Neuroendocrine regulation and pituitary

Question 1

What does the hypothalamus act on?

Answer 1

The pituitary gland.

Question 2

What hormones can the pituitary gland release?

Answer 2

Hormones that can control the gonads, thyroid and adrenal gland.

Question 3

What is the pituitary divided into?

Answer 3

The anterior and posterior pituitary.

Question 4

How is ADH released?

Answer 4

It is modified by the hypothalamus and released from the posterior pituitary.

Question 5

What is ADH involved in?

Answer 5

Regulating the volume of urine that is produced in the kidney.

Question 6

What are some hormones released by the anterior pituitary gland?

Answer 6

Growth hormone, prolactin (released during pregnancy and stimulates mammary glands).

Question 7

What are primary hormones?

Answer 7

Created by endocrine glands that into the circulation and reach their target tissues.

Question 8

What is the neuroendocrine system?

Answer 8

Modified neuro secretory cells that release the hormones into the circulation that can travel to distant target cells.

Question 9

Where is the hypothalamus located?

Answer 9

The base of the brain.

Question 10

How are the hypothalamus and pituitary gland linked?

Answer 10

The pituitary gland is the hypothalamus’ output organ.

Question 11

What is the median eminence?

Answer 11

The small capillary bed where regulatory hormones are released from the hypothalamus into the pituitary.

Question 12

Where do hormones travel that are released into the median eminence?

Answer 12

They travel in the hypothalamo-pituitary portal vessels that then travel in the blood vessels directly to the anterior pituitary.

Question 13

What does the paraventricular nucleus do?

Answer 13

It releases oxytocin that causes lactation.

Question 14

What does the supraoptic nucleus do?

Answer 14

It release vasopressin (ADH).

Question 15

WHat does the arcuate nucleus and periventricular zone do?

Answer 15

They are involved in neuroendocrine control.

Question 16

What do suprachiasmatic neurones do?

Answer 16

Receive retinal innervation and synchronize circadian rhythms in the light-dark cycle and send output to sympathetic and parasympathetic output neurones in the spinal cord to control activity of the ANS.

Question 17

What do neurosecretory cells do?

Answer 17

They are responsible for the release of regulatory hormone to control pituitary gland.

Question 18

What are the key cells in the periventricular zone?

Answer 18

Suprachiasmatic neurones and neurosecretory cells.

Question 19

How is the hypothalamus and anterior pituitary gland linked?

Answer 19

The hypothalamus produces regulatory hormones that stimulate or inhibit hormones produced by the anterior pituitary gland.

Question 20

What are some of the releasing factor hormones the hypothalamus releases?

Answer 20

Corticotropin releasing factor (CRF), thyrotropin releasing hormone (TRH), growth hormone releasing hormone (GHRH), gonadotropin releasing hormone (GnRH), prolactin releasing factor (PRF).

Question 21

What are some of the inhibiting factor hormones the hypothalamus releases?

Answer 21

Growth hormone inhibiting hormone (GHIH), prolactin inhibiting hormone (PIH) and melanocyte stimulating hormone inhibitng hormone (MSH-IH).

Question 22

What tissue makes up the posterior pituitary gland?

Answer 22

The pars nervosa, the pars intermedia and the pars distalis.

Question 23

What does the pars distalis do?

Answer 23

It contains stored hormones waiting to be released.

Question 24

What are the four trophic hormones that are released from the anterior pituitary?

Answer 24

Thyroid stimulating hormone (TSH), Adrenocorticotrophic hormone (ACTH), follicle stimulating hormone (FSH) and luteinizing hormone (LH).

Question 25

What are the two primary hormones the anterior pituitary releases?

Answer 25

Growth hormone (GH) and prolactin (PRL).

Question 26

How does the hypothalamus control the release of hormones from the anterior pituitary?

Answer 26

Hormones are secreted into the hypothalamic neurones that travel through the capillaries in the median eminence. Blood flow is driven by the heart and goes in one direction.

Question 27

What do hypophysiotropic hormones do?

Answer 27

They signal to the anterior pituitary to release a hormone, or prevent hormone release.

Question 28

What are the effects of growth hormone?

Answer 28

1. Increases cell size, number and differentiation | 2. By protein synthesis, fat utilization and altered carbohydrate metabolism.

Question 29

What is growth hormone?

Answer 29

A polypeptide hormone that acts at a receptor tyrosine kinase.

Question 30

What is growth hormone a major regulator of?

Answer 30

Post-natal growth.

Question 31

What are somatomedins?

Answer 31

Small proteins produced by the liver in response to growth hormone. There are at least 4 that are produced and they have a long half life compared to growth hormone (20 hours compared to less than 20 minutes).

Question 32

What does GH trigger the release of?

Answer 32

Somatomedins that cause an increase in cell size and number, differentiation, protein synthesis and bone growth.

Question 33

What is GH released in response to?

Answer 33

Growth-hormone-releasing hormone (GHRH).

Question 34

What is the release of GH inhibited by?

Answer 34

Growth-hormone-inhibiting hormone (GHIH/somatostatin).

Question 35

Where are GHRH and GHIH released from?

Answer 35

Ventromedial hypothalamus.

Question 36

When are surges of GH released?

Answer 36

Birth, puberty.

Question 37

When does GH release stabilise/decline?

Answer 37

Adulthood and old age.

Question 38

What metabolic signals affect GH?

Answer 38

Insulin-induced hypoglycaemia stimulates GH secretion.

Question 39

What other signals stimulate GH release?

Answer 39

Exercise and sleep.

Question 40

What does GH act on?

Answer 40

The liver.

Question 41

Why is GH important in the body?

Answer 41

WIthout it dwarfism may result or accelerated aging.

Question 42

What causes dwarfism?

Answer 42

General anterior pituitary dysfunction, specific GH deficit or normal but heriditary somatomedin deficit.

Question 43

What can an excess of GH cause?

Answer 43

GIgantism and acromegaly.

Question 44

What is acromegaly?

Answer 44

It is caused by an excess production of growth hormone and most commonly affects the middle-aged. It can result in premature death and it is infrequently diagnosed due to slow onset. Most common symptoms are abnormal growth of hand and feet.

Question 45

How can acromegaly be treated?

Answer 45

Surgical removal of a tumour, drug therapy or radiation therapy.

Question 46

What are produced as primary hormones from posterior pituitary

Answer 46

1. ADH | 2. Oxytocin