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