Nervous System 1212 1213 Bell Ringer 1212 What

Nervous System 12/12 – 12/13

Bell Ringer 12/12 What system of the body do you think you absolutely could not live without? What is the function of this system? Why do you think you couldn’t live without it?

Function of the Nervous System Your nervous system is the control and communications center of your body, like an emergency response system.

Stimuli and Responses Your nervous system receives stimuli (signals) from inside and outside your body, then responds to them. * Examples of stimuli: smell of food outside a restaurant, telephone ringing * Examples of responses: stomach rumbling, reaching for your phone

Function of the Nervous System It all starts with the STIMULUS (like the heat of a fire) that leads to a SIGNAL being sent to (like a sprinkler system) the BRAIN, which processes information and makes an appropriate response… (like the fire dept. dispatcher) … leading to a coordinated RESPONSE of the body (like fire trucks going to the fire)

Neurons act as your body’s relay team, sending impulses (messages) throughout your nervous system. The basic unit of communication in the nervous system are called neurons. Neurons carry electric signals like the electric wires in a house.

Neurons Axon Cell Body Dendrites

• Dendrites are short, slender branches that extend from the cell body. These are input channels. They receive information from other neurons.

• At the other end of the cell body is a single, long, tube-like extension called an axon. Axons are output channels. It is along an axon that the neuron sends out messages to other neurons or directly to the muscles.

Transmitting Impulses • Dendrites -> cell body -> axon tip -> synapse -> dendrites • The synapse is a small space between neurons. The impulse from the axon of one neuron causes a chemical to cross the synapse, and an impulse starts in the next neuron.

The Nervous System

The Nervous System Central Nervous System (CNS) Peripheral Nervous System

The Nervous System Central Nervous System (CNS) Brain Spinal Cord

The Nervous System Peripheral Nervous System Motor neurons Sensory neurons

The Nervous System Central Nervous System (CNS) Peripheral Nervous System Brain Motor neurons Spinal Cord Sensory neurons

Bell Ringer 12/13 • Transmitting a signal… half of class should stand on each side of the classroom in the outer aisles in a single-file line facing forward. • Follow instructions on our signal relay! IN YOUR NOTEBOOK: • Can the second student begin before the first student taps their shoulder? • What allows the second and third students to complete their part of the race?

Cerebrum • Functions in language, conscious thought, memories, personality, and other sensations.

Cerebellum • Controls balance, posture, and coordination

Brain Stem • Contains nerves that control breathing, swallowing, digestion, and actions of the heart and blood vessels

Hypothalamus • The Hypothalamus helps regulate blood pressure, heart rate, body temperature, hunger and thirst. • HOMEOSTASIS (a state of balance or equilibrium in the body)

Peripheral Nervous System • All of the nervous system outside of the spinal cord is known as the peripheral nervous system. It carries all the messages sent back and forth between the central nervous system and the rest of the body. There are two main types of neurons in the peripheral nervous system…

Sensory Neurons • Tell the central nervous system what is happening. They carry nerve impulses from sense organs to the central nervous system

Motor Neurons • Carry information from the central nervous system to the muscle or gland. Reflexes are controlled by motor neurons. Motor neurons are even active while you are asleep.