Fundamentals of the Nervous System & PNS

Question 1

Know the divisions of the Nervous System

Answer 1

Central Nervous System: contains brain and spinal cord ( function: integration and control center )

Peripheral Nervous System: the portion of nervous system outside CNS, consists mainly of nerves that extend from brain and spinal cord ( consists of spinal nerves and cranial nerves )

Question 2

Myelination in the CNS & PNS

Answer 2

In CNS: formed by processes of oligodendrocytes, not whole cells ( white matter: regions of brain and spinal cord with dense collections of myelinated fibers ) ( gray matter: mostly neuron cell bodies and nonmyelinated fibers )

In PNS: formed by schwann cells ( wraps around axon in jelly roll fashion ) and myelin sheath gaps ( gaps between adjacent schwann cells )

Question 3

What are the three ways we classify sensory receptors?

Answer 3

type of stimulus, body location, and structural complexity

Question 4

Know the classification categories by stimulus type

Answer 4

• mechanoreceptors: respond to touch, pressure, vibration, and stretch
• thermoreceptors: sensitive to changes in temperature
• photoreceptors: respond to light energy ( ex. retina )
• chemoreceptors: responds to chemicals ( ex. smell, taste, changes in blood chemistry )
• nocieptors: sensitive to pain-causing stimuli ( ex. extreme heat or cold, excessive pressure, inflammatory chemicals )

Question 5

Know the classification categories by stimulus location

Answer 5

• exteroceptors: respond to stimuli arising outside body, receptors in skin for touch, pressure, pain, & temperature, most special sense organs
• interoceptors ( visceroceptors ): respond to stimuli arising in internal viscera and blood vessels, sensitive to chemical changes, tissue stretch, and temperature changes, and sometimes causes discomfort but usually person is unaware of their workings
• propioceptors: respond to stretch in skeletal muscles, tendons, joints, ligaments, and connective tissue coverings of bones and muscles and informs brain of one’s movement

Question 6

Example from Test: which receptors respond to stimuli within the body?

Answer 6

Interoceptors

Question 7

Example from Test: schwann cells in PNS are functionally similar to _____ in the CNS?

Answer 7

Oligodendrocytes