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Peripheral Nerve Neurons: Motor
move away from CNS. may be SOMATIC(one neuron, no synapse) that inervate skeletal muscles. may be AUTONOMIC(pre and postganglionic) that inervate smooth and cardiac muscle and glands
Peripheral Nerve Neurons: Sensory
move towards CNS. not subdivided since there is no overlap in function
3 Divisions of ANS
SYMPATHETIC (fight or flight responses, corresponds with arousal and energy) PARASYMPATHETIC (rest and digest, promotes calming of nerves) ENTERIC (nerve plexuses)
Routes of Sympathetic Axons: SPINAL NERVE
preganglionic axons synapse(at same or different level) with postganglionic neurons within sympathetic chain. The postganglionic neurons exit through the grey rami communications & re-enter spinal nerves.
Routes of Sympathetic Axons: SYMPATHETIC NERVES
Synapse like spinal nerves but exit ganglia through sympathetic nerves.
Routes of Sympathetic Axons: SPLANCHNIC NERVES
preganglionic axons pass chain ganglia & synapse in collateral ganglia, then send fibers to target organs(viscera(internal organs))
Routes of Sympathetic Axons: INNERVATION TO ADRENAL GLAND
preganglionic axons synapse with cells of adrenal medulla. Medullary cells secrete epinephrine and norepinephrine-act as hormones promoting physical activity.
Parasympathetic Division(Craniosacral): FROM BRAINSTEM
preganglionic axons from brainstem pass to terminal ganglia through cranial nerves III, VII, IX, and X.
Parasympathetic Division(Craniosacral): FROM SACRAL REGION
preganglioninc axons from sacral region pass through pelvic splanchnic nerves to terminla gagnlia
Enteric Nervous System: Consists of and sources of neurons(3)..
Consists of nerves plexuses within wall of digestive tract. Sources of neurons: (1)Sensory neurons that connect digestive tract to CNS (2)ANS motor neurons that connect CNS to digestive tract (3)Enteric neurons that are confined to enteric plexuses
Distribution of ANS Fibers: Sympathetic (how axons reach organs through)(4)
Spinal Nerves > Head and Neck Plexuses > Thoracic nerve plexuses > Abdominopelvic nerve plexuses
Distribution of ANS Fibers: Sympathetic > Spinal Nerves
innervate(to supply with nerves) sweat glands, smooth muscle of blood vessels to skeletal muscle, skin and arrector pili (on skin,makes hair stand up)
Distribution of ANS Fibers: Sympathetic > Head and Neck Nerve Plexuses
innervate sweat glands, smooth muscle of blood vessels to skeletal muscle, skin and arrector pili
Distribution of ANS Fibers: Sympathetic > Thoracic Nerve Plexuses
cardiac and pulmonary; heart and lungs
Distribution of ANS Fibers: Sympathetic > Abdominopelvic Nerve Plexuses
celiac, superior & inferior mesenteric, hypogastric plexuses. Organs of the abdominal cavity
Distribution of ANS Fibers: Parasympathetic (how axons reach organs)(4)
(1) Cranial Nerves(Oculomotor III, Facial VII, Glossopharyngeal IX) (2)Vagus nerve and thoracic nerve plexuses (3) Abdominopelvic nerve plexuses (4) Pelvic splanchnic nerves and nerve plexuses
Distribution of ANS Fibers: Parasympathetic > Cranial Nerves
1.Oculomotor (III) through ciliary ganglion, ciliary muscles and iris 2. Facial (VII) through pterygopalatine ganglion and submandibular ganglion. Lacrimal glands, mucosal glands of nasal cavity and palate, some salivary glands. 3. Glossopharyngeal (IX) through otic (ear) ganglion. partoid salivary gland
Distribution of ANS Fibers: Parasympathetic > Vagus & Thoracic Nerve Plexuses
heart, lungs, esophagus through esophageal plexus
Distribution of ANS Fibers: Parasympathetic > Abdominal Nerve Plexuses
parts of vagus nerve supply stomach and other viscera
Distribution of ANS Fibers: Parasympathetic > Pelvic Splanchnic Nerves & Nerve Plexuses
colon, urinary bladder, reproductive organs
Physiology of ANS: Neurotransmitters (define) and 2 types
chemicals produced by neurons of ANS to help cross gaps and synaptic clefts. (1) Acetylcholine > released by cholinergic neurons (2) Norepinephrine > released by adrenergic neurons
Physiology of ANS: Cholinergic Neurons (purpose) and 2 types
bind acetylcholine (1) Nicotinic: all receptors on postganglionic neurons, all skeletal muscles, adrenal glands (2) Muscarinic: all receptors on parasympathetic effectors, receptors of some sweat glands
Regulation of ANS through Autonomic Reflexes
controls most of the activity of visceral organs, glands and blood vessels. symp. and parasymp. divisions influence activities of enteric nervous sys. through autonomic reflexes
Can Enteric nervous system function independently of CNS?
yes, when neccessary through local reflexes
Functional Generalizations of ANS : Dual innervation
---to most organs with sympathetic & parasympathetic having oppisite effects
Functional Generalizations of ANS: cooridinate activities
either divisions alone (para or sympa.) or together can coordinate activities of different structures
Functional Generalizations of ANS: preperation for physical activity
sympathetic prepares body for physical activity or fight or flight response
Functional Generalizations of ANS: at rest blood pressure
is maintained through blood vessel walls, which only recieve sympathetic stimulation
Functional Generalizations of ANS: resting conditions or housekeeping (SLUDD)
parasympathetic more important in this role. (salivation, lacrimation[shedding of tears], urination digestion, defication)
Innervation of organs by ANS
each organ depends on both the parasympathetic and sympathetic to function
Responses to exercise on ANS
Increase heart rate and force of contraction > blood vessel dilation in skeletal and cardiac muscles > dilation of airway passages > energy sources availability increased (glycogen to glucose, fat cells break down triglycerides) > muscles generate heat, temp increases > sweat gland activity increases > decrease in non essential organ activities
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