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SystemNervousT- 1-855-694-8886Email- info@iTutor.comBy iTutor.com
The Nervous System The nervous system is very important in helpingto maintain the homeostasis (balance) of thehuman body. A series of sensory receptors work with thenervous system to provide information aboutchanges in both the internal and externalenvironments. The human nervous system is a complex ofinterconnected systems in which larger systemsare comprised of smaller subsystems each ofwhich have specific structures with specificfunctions.© iTutor. 2000-2013. All Rights Reserved
Structure and functionNeurons (nerve cells) are the basic elements of the nervoussystem.Soma(Cell Body)DendritesAxon Terminal end fibersNucleus© iTutor. 2000-2013. All Rights Reserved
NeuronsCell BodyThe main processing center of the cell.DendritesThin branching extensions of the cell body that conduct nerveimpulses toward the cell body.AxonA single branch (in most neurons) which conducts nerve impulsesaway from the cell body.Myelin sheath and neurilemma are coverings.© iTutor. 2000-2013. All Rights ReservedNeuronsImpulse TransmissionTerminal end fibers are located at the ends of the axon and theytransmit impulses leaving the neuron across a synapse to thenext neuron.
NeuronANeuronBNeurotransmitterSynapseAll neurons have two basic propertiesExcitabilityconductivity© iTutor. 2000-2013. All Rights ReservedThree Types of NeuronsEfferent (motor) Conveys information from the CNS to muscles and glands.Afferent (sensory)Carry information from sensory receptors to the CNS.InterneuronCarry and process sensory information.
Types of NeuronsDendriteAxonAxonAxonCell BodyCell BodyCell Body(i) Efferent (motor) neuron(ii) Afferent (sensory) neuron(iii) InterneuronNeurofilbril NodeReceptorcellMyelin sheath© iTutor. 2000-2013. All Rights Reserved
Neuroglia Support, protect, connect and remove debris from thenervous system Types of Neuroglial CellsAstrocytes Oligodendroglia Microglia© iTutor. 2000-2013. All Rights Reserved
Nervous System All bodily activities, voluntary andinvoluntary, are controlled by the nervoussystem. Two Major Components– Central Nervous System (CNS)• Made up of the brain and spinal cord– Peripheral Nervous System (PNS)• Made up of all the nerves that leadinto and out of the CNS.© iTutor. 2000-2013. All Rights Reserved
Central Nervous System The central nervous system is composed of two majorinterconnected organs:– The brain– The spinal cord. These organs work together to integrate and coordinatesensory and motor information for the purpose ofcontrolling the various tissues, organs, and organsystems of the body. The central nervous system is responsible for higherneural functions, such as memory, learning, and emotion.© iTutor. 2000-2013. All Rights Reserved
Brain Weighs about 3 pounds in adults 75% water 20% of oxygen Contains over 100 billion neurons Controls bodily functions and interactions with the outside world© iTutor. 2000-2013. All Rights ReservedFour Parts: Cerebrum Diencephalons Brain stem Cerebellum
BrainstemMade up of the midbrain; Pons and the medulla oblongata.Midbrain : Involved with visual reflexesPons:• Located between the midbrain and the medulla oblongata• Controls certain respiratory functionsMedulla Oblongata:• Contains centers that regulate heart and lungfunctioning, swallowing, coughing, vomiting and sneezing© iTutor. 2000-2013. All Rights ReservedCerebellumArea that coordinates musculoskeletal movement tomaintain posture, balance, and muscle tone.Inferior to the occipitallobes of the cerebrum.Posterior to the pons andmedulla oblongata .Cerebellum
Cerebrum Located above the cerebellum. Contains two hemispheres with an outer portion called thecerebral cortex. The two hemispheres are connected by a bridge of nerve fibersthat relay information between the two hemispheres called thecorpus callosum. The left and right lobes are each divided into four lobes or partsparietal lobe• Frontal lobe• Temporal lobe• Occipital lobeDiencephalon: The deep portion of the brain containing:• Thalamus• Hypothalamus• Epithalamus• Ventral thalamus© iTutor. 2000-2013. All Rights Reserved
Serves as relay center for sensations like:Heart rateBlood pressureTemperature control© iTutor. 2000-2013. All Rights ReservedBehavioral responsesDigestive functionsWater and electrolyte balance
Spinal CordExtends from the medulla oblongata of the brain to thearea around the first lumbar vertebra in the lower back.Nerves from the peripheral nervous system extend outfrom the spinal cord.Protected by: Vertebral columnMeninges are three layers of membranes that cover thebrain and spinal cord.© iTutor. 2000-2013. All Rights ReservedLayers of the meningesDura materOuter tough fibrous membrane.Arachnoid materMiddle weblike membrane containing CSF.Pia materInnermost layer containing several blood vessels. Cerebrospinal fluid Meninges
Central Nervous SystemBrainSpinal Cord© iTutor. 2000-2013. All Rights Reserved
Peripheral Nervous System The peripheral nervous system (PNS) is a collection ofperipheral nerves, ganglia and specialized sensorystructures that, as a system, carries sensory and motorinformation between the central nervous system and all otherorgans and tissues of the body. The peripheral nervous system is functionally divided intotwo major divisions:– The Sensory or Afferent Division– The Motor or Efferent Division• The Somatic Nervous System• The Autonomic (Visceral) Nervous System.Spinal CordPeripheral nerves
Peripheral Nervous SystemConsists of 12 pairs of cranial nerves and 31 pairs of spinalnervesS.No Cranial Nerves Function1 Olfactory Sense of smell2 Optic Sense of vision3 Oculomotor Eye movements4 Trochlear Aids muscles that move the eyes5 TrigeminalEyes, tear glands,scalp, forehead, teeth,gums, lips, and mouth muscles6 Abducens Muscle conditioning7 FacialTaste, facial expressions, tear and salivaryglands© iTutor. 2000-2013. All Rights Reserved
S.NoCranial Nerves Function8 Vestibulocochlear Hearing and equilibrium9 GlossopharyngealPharynx, tonsils tongue and carotidarteries; stimulates salivary glands10 VagusSpeech, swallowing, heart muscle,smooth muscle and certain glands11 AccessoryMuscles of the soft palate, pharynx,larynx and neck12 Hypoglossal Tongue movement© iTutor. 2000-2013. All Rights Reserved
© iTutor. 2000-2013. All Rights Reserved
Somatic Nervous System Responsible for receiving and processing sensory input from theskin, muscles, tendons, joints, eyes, tongue, nose and ears aswell as excite the voluntary contraction of skeletal muscles.Autonomic Nervous System Carries impulses from the central nervous system toglands, various smooth muscles, cardiac muscle and variousmembranes. Stimulates organs, glands, and senses.The EndCall us for more Information:1-855-694-8886www.iTutor.comVisit
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