Reproduction (Humans)

Question 1

How do oestrogen levels change during the menstrual cycle?

Answer 1

• Levels rise from day one (stimulated by FSH), and peak shortly before day 14 to stimulate LH (ovulation)
• They drop after ovulation, rise slightly to maintain the lining and then drop for menstruation

Question 2

How do progestrone levels change during the menstrual cycle?

Answer 2

• Levels stay low from day 1-14
• They rise signifigantly once ovulation has occured, stimulated by LH, to maintain and thicken the lining, and then drop, causing menstruation

Question 3

How do LH levels change during the menstrual cycle?

Answer 3

• Levels are low from day 1-12
• They rise at day 13, stimulated by oestrogen, and peak at day 14 for ovulation
• They then drop, and are low for the rest of the cycle as progestrone inhibits it

Question 4

How do FSH levels change during the menstrual cycle?

Answer 4

• Levels are high between day 1-12 to mature the egg and stimulate oestrogen production
• Levels drop shortly before ovulation as oestrogen peaks
• They are low for the rest of the cycle as progestrone + oestrogen inhibit it to ensure only one egg is fully matured

Question 5

What are the roles of oestrogen in the menstrual cycle?

Answer 5

• Stimulates the uterus to begin to build up a lining
• Stimulates the production of LH at its peak
• Inhibits FSH production to stop the maturation of another follicle

Oestrogen is produced in the ovaries

Question 6

What are the roles of progesterone in the menstrual cycle?

Answer 6

• Maintains the lining of the uterus
• Inhibits the production of LH and FSH to stop the maturation and release of another egg past day 14

Progesterone is produced by the corpus leutem, which is a dead follice left behind after ovulation

Question 7

What are the roles of FSH in the menstrual cycle?

Answer 7

• Causes an egg to mature inside a follicle in the ovaries
• Stimulates oestrogen production in the follice

FSH is produced in the pituitary glands

Question 8

What are the roles of LH in the menstrual cycle?

Answer 8

• Causes ovulation to occur
• Stimulates progestrone production by causing the formation of a corpus leutum

LH is produced in the pituitary glands