Hormones

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Assalamualaikum wr wb,

 

Our summary for todays topic about Hormones in my  IGCSE class..

 

Puberty

Puberty is the stage in life when a child's body develops into an adult's body. The changes take place gradually, usually between the ages of 10 and 16.

Changes occur at puberty because of hormones:

  
testosterone - produced by the testes - controls the development of male secondary sexual characteristics
  
oestrogen - produced by the ovaries - controls the development of female secondary sexual characteristics

 Changes during puberty

Boys only	Boys and girls	Girls only
Voice breaks	Pubic hair grows	Voice deepens gradually
Hair grows on face and body	Underarm hair grows	Hips get wider
Body becomes more muscular	Sexual organs grow and develop	Breasts develop
Testes start to produce sperm cells		Ovaries start to release egg cells - menstruation starts

The menstrual cycle

 The menstrual cycle is a recurring process which takes around 28 days. During the process, the lining of the uterus is prepared for pregnancy. If pregnancy does not happen, the lining is then shed. This is known as menstruation.

Hormones that control the menstrual cycle

•  they are involved in controlling the release of an egg each month from an ovary, and changing the thickness of the uterus lining.

Hormone	Produced	Role
FSH (follicle stimulating hormone)	Pituitary gland	Causes an egg to mature in an ovary. Stimulates the ovaries to release oestrogen
Oestrogen	Ovaries	Stops FSH being produced (so that only one egg matures in a cycle). Repairs and thickens the uterus lining. Stimulates the pituitary gland to release LH.
LH (luteinising hormone)	Pituitary gland	Triggers ovulation (the release of a mature egg)
Progesterone	Ovaries	Maintains the lining of the uterus during the middle part of the menstrual cycle and during pregnancy.

Hormone levels during the menstrual cycle

 If a woman becomes pregnant, the placenta produces progesterone. This maintains the lining of the uterus during pregnancy and means that menstruation does not happen.


Credit : BBC bitesize