Coordination and Control & Medicines and Drugs

The Menstrual Cycle and Hormones 

• The Menstrual Cycle is controlled by several hormones secreted by the pititary gland and the overies 
• Hormones are chemical messengers used in the body by the endorine systerm 
• Hormones travel more slowly than nerve impulses but have a longer lasting effect.
• Endocrine glands

FSH- 

• Travels from the blood, FSH causes an egg follicle inside the ovary to grow and mature
• FSH simulates Oestrogen, but Oestroegn inhibts FSH. Comes from the Pituitary gland

Oestrogen- 

• Oestrogen is released from the egg follice as it grows and matures. The bigger the egg the more Oestrogen. It also causes the Uterus lining to thicken 
• Stimulates the pitutary gland inhibts FSH and stimulates LH. Released in the egg in the Ovaries 

LH-

• stimulates Oestrogen and is inhibited by Progesterone. It helps releases the egg and protect it.

The Reflex Arc

This example is to do with ptting your hand on a hot surface-

1. Your hand feels the heat, your pain receptor is stimulated 

2. a message is sent along the sensory neuron

3.The message carries on to the bran or relay neuron 

4.The message is immedately sent back along the motor neuron 

5.Your hand immedatly contracts before you burn yourself

The Three Neurons-

Sensory Neuron

Motor Neuron

Relay Neuron