IC3

Question 1

How is testes descended?

Answer 1

Testosterone produced by fetal tests + shortening of gubernaculum stimulates the descent of testes from rear of abdominal cavity to 2 sides of scrotum; usually completed by 7th month of gestation

Question 2

Term for undescended testes into adulthood

Answer 2

Cryptorchidism

Question 3

Temperature of scrotum vs body temp

Answer 3

Scrotum: 35 degree Celsius vs Body: 37 degree Celsius

Question 4

Which cell produces testosterone?

Answer 4

Leydig cells

Question 5

Role of sertoli cells

Answer 5

Provide support for spermatogenesis

Question 6

Where does spermatogenesis take place?

Answer 6

Seminiferous tubule

Question 7

How long is spermatogenesis? Does it occur synchronously throughout the seminiferous tubule?

Answer 7

Around 64 days; No, different tubules are in different stages of spermatogenesis

Question 8

What happens during male puberty?

Answer 8

1. Onset of spermatogenesis
2. Enlargement of testes and development of secondary characteristics
3. Hormonal development ‘raging hormones’ -> Hypothalamus secretes GnRH every 1-3 hours -> stimulate release of FSH & LH from anterior pituitary

Question 9

Predominant negative feedback of testosterone

Answer 9

Decrease GnRH release by acting on the hypothalamus, thus indirectly decreasing BOTH LH and FSH release by anterior pituitary.

Question 10

Which hormone (other than testosterone) selectively inhibits FSH secretion?

Answer 10

Inhibin (produced by sertoli cells)

Question 11

Effect of anabolic androgenic steroids on testes and testosterone

Answer 11

Anabolic androgenic steroids inhibits secretion of GnRH from hypothalamus -> decrease in LH and FSH release from gonadotrope -> Testosterone secretion & sperm production decrease & testes shrink

Question 12

How is testosterone converted to dihydrotestosterone (DHT) & estradiol respectively?

Answer 12

By 5 alpha-reductase & aromatase

Question 13

Which hormone contributes to hair loss in men,andhow?

Answer 13

DHT; shortens the growing phase of hair follicles, causing them to shrink until there are fewer visible hairs left on the scalp

Question 14

What are androgens?

Answer 14

Any steroid hormone that promotes male secondary sex characteristics

Question 15

What is an oocyte?

Answer 15

An immature ovum; found in ovary

Question 16

Similarity btw ovary & testes

Answer 16

They are both gonads, produce sex hormones & are endocrine glands.

Question 17

What is a primary follicle made up of?

Answer 17

Primary oocytes + surrounding granulosa cells

Question 18

Follicular vs Luteal phase

Answer 18

Follicular: dominated by maturing follicles
Luteal: characterised by presence of corpus luteum

Question 19

3 main types of estrogen made the body

Answer 19

1. Estradiol (commonly found in women of childbearing age)
2. Estriol (main estrogen during pregnancy)
3. Estrone (only estrogen found in postmenopausal women)

Question 20

What is the estrogen storage site?

Answer 20

Antrum

Question 21

Role of FSH and LH in female repro system

Answer 21

1. FSH: Maturation of follicle cells and induces antrum formation
2. LH: Differentiation of follicle cells into luteal cells and ovulation (release of mature eggs)

Question 22

What is corpus luteum?

Answer 22

Remnanat of egg release

Question 23

Role of corpus luteum

Answer 23

Produces estrogen & progesterone:
1. High levels of progesterone cause inhibition both LH & FSH secretion
2. High levels of estrogen selective stimulates LH secretion

Question 24

2 main functions of ovaries

Answer 24

1. produce ova (oogenesis)
2. Secrete sex hormones (estrogen and progesterone) which act together to promote fertilization of the ovum and to prepare the female reproductive tract for pregnancy.

Question 25

Action of rising, moderate levels of estrogen

Answer 25

1) Hypothalamus - to inhibit GnRH secretion (decrease FSH, LH). 2) Pituitary - to inhibit FSH secretion. *Follicular cells secrete inhibin (which then acts to inhibit FSH secretion). -> LH secretion continues to rise slowly during the follicular phase .

Question 26

Action of rising high levels of estrogen

Answer 26

As the follicle matures: * Rising HIGH levels of estrogen act on the hypothalamus and pituitary to increase GnRH and selectively stimulate LH secretion -> POSITIVE-feedback * Follicular cells secrete inhibin (which selectively inhibits FSH secretion). -> resultant SURGE in LH secretion Massive increase in LH secretion brings about: 1) Differentiation of follicular cells into luteal cells 2) Ovulation (release of mature egg)

Question 27

Luteal phase: Under influence of LH

Answer 27

* Under the influence of LH, the Corpus luteum (CL) secretes both estrogen (E) and progesterone (P) with P being its most abundant hormonal product to support ovum should fertilization occur * P acts to inhibit both LH and FSH secretion. * E Selectively stimulates LH secretion -> without FSH and LH, new follicular maturation and ovulation is prevented

Question 28

Luteal phase: No fertilisation

Answer 28

If no fertilization -> CL degenerates, no E or P is produced -> negative feedback inhibited -> New follicular phase begins

Question 29

Signs of puberty (in succession)infemale

Answer 29

– Thelarche (earliest) – development of breasts – Pubarche – growth of pubic and axillary hair – Menarche – the first menstrual period

Question 30

at what ages does menopause occur?

Answer 30

between the ages of 45 and 55

Question 31

Signs of menopause

Answer 31

Cessation of menstrual cycles (12mths after last menstrual period) Gradual atrophy genital organs Vasomotor changes (regulation of blood vessel dilation & constriction -> hot flushes) Skin changes Psychological, emotional Increased cholesterol level – risk of cardiovascular disease Increased risk of osteoporosis (decreased bone mass due to less E)