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The Menstrual Cycle The Menstrual Cycle
L.O: To know how hormones are used to control the
menstrual cycle
L.O: To know how hormones are used to control the
menstrual cycle
Complete this tableProcess Type of response
(nerve/hormone)Target organ
Adrenalin increasing heart rate and sugar in the blood
Heart and liver
Insulin controlling sugar
Touching a hot tripod
Testosterone in men Male reproductive organs
Airzooka and blinking
ADH (anti-diuretic hormone)
kidneys
Oestrogen Ovaries, uterus, pituitary gland
What are hormones?
The Endocrine System
Hormones • Hormones are used to send
information around the body • They work more slowly than nerves• They are secreted by glands (e.g.
the pituitary gland• They travel in the blood • They go to all organs but usually
only affect target organs e.g. ovaries and pancreas
Why is the menstrual cycle important?
• Matures the ovum for ovulation • Controls the release of the ovum
(ovulation) • Thickens the uterus to receive an ovum • Maintains the lining of the uterus in
pregnancy • Induces menstruation ‘a period’ if the
ovum is not fertilized
pituitary gland The pituitary gland produces several
specific hormones in females:
follicle stimulating hormone (FSH)luteinizing hormone (LH)
The ovaries produce oestrogen and progesterone
Endocrine glands
20/04/23
The menstrual cycle – can we model this?
3 hormones are involved in the menstrual cycle: oestrogen, LH and FSH. Here’s how:
Step 3: LH stimulates the release of the mature egg in the middle of the menstrual cycle
Step 1: FSH produced by the pituitary gland causes both an egg to mature and the ovaries to start producing oestrogen
Step 2: The rising levels of oestrogen cause the pituitary gland to stop producing FSH and produce LH instead
Worksheet
FSH
• FSH (follicle stimulating hormone)• Secreted by the pituitary gland • Causes eggs to mature in the
ovaries • Stimulates the ovaries to produce
oestrogen
Oestrogen
• Secreted by the ovaries • Stimulates the lining to be made• Stops productions of FSH so no
more eggs mature • Causes the release of LH which
causes an ovum to be released (ovulation)
Progesterone
• A high level of Progesterone maintains the lining of the uterus
• When the level of progesterone falls the uterus lining breaks down resulting in menstruation (a period)
Quick Quiz 1. Give 2 differences between the way information
travels by nerves and hormones 2. Give 2 reasons the menstrual cycle is important 3. Which hormone is responsible for maintaining
the lining of the uterus?4. Which hormone causes the ovum to mature? 5. Which hormone is associated with the release of
an ovum (ovulation)?6. On which day is a woman most likely to get
pregnant?
• http://www.nelsonthornes.com/4uresources/resources/Biology/AQA/interactives/B1a-1/Menstrual_cycle_animation/interface.swf