The Autonomic Nervous System Flashcards
What are the 2 parts of the PNS?
- somatic: voluntary muscle control of skeletal muscle
- autonomic: involuntary control of viscera
The autonomic system consists or what?
- sympathetic: fight or flight
- parasympathetic: rest, digest
What lays close to the spinal cord in the sympathetic division?
paravertebral ganglia
What are the pre-ganglionic neurons in the sympathetic system?
short cholinergic projections leave CNS and innervate ganglia
What are the post-ganglionic neurons in the sympathetic system?
long adrenergic projections leave ganglia to innervate effector
What is the exception in post-ganglionic neurons?
kidney has dopaminergic innervation
What is the tissue and sympathetic action response in the eye?
- tissue: radial muscle
- response: contracts
What is the tissue and sympathetic action response in the heart?
- tissue: SA node, contractility
- response: SA node ->accelerates; contractility: increases
What is the tissue and sympathetic action response in the blood vessels?
- tissue: skeletal muscle, coronary
- response: both relax
What is the tissue and sympathetic action response in the lung?
- tissue: bronchial smooth muscle
- response: relaxes
What is the tissue and sympathetic action response in the genitourinary smooth muscle and GI tract?
- tissue: walls, sphincters
- response: walls -> relax; sphincter -> contracts
What is the tissue and sympathetic action response in the skin?
- tissue: sweat glands
- response: increase
What is the tissue and sympathetic action response in metabolism?
- tissue: liver, adipose tissue
- response: liver -> gluconeogenesis & glycogenolysis; adipose tissue -> lipolysis
What is the pre-ganglionic neuron in the parasympathetic division?
long cholingeric projections that innervate ganglia near target organ
What is the most important pre-ganglionic neuron in the parasympathetic system?
CN X (vagus)
What is the post-ganglionic neuron in the parasympathetic division?
short cholinergic projections to target organ
What is the tissue and parasympathetic action response in the eye?
- tissue: sphincter
- response: contracts
What is the tissue and parasympathetic action response in the heart?
- tissue: SA node, contractility
- response: SA node -> decelerates; contractility -> decreases
What is the tissue and parasympathetic action response in the lung?
- tissue: bronchial smooth muscle
- response: contracts
What is the tissue and parasympathetic action response in the GI tract?
- tissue: walls, sphincters, secretion
- response: walls -> contracts; sphincters ->relaxes; secretion -> increases
What is the tissue and parasympathetic action response in genitourinary smooth muscle?
- tissues: walls, sphincters
- response: walls -> contracts; sphincters -> relaxes
What type of innervation do most organs receive?
dual innervation
How does the sympathetic system affect the eye?
radial muscle contracts dilating the pupil
How does the parasympathetic system affect the eye?
circular muscle contracts constricting the pupil
What DOES NOT receive parasympathetic innervation?
- blood vessels
- sweat glands
- hair follicles
What are the nicotinic receptors?
- ligand gated (fast)
- Nm and Nn
What are the muscarinic receptors?
- G protein coupled (slow)
- M1, M2, M3, M4, M5
Where are nicotinic Ach receptors found?
ganglia + skeletal muscle
What are nicotinic agonists?
nicotine, DMPP, epibatidine
What is the location and physiological response of Nm?
- location: neuromuscular juncture
- repsonse: skeletal muscle contraction
What is the location and physiological response of Nn?
- location: autonomic ganglia, brain
- response: ganglionic transmission
What are the muscarinic agonists?
muscarine, pilocarpine, oxotremorine
What are the excitatory muscarinic receptors?
- odd numbers: M1, M3, M5
- elevate intracellular Ca
What is the location and physiological response of M1?
- location: nerves
- response: depolarization of neuron
What is the location and physiological response of M3?
- location: glands, smooth muscle, endothelium, nerves
- response: contraction of GI and bronchial smooth muscle, increase of GI secretions
What is the location and physiological response of M5?
- location: CNS
- response: modulate neuroexcitability and vascular tone
What are the inhibitory muscarinic receptors?
- even numbers: M2, M4
- inhibit adenylyl cyclase -> decrease cAMP
What is the G protein, location and physiological response of M2?
- G protein: Gi
- location: heart, nerves, smooth muscle
- response: decrease SA node firing rate, decrease ventricular contractile force
What are the subtypes of adrenergic receptors?
- alpha receptors (GPCR)
- beta receptors (GPCR)
What is the biochemical factor, location, and physiological response for alpha 1?
- biochemical factor: increase intracellular Ca
- location: vascular smooth muscle, heart, liver
- response: vasoconstriction, increase contractile force, glycogenolysis, gluconeogenesis
What is the biochemical factor, location, and physiological response for alpha 2?
- biochemical factor: inhibit adenylyl cyclase
- location: pancreas islets
- response: decrease insulin secretion
What is the effect of beta adrenergic receptors on cAMP?
increase cAMP via activation of adenyl cyclase
What is the role of cAMP in beta receptors?
- increases contraction of the heart (beta 1)
- decreases contraction vascular and bronchial smooth muscle
What is the location and physiological response for beta 1?
- location: heart, juxtaglomerular cells
- response: increase force and rate of contraction, increase renin secretion
What is the location and physiological response for beta 2?
- response: relaxation, increasing bronchial secretions glycogenolysis, gluconeogenesis, increase insulin secretion
- location: smooth muscle bronchial glands, liver
What is the location and physiological response for beta 3?
- location: adipose tissue
- response: lipolysis, no release
The amygdala is known as what?
“higher centers” of control
What is the baroreceptor reflex?
sensory afferent neurons that help modulate control based on various internal stimuli
Sympathetic output relates to what?
peripheral vascular resistance
Parasympathetic output relates to what?
heart rate
What is the role of the spinal cord if the bladder is damaged?
sensory neurons at the dorsal root ganglion send signal to the spinal cord and trigger voiding
What 2 things can be associated with the failure of the ganglion loop?
CHF and arrhythmias
What allows for regulation of synaptic signaling?
the presence of heteroreceptors
What is the role of heteroreceptors?
act as terminal receptors for other transmitters that may act either to stimulate or inhibit release at that terminal
