ANS Function Flashcards
Function of PSNS
Maintain homeostasis
Internally balanced environment
Function of SNS
Respond to emergencies
Mobilize energy storage
ANS Function - Enteric
Coordinated gut motility
How many neurons does the SNS and PSNS have?
2 neuron system
Where is the presynaptic/preganglionic? SNS and PNS
Soma in CNS
Where is the postsynaptic/postganglionic? SNS and PSNS
Soma always in a ganglion in the PNS
Major regulation and preparation the SNS does?
Regulate blood flow
Preparation for energy expenditure
- Shunt blood from where you don’t need it to where you do
- Mobilize energy stores
Where are the presynaptic and postsynaptic somas located?
SNS
Presynaptic - Lateral horn T1-L2(3) (IML cell column)
Postsynaptic -
1) Paravertebral ganglion of sympathetic trunk
2) Prevertebral ganglia
All presynaptic axons release acetylcholine and goes to?
Cholinergic receptors on all postsynaptic neurons
Smooth muscle of the faces travel with?
Branches of common carotid artery
Limbs or walls of the trunk travel with?
Spinal nerves - Dorsal/ventral rami - peripheral nerves
Thoracic cavity travel with?
Cardiopulmonary splanchnic nerves
Visceral in abdominal/pelvic cavity travel with?
Abdominopelvic splanchnic nerves - prevertebral ganglia - branches of abdominal aorta (or to adrenal gland)
SNS Postsynaptic axons contain what?
Some release ACh
Cholinergic receptors
Sweat glands and arrector glands
SNS Postsynaptic axons most release?
Norepinephrine
Adrenal glads and epinephrine into the blood stream making it a hormone
Adrenergic receptors are?
Alpha receptors and Beta receptors
What is autonomic dysreflexia?
Associated with SCI
- Highest risk with injuries at T6 or above
- Overactivity of SNS with inability to inhibit the presynaptic neurons in the spinal cord leads to excessive vasoconstriction (increase in BP)
What is Horner’s Syndrome?
Lesion of SNS pathway to the face
- Descending sympathetic tract = Brainstem, cervical spinal cord, upper thoracic spinal cord
- Lateral horn upper thoracic spinal cord
- Superior cervical paravertebral ganglion and upper levels of sympathetic trunk
Signs/Symptoms of Horner’s Syndrome?
Ipsilateral drooping eyelid - ptosis
- Pupillary constriction (loss of pupilary dilator) = miosis
- Absense of sweating - anhidrosis
- Skin vasodilation - flushing
