hypothalamus, pituitary and pineal gland

Question 1

hypothalamus and pituitary is the major link between what

Answer 1

nervous & endocrine systems

Question 2

Hypothalamic nerve cells synthesise at least how many hormones

Answer 2

9

Question 3

Pituitary endocrine cells synthesise how many hormones

Answer 3

7

Question 4

together, hypothalamus and pituitary regulate what

Answer 4

growth, development, metabolism & homeostasis

Question 5

describe the structures of The Pituitary Gland/Hypophysis

Answer 5

Two lobes; anterior & posterior

Hypophyseal portal veins
- Connect capillaries in hypothalamus to capillaries in anterior pituitary

Question 6

describe the structure and functions of the hypothalamus control

Answer 6

Axons of hypothalamic neurons (neurosecretory cells) end near capillaries of hypothalamus

Secrete releasing hormones or inhibiting hormones to portal veins
to Regulate release of anterior pituitary hormones

Question 7

name the anterior pituitary/Adenohypophysis hormones:

Answer 7

1. Human Growth Hormone (hGH)
2. Thyroid Stimulating Hormone
3. Follicle Stimulating Hormone (FSH) & 4.Luteinising Hormone (LH)
4. Prolactin (PRL)
5. Adrenocortcotrophic Hormone (ACTH)
6. Melanocyte-Stimulating Hormone (MSH)

Question 8

explain the anterior Pituitary/Adenohypophysis hormone:
human growth hormone (hGH)

Answer 8

Promotes synthesis of Insulin-like Growth Factors (IGFs) = somatomedins
- in liver, muscle, cartilage & bone

Released in bursts (~2 hour intervals)

Hypothalamus produces Growth Hormone Releasing Hormone (GHRH) & Growth Hormone Inhibiting Hormone (GHIH )

Question 9

explain the control of the growth hormone released from the anterior pituitary

Answer 9

Regulated by blood glucose levels

Hypoglycaemia (low blood sugar) : > GHRH and < GHIH

Hyperglycaemia (high blood sugar):<GHRH>GHIH</GHRH>

More GH released during sleep

Question 10

explain the anterior Pituitary/Adenohypophysis hormone:
Thyroid Stimulating Hormone

Answer 10

Stimulates the synthesis & secretion of Thyroid hormones from the thyroid gland

Hypothalamus has control over Thyrotropin Releasing Hormone (TRH) - no TIH
- Regulated by circulating thyroid hormone levels

Question 11

explain the anterior Pituitary/Adenohypophysis hormone:
Follicle Stimulating Hormone (FSH) &

Answer 11

FSH initiates follicle development in ovaries

FSH stimulates sperm production in testes

Question 12

explain the anterior Pituitary/Adenohypophysis hormone:
Luteinising Hormone (LH)

Answer 12

LH together with FSH stimulates ovulation, formation of corpus luteum & secretion of progesterone

LH stimulates release of testosterone

Question 13

explain what Gonadotrophin releasing Hormone (GnRH) from hypothalamus is suppressed by

Answer 13

high levels of oestrogen in females and testosterone in males.

Question 14

explain the anterior Pituitary/Adenohypophysis hormone:
Prolactin (PRL)

Answer 14

Initiates & maintains milk production by mammary glands (ejection of milk depends on oxytocin from the posterior pituitary)

Prolactin inhibiting hormone (PIH) suppresses prolactin release

High levels of oestrogens (during pregnancy) stimulate Prolactin Releasing Hormone (PRH)  prolactin release (can affect the baby too (to produce some milk) - neonatal milk)

Question 15

explain the anterior Pituitary/Adenohypophysis hormone:
Adrenocortcotrophic Hormone (ACTH)

Answer 15

Controls production & secretion of glucocorticoids (cortisol) from adrenal cortex

Corticotrophin Releasing Hormone (CRH) from hypothalamus stimulates secretion of ACTH

Stress related stimuli can also stimulate ACTH release

Adrenal glucocorticoids inhibit CRH & ACTH release – negative feedback

Question 16

explain the anterior Pituitary/Adenohypophysis hormone:
Melanocyte-Stimulating Hormone (MSH)

Answer 16

Only found in Small circulating amounts

Excess causes skin darkening, if too much produced

Question 17

where are Posterior Pituitary Hormones synthesised and stored prior to release

Answer 17

synthesised in the hypothalamus and travel down nerve axons to terminals in the posterior pituitary where they are stored prior to release.

Question 18

name the types of Posterior Pituitary hormones

Answer 18

oxytocin
Antidiuretic Hormone (ADH)

Question 19

explain the Posterior Pituitary hormone:
oxytocin

Answer 19

enhances smooth muscle uterine contraction during birth & milk ejection

• may play role in emotional bonding

Question 20

explain the Posterior Pituitary hormone:
Antidiuretic Hormone (ADH)

Answer 20

= vasopressin

Causes kidney to retain more water

Causes vasoconstriction which is increase in blood pressure

high blood osmotic pressure i.e. high conc. of solutes detected in hypothalamus causing increase secretion

Question 21

what pituitary hormones could we potentially live without

Answer 21

Could potentially live without the posterior pituitary hormones but not without the anterior pituitary hormones

Question 22

explain the pineal

Answer 22

Small gland attached to roof of third ventricle of brain

Produces melatonin

Sets the body’s biological clock
- More released in darkness