Functional Organization of Nervous Tissue

Question 1

3 main functions of the nervous system

Answer 1

1. SENSORY: sense changes through sensory receptors
2. MOTOR: respond to stimuli
3. INTEGRATIVE: analyze incoming sensory information and decide what to do with it (store it vs make appropriate motor decisions)

Question 2

Components and 2 subdivisions of the nervous system

Answer 2

Components:
brain, spinal cord, nerves, sensory receptors

Subdivisions
- Central nervous system (CNS): brain and spinal cord
- Peripheral nervous system (PNS): everything else (nerves and sensory receptors)

Question 3

How are nerves named/classified?

Answer 3

Based on where they enter and exit. Info can only travel one way!

Question 4

Components of PNS

Answer 4

SENSORY RECEPTORS: endings of neurons or specialized cells that detect senses
NERVES: bundles of axons that connects CNS to sensory receptors, muscles, glands
- CRANIAL: 12 pairs
- SPINAL: 31 pairs
GANGLION: collection of neural cell bodies outside CNS (used for sensory info, one motor system)
PLEXUS(ES): extensive network of axons and sometimes neuron cell bodies outside CNS

Question 5

General divisions of PNS

Answer 5

2 main divisions
- SENSORY (AFFERENT)
- MOTOR (EFFERENT)

SENSORY (afferent)
- takes in sensory input
- transmits action potentials from receptors to CNS

MOTOR (efferent)
- produces motor output
- transmits action potentials from CNS to effectors

Question 6

Difference between efferent and afferent nerves

Answer 6

afferent: sensory receptors to CNS
efferent: CNS to muscles and glands

Question 7

Sensory divisions of PNS

Answer 7

GENERAL SENSES
- receptors throughout the body
SPECIAL SENSES
- receptors in specific organs

one neuron system

Question 8

Motor divisions of the PNS

Answer 8

3 types of motor divisions

1. SOMATIC NERVOUS SYSTEM (voluntary control)
   “move my arm”
   - synapse with skeletal muscles (via NEUROMUSCULAR JUNCTION)
   - single neuron system
2. AUTONOMIC NERVOUS SYSTEM (involuntary control)

• synapse with
  affects cardiac and smooth muscle, glands
• two neuron system (CNS to ganglion, ganglion to effector)
• SYMPATHETIC (fight or flight)
• PARASYMPATHETIC (rest & digest)

3. ENTERIC NERVOUS SYSTEM (ENS)
   - plexuses within walls of digestive tract
   - can control digestion independently of CNS
   - uses ANS to communicate with CNS
   - sensory (monitors chemical environment), motor (contracts smooth muscle and controls secretions of GI organs and endocrine cells)

Question 9

How does neural information pass in and out of the spinal cord?

Answer 9

motor info out on anterior side (VENTRAL ROOT)
sensory information in on posterior side (DORSAL ROOT)

both roots connect to SPINAL NERVE

Question 10

You see a bear in the forest! what’s the order of nervous system response

Answer 10

• sensory input (bear)
  sensory division response
• PNS (receptors, afferent nerves, ganglia, plexuses)
• CNS (brain, spinal cord)
• PNS (efferent nerves, ganglia, plexuses)
  motor division
• somatic (skeletal muscles) and autonomic nervous systems (fight or flight; cardiac, smooth muscle and glands)

Question 11

How many pairs of spinal nerves?

Answer 11

31

Question 12

How many pairs of cranial nerves?

Answer 12

12