Startup: CST Prep Nervous System Which statement is true about the nervous system? It is made up of cells called the peripheral cells. It has two major parts: the brain and the central nervous system. Its messages are carried by the bloodstream. It controls functions throughout the body.

Startup: CST Prep Nervous System What is a role of the central nervous system? receiving messages from sense organs receiving messages from the brain transmitting messages from sense organs transmitting messages to the brain

Communication is the key to success On any team, communication essential for success The same is true in your body The Nervous System controls and coordinates functions throughout the body and responds to internal and external stimuli

The Nervous System Structures: Function/Purpose Brain Spinal Cord Peripheral Nerves Function/Purpose Recognize and coordinate the body’s response to changes in the internal and external environments Communication System for the Body

Can You think of Examples of a message being transmitted from your body to your brain or vice versa?

Basic Unit of the Nervous System Neurons Cell that carries messages throughout the Nervous System What kind of tissue is made of Neurons? Nervous Tissue

Axon terminals Myelin sheath Nodes Cell body Axon Nucleus Dendrites

Parts of the Neuron Cell Body Dendrites Axon Contains nucleus & cytoplasm. Center of metabolic activity Dendrites Carry impulses from the environment or other neurons TOWARD the cell body Axon Long fiber that carries the impulse away from the cell body

Parts of the Neuron Myelin Sheath Nodes Axon Terminals Insulating membrane that surrounds the Axon Nodes Gaps in the Myelin Sheath. Helps impulse travel down neuron faster Axon Terminals Branches at the end of the Axon through which the nerve impulse leaves the nerve.

Axon terminals Myelin sheath Nodes Cell body Axon Nucleus Dendrites

3 Kinds of Neurons Classified according to the DIRECETION in which an impulse travels Sensory Neurons Carry impulses from the sense organs to the spinal cord and brain (senses to brain) Motor Neurons Carry impulses from the brain and spinal cord to muscles and glands (brain to muscle) Interneurons Connect sensory and motor neurons and carry impulses between them. (neuron connectors)

Quick Quiz What part of the neuron carries the message into the cell body of th neuron? What part of the neuron sends the message out of the neuron? What type of neuron carries messages from the environment to the brain? What type of neuron carries messages from the brain to the muscles?

Color and Label your Neuron You will get a worksheet with a neuron on it It must be fully colored Fully Labeled Complete definitions on back

The Nerve Impulse So, what the heck is this “impulse” we keep talking about?

Startup: CST Prep Nervous System What is the function of motor neurons? Carrying impulses from sensory neurons to interneurons Carrying impulses from sense organs to the spinal cord and the brain Carrying impulses from the brain and spinal cord to muscles and glands All of the above

Classroom Business: Weekly quiz on Friday! Week 5 grades are posted! Open house on Thursday +5 for the class with the highest attendance +5 if we beat my record of 40 parents Outline 35-2 and 35-3 due this week!

Nerve Impulse Stimulus Impulse travels through neuron from Dendrite through Cell Body to Axon and out Axon Terminals Neurotransmitters relay message to next neuron

Stimulus Stimulus A signal to which an organism responds Stimulus - From senses to brain: Touching a hot stove Turning the lights out Response - From brain to muscles: Brain tells muscles to contract to pull your hand away from the hot stove Brain tells pupils to dialate (get big) so you can see better in the dark

Quick Quiz Give an example of a stimulus

The Nerve Impulse A stimulus excites nerve endings (Dendrites) which sends an impulse, like an electrical current, through the neuron

The Resting Neuron When there is no impulse traveling through a neuron Resting Potential Electrical charge across the cell membrane of a resting neuron Negative on the Inside Positive on the outside

Resting Neuron Positive Charge Positive Charge Negative Charge

The Moving Impulse When a neuron receives an impulse From the environment OR from another neuron The impulse must be strong enough to stimulate a response Impulse is ALL OR NOTHING

The Moving Impulse Action Potential A.K.A. a nerve impulse A rapid reversal of charges, from negative to positive along the neruon - from Dentrites to Axon Terminals.

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 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.

The Action Potential is an “all or nothing” response

The Action Potential moves down the neuron from dendrite to axon then to the synapse ----++++++++++++++++++ ++++++++++++++++++---- ++++++++++++++++++++ ++++++++++++++++++++ ++++++++++++++-------++ ++++-------++++++++++++ ++++++++-------- +++++++

The Synapse A gap between the Axon Terminals of a neuron and another cell through which the impulse is transferred. For example, where the Axon Terminal of one neuron ends, and the Dendrite of another neuron begins

Neurotransmitters Chemicals used by a neuron to transmit an impulse across a Synapse to another cell Neurotransmitters are secreted from the end of the Axon Terminals and stimulate an adjacent cell.

Quick Quiz What direction does an impulse travel through a neuron? What is an Action Potential? What is happening when the neuron is experiencing Action Potential?

Startup: CST Prep Nervous System Which type of neuron transmits messages to the central nervous system? Sensory neuron Interneuron Motor neuron Synaptic neuron

Dendrite of adjacent neuron Figure 35-8 The Synapse Direction of Impulse Dendrite of adjacent neuron Axon Receptor Vesicle Axon terminal Synaptic cleft Neurotransmitter

Classroom Business Open House Tonight!!! Reading Quiz Tomorrow: 35-2

Today’s Assignment Three Choices! 1. Outline 35-2 and Outline 35-3 Due Tomorrow 5 HP/section 2. Action Potential Travel Brochure You are a tour guide through the neuron. 10 HP. Due Monday. 20 HP if you do it in a word document or PowerPoint presentation Workbook Chapter 35-2 thru 35-5 5 HP per section Due Thursday after the CAHSEE

Quiz Tomorrow! Reading Quiz on 35-2 Structures and Functions of a Neuron The Nerve Impulse The synapse Pay close attention to figures and examples from the book!!

Startup: CST Prep Nervous System A nerve impulse begins when Positive ions move across the cell membrane of a neuron. Neurotransmitters flow down an axon of a neuron. Dendrites let negative ions pass through an axon of a neuron. Negative ions flow down an axon and change the electric charge of a neuron.

Questions, Comments, Concerns, Queries? Structure of a Neuron Types of Neurons Nerve Impulse Synapse

Homework LAST WEEK THIS WEEK NEXT WEEK WORKBOOK 38 OUTLINE 35-2 ACTION POTENTIAL BROCHURE/PPT OUTLINE 35-4 OUTLINE 35-5 NEXT WEEK OUTLINE 19-1 OUTLINE 19-2 READ CH. 40