Aim: How does the nervous system function? Do Now: What is a stimulus? How do your senses work? Homework: #1-5

The Nervous System

How do we respond to stimuli? Stimulus – Any internal or external change that causes a response Stimulus – Any internal or external change that causes a response We come in contact with thousands of stimuli We come in contact with thousands of stimuli External - Noise, External - Noise, light, smell, temperature Internal – hormones, Internal – hormones, or other chemicals in your body

Nerve Cells Your nervous system is made up of nerve cells called NEURONS Your nervous system is made up of nerve cells called NEURONS Dendrites Axon Cell Body Nucleus Axon Terminal

Parts of the Neuron Dendrite – Receive the impulses from other neurons and send them to the cell body Dendrite – Receive the impulses from other neurons and send them to the cell body Cell Body – Where life processes take place Cell Body – Where life processes take place Nucleus – control center of the cell Nucleus – control center of the cell Axon – carry impulses away from the cell body Axon – carry impulses away from the cell body Axon Terminals – the end of the axons, sends impulse to other neurons Axon Terminals – the end of the axons, sends impulse to other neurons (Impulse – any message carried by a neuron)

Types of Neurons Sensory Neurons – receive information and send impulses to the brain or spinal cord Sensory Neurons – receive information and send impulses to the brain or spinal cord Example: loud noise detected Example: loud noise detected Interneurons – send messages to motor neurons Interneurons – send messages to motor neurons Example: message sent from brain to motor neurons Example: message sent from brain to motor neurons Motor Neurons – send impulses from the brain or spinal cord to the muscles or glands Motor Neurons – send impulses from the brain or spinal cord to the muscles or glands Example: sends message to muscles, they tighten and you jump Example: sends message to muscles, they tighten and you jump

Synapses The area where neurons send signals from one cell to another The area where neurons send signals from one cell to another It is a gap between the dendrites of one neuron and the axon terminal of another neuron It is a gap between the dendrites of one neuron and the axon terminal of another neuron

Central Nervous System Brain Brain Receives information from the spinal cord and its own nerves Receives information from the spinal cord and its own nerves Processes the information and sends signals to various parts of the body Processes the information and sends signals to various parts of the body Spinal Cord Spinal Cord Brings information from the peripheral nervous system to the brain Brings information from the peripheral nervous system to the brain Sends information from the brain to muscles and glands Sends information from the brain to muscles and glands

Parts of the Brain Cerebrum – thinking takes place here Cerebrum – thinking takes place here Cerebellum – Stimuli are interpreted, controls voluntary muscles, balance Cerebellum – Stimuli are interpreted, controls voluntary muscles, balance Brain Stem – Controls involuntary muscles and actions Brain Stem – Controls involuntary muscles and actions Cerebrum Cerebellum Brain Stem

Peripheral Nervous System All nerves and neurons that branch away from the brain and spinal cord All nerves and neurons that branch away from the brain and spinal cord

Malfunctions Polio Polio Virus that causes full or partial paralysis Virus that causes full or partial paralysis Rare now, a vaccination exists Rare now, a vaccination exists Meningitis Meningitis Inflammation of meninges, or the covering of the brain Inflammation of meninges, or the covering of the brain Treated with antibiotics Treated with antibiotics Alzheimer’s Alzheimer’s Gradual memory loss at a faster pace than expected with natural aging Gradual memory loss at a faster pace than expected with natural aging

ADHD Attention Deficit Hyperactivity Disorder (ADHD) Attention Deficit Hyperactivity Disorder (ADHD) affects an estimated 5% of all boys and 2% of all girls. affects an estimated 5% of all boys and 2% of all girls. Up to 60% of these children will continue to have symptoms into adulthood Up to 60% of these children will continue to have symptoms into adulthood Over a million children take prescription medicines to control hyperactive behavior Over a million children take prescription medicines to control hyperactive behavior The cause is not yet known The cause is not yet known