B11.6 - Hormones And The Menstrual Cycle + B11.5 Human Reproduction Flashcards
How long is the average mensural cycle?
28 days
What happens at the start of each month in the mensural cycle?
- The lining of the uterus thickens to support a developing baby
- The eggs start maturing in the follicles of the oviaries
What happens about 14 days into the menstrual cycle?
One of the eggs is released fro the ovary in ovulation
What happens if the egg is not fertilised about 14 days after ovulation?
Te lining of the uterus and egg are shed from the body in a period
What does the lining of the uterus do?
Provides food for a developing embryo
What does Follicle stimulating hormone (FSH) do?
It makes eggs mature in follicles in the ovaries and stimulates the ovaries to produce hormones including oestrogen
Where and why is oestrogen made?
It is made and secreted in the ovaries in response to FSH
What does oestrogen do?
It stimulates the lining of the uterus to grow in preparation for a pregnancy, slows FSH production and stimulates release of LH
How is FSH secretion from the pituitary gland stopped?
It is slowed by rising levels oestrogen
Where and why is Luteinising Hormone made?
LH is stimulated to be secreted from the pituitary gland by oestrogen
What does Lutenising Hormone do?
It stimulates the release of a mature egg from the oviaries
What does progesterone do?
It inhibits both FSH and LH production and maintains the uterus lining in the second half of the cycle
When is progesterone secreted and where from?
It is secreted by the empty egg follicle after ovulation
What happens at puberty?
The body starts releasing sex hormones that trigger off secondary sexual characteristics and cause eggs to mature in women
What is the main reproductive hormone in men?
Testosterone
