Session 2

Question 1

What are the 2 glands that make the Pituitary gland?

Answer 1

Anterior

Posterior

Question 2

What does the Anterior Pituitary gland arise from?

Answer 2

Rathke’s pouch in the roof of the mouth and then migrates.

It is NOT nervous tissue

Question 3

What does the Posterior Pituitary gland arise from?

Answer 3

Nervous tissue. It is a neurosecretory gland

Question 4

What does the Anterior Pituitary gland secrete?

Answer 4

Mainly trophic hormones.
Glycoprotein hormones - FSH, LH, TSH
Polypeptide hormones - GH, ACTH, Prolactin

Question 5

What cells secrete FSH & LH?

Answer 5

Gonadotrophs

Question 6

What cells secrete TSH?

Answer 6

Thyrotrophs

Question 7

What cells secrete GH?

Answer 7

Somatotrophs

Question 8

What cells secrete ACTH?

Answer 8

Corticotrophs

Question 9

What cells secrete Prolactin?

Answer 9

Lactotrophs

Question 10

What does the Posterior Pituitary gland secrete?

Answer 10

ADH

Oxytocin

Question 11

What controls Anterior Pituitary gland secrete?

Answer 11

Hypothalamus via Releasing hormones

Question 12

How do Releasing hormones travel to the Anterior Pituitary gland?

Answer 12

Hypophyseal portal circulation (Released from Median eminence –> Anterior Pituitary)

Question 13

What hormone does the Hypothalamus use to control FSH & LH?

Answer 13

Gonadotrophin releasing hormone (GnRH)

Release is pulsatile (Around once per hour)

Question 14

What is the effect of GnRH?

Answer 14

Stimulates the Gonadotrophs to secrete FSH & LH.

Response is variable

Question 15

What is the primary tissue that FSH & LH act on?

Answer 15

Gonads

Question 16

What does the action of FSH & LH on Gonads cause?

Answer 16

Stimulates the secretion of gonadal steroids that will go on to control other reproductive processes.

Question 17

What acts as negative feedback on the Hypothalamic-Pituitary-Gonadal axis?

Answer 17

FSH & LH

Question 18

What is GnRH secretion controlled by?

Answer 18

Neurones that are influenced by;

• Other neurones in the brain (Allows influence of environmental factors)
• Feedback from the gonads

Question 19

What causes an increase in Inhibin secretion?

Answer 19

Increased Spermatogenesis

Question 20

Where does Inhibit act?

Answer 20

On the Anterior Pituitary gland

Question 21

What is the effect of increased Inhibin?

Answer 21

Decrease in FSH secretion, therefore Sertoli cells are stimulated less

Question 22

How does the Testosterone level vary?

Answer 22

Long term it is constant, but in the short term it varies via a Circadian rhythm

• Peaks in the morning
• Lowest levels in the evening

Question 23

How can Testosterone be influenced by the environment?

Answer 23

Different stimuli can cause an increase in Testosterone levels

Question 24

In males, how does Testosterone effect FSH & LH?

Answer 24

It causes the levels to decrease

Question 25

In females, how does Oestrogen effect FSH & LH?

Answer 25

Normal levels = Decrased FSH & LH | High levels = Increased FSH & LH

Question 26

In males, how does Testosterone effect GnRH?

Answer 26

Decreases its secretion

Question 27

In females, how does Oestrogen effect GnRH?

Answer 27

Normal levels = Decreased GnRH | High levels = Increased GnRH

Question 28

How does the LH surge occur?

Answer 28

Oestrogen levels are above a threshold point which causes GnRH to be high. This causes lots of GnRH to be secreted in a positive feedback loop

Question 29

How does Progesterone change the effects of Oestrogen?

Answer 29

When Progesterone is high, the inhibitory effects of Oestrogen are increased. It also prevents positive feedback of the high levels of Oestrogen resulting in no LH surge

Question 30

What produces Inhibin?

Answer 30

The gametes, therefore the more gametes there are the more Inhibin

Question 31

Inhibition from the gonads selectively suppresses which hormone?

Answer 31

FSH | No effect on LH

Question 32

How are the Testosterone levels maintained?

Answer 32

Negative feedback control

Question 33

How does the negative feedback control effect Testosterone levels?

Answer 33

FSH binds to Sertoli cells (Testicular cells) which are the supporting cells of Spermatogenesis (Which would cause more gametes to form so more Inhibin)

Question 34

What does LH bind to?

Answer 34

Leydig cells (Testicular cells)

Question 35

What do Leydig cells secrete?

Answer 35

Testosterone

Question 36

What does LH promote the secretion of?

Answer 36

Testosterone

Question 37

What does Testosterone inhibit?

Answer 37

GnRH