1. Neurons

2. 5 Components of a Reflex Arc:
1. Sensory receptor -senses something
2. Sensory neuron -sends signal to the CNS
3. Interneuron- registers signal, it connects the sense to the motor neuron
4. Motor neuron -sends response back
5. Effector- caries out the action

3. Reflex Arc
automatic, quick, involuntary responses to internal or external stimuli.
does not immediately involve the brain.
allows quicker reaction times to a potentially harmful stimulus

4. Anatomical Divisions of the Nervous System
Central Nervous System (CNS)
brain
spinal cord
Peripheral Nervous System (PNS)
cranial nerves
spinal nerves

5. Multipolar Neuron
dendrite
cell body
Myelin sheath
Synapse
axon

6. Myelin Sheath
& Shwann Cell
Nodes of Ranvier
Schwann Cells
Axon

7. Types of Neurons multipolar Unipolar (pseudo) bipolar
All the rest. Most abundant.
Motor Neuron
Types of Neurons
Unipolar (pseudo)
bipolar
eye and olfactory
Interneuron
Dorsal root
ganglion cells
Sensory Neuron

8. Reflex Arc - A reflex is an autonomic response.

9. Nervous System
Living cells can only survive and function within a very narrow range of conditions. Homeostasis is the body’s ability to keep normal body functions (the internal environment) in the same stable state or order despite variation in the external environment.

10. Human survival depends on a system of communication between the internal environment and the external environment.
Both the nervous system and the endocrine system (hormones) perform this function. Responses to internal/external environments are made possible by the electrochemical messages relayed from the brain (nervous system) or by chemical messengers (hormones/blood).

11. The main functions of the nervous system:
Receive information and carry it to the central nervous system
Interpret impulses and make decisions about the response
Sorts impulses and sets priorities for action
i.e. walking across the street – eat a bug or get hit by a car
Transmit impulses to the motor units (muscles) which carry out appropriate action