Gross Anatomy PNS and Spinal Cord For more

Gross Anatomy PNS and Spinal Cord For more info, visit http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/PNS.html Or http://www.becomehealthynow.com/article/bodynervousadvanced/822

Today: PNS & spinal cord Tomorrow: CNS

Nervous system Peripheral nervous system (PNS): nerves outside brain and s.c. Central nervous system (CNS): brain & spinal cord Somatic NS: nerves going from sense organs to CNS & from CNS to muscles & glands Autonomic NS: controls heart, intestines, other organs Sympathetic NS: for vigerous activity (fight or flight) Parasympathetic NS: vegetative, nonemergency responses

The Spinal Cord The Spinal Cord Figure 4.7, p82 http://www.bcs.rochester.edu/~dlee/bcs245/spinal_cord.jpg Know above terms (for left figure) + terms circled in red for right figure!! To be clear, DRG: collections of cell bodies of sensory neurons; cell bodies of motor neurons are within SC

http://www.unm.edu/~jimmy/spinal_neurons.jpg Bell-Magendie law: The entering dorsal roots carry sensory information to the brain & the exiting ventral roots carry motor information to the muscles and glands In other words: Dorsal=sensory Ventral=motor

http://www.carleton.ca/ics/courses/cgsc5001/img/06/neuron.jpg http://home.earthlink.net/~dayvdanls/REFLEXARC.GIF

Dorsal root (sensory in) Ventral root (motor out) rostral

Spinal nerves http://dentistry.ouhsc.edu/intranet-web/Courses/DH3342/images/spin_nerves.JPG Cauda equina

Peripheral NS Autonomic NS Sympathetic NS: axons activate organs for “fight or flight” Sympathetic ganglia are closely linked and act “in sympathy” with each other Chain outside spinal cord

Facilitates energy expenditure Behaviors? Physiology? Fibers (short pre, long post, NT?)

Peripheral NS Autonomic NS Parasympathetic NS: facilitate vegetative, nonemergency functions Para means “beside” or “related to”; opposite action of sympathetic NS Aka. Craniosacral b/c consists of cranial nerves and nerves of sacral SC

Facilitates energy conservation Behaviors? Physiology? Fibers (long pre, short post, NT?)

Neurotransmitters http://members.aol.com/Bio50/LecNotes/LNPics/ln26a.gif Few exceptions: sweat glands stimulated by Ach. Why does that matter?? Drugs!! OTC cold meds block parasymp or increase symp activity b/c flow of sinus fluids is parasympathetic. Side effect: inh salivation & digestion and inc HR

Peripheral NS Somatic NS Sense organs  CNS  muscles and glands Something touches leg  message to brain  message from brain to arm muscle  brush thing off leg