1. 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.

2. 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

3. 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

4. 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

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

7. 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

8. Axon terminals
Myelin sheath
Nodes
Cell body
Axon
Nucleus
Dendrites

9. 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

10. 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.

11. Axon terminals
Myelin sheath
Nodes
Cell body
Axon
Nucleus
Dendrites

12. 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)

13. 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?

14. 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

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

16. 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

17. 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!

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

19. 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

20. Quick Quiz
Give an example of a stimulus

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

22. 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

23. Resting Neuron Positive Charge Positive Charge Negative Charge

24. 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

25. 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.

26. 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.

27. The Action Potential is an “all or nothing” response

28. The Action Potential moves down the neuron from dendrite to axon then to the synapse

30. 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

31. 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.

32. 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?

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

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

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

36. 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

37. 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!!

38. 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.

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

42. 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