Sympathetic Nervous System

Sympathetic Nervous System

1. What does it control?

   • fight/flight: eyes, lungs, heart rate, stomach,

2. Symptoms:

   • mydriasis (pupil dilation), tachycardia (increased heart rate), hypertension (increased blood pressure)
   • EXCEPTION: controls sweating

3. Where is it: lumbar, thoracic regions of the spinal cord

4. Ganglion

   • Preganglionic: shorter Postganglionic: longer

5. Neurochemical Aspect

   • Preganglionic Neurotransmitter: Acetylcholine Postganglionic Neurotransmitter: norepinephrine
     • Sweat uses Acetylcholine as neurotransmitter at target cells
     • Transmitter Clearance Mechanisms for acetylcholine: Acetylcholinesterase
     • For Postganglionic Neurotransmitter: there are 4 different ADRENERGIC receptors (detect norepinephrine)
       • Alpha-1: postganglionic nerve, constriction of smooth muscle Alpha-2:presynaptic post ganglionic membranes, negative feedback Beta-1: heart muscle and kidney, decrease heart rate Beta-2: blood vessels and smooth muscles, dilate vessels
     • Transmitter Clearance Mechanism for NE: reuptake
     • Adrenal glands: have SNS preganglionic nerves go all the way to the adrenal glands