efferent nervous system

sensory : afferent nervous system

first order neuron (PNS-CNS), second order neuron (CNS-thalamus), third order neuron (thalamus-cerebrum (conscious) or thalamus-cerebellum (unconscious))

motor : efferent nerous system

somatic motor tract: uppermotor neuron (all CNS)- lower motor neuron (skeletal muscle)
autonomic motor tract: upper motor neuron (all CNS) - pre-ganglionic - post-ganglionic

parasympathetic

rest, digest and repair, restorative functions (ganglia near target organs)

sympathetic

fight or flight, energetic functions (ganglia near spinal cord)

divergence

single preganglionic synapses with multiple postganglionic

parasympathetic pathway

pre-ganglionic releases ACH to a nictonic receptor (ion channel) → postganglionic releases ACH to a muscarinic receptor (GPCR) for a sustained response

sympathetic pathway

preganglionic releases ACH to a nictonic receptor (ion channel) → postganglionic releases norepi to an adrenergic receptor (alpha or beta) (GPCR)

what receptor is responsible for stimulatory effects

beta receptors

what receptor is responsible for inhibitory effects

alpha receptors

alpha 1 receptors

found in most sympathetic target tissues, NE>E, activates IP3 and DAG

alpha 2 receptors

found in digestive tracts, NE>E, decreases CAMP

beta 1 receptors

found in heart muscle and kidney, NE=E, increases CAMP

beta 2 receptors

found in blood vessels and smooth muscles, E>NE, need to be activated by a neurohormone bc a lot of receptors, increase CAMP

beta 3 receptors

found in adipose tissue, NE>E, increases CAMP

adrenal cortex

a true endocrine gland- for sustained response

adrenal medulla

modified ganglion neural tissue, fast response

chromaffin cells

specified post-ganglion that do exocytosis of a neurohormone for a sustained response

indirect upstream drug

alters ligand availability, works before the receptor

direct drug

binds directly to the receptor to work as an agonist (increase transduction) or antagonist (decrease transduction)

indirect downstream drug

alters transduction pathway, works after the receptor