NERVOUS SYSTEM Human physiology

THE BODY’S CONTROL CENTER  The brain is the control center of the human body. It is made up of billions of nerve cells, or neurons. Sends messages around the body Receives messages from the body Stores information

THE BODY’S CONTROL CENTER  Message go from your brain down to your spinal cord. Big rope of nerve cells Runs along the inside of your back bone Connects to neurons all over your body

THE BODY’S CONTROL CENTER  Hormones are substances made by organs called glands Hormones control body functions Some circulate in the blood and cause changes Estrogen and testosterone are examples of hormomes

THE NERVOUS SYSTEM  Body parts: brain, spinal cord, sense organs and neurons are all parts of the nervous system  Function of the nervous system: Main controlling and communicating system of body

THE FIVE SENSES  All part of the nervous system  Sight – eyes are organs of sight  Hearing – ears are organs of hearing  Taste – tongue is the organ of taste  Smell – nose is the organ of smell  Touch – skin is the organ of touch

SIGHT  Sight – eyes are organs of sight Light bounces off objects and enter your eye Nerves in back of eye sends messages to brain

HEARING  Hearing – ears are organs of hearing Sounds are made by vibrations Tiny bones in your ears pick up vibrations Nerves pick up movement and send message to brain

TASTE  Taste – tongue is the organ of taste Four types of flavors: sour, sweet, salty and bitter Different areas of tongues taste different flavors Taste buds pick up tastes and send them to brain

SMELL  Smell – nose is the organ of smell Molecules leave object and trigger nerve cells in nose Sends messages to brain

TOUCH  Touch – skin is the organ of touch Some areas are more sensitive to touch than others Fingertips very sensitive to heat, cold, touch and pain Skin is the largest organ of body Also part of immune system – keeps germs out of body

EXIT SLIP 1.List the five senses and the organs that go with that sense 2.What are the parts of the nervous system? 3.What does the nervous system do (function)?