Aim: How does the nervous system communicate with other body systems? HW 16 Text chapter 35 Pg 897 vocabulary Pg 900 Q#1 to 4

Neuron Structure  Function A Neuron Section 35-2 Nucleus Axon terminals Myelin sheath Nodes Cell body Axon Nucleus Dendrites Cell body – largest part of a neuron (contains the nucleus and most of the cytoplasm Dendrites are the short branched extensions. They receive impulses from the environment or from other neurons. Axons is the long fiber that carries impulses away from the cell body. The Axon is covered by an insulating myelin sheath (mainly fat)

Neuron to Neuron communication Neurons communicate with each other. The dendrite of one neuron picks up a stimulus from the environment or another neuron and the impulse travels along the axon to the next neuron. Let’s see how this happens

Nerve Impulse Figure 35-7 An Impulse Section 35-2 Action Potential At rest. As the action potential passes, potassium gates open, allowing K+ ions to flow out. Action Potential Action Potential The production of a nerve impulse can be compared to the flow of electricity through a wire. At rest the inside of the neuron’s membrane has a negative charge. The change in charge on the membrane occurs like a wave until it arrives at the axon terminal. At the leading edge of the impulse, the sodium gates open. The membrane becomes more permeable to Na+ ions and an action potential occurs. The action potential continues to move along the axon in the direction of the nerve impulse.

Dendrite of adjacent neuron Figure 35-8 The Synapse The Synapse When an impulse reaches the end of one neuron, neurotransmitters are released into the synaptic cleft Section 35-2 Direction of Impulse Dendrite of adjacent neuron Axon Receptor Vesicle Axon terminal Synaptic cleft Neurotransmitter The neurotransmitters binds to receptors on the membrane of an adjacent neuron. Neurotransmitters are chemicals used by a neuron to transmit an impulse across a synapse. The neurotransmitters molecules diffuse across the gap and attach themselves to receptors on the membrane of the neighboring cell. This stimulus causes a new impulse to begin. You may ask yourself, what happens to the neurotransmitter after it does its job? It is destroyed by an enzyme.

Central Nervous System – Brain and Spinal Cord Figure 35-9 The Brain Central Nervous System – Brain and Spinal Cord Pons Pituitary gland Hypothalamus Cerebrum Medulla oblongata Spinal cord Cerebellum Pineal gland Thalamus Brain 100 billion neurons Function is to relay messages, process information and analyze information Consists of the cerebrum, cerebellum and brain stem. Each area of the brain produces different chemical messengers.

Interneuron (relay neuron): Relays message from sensory neuron to motor neuron Make up the brain and spinal cord

Spinal Cord Figure 35-11 The Spinal Cord Section 35-3 Spinal nerve Central canal Gray matter White matter Meninges Major nerve pathway to and from the brain. Meningitis is an inflammation of the coverings.

Nerves are made of bundles of neurons that go to all parts of the body.

Figure 35-2 Human Organ Systems Part 2 In what ways does the nervous system interact with the other systems below ? Section 35-1 Respiratory System Digestive System Excretory System Students can work in groups to answer this question. Reproductive System Endocrine System Lymphatic System

Autonomic Nervous System Controls the functions of the body that are not under conscious control Nerves go to all the organs also.