Functional Organization of Nervous Tissue

Functions of the nervous system

sensory, integrative, motor

Sensory Function

Senses change through receptors, such as touch, vision, heating, pressure

Motor Function

Responds to stimuli, affects glands and muscles

Integrative Function

- Analyzes and stores sensory information
- Higher Order Processing Responses/ executive function

Componants of PNS

Sensory receptors, cranial nerves, spinal nerves, ganglion, plexus

Sensory receptors

sending of neurons or separate specialized cells that detect pain, temp, pressure

Nerves

- Bundle of axons and their sheaths that connect CNS to receptors, muscles and glands
- Cranial Nerves: originate/terminate in brain; 12 pairs
- Spinal nerves: originate/ terminate in spine; 31 pairs

Ganglion

- Collection of neuron cell bodies outside CNS
- Sensory info: info not going to brain have their cell bodies in ganglion
- Two-neuron system: motor systems can have a two-neuron system connect in the ganglion

Plexus

network of axons, sometimes somas/cell bodies, located outside CNS

Sensory/afferent

- transmits action potential from receptors to CNS
- General Senses: receptors spread throughout the body
- Specialized Senses: specialized receptors in specific organs
- Dorsal Root: sensory info enters here

Motor/efferent

- transmits action potential from CNS to effectors

Action potential

electrical signals created by
triggered receptors

Somatic Nervous System

- targets skeletal muscles
- voluntary control

single neuron system (somatic)

soma inside spinal cord, axon exists and goes to target tissue

Neuromuscular junction

synapse with skeletal muscle, goes through ventral root of spine

Autonomic

-Targets cardiac muscle, smooth muscle and some glands
- involuntary
- two neuron system
-sympathetic NS: fight or flight; prepares for physical activity
- parasympathetic NS: rest and digest; regulates resting and vegetative function; can run at same time as sympathetic but not same target tissue

Enteric NS

plexuses in the wall of the digestive
tract; controls tract independently of CNS but
still communicates with it via ANS;