1. Nervous System Supplemental Questions
Biology 12

2. The main functions of the nervous system
Somatic: Part of peripheral nervous system  controls skeletal muscles (voluntary)
Autonomic: Central nervous system  controls organs (sympathetic & parasympathetic)… involuntary
Sympathetic: Associated with “fight or flight” response; uses norepinephrin as neurotransmitter
Parasympathetic: Maintains/establishes “normal” conditions in body; uses Ach as neurotransmitter

5. Cranial & Spinal Nerves
Cranial- 12 pairs; in head, neck, facial region, internal organs
Spinal- 31 pairs; in specific body areas near the CNS

6. Cranial Nerves

7. Myelinated Nerve Fibers
Good insulators of nerve
Myelin formed from Schwann cells
Speeds up process of impulse transmission

9. Spinal Cord & Spinal Nerves
White matter- takes messages to & from brain
Grey matter- interneurons found here
Spinal nerve- brings messages to/from spinal cord
Ventral root- contains motor neurons leaving grey matter
Dorsal root- contains sensory fibers entering grey matter
Dorsal root ganglion- cell body of a sensory neuron

10. Spinal Nerve diagram

11. Reflex Arc Travels via dorsal root (sensory neuron)
Moves to interneurons in grey matter
Out via motor neurons in ventral root
An autonomic response
* Brain processing is bypassed

13. Nerve impulse transmission (diagram)
Impulse travels from Y  Z  X  W
Axon  axon bulb  synaptic cleft  dendrite
Structure “Y” is a(n) axon and structure “W” is a(n) dendrite