Autonomic NS
controls involuntary bodily functions, such as heart rate, digestion, and breathing, without conscious thought
Sympathetic vs. Parasympathetic NS
Fucntion
SNS: fight or flight
PNS: rest & digest
Sympathetic vs. Parasympathetic NS
Origin
SNS: Thoracolumbar (T1 - L2)
PNS: Craniosacral (CN III, VII, IX, X, S2-S4)
Sympathetic vs. Parasympathetic NS
Ganglia
SNS: along the vertebral column
PNS: within/close to effector organs
Sympathetic vs. Parasympathetic NS
Fiber Length
SNS
-Short preganglionic
-Long postganglionic
PNS
-Long reganglionic
-Short postganglionic
Sympathetic vs. Parasympathetic NS
Neurotransmitters
SNS
-Preganglionic - ACh
-Postganglionic - NE (ACh in sweat glands)
PNS
-Preganglionic & post ganglionic: ACh
Sympathetic vs. Parasympathetic NS
Activation
SNS - mass activation (due to adrenal medulla & chain)
PNS - localized, specific response
Sympathetic vs. Parasympathetic NS
clinical association
SNS overactivity: hypertension, stress responses
PNS dominance: bradycardia syncope
3 Routes Sympathetic Fibers can follow
Spinal Nerve Route
Sympathetic Nerve Route
Splachnic Nerve Route
Spinal Nerve Route
sweat, skin, shivers
-Sweat glands
-Arrector pili muscles (goosebumps)
-Blood vessels in skin & skeletal muscle
Sympathetic Nerve Route
“chest stuff”
-Heart
-Lungs
-Esophagus
-Thoracic organs
Splachnic Nerve Route
“Stomach & Stuff Below”
-Stomach
-Liver
-Intestines
-Adrenal medulla
-Abdominopelvic organs
Receptors
proteins on the surface of target cells that bind to neurotransmitters, initiating a response from the autonomic nervous system
A1
Vascoconstriction
- vessels
B1
1 heart
-increases HR, BP, etc
B2
2 lungs
- brochodilation
B3
3 letters = FAT
- adipose tissue
- lypolysis
Cholinergic (ACh)
Nicotinic - SNS
Muscarnic - PNS
Nicotinic
NMJ & all ANS ganglia
Muscarinic
PNS response in all effector organs
