#119 Sex hormones

Credit: revision world

Sex hormones (testosterone in boys and oestrogen in girls) are responsible for the development of secondary sexual characteristics at puberty. 

Sex hormones 

	Testosterone	Oestrogen
Secreted by	testes	ovaries
Make changes	in boys	in girls

Puberty  

- the sex organs (ovaries in girls, testes in boys) become mature and start to secret hormones, making gametes (ova and sperms)

- happens at about 10-14 years.

Secondary sexual characteristics at puberty

Male	Female
Voice becomes much lower (breaks)	Breasts grow, nipples enlarge
Hair start to grow on chest, face, under arms and in pubic area	Hair develops under arms and in pubic area
Body becomes more muscular	Hip become wider
Penis becomes larger	Uterus and vagina become larger
Testers start to produce sperm	Ovaries start to release eggs and period begin (menstruation)

Sites of production of oestrogen and progesterone in the menstrual cycle and in pregnancy 

  

Hormones	Site of production
	In the menstrual cycle	In pregnancy
Oestrogen	Ovaries	Placenta
Progesterone	Corpus luteum (remains of follicle in ovary after ovulation)	Placenta

Try this

Answer

a) i) Sperm duct labeled correctly between the testes and urethra.

ii) Urethra labeled correctly between bladder and tip of penis.

b) In males the urethra carries urine and semen at different times; in females the urethra only carries urine.

c) i) Two male secondary sexual characteristics from:

- voice becomes much lower (breaks)

- hair starts to grow on chest, face, under arms and pubic area

- body becomes more muscular

- penis becomes larger

- testes start to produce sperm.

  
ii) Testis (or testes) labeled correctly.

  
iii) testosterone makes muscles grow, so the athletes can run faster or perform better.