Conduct impulses necessary for sensations and voluntary movements.
A dermatome is an area of skin that is mainly supplied by a single spinal nerve.A dermatome is an area of skin supplied by sensory neurons that arise from a spinal nerve ganglion. Symptoms that follow a dermatome (e.g. like pain or a rash) may indicate a pathology that involves the related nerve root. Examples include somatic dysfunction of the spine or viral infection. Referred painusually involves a specific, "referred" location so is not associated with a dermatome.Viruses that hibernate in nerve ganglia (e.g. Herpes zoster or Varicella Zoster viridae) often cause either pain, rash or both in a pattern defined by a dermatome. However, the symptoms may not appear across the entire dermatome.
Medial rectus, Inferior rectus, Superior rectus, Inferior Oblique
Sciatica – a form of neuritis caused by a painful inflammation of the spinal nerve branch in the thigh called the sciatic nerve. Characterized by nerve pain or neuralgia.
Also called tic douloureuxCharacterized by recurring episodes of:Stabbing pain radiating from the angle of the jaw along a branch of the trigeminal nerve.Nerve pain of one branch occurs over the forehead and around the eyes.Pain along another branch is felt in the cheeck, nose, and upper lip.Neuralgia of the third branch results in stabbing pains in the tongue and lower lip.
Characterized by paralysis of some or all of the facial features innervated by the facial nerve, including the eyelids and mouth.Often temporary but in some cases is irreversible. Treatment: plastic surgery
Varicella Zoster VirusThe virus travels through a cutaneous nerve and remains dormant in a dorsal root ganglion for years after an episode of the chickenpox.After immune system is depressed, the virus travels over the sensory nerve to the skin of a single dermatome.Resulting to:Painful eruption of red, swollen plaques or vesicles that eventually rupture and crust before clearing in 2-3 weeks.In severe cases, extensive inflammation, hemorrhagic blisters, and secondary bacterial infection may lead to permanent scarring.In most cases, the eruption of vesicles is preceded by 4-5 days of pre-eruptive pain, burning, and itching in the affected dermatome.Usually affects a single dermatome, producing characteristic painful plaques or vesicles.Photograph of a 13 y/o boy with eruptions involving dermatome T4.
The ANS consists of parts of the nervous system that regulate involuntary function.On the other hand, motor nerves that control the voluntary actions of skeletal muscles are called the Somatic Nervous System.
Dendrites and cell bodies of some autonomic neurons are locate in the gray matter of the spinal cord or brainstem.Their axons extend from these structures and terminate in peripheral “junction boxes” called ganglia.Visceral/Autonomic Effectors – are the tissues to which autonomic neurons conduct impulses.Cardiac muscleSmooth Muscles of blood vessels and other hollow organsGlandular Epithelial tissues – secreting part of glands
Conduction paths to visceral and somatic effectors from the CNS (spinal cord or brainstem) differ somewhat.Autonomic paths to visceral effectors consist of two-neuron relays. Impulses travel over preganglionic neurons from the spinal cord or brainstem to autonomic ganglia. There they are relayed across synapses to postganglionic neurons, which then conduct impulses from the ganglia to visceral effectors.Somatic motor neurons conduct all the way from the spinal cord or brainstem to somatic effectors with no intervening synapses.
In short, when we must cope of stress of any kind, sympathetic impulses increase to many visceral effectors and rapidly produce widespread changes within our bodies.Heart beats fasterBlood vessels constrictBlood pressure increaseBlood vessels in skeletal muscles dilate. (supplying more blood to the muscles)Sweat glands and adrenal glands secrete more abundantly.Salivary and other digestive glands secrete more sparingly.GUT (peristalsis) become sluggish hampering digestion.All actions make us ready for strenous muscular work, or they prepare us for Fight or Flight.The group of changes induced by sympathetic control is known as the fight or flight response.
The axon of the preganglionic neuron leaves the spinal cord in the anterior (ventral) root of a spinal nerve. It next enters the spinal nerve but soon leaves it to extend to and through sympathetic ganglion and terminate in a collateral ganglion. There it synapses with several postganglionic neurons whose axons extend to terminte to visceral effectors.Notice also that branches of the preganglionic axon may ascend or descend to terminate in ganglia above and below their point of origin. All sympathetic preganglionic axons therefore synapse with many postganglionic neurons, and these frequently terminate in widely separated organs.Therefore sympathetic responsess are usually widespread, involving many organs rather than just one.
Sympathetic ganglia are located in front and at each side of the spinal column. Because short fibers extend between the sympathetic ganglia, they look a little like two chains of beads. (called sympathetic chain ganglia)Axons of sympathetic postganglionic neurons travel in spinal nerves to blood vessels, sweat glands, and arrector hair muscles all over the body.
The image illustrates information regarding autonomic neurotransmitters, the chemical compounds released from the axon terminals of autonomic neurons.Notice that 3 axons on the image release acetylcholine therefore you call them as cholinergic fibers.Only one type of autonomic axon releases the neurotransmitter norepinephrine (noradrenaline) this is the postganglionic neuron. Classified as adrenergic fibers.
They act on one or more adrenergic receptors sites located on the cells of smooth muscles such as the heart, bronchiole walls, gastrointestinal tract, urinary bladder, and ciliary muscle of the eye. There are many adrenergic receptors; the four main receptors are alpha1, alpha2, beta1 and beta2 which mediate major responses.
Pns 3rd meeting
Peripheral Nervous System• Includes nerves connecting the brain and spinal cord to other parts of the body.• Includes Cranial and Spinal Nerves that connect brain and spinal cord, respectively, to peripheral structures such as the skin surface and the skeletal muscles. The Anatomy & Physiology of the nervous system
Spinal Nerves• 31 pairs- contain dendrites of sensory neurons and axons of motor neurons.• Conducts impulses between the spinal and the parts of the body not supplied by the cranial nerves. The Anatomy & Physiology of the nervous system
Dermatomes The Anatomy & Physiology of the nervous system
Cranial Nerves The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN I: OLFACTORY ABNORMALITY:FUNCTION: Hyperosmia – AcutePurely Sensory sense of smellPURPOSE: Parosmia – AbnormalTransmits sense of sense of smellsmell Anosmia – Loss of senseTEST: of smellCoffee Smell The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN II: OPTIC ABNORMALITY:FUNCTION: BlindnesssPurely Sensory Papilledema or chokedPURPOSE: disc – blurred optic discVision during ophthalmoscopyTEST:OphthalmoscopySnellen ChartVisual Field/COnfrontation The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN III: OCULOMOTOR ABNORMALITY:FUNCTION: Tropia – muscleMainly Motor weaknessPURPOSE: Strabismus – cross-eyedPupil constrictionAccomodation (4 eom)TEST:Pupil light reactionEyeball movements The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN IV: TROCHLEAR ABNORMALITY:FUNCTION: Nystagmus –Mainly Motor Rapid, involuntaryPURPOSE: irregular movement ofInnervates SOM of the the eyeballseyeball, looking to the Tropias – weakness ofumbilicus area (turns eye EOM’sdown and laterallyTEST:Extraocular movement The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN V: TRIGEMINAL ABNORMALITY:FUNCTION: Trigeminal Neuralgia –Mixed neuropathic disorder ofPURPOSE: 1 or both trigeminalMasticate (motor) nervesFacial SensationCorneal ReflexTEST:Assess temporal/masseter musclestrength, test the corneal reflex, andsensation of pain, temp., & touch on The Anatomy & Physiology of the nervous systemface
The 12 Cranial NervesCN VI: ABDUCENS ABNORMALITY:FUNCTION: Diplopia – double visionMainly MotorPURPOSE:Innervates the lateral rectusmuscles, to the ear directionTEST:Extraocular movement The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN VII: FACIAL NERVE ABNORMALITY:FUNCTION:Mixed Bells palsy – paralysis of the muscles of facialPURPOSE:Facial Expression, salivation & expression and inabilitytearing, Tasting in the anterior 2/3 of to binl eyelidsthe tongueSensation in the earTEST:Tearing: ammonia fumesFacial ReactionsTest ability to taste sweet, salty, sour &bitter substances. The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN VIII: ACOUSTIC ABNORMALITY:FUNCTION: Tinnitus – ringing in thePurely Sensory ear/sPURPOSE: Meniere’s disease orHearing and Balance endolyphatic hydropsTEST:Screen hearingWeber’s TestRinne’s Test The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN IX: ABNORMALITY:GLOSSOPHARYNGEAL Loss of Gag ReflexFUNCTION: Dysphagia – Difficulty ofMixed swallowingPURPOSE:Taste in the posterior 1/3 ofthe tongue; swallowing andsalivationTEST:Gag ReflexSwallowing The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN X: VAGUS ABNORMALITY:FUNCTION: DysphagiaMixed Dysphonia– impairmentPURPOSE: of voiceLaryngeal control, inhibitsHR, stimulates peristalsisTEST:VoiceHR The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN XI: ACCESSORY ABNORMALITY:FUNCTION: Difficulty in rotatingMainly Motor head and raisingPURPOSE: shoulder/chin againstMovements of the head and resistanceshrugging of shouldersTEST:Shoulder strengthHead Rotation The Anatomy & Physiology of the nervous system
The 12 Cranial NervesCN XII: HYPOGLOSSAL ABNORMALITY:FUNCTION: Fasciculations – coarseMainly Motor involuntary movementPURPOSE: of the tongueMovement of the tongueTEST:Tongue deviations The Anatomy & Physiology of the nervous system
Peripheral Nerve Disorders Neuritis • damage to nerves of the peripheral nervous system, which may be caused either by diseases of or trauma to the nerve or the side-effects of systemic illness. The Anatomy & Physiology of the nervous system
Peripheral Nerve Disorders Trigeminal Neuralgia • Compression or degeneration of the fifth cranial nerve, the trigeminal nerve. The Anatomy & Physiology of the nervous system
Peripheral Nerve Disorders Bell’s Palsy • Compression, degeneratio n, or infection of the seventh cranial nerve (facial nerve). The Anatomy & Physiology of the nervous system
Peripheral Nerve Disorders Herpes Zoster (Shingles) • Viral infection caused by chickenpox virus that has invaded the dorsal root ganglion and remained dormant until stress or reduced immunity precipitate an episode of shingles. The Anatomy & Physiology of the nervous system
Review of the Major Divisions of theNervous System The Anatomy & Physiology of the nervous system
Autonomic Nervous System• It consists of motor neurons that conduct impulses from the spinal cord or brainstem to the following kinds of tissues: 1. Cardiac muscle tissue 2. Smooth muscle tissue 3. Glandular muscle tissue The Anatomy & Physiology of the nervous system
2 Subdivisions of the ANS1. Sympathetic Nervous System2. Parasympathetic Nervous System The Anatomy & Physiology of the nervous system
Functional Anatomy of the ANS• Autonomic Neurons make up the ANS.• Ganglia- is a biological tissue mass, most commonly a mass of nerve cell bodies. 1. Preganglionic neurons –conduct impulses between the spinal cord and a ganglion. 2. Postganglionic neurons – conduct impulses from a ganglion to a cardiac muscle, smooth muscle, or glandular epithelial tissue. The Anatomy & Physiology of the nervous system
Autonomic Conduction Path The Anatomy & Physiology of the nervous system
The Anatomy & Physiology of the nervous system
Sympathetic Nervous System• Functions as an emergency system of the body. (Fight or Flight Response)• Impulses over sympathetic fibers take control of many internal organs when we exercise strenously and when strong emotions (anger, fear, hate, anxiety) are elicited. The Anatomy & Physiology of the nervous system
Sympathetic Nervous System STRUCTURE • Sympathetic Preganglionic Neurons- dendrites and cell bodies in the gray matter of the thoracic and upper lumbar segments of the spinal cord. The Anatomy & Physiology of the nervous system
Sympathetic Nervous System STRUCTURE • Sympathetic Post ganglionic Neurons- dendrites and cell bodies in sympathetic ganglia. The Anatomy & Physiology of the nervous system
Autonomic Neurotransmitters The Anatomy & Physiology of the nervous system
SNS Neurotransmitters(Postganglionic Neurons-Effectors)• Norepinephrine/Epinephrine• 4 Adrenergic Receptors a) Alpha1 b) Alpha2 c) Beta1 d) Beta2 The Anatomy & Physiology of the nervous system
Effects of Stimulation of Adrenergic Receptors
Effects of Stimulation of Adrenergic Receptors
Sympathetic Responses The Anatomy & Physiology of the nervous system