growth factor (IGF-I)

Question 44

What is another protein synthesized by the anterior pituitary that is similar to GH?

Answer 44

PRL and human placental lactogen (hPL)

Question 45

What peptide does the hypothalmus use to inhibit the release of GH and TSH?

Answer 45

Somatostatin | Remember that GH is released by **Somato**trophs

Question 46

What does Gherlin do in relation to GH and how does it work on receptors?

Answer 46

It stimulates the release of GH from GHS-R on somatotropes

Question 47

What is the form the 50% of GH is in serum?

Answer 47

50% of GH in serum is bound to GH-binding protein (GHBP)

Question 48

How are IGFs transported in serum?

Answer 48

IGFs are transported in serum bound to IGF binding proteins (IGFBP)

Question 49

What are the two ways the IGF-1 inhibits GH?

Answer 49

IGF-1 inhibits GH secretion from somatotropes and stimulates somatostatin release from hypothalamus

Question 50

The receptor of what other anterior pituitary hormone can GH stimulate?

Answer 50

Human GH can also act as an agonist of the PRL receptor | Makes sense since GH is similar to PRL

Question 51

Where is GHBP derived from and how does this explain the symptoms of **Laron syndrome**?

Answer 51

GHBP is derived from N terminal of the GH receptor Individuals with **Laron syndrome**, who lack normal GH receptors but have normal GH secretion, do not have detectable GHBP in their serum