Reproductive system 2

Question 1

The Endocrine System hormones

Answer 1

• Collection of glands located throughout the body that manufacture and secrete hormones to regulate physiological function
• Produced by ductless glands within the endocrine system

Question 2

Major endocrine gland

Answer 2

• Adrenal glands
• Hypothalamus
• Ovaries and testes
• Pancreas
• Thyroid and parathyroid
• Pineal gland
• Pituitary gland
• Thymus gland

Question 3

Classes of hormones

Hormones derived from amino acids

Answer 3

• Dopamine, epinephrine that have a tyrosine precoursor

Question 4

Classes of hormones

Proteins and peptides

Answer 4

Insulin and growth hormone are examples of protien hormones

Question 5

Classes of hormones

Hormones derived from lipids

Answer 5

• Prostaglandins are derived from phospholipids
• Steroids derived from cholesterol
• Most RH steroids but stimulated by other classes

Question 6

Reproductive hormones

Answer 6

Synthesised and secreted Increasing at puberty and normally decreasing in old age

Question 7

Cholesterol acts as a precoursor for

Answer 7

• Steroid hormones
• Adrenal steroids
• Glucocorticoids
• Mineralcorticoids

Question 8

Structure of cholesterol

Answer 8

• 4 cycloalkane rings
• Large hydrocarbon chain
• Essential component of cellular membrane
• From diet

Question 9

Reproductive hormones

Answer 9

• Sex steroids or steroid hormones
• Produced mainly by the gonads (ovaries and testes)
• Some production by placenta, adrenal glands

Question 10

Classes of Reporductive hormone

Answer 10

• Oestrogens
• Androgens
• Progestogens
• These bind with the respective receptors

Question 11

Oestrogens

Answer 11

• Oestradiol
• Oestrone
• Oestriol

Question 12

Androgens

Answer 12

• Testosterone
• 5a-dihydrotestosterone
• Androstenedione
• Dehydroepiandrosterone

Question 13

Major functions of
reproductive hormones

Answer 13

• Binds to the complementory receptor on target tissue

Question 14

Primary role of reproductive organs

Answer 14

Maturation of reproductive organs, fertility and pregnancy

Question 15

Secondary role of reproductive hormones

Answer 15

• Development of physical characteristics

Question 16

Testes anatomy where is hormone produced?

Answer 16

• Testosterone is produced in Leydig cells

Question 17

Ovarian anatomy steroid hormone
production

Answer 17

• Ovarian granulosa cells produce oestrogen

Question 18

Where are androgens produced

Answer 18

Ovarian theca cells

Question 19

Where is progesterone produced

Answer 19

• placenta - placental syncytiotrophoblasts
• Eventually takes over from corpus luteum

Question 20

Generic mechanism of action

Answer 20

• Hormones enter cells
• Hormones bind to intracellular receptor
• Conformation change and translocation
• DNA binding
• Gene expression

Question 21

Regulation of gonadal steroidogenesis

Answer 21

• Regulation via the HPG axis hypothalamus, pituitary and gonad

Question 22

Hypothalamus

Answer 22

• Small structure at base of forebrain
• Hypothalamus releases GnRH
• Released into blood
• Reach pituitary

Question 23

Pituitary

Answer 23

• Pea-sized gland located at the base of the
  skull ventral to the hypothalamus
• Posterior and anterior lobes
• Anterior pituitary contains specialised cells
• GnRH stimulates gonadotropes to
• Produce gonadotrophins

Question 24

What produces gonadotrophins

Answer 24

• glycoproteins
• FSH (follicular stimulating hormone)
• LH (Lutenising hormone)
• hCG

Question 25

LH main functions

Answer 25

- In females acts on ovarian follicle inducing ovulation - Acts on testes producing testosterone

Question 26

FSH main functions

Answer 26

- In females promotes ovarian follicle development & oestrogen production - In males it stimulates spermatogenesis in testes

Question 27

HPG axis (LH)

Answer 27

- Hypothalamus stimulates the GnRH and the fast GnRH pulse causes LH synthesis and secreation - LH stimulates the steroidogenesis and reproductive hormone synthesis - Physological effects

Question 28

HPG axis (FSH)

Answer 28

- Hypothalamus stimulates the GnRH and the slow GnRH pulse causes FSH synthesis and secreation - FSH stimulates the steroidogenesis and reproductive hormone synthesis - Physological effects

Question 29

Negative feedback

Answer 29

Decreases level of signal and maintains homeostasis

Question 30

Direct negative feedback

Answer 30

- Steroid hormones testosterone/oestrogen decrease secretion of gonadotrophins

Question 31

Indirect negative feedback

Answer 31

- Steroid hormones inhibit their own production indirectly by inhibiting hypothalamus GnRH - Decreased pituitary gonadotrophin secretion - Reduced steroid hormone production

Question 32

Negative regulation of steroidogenesis by inhibin

Answer 32

- Protein hormone and in females, released by granulosa cells in response to FSH - In males, produced by Sertoli cells in response to androgens - Negative regulator of FSH

Question 33

Positive feedback

Answer 33

- Leads to an increase in hormone level * Occurs within follicular phase of uterine cycle * Oestrogen-induced LH to trigger ovulation