Chapter 15: Autonomic Nervous System Flashcards
Difference between somatic and autonomic nervous system
Somatic is voluntary
Autonomic is involuntary
Somatic nervous system has only one
motor neuron that extends from the CNS to skeletal muscle fiber it innervates
Autonomic nervous system has two
motor neurons; preganglionic neuron and postganglionic neuron
The autonomic nervous system is divided into
sympathetic and parasympathetic nervous system
Preganglionic neuron
has its cell body in the CNS and axon extends to autonomic ganglion
Postganglionic neuron
has its unmyelinated axon extending from the ganglion to the effector
Where do the preganglionic neurons reside in the sympathetic division
in the lateral gray horns of the gray matter in the 12 thoracic segments and first 2 lumbar segments of the spinal cord
The sympathetic division is also called
the thoracolumbar division
What are the 2 major types of sympathetic ganglia and where are they located
- Sympathetic trunk ganglia: vertical row on either side of the vertebral column
- Prevertebral ganglia: lies anterior to vertebral column
What do sympathetic trunk ganglia mostly innervate
mainly organs above the diaphragm:
- head, neck, shoulders and heart
Sympathetic trunk ganglia names
- superior, middle and inferior cervical ganglia
Most sympathetic preganglionic axons are…
short and postganglionic axons are long
In general postganglionic axons of prevertebral innervates..
organs below the diaphragm
Five major prevertebral ganglia are…
- Celiac ganglion
- Superior mesenteric ganglion
- Inferior mesenteric ganglion
- Aorticorenal ganglion
- Renal ganglion
Where are cell bodies of preganglionic neurons of the parasympathetic division located
in the nuclei of four cranial nerves in the brainstem (III, VII, IX, X) and in the lateral gray matter of the second through 4th sacral segments of the spinal cord
the parasympathetic division is also known as the
craniosacral division
Preganglionic axons of the parasympathetic division synapse with
postganglionic neurons located closer to or actually within the wall of a visceral organ
Names of parasympathetic ganglia
- Ciliary ganglion
- Pterygopalatine
- Submandibular
- Otic
In the parasympathetic division, preganglionic axons are long and
postganglionic axons are short
Cholinergic neurons release
ACh (acetylcholine)
Adrenergic neurons release
norepinephrine or noradrenalin
Cholinergic receptors include
nicotinic and muscarinic receptors
Major sympathetic response to stimulation
- pupils dilate (need to see more)
- vasoconstriction of blood vessels to skin and digestive canals, and kidneys
- dilation of airways
- heart rate and blood pressure increases
- blood supply to specific organs increases such as heart, muscle, liver and adipose tissue
- liver cells perform glycoenolysis
- adipose tissue cells ; break down triglycerides to fatty acids
Parasympathetic responses
SLUDD:
- salivation
- lacrimation
- urination
- digestion
- defecation
AND
- decrease in hr and bp
- decrease in diameter of airways
- decrease in diameter of pupils
The posterior and lateral parts of the hypothalamus controls
the sympathetic division
The anterior and medial parts of the hypothalamus controls the
parasympathetic division
Components of an autonomic reflex arc
- sensory receptor
- sensory neuron
- integrating center
- motor neurons
- effector
Autonomic dysreflexia
- exaggerated response of the sympathetic nervous system occuring in 85% of injuries above level of T6
If autonomic dysreflexia is untreated it can lead to
- stroke,
- seizures
- heart attack
Raynaud phenomenon
- excessive sympathetic stimulation of smooth muscles in arterioles of digits
- vasoconstriction leads to numbness and ischemia
Raynauds phenomenon is more common in
young females
Dysautonomia
inherited disease and refers to the signs and symptoms that result from damage to the ANS
- S&S:
- orthostatic hypotension
- abnormal hr
- digestive problems
- urinary problems
- sweating problems
- sexual problems
- vision problems
Reflex sympathetic dystrophy
spontaneous pain, painful hypersensitivity to stimuli such as light touch and excessive coldness
