The skin performs all of the following except

The skin performs all of the following except a. PRODUCTION OF CHEMICAL b. c. MESSENGERS ELIMINATION OF WASTE PRODUCTS CONTROL OF BODY TEMPERATURE d. PROTECTION

Students will know… Explain what an action potential is? K+ ions are entering the neuron Negatively charged proteins are leaving the neuron Na+ ions are entering the neuron The myelin coat has broken down and ions are crossing freely

Students will know… Which is the correct path a nerve impulse will follow in a reflex arc? Put these three terms in order Motor neuron, sensory neuron and interneuron

Nervous System Chapter 33. 1

Structure of the Nervous System Neurons conduct electrical impulses allow cells, tissues, and organs detect and respond to stimuli

Neurons Specialized cells Help you gather information

Neuron

Neuron Dendrites – receive signals and send them to the cell body

Neuron Dendrites – receive signals and send them to the cell body Cell body – nucleus of the neuron and other organelles

Neuron Dendrites – receive signals and send them to the cell body Cell body – nucleus of the neuron and other organelles Axon – caries the nerve impulse from cell body to other neurons and muscles

Reflex Arc Nerve pathway Basic structure of the nervous system Sensory neuron to an interneuron, and a motor neuron

An Action Potential Nerve impulse A stimulus reaches threshold Channels in the plasma membrane open Potassium ions leave the cell Change in charge moves

Action Potential

Which of the following pairs lists the fiber-like extensions that are components of neurons? a. AXONS AND MYELIN b. SYNAPSES AND MYELIN c. DENDRITES AND SYNAPSES d. DENDRITES AND AXONS

Organization of Nervous System Chapter 33. 2

Organization of the Nervous System Central nervous system Peripheral nervous system

The Central Nervous System CNS Spinal Cord Brain Relays messages Processes information Analyzes responses

The Brain Made up of 100 billion neurons Maintains homeostasis Control center

The Brain Made up of 100 billion neurons Maintains homeostasis Control center Homeostasis – maintains a constant condition

The Brain

The Brain

Cerebrum Largest part Divided into two hemispheres Thought process of memory, language, speech, voluntary body movements and sensory perception

Cerebellum Controls balance, posture and coordination Back of brain

Brain Stem Connects the brain to the spinal cord Made up of Medulla oblongata (signals between brain and spinal cord) Pons (signals between cerebrum and cerebellum)

Spinal Cord Nerve column from your brain to the lower back Protected by vertebrae

Spinal Cord

The Peripheral Nervous System Somatic Nervous System Autonomic Nervous System

Somatic Nervous System Relays information to and from skin and skeletal muscles Voluntary

Autonomic Nervous System Relays information to internal organs Involuntary

Autonomic Nervous System Sympathetic Parasympathetic Pupil dilation Pupil constriction Heart rate increased Heart rate decrease Bronchial muscles relaxed Small intestine muscle contractions reduced contracted Digestion increased

Unit 9 CHAPTER 33. 3

Quiz 1. Draw and label a neuron 2. Describe a Reflex Arc Pathway 3. Describe an Action Potential

The Senses Chapter 33. 3

The Senses Sensory receptors allow you to detect the world around you

Taste and Smell Stimulated by chemicals Work together

Smell Sensory receptors high in the nose Respond to chemicals Signal the brain

Taste buds Detect sweet, sour, salty and bitter

Nature August 2006 Wrong!

Sight Light enters the eye Through the cornea Behind the iris is the lens To the retina (rods and cones) Signals sent to brain Brain interprets

Sight

Hearing and Balance Function of the ear Volume Highness and lowness

To Hear Sound waves Ear canal Eardrum to vibrate Through the malleus, incus, stapes Inner ear cochlea Sends signals to the brain

Ear

To Balance Cochlea Semicircular Canals At 900 Fluid filled, lined hairs Head moves the fluid moves and sends signals to brain

Ear

Touch Sensory receptors Respond to temperature pressure and pain Epidermis and dermis Tips of fingers have lots Not everywhere