Autonomic Nervous System

CRS101 HUMAN ANATOMY | CRS102 HUMAN PHYSIOLOGY

Autonomic nervous system

controls visceral functions and regulates internal environment in an involuntary reflexive manner acting on cardiac muscle smooth muscle and glands

Sympathetic division

thoracolumbar division of the autonomic nervous system associated with fight or flight responses

Parasympathetic division

craniosacral division of the autonomic nervous system associated with rest and digest responses

Enteric nervous system

nerve plexuses within the wall of the digestive tract

Sympathetic chain ganglia

sympathetic ganglia located along both sides of the vertebral column forming a chain-like paravertebral structure extending into cervical and sacral regions

Collateral ganglia

sympathetic prevertebral ganglia where preganglionic neurons of splanchnic nerves synapse

Terminal ganglia

parasympathetic ganglia located near or on the effector organ

Autonomic nerve plexuses

complex interconnected neural networks formed by neurons of the sympathetic and parasympathetic divisions named according to organs they supply or blood vessels along which they are found

Enteric sensory neurons

neurons that detect changes in the chemical composition of contents of digestive tract or stretch of digestive tract wall

Enteric motor neurons

neurons that stimulate or inhibit smooth muscle contraction and gland secretion

Enteric interneurons

neurons that connect enteric sensory and motor neurons

Cholinergic neuron

a neuron that releases acetylcholine

Adrenergic neuron

a neuron that releases epinephrine or norepinephrine

Nicotinic receptors

cholinergic receptors located on postsynaptic neurons of autonomic ganglia and skeletal muscle fibers

Muscarinic receptors

cholinergic receptors located on cells of all parasympathetic effectors and some sympathetic effectors

Adrenergic receptors

receptors that respond to norepinephrine located on most sympathetic effectors

Autonomic reflexes

involve adjustments to cardiac muscle smooth muscle and glandular tissues in response to stimuli through reflex arcs involving sensory receptors sensory neurons interneurons motor neurons and effector cells

Local reflex

does not involve the CNS but produces an involuntary unconscious stereotypical response to a stimulus

Autonomic dysreflexia

product of dysregulation of the autonomic system leading to an uncoordinated response to a noxious stimulus defined as an acute episode of systolic blood pressure elevated by 25 mm Hg or above normal measurements

Horner syndrome

a rare condition classically presenting with partial ptosis miosis and facial anhidrosis due to a disruption in the sympathetic nerve supply