1. Nervous System
Chapter 9

2. 9.1 Introduction
Neurons – mass of nerve cells that transmits information (nerve impulses) to nerves, tissues, or cells (3 big parts):
Cell body – contains nucleus and two extensions
Dendrites – receive the nerve impulse (shorter and more of them)
Axons – transmit information away from the cell body (single long fiber)

3. Neuron basic structure

4. A Nerve is a bundle of axons
Nervous tissues also include neuroglial cells which are supporting cells
2 parts make up the nervous system:
1. Central Nervous System (CNS)
Brain & spinal cord
2. Peripheral Nervous System (PNS)
Peripheral nerves throughout the body

5. http://images2. wikia. nocookie

6. General Functions of Nervous system
Three basic functions:
1. Sensory function
Gathers info by detecting changes inside and outside the body
Have sensory receptors at the ends of the peripheral nerves which send impulses to central nervous system sensory neurons

7. 2. Integrative function 3. Motor function
Info is brought together and interpreted, to create sensations, create thoughts, add to memory, make decisions
3. Motor function
A Responses to nerve impulses
Signals are sent from the CNS to effectors (muscles or glands).
The goal is usually to maintain stable homeostasis

9. 2 categories of the motor functions in the nervous system:
1. Somatic nervous system
Consciously control skeletal muscles
2. Autonomic nervous system
Controls the involuntary effectors (heart, smooth muscle in blood vessels, and various glands)

11. Neuroglial cells
Specialized cells in nervous tissue that fill spaces, provide structural frameworks, produce myelin, and carry on phagocytosis (5 types)
1. Microglial cells – scattered throughout central Nervous system, support neurons and phagocytize bacterial cells and cellular debris

12. 2. Olgiodendrocytes – provide insulating layers of myelin (myelin sheaths) around axons within the brain and spinal cord.
3. Astrocytes – Connect blood vessels to neurons

13. 4. Ependymal cells - forms a membrane that covers brain parts
5. Schwann cells - Form the insulating myelin sheath around the neurons

14. Neuron Structure

17. Neuron structural differences

18. Neuron functional differences

20. Threshold

21. http://biobook. nerinxhs

22. Action Potential animation

23. Nerve impulse