Ch. 16.1-16.2 Organization & Divisions of ANS Flashcards
Autonomic Nervous System
VISCERAL EFFETORS
Divided into sympathetic and parasympathetic.
* Motor neurons of the CNS snyapse at visceral motor neurons in autonomic ganglia
*Ganglionic neurons control visceral effectors
Somatic Nervous System
SKELETAL EFFECTORS
* SNS motor neurons of the CNS synapse directly at skeletal muscle
Visceral effectors
- smooth muscles
- glands
- cardiac muscle
- adipocytes
Where are the integrative centers for autonomic activity?
the hypothalamus
Which ANS neurons are comparable to upper motor neurons of the SNS?
The integrative neurons in the hypothalamus
Visceral motor neurons in the brain stem and spinal cord
pre-ganglionic neurons
What are visceral reflex arcs?
Made up of visceral motor neurons (pre-ganglionic neurons) that respond to reflexes, rather than integrated commands in the hypothalamus.
Motor commands are distrubted by the ANS
e.g. goose bumps; HR increase due to a loud noise. Result from neurotransmitters released by post-ganglionic neurons into effectors
The axons of preganglionic neurons
preganglionic fibers
visceral motor neurons that originate outside the brain stem and spinal cord
ganglionic neurons
the axons of post-ganglionic neurons
post-ganglionic fibers
ganglia that are outside the brainstem and spinal cord
autonomic ganglia
these neurons innervate visceral effectors
ganglionic neurons
The thorocolumbar division of the ANS
sympathetic
the craniosacral division of the ANS
parasympathetic
autonomic ganglia are close to spinal cord
thorocolumbar (sympathetic) division
autonomic ganglia that synapse closer to or within visceral effectors
craniosacral (parasympathetic) division
short pre-ganglionic fibers, long post-ganglionic fibers
sympathetic
(thoracolumbar)
long pre-ganglionic fibers, short post-ganglionic fibers
parasympathetic (craniosacral) division
What are the 7 general responses to sympathetic activity?
- mental alertness
- increased metabolism
- reduced digestive and urinary
- energy reserves activate
- increased RR + passageways
- increased HR + BP
- sweat glands on
where do pre-ganglionic fibers of the sympathetic division originate?
between segments** T1 and L2** of the spinal cord
(the thoracic and lumbar segments of the spinal cord)
where do pre-ganglionic fibers of the parasympathetic nervous system originate?
in the brain stem and sacral segments of the spinal cord
prepares the body for heightened activity
the thoracolumbar division
stimulates visceral activity
the craniosacral division
What are the 5 main responses to craniosacral activation?
- decreased metabolic rate
- decreased HR and BP
- salivary and digestive secretion
- increased digestive motility and blood flow
- urination & defecation
The enteric nervous system (ENS)
an extensive network of neurons and nerve networks in the walls of the digestive tract. Influenced by both sympathetic and parasympathetic. Controlled by many complex visceral reflexes without instructions from CNS
where are the cell bodies of sympathetic pre-ganglionic fibers located?
in the lateral gray horns of T1 to L2
where do the axons of sympathetic pre-ganglionic fibers enter?
the ventral roots of segments T1 to L2
Where are the three locations of sympathetic ganglionic neurons?
- Sympathetic chain ganglia (both sides of vertebral column)
- Collateral ganglia (pre-vetebral ganglia) anterior to veterbral bodies
- The Adrenal Medulla
Where are the neurotransmitters of sympathetic ganglia in the adrenal medullae released?
into the bloodstream… not a synapse!! allowing them to function as hormones
