Reproductive Hormones

Question 1

in females, the sex hormones control what?

Answer 1

-Development and maintenance of female secondary sexual characteristics
-Maturation of sex cells (ova) – ensures that normally only one ova at a time matures
-Changes that occur during the monthly reproductive cycle – prepare the uterine lining for implantation
-Gonadotropin-releasing hormone from hypothalamus stimulates the anterior pituitary to release: Follicle stimulating hormone, Luteinizing hormone
(both act on the ovary)

Question 2

Oestrogen in non-pregnant female primary source

Answer 2

primary source of oestrogen is the ovaries

Some oestrogen is also synthesised in adipose tissue from adrenal androgens formed in the adrenal cortex

Question 3

Oestrogen in pregnant female primary source

Answer 3

primary source of oestrogen is the placenta

Some oestrogen is also synthesised in adipose tissue from adrenal androgens formed in the adrenal cortex

Question 4

females at puberty

Answer 4

• Under the influence of the anterior pituitary, the ovaries secrete increasing amounts of oestrogen
• Oestrogen stimulates the enlargement of accessory organs including the: vagina, uterus, uterine tubes (Fallopian tubes) and ovaries as well as external structures

In the fallopian tubes, oestrogen 
stimulates the development of 
extensive mucosal folds and the 
formation of cilia on these 
epithelial cells(Cilia - aid in ovum transport)

Question 5

Oestrogen is also responsible for the development and maintenance of what?

Answer 5

secondary sexual characteristics

• development of breast and ductile systems for mammary glands within breast in preparation for breast feeding
• increase vascularisation of skin”glow” which purpose is temp control during pregnancy
• increased deposition of adipose tissue in subcut layer, especially in breast, thighs and buttocks. purpose is sexual appeal and to lay down NRG stores to be used during preg.

Question 6

Progesterone sources

Answer 6

• Ovaries are the prime source of progesterone in the non pregnant female.
• Placenta is prime source of progesterone in pregnant female

Question 7

effects of progesterone

Answer 7

promotes changes that occur in the uterus during the female reproductive cycle
The changes are aimed at preparing the uterus for the fertilized ovum

Question 8

effects of progesterone on mammory glands

Answer 8

-prepare them for breast feeding
-Helps regulate secretion of Gonadotropins (FSH & LH) from the anterior pituitary - by negative feedback control
This helps to ensure that there is only one fertilization at a time, ex ensures that one fertilized egg gets a chance to be implanted etc. without the interference of another cycle

Question 9

What are androgens

Answer 9

Male sex hormones

Question 10

What role do androgens have in females experiencing puberty

Answer 10

Increase in the growth of hair in pubic and axillary regions is due androgen secretion from the adrenal cortex

Conversely, development of the female skeletal configuration of narrow shoulders and broad hips seems to be related to low concentrations of androgen

Question 11

males – the sex hormones roles

Answer 11

• Initiate and maintain sperm cell production
• Initiate development and oversee the maintenance of male sexual characteristics

Hypothalamus secretes increasing amounts of GnRH (Gonadotropin Releasing Hormone)

travels in the hypothalamo-hypophyseal tract (i.e. circulatory connection), to the anterior pituitary
This stimulates the anterior pituitary to release the gonadotropins
Follicle Stimulating Hormone (FSH)
Interstitial Cell Stimulating Hormone (ICSH) = Luteinizing Hormone (LH)

Question 12

FSH in males

Answer 12

stimulates Sertoli cells (Sustentocyte) lining the seminiferous tubules and initiates spermatogenesis… to support , nourish and regulate the making of sperm, also stimulates production of androgen bnding protein (binds with testosterone to mature sperm)

Inhibin - negative feedback on release of FSH – slows down making of sperm

Question 13

LH in males

Answer 13

stimulates the Leydig cells in the testes to secrete testosterone.
It helps sperm to mature,
Induces differentiation of male accessory reproductive organs and maintains their function
Stimulates protein anabolism, bone growth and cessation of bone growth
Maintains sex drive

Question 14

Testosterone

Answer 14

Is the most abundant androgen
It is a steroid with a masculinising or virilising effect
Has 2 classes of action:

1. Those aimed at the reproductive organs and secondary sexual characteristics
2. Those involving the general anabolic actions which are manifested in many tissues

Question 15

Actions of testosterone (lots of them 🙄)

Answer 15

-promotes growth and development of primary sex organs (testes, penis etc.) and accessory sex glands (prostate, seminal vesicles etc.)
-maintains spermatogenesis and secretory functions of the epididymis
-causes ducts and accessory glands of the reproductive system to enlarge
- promotes the development of secondary sexual characteristics (voice, hair, stature etc.)
-Transforms adolescent boys into young men, enabling them to engage in sexual activity and produce fertile sperm and father children
-Promotes libido
-promotes anabolic activity and vigour in muscles and bone
It enhances muscular and skeletal growth
-Testosterone enhances red blood cell production (RBC) production
-Gives men a higher haematocrit
-stimulates erythropoiesis by stimulating erythropoietin
This provides the extra oxygen carrying capacity for the increased muscle mass and higher metabolic rate

Question 16

Pubertal Changes in males

Answer 16

The first “visible” sign of puberty is usually enlargement of the penis, testes and scrotum around age 13
Testosterone stimulates development of Pubic, Axillary and Facial hair.

The skin becomes darker and thicker and secretes more sebum - often leads to acne

It stimulates increased secretion of Growth Hormone: spurt of growth, increase in muscle mass, higher metabolic rate – leads to an increase in appetite, larger larynx – leads to a deepening voice and makes the thyroid cartilage (Adam’s apple) more prominent in the neck.
Thickening of the vocal cords lowers the pitch of the voice