The Autonomic Nervous System Flashcards
Sympathetic
“fight or flight” – dilates pupils, inhibits salivation, accelerates heart, facilitates breathing, inhibits digestion, stimulates release of glucose, secretes epinephrine and norepinephrine, relaxes bladder, inhibits sex organs. Has Alpha and Beta (beta 1 and beta 2) receptors. THORACIC AND LUMBAR NERVES.
Parasympathetic
“rest and digest” – constricts pupils, stimulates salivation, slows heart, constricts breathing, stimulates digestion, stimulates gallbladder, contracts bladder, stimulates sex organs. Has Nicotinic and Muscarinic receptor sights. CRANIAL AND SACRAL NERVES.
Neuron
an electrically excitable cell that processes and transmits information through electrical and chemical signals PARTS: Dendrite Soma Nucleus Axon Myeline Sheath Schwaan Cells Nodes of Ranvier Synaptic (axon) Terminals
Endocrine
Neurotransmitters are released and affect this system. Collection of glands of an organism that secrete hormones directly into the circulatory system to be carried towards a distant target organ
Exocrine
part of the endocrine system. Glands that release by way of ducts
Autonomic Nervous System
Involuntary
a division of the peripheral nervous system that influences the function of internal organs
Controls:
smooth muscles (vasculature, respiratory, GI)
cardiac muscles
glands (endocrine, exocrine)
Somatic Nervous System
is part of the peripheral nervous system associated with skeletal muscle voluntary control of body movements
consists of afferent and efferent nerves
Ganglion
a mass of nerve cells outside of the central nervous system
Neurotransmitters
Chemical “messengers”
Bind with receptor sites on post synaptic membrane
• May stimulate response
• May inhibit response
• KEY: neurotransmitter
• LOCK: receptor
Molecules that communicate information between neurons and target cell/organs at a synapse
1. Amino Acids
a. Glutamate
b. GABA
c. Glycerine
2. Monoamines *
a. Seratonin
b. Histamine
c. Catecholomines (neurotransmitter for sympathetic)
i. Dopamine
ii. Epi
iii. NorepiVagus Nerves
Enervation to the parasympathetic division of the ANS is primarily through the vagus nerve. But not only source of enervation.
Starts at Medulla, goes through bifurcation of carotids, and goes to heart (Atria) and other organs
“The wanderer”
Cranial Nerve X
Cardiac Effects ofParasympathetic Stimulation
– Slows heart rate • Negative chronotropic – Decreases AV conduction • Negative dromotropic – Decreases myocardial contractility • Negative iontopic – Decreases myocardial irritability – Enervates only the atria - little or no ventricular effects. If Bundle of HIS knocked out, Atria will beat independently of ventricles (Complete Heart Block) Atropine will not work because the block is below Atria, where Atropine works (Muscatine / Acetylcholine). Consider this, but do not withhold Atropine from them – KNOW POLICY / PROTOCOLS
Other Effects ofParasympathetic Stimulation
– Decreases cerebral blood flow • because vagus nerve decreases cardiac output – Constricts pupils – Increases oral secretions – Increases digestion – Decreases skeletal muscle blood flow
Alpha Receptor Sites
– Located in the peripheral vessels
• Alpha receptor Stimulation causes Peripheral Vasoconstriction
– Some bronchoconstriction – smooth muscles of bronchial tree – little to minimal of this
– Little to no effect on the heart
– Other effects throughout the body
Beta I Receptor Sites
– Beta 1 Works on both atria & ventricles
• Increases heart rate (+ Chronotropic)
• Increases AV conduction (+ Dromotropic)
•Increases irritability – Ectopic beats, stimulus to fire PVC’s
•Increases contractility – ability of muscle fibers to shorten and contract (+ Inotropic
Beta II Receptor Sites
– Lungs • Stimulation • Smooth Muscle Bronchodilation • Blockade • Smooth Muscle Bronchoconstriction
– Peripheral Vasculature
• Vasodilation
