1. chapter 11-1: intro to nervous system
Essential Question:
What is the function of the Nervous System? What are the two divisions of the Nervous System?
chapter 11-1: intro to nervous system
Learning Targets
Identify structure and function of 3 types of muscle tissue.
Identify the functional characteristics of muscle tissue.
List the functions of muscle
Describe the anatomy of skeletal muscle

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3. The master controlling and communicating system of the body Functions
Nervous System
The master controlling and communicating system of the body
Functions
Sensory input – monitoring stimuli occurring inside and outside the body
Integration – interpretation of sensory input
Motor output – response to stimuli by activating effector organs

4. Nervous System
Figure 11.1

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6. Organization of the Nervous System
Central nervous system (CNS)
Brain and spinal cord
Integration and command center
Peripheral nervous system (PNS)
Paired spinal and cranial nerves
Carries messages to and from the spinal cord and brain

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8. Peripheral Nervous System (PNS): Two Functional Divisions
Sensory (afferent) division
Sensory afferent fibers – carry impulses from skin, skeletal muscles, and joints to the brain
Visceral afferent fibers – transmit impulses from visceral organs to the brain
Motor (efferent) division
Transmits impulses from the CNS to effector organs

9. PNS Motor Division: Two Main Parts
Somatic nervous system
Conscious control of skeletal muscles
Autonomic nervous system (ANS)
No conscious control
Regulates smooth muscle, cardiac muscle, and glands
Has two divisions – sympathetic and parasympathetic

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11. The two principal cell types of the nervous system are:
Nerve Tissue
The two principal cell types of the nervous system are:
Neurons – excitable cells that transmit electrical signals
neuroglia or glial cells (Supporting cells) – cells that surround and wrap neurons
Provide support & insulation
Promote health and growth

12. Structural units of the nervous system
Neurons (Nerve Cells)
Structural units of the nervous system
Composed of a body, axon, and dendrites
Their plasma membrane functions in Electrical signaling

13. Whitish, fatty, segmented sheath around most long axons
Myelin Sheath
Whitish, fatty, segmented sheath around most long axons
It functions to:
Protect the axon
Electrically insulate fibers from one another
Increase the speed of nerve impulse transmission

14. Formed by Schwann cells in the PNS A Schwann cell:
Myelin Sheath
Formed by Schwann cells in the PNS
A Schwann cell:
Envelopes and encloses the axon with its plasma membrane

15. Neurons (Nerve Cells) Dendrites receive stimuli
Cell body (soma) is where most cellular machinery is found
Axon sends message to next cell
Myelin sheath surrounds the axon
Schwann cells make up the myelin sheath
Figure 11.4b

16. Dendrites
Cell Body
Impulse Direction
Terminal Branches
Axon
Nodes
Myelin Sheath

17. On a sheet of paper copy the question and then answer it.
Do Now Activity
On a sheet of paper copy the question and then answer it.
What are the two main divisions of the nervous system?
The motor division of the PNS has two parts. The part we can’t control is called what?
Schwann cells form what?

18. chapter 11-2: nervous system
Essential Question:
What is the function of an impulse in the Nervous System?
chapter 11-2: nervous system
Learning Targets
Identify structure and function of 3 types of muscle tissue.
Identify the functional characteristics of muscle tissue.
List the functions of muscle
Describe the anatomy of skeletal muscle

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20. Neuron Functional Classification
Neurons are classified based on structure and function (we will only cover function)
Functional:
Sensory (afferent) — transmit impulses toward the CNS
Motor (efferent) — carry impulses away from the CNS
Interneurons (association neurons) — shuttle signals through CNS pathways

21. Comparison of Functional Classes of Neurons
Table

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23. The Moving Impulse
The minimum level of a stimulus that is required to activate a neuron is called a threshold.
A stimulus must be equal to or greater than the threshold to cause a neuron to produce an impulse.

24. The Nerve Impulse
The way the nerve impulse travels through neurons is like how electricity travels through wires.
Nerves generate tiny amounts of electrical charges, based on amounts of sodium ions (Na+) and potassium ions (K+).

25. This temporarily changes the charge of the neuron…
The Moving Impulse
A nerve impulse begins when a neuron is stimulated by another neuron or by its environment.
At the leading edge of an impulse, the sodium gates open and sodium flows into the neuron.
This temporarily changes the charge of the neuron…
Potassium gates then open and allow potassium out of a neuron.
This continues to reverses the charges further, forming an action potential …

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27. Restoring the Resting Potential
The sodium-potassium pump then moves sodium out of the cell and potassium into the cell
This restores the original charge across the membrane

28. How the Action Potential is Generated…
At rest.
As the action potential passes, potassium gates open, allowing K+ ions to flow out.
Action Potential
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.

29. How the Action Potential is Generated…
At rest.
As the action potential passes, potassium gates open, allowing K+ ions to flow out.
Action Potential
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.

30. How the Action Potential is Generated…
At rest.
As the action potential passes, potassium gates open, allowing K+ ions to flow out.
Action Potential
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.

31. How the Action Potential is Generated…
At rest.
As the action potential passes, potassium gates open, allowing K+ ions to flow out.
Action Potential
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.

32. The movement of Na and K changes the charge across the cell membrane
Quick review
When a stimulus overcomes the threshold a neuron starts an action potential
The action potential is created by moving ions of sodium (Na) and potassium (K)
The movement of Na and K changes the charge across the cell membrane
When the Na and K levels are restored, the charge is reversed and the cell is at rest (resting potential)

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34. Neurons do not touch other neurons.
The Synapse
Neurons do not touch other neurons.
The tiny space between two neurons is called a synapse.
Neurotransmitters are chemicals released by one neuron to transmit an impulse across a synapse and stimulate the next neuron.

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37. Neurons are highly irritable
Neurophysiology
Neurons are highly irritable
Action potentials, or nerve impulses, are:
Electrical impulses carried along the length of axons
Always the same regardless of stimulus
The underlying functional feature of the nervous system

38. Supplemental Videos

41. Supplemental Questions

42. Add the following to the DNA paper you created yesterday:
Do Now Activity
Add the following to the DNA paper you created yesterday:
Draw a diagram or chart of how our nervous system is organized.

43. The movement of what substance reverses the charge of a neuron?
Do Now Activity
PLEASE COPY AND THEN ANSWER THE FOLLOWING onto the paper that has the other two DNAs:
The movement of what substance reverses the charge of a neuron?
What is the name of the gap between two neurons?
List in correct order the flow of a nerve impulse through the neuron ( e.g. name the parts)?