Please enable JavaScript.
Coggle requires JavaScript to display documents.
Hormonal Influence on Puberty - Coggle Diagram
Hormonal Influence on Puberty
Hormonal Onset of puberty
On the onset of puberty, the hypothalamus secretes a releaser hormone which targets the pituitary gland
The two pituitary gland releases the hormone FSH (follicle stimulating hormone) and ICSH (interstitial cell stimulating hormone)
In males: ICSH stimulates the development of testosterone in the testes, also causes the development of male sex organs and secondary sexual characteristics
In females: LH stimulates the ovaries to produce oestrogen, this causes the development of female sex organs and secondary sexual characteristics
Hormonal Control of Sperm Production
FSH promotes sperm production in the seminiferous tubules, whilst the interstital cells release testosterone
Testosterone also stimulates sperm production and activates the accessory glands to produce their secretions
The release of testosterone is controlled by a negative feedback system:
Accumulated testosterone inhibits pituitary hormones
The reduction of FSH and ICSH results in a drop of testosterone
Reduction of testosterone stops inhibition of pituitary hormones
The production and release of the pituitary hormones increases, stimulating increased production of testosterone
Hormonal Control of Menstrual Cycle
The menstrual cycle lasts about 28 days
Menstrual Cycle
Day 1 - bleeding from vagina begins due to loss of uterus lining (menstruation / period)
Day 5 - bleeding stops. Uterus lining begins to re-grow and egg cell starts to mature in the ovaries
Day 14 - ovulation. Mature egg cell is released from the ovaries, travels through the oviduct towards the uterus
If the egg cell does not meet with a sperm cell in the oviduct, the endometrium begins to break down and the cycle repeats
If fertilisation occurs, the zygote attaches to the endometrium so it does not break down and menstruation does not occur
Oestrogen and Progesterone in the Control of the Menstrual Cycle
FSH causes an egg to mature in the ovary and produces oestrogen
Oestrogen stops FSH being produced, proliferates the endometrium. Stimulates production of LH.
LH triggers ovulation
Progesterone promotes the development and vascularisation of the endometrium. If a woman becomes pregnant the placenta produces progesterone which maintains the endometrium and stops menstruation
Interaction of hormones in control of the menstrual cycle
Pituitary gland produces FSH which causes the development of a follicle in the ovary
As the egg matures inside the follicle, it secretes oestrogen
Oestrogen proliferates the endometrium and inhibits FSH secretion
High oestrogen levels, there is a surge of LH which starts ovulation - egg is released from the follicle
Follicle becomes a corpus luteum which produces both ovarian hormones, inhibiting production of pituitary hormones - negative feedback
Progesterone maintains the endometrium
If egg is not fertilised, corpus luteum degenerates progesterone levels drop, causing menstruation