Peripheral Nervous System

What do you see? CNS AND PNS

 Nerves that branch out from brain, spinal column  Not covered w/ meninges  No CSF  Divided into somatic and autonomic branches Characteristics of the P.N.S.

 Somatic Nervous System  CRANIAL & SPINAL nerves  Afferent Sensory nerves  Efferent, VOLUNTARY Motor nerves  Autonomic Nervous System  Parasympathetic & Sympathetic Systems  INVOLUNTARY motor nerves  Maintains homeostasis 2 Divisions:

Peripheral Nervous System Somatic Nervous System: Cranial & Spinal Nerves Sensory Nerves (send impulses to the brain/spinal cord) Motor Nerves (Send impulses away from brain/spinal cord) Autonomic Nervous System Parasympathetic Nervous System (Rest & Digest) Sympathetic Nervous System (Fight or Flight)

PNS: Cranial & Spinal Nerves

 Twelve total  Arise from brain, passing through various foramina  Specialized tasks – some sensory, motor, or both  Some with multiple branches  Identified by Roman numeral and anatomical name You’ve got a lot of nerve! (Cranial Nerves, that is!)

 “Oh, Oh, Oh, To Touch And Feel Very Green Vegetables… Aah, Heaven”  …there are more out there… They help you remember…  Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharangeal, Vagus, Accessory, Hypoglossal Mnemonic time!

 Sammy Sosa Made Money, But My Brother Says Barry Bonds Made More  S = sensory  M = motor  B = both Functions!

 Sensory and motor Spinal nerves have their ups and downs…

PNS: Autonomic Nervous System Can you explain each of these?

 Regulates internal environment  Controls glands, cardiac muscle, smooth muscle  Homeostasis!  Integrated with endocrine system  Digestion, sexual functions, stress responses  No conscious thought… Autonomic Nervous System

A nervous system divided… Parasympathetic  Cranial nerves, sacral spinal nerves  Promotes relaxation, digestion  “Post-stress”, P.S. Sympathetic  Thoracic, lumbar spinal nerves  Prepares body to react to stress  “Fight or Flight”  “S for stress”

 Somatic nerves:  Full length of nerve connects spinal cord to body component  Cell body in gray matter… terminus contacts effector  Autonomic nerves:  Two neurons working together  Preganglionic originates in brain/spinal cord  Myelinated  Synapses with postganglionic neuron (non-myelinated) It’s all about connections…

 In parasympathetic nervous system…  Preganglionic neurons long, terminate close to effector (short postganglionic neuron)  Allows specific, targeted control  In sympathetic nervous system…  Preganglionic neurons short, terminate close to spinal cord (sympathetic ganglion chain)  Postganglionic neurons long, travel from ganglion to effector  Allows widespread activation of body systems Form follows function…

 Effectors receptive to both systems… how?  Preganglionic nerves of Symp, Parasymp NS secrete acetylcholine…  Postganglionic nerves secrete different NT’s  Parasympathetic NS  acetylcholine  Sympathetic NS  norepinephrine  Cause antagonistic effects in effector Double agents?

EffectorSympathetic ActionParasympathetic Action IrisOpens pupilCloses pupil Salivary glandsReduces saliva productionIncreases saliva production Oral/nasal mucosaReduces mucus productionIncreases mucus production HeartIncreases activityDecreases activity LungRelaxes respiratory musclesConstricts respiratory tree muscles StomachReduces digestive actionIncreases digestive action Small intestineReduces digestive actionIncreases digestive action Large intestineReduces digestive actionIncreases digestive action KidneyDecreases urine prod.Increases urine prod. BladderRelaxes bladderContracts bladder Antagonistic effects…