Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.19

PNS Somatic NS Autonomic NS Parasymathetic NS Sympathetic NS “fight or flight” “rest and repair” Voluntary control Normal stimulation of involuntary action Prevents over-stimulation of involuntary action NorepinephrineEpinephrine Acetylcholine

Sympathetic Nervous System Neurotransmitters Norepinephrine-stimulates normal functioning of the smooth and cardiac muscles Norepinephrine-stimulates normal functioning of the smooth and cardiac muscles Epinephrine-causes “flight or fight response” Epinephrine-causes “flight or fight response” Increased heart rate and strength of contraction Increased heart rate and strength of contraction Dilation of blood vessels in muscles Dilation of blood vessels in muscles Constriction of blood vessels in digestive system Constriction of blood vessels in digestive system Dilated airways and increases respiration rate Dilated airways and increases respiration rate Increased conversion of glycogen to glucose Increased conversion of glycogen to glucose

Parasympathetic Nervous System Neurotransmitter Acetylcholine- reverses the effects of norepinephrine to maintain homeostasis Acetylcholine- reverses the effects of norepinephrine to maintain homeostasis Slows the heart rate Slows the heart rate Increase rate of peristalsis Increase rate of peristalsis Stimulates digestive and salivary glands Stimulates digestive and salivary glands

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cranial Nerves (Don’t Write Down! In Ex.14)  I Olfactory nerve – smell  II Optic nerve – vision  III Oculomotor nerve – eye lids  IV Trochlear – eye muscles  V Trigeminal nerve – sensory for face chewing muscles  VI Abducens nerve – eye muscles  VII Facial nerve – taste; face muscles  VIII Vestibulocochlear nerve – Balance and hearing

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  IX Glossopharyngeal nerve – taste; pharynx  X Vagus nerves – pharynx, larynx, and viscera  XI Accessory nerve – muscles of neck/upper back  XII Hypoglossal nerve – muscles of tongue Cranial Nerves (Don’t Write Down! In Ex.14)

Cranial Nerves

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structure of a Nerve  Endoneurium  Perineurium  Around fascicles  Epineurium Figure 7.20

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Anatomy of Spinal Nerves Figure 7.22b

Spinal Nerve Structure Spinal nerves branch out of the spinal cord. Spinal nerves branch out of the spinal cord. Dorsal root carries sensory information to CNS(afferent) Dorsal root carries sensory information to CNS(afferent) Ventral root carries motor information to effectors(efferent) Ventral root carries motor information to effectors(efferent) Ramus is a initial large branching of spinal nerve Ramus is a initial large branching of spinal nerve Plexus is network of nerves that come together to innervate specific regions Plexus is network of nerves that come together to innervate specific regions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Spinal Cord Anatomy  White matter - conduction tracts  Gray matter - cell bodies  Central canal: cerebrospinal fluid Figure 7.19

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Spinal Cord Anatomy Figure 7.19

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Spinal Cord Anatomy  Membrane covered  Nerves at each vertebrae (PNS)  Dorsal/ventral root

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 5 Sections  Cervical  Thoracic  Lumbar  Sacral  Coccygeal

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Sections of Spinal Cord

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Spinal Cord Nerves SectionFunction# of Nerves Cervical Innervate back of head, upper back, neck 8 Thoracic Innervate trunk and parts of arms 12 Lumbar Innervate lower abdomen and anterior legs 5 Sacral Innervate posterior legs, buttocks 5 CoccygealInnervate anal sphinctor1

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings How do I remember how many nerves are in each section?  Meal Times!  Breakfast at 8 AM = Cervical 8 nerves  Lunch at 12 PM = Thoracic 12 nerves  Dinner at 5 PM = Lumbar 5 nerves  Dessert at 5PM = Sacral 5 nerves  Late Night Snack at 1 AM = Coccygeal 1 nerve

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Spinal Nerves Figure 7.22a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

C1 does not take part in dermatomal distribution as it is busy with the spinal accessory nerve (11 th cranial nerve).

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Examples of Nerve Distribution Figure 7.23

Disorders of PNS Shingles(herpes zoster) is a viral infection usually caused by the varicella virus(chicken pox) It usually affects on dermatome It usually affects on dermatome Dermatome is a specific region of skin innervated by a given spinal nerve Dermatome is a specific region of skin innervated by a given spinal nerve Mytome is specific muscle group innervated by one spinal nerve Mytome is specific muscle group innervated by one spinal nerve

Disorders of PNS Sciatica Causes severe pain in the leg caused by compression, irritation, or inflammation of the sciatic nerves, which are thick nerves extending down the back of each leg. Causes severe pain in the leg caused by compression, irritation, or inflammation of the sciatic nerves, which are thick nerves extending down the back of each leg.

Disorders of PNS Neurofibromatosis Tumors start in the schwann cells of the peripheral nervous sys Tumors start in the schwann cells of the peripheral nervous sys Tumors can be mild(Cafe Au Lait) spots or disfiguring tumors Tumors can be mild(Cafe Au Lait) spots or disfiguring tumors