2H Autonomic Nervous System Flashcards
Sensory receptors
Carry nerve impulses from receptors to CNS
Motor receptors
Carry nerve impulses from CNS to effectors
ANS
Responsible for control of:
- Smooth muscle
- Cardiac muscle
- Endocrine glands
- Exocrine glands
- These effectors can function without any conscious knowledge and independent of the will
- The term autonomy means “self-government”
Somatic pathway
The somatic pathway from CNS to skeletal muscle effector involved only 1 neuron
ANS pathway
The pathway from CNS to effectors involves 2 neurons
Preganglionic Neuron
Cell body in the CNS and courses to AUTONOMIC GANGLION
Postganglionic Neruon
Cell body in AUTONOMIC GANGLION and carries impulses to EFFECTOR
Sympathetic System
“fight or flight”
-Involes all thoracic and 2-3 lumbar vertebrae, called THORACOLUMBAR SYSTEM
Parasympathetic System
“rest and digest”
-Involves CN 3,7,9,10 and sacral spinal cord S2, S3, S4, called CRANIOSACRAL SYSTEM
Sympathetic ganglia
Located near the spinal cord
Parasympathetic ganglia
Near or within the wall of the organ innervated
Sympathetic Length of Fibers
- Short PREganglionic fibers
- Long POSTganglionic fibers
Parasympathetic Length of Fibers
- Long PREganglionic fibers
- Short POSTganglionic fibers
Sympathetic # of organs
-Exhibits unit action, activates many organs at once
Parasympathetic # of organs
Stimulus only involves one organ at a time
Eye (iris)
Sympathetic:
Dilates eye
Parasympathetic:
constricts eye pupils
Glands (nasal, lacrimal, salivary, gastric, pancreas)
Sympathetic:
-Inhibits saliva, causes vasoconstriction of blood vessels supplying the glands
Parasympathetic:
-Stimulates secretory activity (flow of saliva)
Sweat glands
Sympathetic:
-Stimulates copious sweating
Parasympathetic:
- no effect
Arrector pilorum muscles
Sympathetic:
-Stimulates to contract (erect hair, goosebumps)
Parasympathetic:
-No effect
Heart Muscle
Sympathetic:
-Increases rate and force of heartbeat
Parasympathetic:
-Decreases rate; slows and steadies heart
Digestive tract organs
Sympathetic:
-decreases activity of glands and muscles of digestive system and constricts sphincters
Parasympathetic:
-Increased motility and amount of secretion by digestive organs; relaxes sphincters to allow movement of food along tract
Blood vessels
Sympathetic:
-Constricts most vessels and increases blood pressure; constricts vessels of abdominal viscera and skin
Parasympathetic:
-Little or no effect
Mental activity
Sympathetic:
-Increases alertness
Parasympathetic
-No effect
