11 Unit 1 Chapter 11

11 Unit 1 Somatic systems- conscious awareness Autonomic sensory - not consciously perceived Monitors internal conditions- blood gasses, viscera operation, etc Autonomic motor- cardiac muscle, smooth muscle & glands Often adjustment of internal controls in relation to whole body needs

11 Unit 1 Somatic motor neurons go directly from spinal cord to skeletal muscle Autonomic motor systems includes two motor neurons: Preganglionic neuron from CNS to autonomic neuron from cell body in ganglion to effector

11 Unit 1 Sympathetic division Parasympathetic division both divisions often innervate the same effector They have opposite effects E.g. sympathetic stimulates heart rate and parasympathetic slows it

Figure 11.1a

Figure 11.1b

11 Unit 1 Thoracolumbar division- outflow from thoracic & lumbar segments of spinal cord Preganglionic fibers – From lateral horns via ventral roots to sympathetic ganglia synapse with postganglionic cells in ganglia

11 Unit 1 Sympathetic Trunk Ganglia Vertical rows on either side of vertebral column Post synaptic fibers mostly got to organs above diaphragm Prevertebral ganglia Anterior to vertebral column- celiac, superior mesenteric & inferior mesenteric Innervate organs below diaphragm

11 Unit 1 To postganglionic neuron 1. in trunk ganglion at level of root 2. In ganglion higher or lower in chain 3. in prevertebral ganglion 4.Directly to target organ-adrenal medulla average preganglionic neuron synapses with 17 postganglionic neurons

Figure 11.2

11 Unit 1 Output at top-medulla nuclei Cranial nerves II, VII,IX, X Bottom of spinal cord- sacral nerves Synapse in terminal ganglia Near or in the innervated organ localized to single effector organ

Figure 11.3

11 Unit 1 Acetylcholine- All preganglionic fibers terminals parasympathetic postganglionic terminals A few postganglionic sympathetic terminals Short-lived effects Norepinephrine- Most postganglioic sympathetic terminals Longer effects Amplified by adrenal release with epinephrine

11 Unit 1 Balance between sympathetic & parasympathetic “tone” regulated through hypothalamus Only sympathetic to: Sweat glands, arrrector pili muscles, kidneys, spleen, blood vessels & adrenal medulla

11 Unit 1 fight-or-flight activities Dilate pupils Increase HR, heart contraction & BP Dilate airways Constrict blood vessels to non essential organs: kidneys, GI tract Dilate vessels to muscles, cardiac muscle, liver & adipose Mobilize nutrients: glucose & fats

11 Unit 1 Rest-and–digest act ivies SLUDD Salvation Lacrimation Urination Digestion Defecation Decrease- HR, airway diameter, pupil diameter