S10 Neuro ANS Flashcards
visceral afferents
release transmitters from the tachykinin family
responsible for visceral pain (primarily in SNS pathways)
afferent endings can produce neurotrophic effects and neurogenic inflammation
primary baroreceptor and chemoreceptor afferent nerves project to the
solitary nucleus (nucleus tractus solitarius) of the medulla and play a critical role in integrating cardiovascular and respiratory functions.
Pons contains
neurons that promote coordination of respiratory activity
contains the micturition center
lower region of pons adjacent to the medulla contributes to integration of cardiovascular function
Hypothalamus is the main
integration center of the autonomic nervous system
hypothalamus contains
osmoreceptors
core temperature- hypothalamus is the thermostat
eating behavior-hypothalamus contains the feeding and satiety centers
Autonomic integration
- Cerebral cortex and limbic system
- Hypothalamus
Reticular centers of brainstem
Preganglionics
Postganglionics
Local neurons (e.g. enteric neurons)
Parasympathetic division cranial and sacral outflow
Cranial outflow
• CN III, VII, IX, X
• Vagus nerve (CN X) is major preganglionic parasymp supply to thorax & abdomen
Sacral outflow:
• Hindgut, pelvic viscera, and external genitalia
cholinergic receptors
Ach is an agonist for both nicotinic and muscarinic receptors
Nicotinic receptors
nicotine is an agonist
located on postganglionic autonomic neurons and neuromuscular junction of skeletal muscles
curare is an antagonist
Muscarinic receptors
muscarine is an agonist
located at the neuromuscular junctions of cardiac and smooth muscles and glands
atropine is an antagonist
Norepinephrine is an
agonist for adrenergic receptors
Alpha and/or beta receptors are located on all
post ganglionic neuron targets except sweat glands
M2 and M4 are what g receptors
Gi
M1, M3, M5
Gq
increase PLCb
Increase Ca2+
increase MAPK
M2, M4
Gi
increase AC
increase MAPK
increase GIRK ch.
decrease cAMP
Nicotinic receptors
increase CA
increase VDCC
increase PKC
nicotinic receptors require
2 molecules of acetylcholine
Alpha 1
Gq/11
activates phospholipase C
Alpha 2
Gi;Go
inhibits adenylyl cyclase; Ca++, K+ channels
Gs
stimulates adenylyl cyclase; Ca++
Sympathetic tone
sympathetic nervous systems exerting a continuous level of control
i.e. ateriole diameter is controlled by tonic release of norepinephrine.
Autonomic innervation of the lungs
parasympathetic via vagus:
Motor to the smooth muscle of the bronchial tree (bronchoconstrictor).
Inhibitor to the pulmonary vessels (vasodilator).
Secretor to the glands of the bronchial tree (secretomotor).
Sympathetic:
Inhibitors of the bronchial tree (bronchodilator).
Motor to the pulmonary vessels (vasoconstrictor).
Inhibitor to the glands of the bronchial tree.
Autonomic innervation of the kidneys
100% sympathetic
The release of norepinephrine from renal postganglionic sympathetic nerves has 3 effects:
1. inc. renin release from juxtaglomerular cells via a β adrenergic mechanism 2. dec sodium excretion (or inc. sodium reabsorption) (α1 adrenergic receptors) 3. Vasoconstriction of renal arteries, which dec. renal blood flow (α1 adrenergic receptors)
Miosis
parasympathetics. M3
