1. What do you know about the nervous system
What do you know about the nervous system? Write 3 things you are fairly confident about and 3 things you would like to know.

2. The Role of the Nervous System

3. Look at the diagram of a nerve cell on the next slide.
How does it look different from a “regular” animal cell? Hypothesize might it be shaped like this?

4. Neurons neuron - is the functional unit of the nervous system
3 classes of neurons:

5. 3 classes of neurons:
afferent neurons (aka sensory neurons) - transmit stimuli from receptors to interneurons
interneurons - integrate information (found in brain & spinal cord)
efferent neurons - carry response signal from interneurons to effectors (muscles & glands)
- motor neurons are efferent neurons that send signals to skeletal muscles

6. dendrites - receive signals and transmit them toward the cell body
cell body - “normal cell function”
nerve signal - ions flowing down conc gradients
axon terminals - points of transmission
axons - long part of the cell that conduct signals away from the cell body to another neuron or effector

7. nerve - bundle of neurons
- neurons connect to each other - axon terminals connect to another cell’s dendrites

8. Accessory Cells Glial cells - provide nutrition & support to neurons
eg: Schwann cells - tightly wrapped layers of myelin sheaths (plasma membrane)
electrical insulators
Nodes of Ranvier are gaps between Schwann cells
together the insulated stretches of axon & exposed gaps increase the speed of electrical impulses

9. Guillain–Barré- disorder that affects the myelin sheaths
What do you predict would be a symptom that people would have who have Guillain-Barre? Explain.
Guillain–Barré- disorder that affects the myelin sheaths

10. Neural Circuits & Reflex Arc
receptor —> afferent neuron —> interneuron —> efferent neuron —> effector
eg: seeing a glass of water
(eyes) (ocular nerves) (in brain) (motor neuron) (muscles of the arm)

11. Why are reflex arcs faster than other signals?

12. Reflex Arc = simplest neural circuit
receptor —> afferent neuron —> interneuron —> efferent neuron —> effector
(hand) (nerves in arm) (in spinal cord) (motor neuron) (muscles of arm/hand)
note, additional signals sent to brain
often pain happens after reaction!