Brainiac! What is the function of the nervous system? Unit 1 Lesson 5 The Nervous System Brainiac! What is the function of the nervous system? The nervous system is made up of the structures that control actions and reactions of the body in response to stimuli in the environment. The nervous system has two parts: the central nervous system (CNS) and the peripheral nervous system (PNS). Copyright © Houghton Mifflin Harcourt Publishing Company 1

What is the function of the nervous system? Unit 1 Lesson 5 The Nervous System What is the function of the nervous system? The CNS is made up of the brain and spinal cord. The brain is the body’s central command organ. The spinal cord allows the brain to communicate with the rest of the body. Copyright © Houghton Mifflin Harcourt Publishing Company 2

What is the function of the nervous system? Unit 1 Lesson 5 The Nervous System What is the function of the nervous system? The PNS connects the CNS to the rest of the body. Involuntary processes are those you have no control over, such as your heart beating. Voluntary processes are actions your brain can control, such as moving an arm or a leg. Copyright © Houghton Mifflin Harcourt Publishing Company 3

What are the parts of the CNS? Unit 1 Lesson 5 The Nervous System What are the parts of the CNS? The CNS is made up of the brain and the spinal cord. The cerebrum is the largest part of the brain. It is where you think, solve problems, and store memories. The cerebrum controls voluntary movements and processes information from your senses. Copyright © Houghton Mifflin Harcourt Publishing Company 4

What are the parts of the CNS? Unit 1 Lesson 5 The Nervous System What are the parts of the CNS? The cerebellum processes information from your body, keeps track of body position, and coordinates movements. The brain stem connects your brain to the spinal cord. A part of the brain stem called the medulla controls involuntary processes in the body. Copyright © Houghton Mifflin Harcourt Publishing Company 5

What are the parts of the CNS? Unit 1 Lesson 5 The Nervous System What are the parts of the CNS? Describe the part of the brain that made one activity that you did today possible. Copyright © Houghton Mifflin Harcourt Publishing Company 6

What are the parts of the CNS? Unit 1 Lesson 5 The Nervous System What are the parts of the CNS? The spinal cord is a bundle of nerves protected by bones called vertebrae. Nerves are a collection of nerve-cell extensions bundled together with blood vessels and connective tissue. The spinal cord carries messages to and from the brain. Copyright © Houghton Mifflin Harcourt Publishing Company 7

You’ve Got Nerves! How do signals move through the nervous system? Unit 1 Lesson 5 The Nervous System You’ve Got Nerves! How do signals move through the nervous system? The nervous system translates environmental information into electrical signals. A neuron is a special cell that moves messages in the form of fast-moving electrical energy. These messages are called impulses. Copyright © Houghton Mifflin Harcourt Publishing Company 8

How do signals move through the nervous system? Unit 1 Lesson 5 The Nervous System How do signals move through the nervous system? Signals move through the CNS and PNS with the help of glial cells that protect and support neurons. Sensory neurons gather information from in and around your body and move it to the brain. Motor neurons move impulses from the brain and spinal cord to other parts of the body. Copyright © Houghton Mifflin Harcourt Publishing Company 9

What are the parts of a neuron? Unit 1 Lesson 5 The Nervous System What are the parts of a neuron? The cell body of a neuron has a nucleus and organelles. A dendrite is a typically short, branched extension of the cell body. The cell body gathers information from dendrites and creates an impulse. Copyright © Houghton Mifflin Harcourt Publishing Company 10

What are the parts of a neuron? Unit 1 Lesson 5 The Nervous System What are the parts of a neuron? An axon is an extension of the neuron that carries impulses away from the cell body. A neuron has only one axon. At the end of the axon is the axon terminal that changes the electrical signal to a chemical signal, or neurotransmitter. Copyright © Houghton Mifflin Harcourt Publishing Company 11

What are the parts of a neuron? Unit 1 Lesson 5 The Nervous System What are the parts of a neuron? How is a message transformed from an electrical message to a chemical message in a neuron? What are disorders of the nervous system? Parkinson’s disease, multiple sclerosis, and spinal-cord injuries are disorders of the nervous system. Copyright © Houghton Mifflin Harcourt Publishing Company 12