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)
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?