Reproductive hormones (56)

Penis

delivers sperm to vagina

Scrotum

holds testes

Testes

produces testosterone and sperm

epididymus

stores maturing sperm before ejaculation

Vas Deferens

a duct/pathway that carries sperm away from epididymus

seminal vesicle

produces fluid containing nutrients

prostate gland

produces fluid that neutralizes vaginal fluids

urethra (M)

sperm leaves via urethra

Ovary

produces egg, oestradiol and progesterone

Oviduct/Fallopian tube

pathway the egg travels from ovary to uterus

uterus

where the foetus develops

cervix

muscular opening to vagina

Vagina

part of the birth canal and where sperm in inserted into

labia

protects vaginal opening

Urethra (F)

urination

state 3 steroid hormones

testosterone, progesterone, and oestradiol

How do steroid hormones travel? (example, testosterone)

1. Testosterone is hydrophobic and can diffuse (simple diffusion) through the plasma membrane of a cell

2. Testosterone binds to the receptor to form an active hormone-receptor complex

3. The active hormone-receptor complex enters and binds to the nucleus

4. The active hormone-receptor complex binds to specific DNA sequences and promotes/stimulates transcription

FSH

• produced by the pituitary gland

• stimulates the development of follicles containing egg(s)

LH

• produced by pituitary gland

• stimulates follicles to mature and release and egg (ovulation)

Oestradiol

stimulates the repairment of the endometrium

Progestorone

• stimulates the repairment of the endometrium

• maintains the endometrium in preparation for pregnancy

List three roles of testosterone in males.

• pre-natal development of male genitalia;

• development of male secondary sexual characteristic;

• maintenance of sex drive;

Outline the process of in vitro fertilization (IVF)

• IVF is fertilization outside body;

• drugs stops normal menstrual cycle;

• inject FSH to stimulate production of eggs;

• hCG matures the follicles;

• eggs are removed from woman;

• male provides sperm;

• eggs are mixed with sperm;

• 2–3 embryos are implanted into uterus;

• pregnancy has occurred;

Discuss the ethical issues associated with IVF. (Against)

• some view a fertilized egg as having special status;

• IVF requires the production of multiple embryos;

• fate of extra embryos is an ethical concern;

• expensive;

Discuss the ethical issues associated with IVF. (For/Support)

• helps infertile couples;

• allows for surrogate mothers;

Why do women go through Hormone replacement therapy (HRT)?

levels of oestradiol and progesterone decrease in women after menopause and the reduction of these hormones leads to risks (bone fractures).

Outline the roles of hormones in the menstrual cycle

1. FSH is secreted at the start of the cycle when progesterone/oestradiol is low;

2. FSH stimulates the development of follicles;

3. The developing follicles secrete oestradiol/FSH stimulates oestradiol secretion;

4. Oestradiol stimulates the repair of the endometrium

5. Oestradiol reaches a peak which stimulates the release LH (positive feedback);

6. low levels of oestradiol initially inhibit FSH (and LH) secretion;

7. LH is secreted and causes egg to be released from the follicle

8. LH causes the development of the corpus luteum;

9. LH causes the secretion of progesterone;

10. LH causes less oestradiol to be secreted (negative feedback);

11. Progesterone prepares the endometrium for pregnancy;

12. Progesterone inhibits the secretion of LH / FSH;

13. Low levels of progesterone at the end of the cycle promote FSH production;

14. Lower concentrations of progesterone result in menstruation;