1 / 12

Autonomic Nervous System

Autonomic Nervous System. Chapter 14. Human Nervous System Divisions. Info in & out. Integration & Command. Comparing Somatic and Autonomic. Effectors Innervates skeletal muscle Innervates visceral organs and glands Efferent pathways Single axon = faster signal

ruby
Download Presentation

Autonomic Nervous System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Autonomic Nervous System Chapter 14

  2. Human Nervous System Divisions Info in & out Integration & Command

  3. Comparing Somaticand Autonomic • Effectors • Innervates skeletal muscle • Innervates visceral organs and glands • Efferent pathways • Single axon = faster signal • Two axons = slower signal • Target organ responses • Cholinergic (ACh) synapses exite • Cholinergic, epinephrine, or norepinephrine synapses  excite or inhibit

  4. Autonomic Nervous System • Stabilize internal environments • Adjustments from changes to sensory stimuli • Dual innervation • 2 divisions counter the effects of each other • Parasympathetic • Nonstressful situations (rest and digest) • Sympathetic • Emergency or threatening situations (fight or flight) • Rare in actuality • Antagonistic relationship with continuous adjustments by both • Anatomical characterizations • Origin: craniosacral or thoracolumbar regions • Length of fibers: long preganglionic, short post- or opposite • Location of ganglia: in effectors or close to spinal cord

  5. Parasympathetic Roles • D division (digest, defecate, diuresis) • Pupils constrict • Stimulates salivary, lacrimal, and pancreas glands • Decrease heart rate • Causes contraction and emptying of hollow organs: • Bladder, gallbladder, stomach, intestines (peristalsis) • Vasodilation of penis (erection) • No effect on blood vessels

  6. Sympathetic Roles • E division (exercise, excitement, emergency, embarrassment) • Dilates pupils • Inhibits secretion of glands • Stimulates sweating • Stimulates arrectorpili • Stimulates medulla of adrenal gland to secrete epi- and norepinephrine • Increases heart rate • Decreases digestive processes • Decreases urine output • Causes ejaculation • Stimulates glycogenolysis in liver (glucose release) • Blood vessel constriction/dilation and blood coagulation • Bronchiole dilation

  7. Craniosacral Division • CN III (oculomotor) • From midbrain  ciliary ganglia • CN VII (facial) • From pons pterygopalatine and submandibular ganglia • CN IX (glossopharyngeal) • From medulla  otic ganglia • CN X (90%) (vagus) • From medulla  cardiac, pulmonary, and celiac plexuses • S2 – S4 • Lateral gray spinal mater  pelvic splanchnic nerves into the inferior hypogastric plexus

  8. Thoracolumbar Division • Pre- from gray matter in lateral horns of T1 – L2 to sympathetic trunk via rami communicates • Synapse varies • W/ a postganglionic neuron w/i same ganglion(1) • Ascend/descend w/i sympathetic trunk to another ganglion (2) • Pass through ganglion w/o synapsing (collateral ganglia or adrenal medulla)(3)

  9. Trunk Ganglia • Post- enter rami via rami communicates • Superior cervical ganglion • Dilates pupils • Inhibit nasal and salivary secretions • Stimulates sweating, arrectorpili muscles, and vasodilation • Middle cervical ganglion • Heart and skin • Inferior cervical ganglion • Heart, aorta, bronchiole dilation, and esophageal sphincter constriction

  10. Collateral Ganglia • Pre- form splanchnic nerves which synapse w/ collateral ganglia • Post- from collateral ganglia to effectors • Greater splanchnic nerve • Celiac ganglia • Stomach, adrenal medulla, liver, kidney, and intestine • Lesser splanchnic nerve • Superior mesenteric (via celiac) • Small intestine • Lumbar splanchnic nerve • Inferior mesenteric ganglion • Large intestine • Hypogastric ganglion • Bladder, urethra, and genitalia

  11. ANS Neurotransmitters • Acetylcholine (cholinergic fibers) • All pre- and all parasympathetic post- • Nicotinic receptors (stimulatory) • Skeletal muscle, all ganglionic neurons, and adrenal medulla • Muscarinic receptors (stimulatory or inhibitory) • All parasymapthetic targets and some sympathetic organs • Norepinephrine (adrenergic fibers) • Most sympathetic post- • Alpha (generally stimulatory) • Beta (generally inhibitory)

  12. Select ANS Effecting Drugs • Atropine • Anticholinergic (blocks muscarinic receptors) • Prevent salivation, dilate pupils, and dry up respiratory secretions • Neostigmine • Anticholinesterase • Treat myasthenia gravis by preventing ACh degradation • Ephedrine • Stimulates alpha adrenergic receptors • Beta-blockers • Inhibit beta receptors • Reduce heart rate and arrhythmias w/o disrupting other sympathetic effects

More Related