control and communication

• the entral nervous system is made from the brain and spinal cord
• receptor to sensory neuron to inter neuron to motor neuron to effecter( muscle or gland)
• cerebrum is memory and thought
• cerebellum is balance and coordination
• medulla controls breathing and heart rate
• hormones are chemical messengers that travel in the blood stream, released from endocrine glands, they have target tissues and are complementory to receptors
• if glucose is too low the pancreas produces glucagon and the liver turns glycogen to glucose
• if glucose is to high the pancreas releases insulin and the liver stores glucose as glycogen