Human Anatomy and Physiology I - Nervous System Organization PDF

6/28/20 Biology 223 Human Anatomy and Physiology I Nervous System Organization Chapter 13 General organizations of the nervous system Gross Anatomy of the spinal cord Chapter 14 Organiz...

6/28/20 Biology 223 Human Anatomy and Physiology I Nervous System Organization Chapter 13 General organizations of the nervous system Gross Anatomy of the spinal cord Chapter 14 Organization of the brain Protection and support of the brain 1 Nervous System General functions - 3 types Sensory function Receives incoming information (stimuli) from sensory F: receptors Integrative function - CNS Interprets and processes information to determine Fi appropriate response Effector function Produces outgoing signals to initiate a response in muscles Fi (skeletal, smooth, cardiac) or glands 2 m CNS info processing integrates , processes , coordinates > - sensory inputB motor commands PNS PNS afferent +o a CNs efferent CNS + C I * - SN special Sensory Receptors visceral somatic A monitor smell , monitor internal Munitar Skeletal faste visim oryons muscles joints S g , , , bulance hearing 3 , skin surfaces , · parasym Symp Effectors ? Skeletal muscle SmoothMea D adipose tissue ⑭ 1  6/28/20 Figure 1.2 4 Organization of the Nervous system Two primary subdivision I CNS (Central Nervous system) Brain and spinal cord I PNS (Peripheral Nervous system) Neural tissue outside CNS 5 CNS and PNS Figure 13.9 Figure 13–9 6 2  6/28/20 CNS (Central Nervous system) Brain and spinal cord Contained within skull and vertebral -- column Integrative in function Simple reflexes Complex reflexes Higher order functions Memory, learning, intelligence 7 Fig. 14-18 8 Cerebral hemisphere Half head Diencephalon Midbrain Cerebellum Pons Medulla Spinal Cord Atlas page 17 9 3  6/28/20 MRI scan of brain Atlas, page 17 10 f PNS (Peripheral Nervous system) -S terms T Neural tissue outside CNS Mostly outside of skull & vertebral column · Peripheral nerves outside t Cranial nerves and Spinal nerves - all bodies Peripheral ganglia CNS Sensory ganglia Autonomic nervous system ganglia (sympathetic, parasympathetic) Sensory organs of vision, hearing, etc. ganglion 11 Cluster of cell bodies outside CNS Peripheral Nerves ascending F: Afferent division brings sensory information = from receptors F Efferent division carries motor commands to : = effectors Somatic nervous system to skeletal muscles Autonomic nervous system to cardiac muscle, smooth muscle, glands & Sympathetic Parasympathetic 12 4  6/28/20 excitable rem lack Centrioles , , highly metabolic white Matter gray mutter = = - cell bodies axons Functional Organization PN3 : ganglia = Collection of Newon all bodies nerves = Dundles of Mons gray Mutter CNS : Neural Cortex giay Mutter in brin surface = collections of mun all bodies (enterhaatucta)) * Centers · = Nuclei Collections of newon all bodies inside CNs = higher Centers most complex centers in brain = white matter 15 Pathways = Centers I track that connect tracts = bundles of axuns that share commun origin a destination wy other ↑ the bruin organs $ columns several tracks that form an : mnatomically distinct muss systems in body 5  6/28/20 min auth Visceral motor neurons = 100 mil = Carries elec controls connections of Smooth & Cordial muscle enteric NC neurons. Signals initiates & cordinates that many complex reflexes in walk of digestine tract 16 Functional Organization of the Nervous System Collection of nerve cell processes (fibers) for Fi transmission of information PNS – nerve CNS – white matter, fiber tract, column, Collection of nerve cell bodies for processing of F : information PNS – ganglin CNS – grey matter, nucleus, cortex Neuroglial cells surround and support both nerve cell bodies - and processes 17 Anatomy of the Adult dendrite = primarily receives communication Spinal Cord Somatic NS = Controls Skeletal muscle contractions extrreceptors outside/external - sensory multipolar newrns = a newon hy at dendries/all Motor neunus Figure 13.2 18 6  6/28/20 Grey matter of spinal cord (processing and integration) ↓ Posterior (dorsal) gray horns contains somatic and visceral sensory nuclei Anterior (ventral) gray horns deal with somatic motor control Lateral gray horns contain visceral (ANS) motor neurons Size of grey matter ( # of nerve cells ) related to size of body area innervated Cervical and lumbar enlargements 19 White matter of spinal cord (transmission of information) Divided into 0- six columns (funiculi) containing tracts Posterior, anterior, lateral columns app Ascending tracts relay information from the spinal cord to the bruin even tracts carry information from the brain to Descending the spinal cord no necron all bodies located in ganglion 20 Adult spinal cord dorsal (post) > - Sensory (offerent A single continuous structure ventral (ant). > - motor (efferent ( 31 spinal cord “segments”: defined by spinal nerves (8C, 12T, 5L, 5S, 1Co) dorsal (posterior) root of spinal nerve is (afferent) ventral (anterior) root of spinal nerve is See (efferent) is Spinal nerves are a mixture of sensory & motor fibers Each spinal nerve receives sensory input from one dermatome ↑ region of body 21 7  6/28/20 dwa mater = attached by loned ligument Front of Back of body Dermatomes body Region of skin monitored by the sensory afferents of a single spinal = segment 22 Jenson Neaving enter 3C this dursal roots of spirat Nerve "autonomic" post medium solous mini Figure 13-7a Figure 13.9a 23 Somatic = senses ext. environ $ Controls bodily motions - voluntary activities by sending signals > - walk Vol A. Somatic motor neuron - +. , B. Sensory neuron & > Ur invol C. Autonomic motor neuron - , D. & Neuroglia & E. Interneuron 25 Adult Brain hypothalams & pituitary gland functioning > - of Nervous & endrine medulla going up binster : pans ↑ midbmin choroid plexus = removal of haste 26 gracile necess t Curiate nuclas = relay sensory into to thalamus D Adult brain and brainstem Telencephalon (cerebrum or cerebral hemispheres) * Diencephalon (thalamus & hypothalamus) Mesencephalon (midbrain) Metenchephalon (pons and cerebellum) & Myelencephalon (medulla oblongata) D 27 9  6/28/20 Fig. 14-18 28 29 Grey matter of brainstem and brain (processing and integration) Cortex of cerebral hemispheres Highest level of processing to Not Crtex achometri Basal nuclei of cerebral hemispheres > - control deeper grey Thalamus Mutty Processing sensory information Hypothalamus ANS & control Cortex of Cerebellum Motor control - Various brainstem nuclei 30 10  6/28/20 Brain Functions Figure 14.2 31 White matter of brainstem and brain (transmitting information) etuff E Projection fibers – ascending and descending tracts of the spinal cord, brain stem, and brain - Association fibers – connect between areas on the side of the CNS Commissural fibers – connect between areas on Opposite sides of the CNS - 32 http://www.youtube.com/watch? v=AfDEAIszuQI 33 11  6/28/20 Embryology of the brain Brain and spinal cord tissue neurons and glial cells - - develop from the cells in the walls of of the developing - - hollow neural tube Ventricles of the brain and spinal canal of spinal cord develop from- hollow center of developing neural tube 34 midbrain Puebellur Embryology thalums hypothal redla of the brain Cerebrum , Cerebella cortex 35 36 12  6/28/20 Protection and support of CNS Multiple support and protective systems list - Skull, vertebrae, ligaments, muscles the support 1 meninges protecting Cerebral spinal fluid (CSF) system Blood-brain barrier 37 38 Meninges Specialized connective tissue layers - Dura mater 1 Arachnoid Pia mater Provide physical stability & shock F: absorption Support blood vessels entering and exiting CNS tissue 39 13  6/28/20 Spinal meninges Fi Anchor spinal cord Base - to coccyx via filum terminale and coccygeal [ ligament Top - to periosteum of foramen magnum Laterally - denticulate ligaments Fi Provide cushioning Epidural space with epidural fat separates dura mater from walls of vertebral canal Subarachnoid space is filled with CSF ↑ 40 Cerebrospinal Hud Spinal Cord and Spinal Meninges CSF 41 Anatomy of the Adult Spinal Cord Figure 13.2 42 14  6/28/20 Cranial meninges Continuous with the three layers of the spinal cord Two layers of dura Mater Folds of dura mater help stabilize the position of the brain Falx cerebri, Tentorium cerebelli, Falx cerebelli Contain sinuses that serve as veins Subarachnoid space filled with CSF 43 Cranial Meninges 44 Cerebrospinal fluid (CSF) Produced in the ventricles - Fluid diffuses out of capillaries of the choroid Plexusinto ventricles -Exits ventricles into subarachnoid - space through apertures of 4th ventricle - Circulates through subarchnoid space of spinal and cranial meninges - Exits across the arachnoid granulations into the superior sagittal - sinus (vein) - 45 15  6/28/20 Ventricles and spinal canal 46 47 Cerebrospinal fluid (CSF) Comes from blood , returns to blood (but. not BLOOD. ) ! Transports nutrients, chemical messengers, and waste F products Provides cushioning and buoyancy Blockage of CSF circulation causes pressure in ventricles Enlarging ventricles damage neural tissue Hydrocephalus – “water on the brain” 48 16  6/28/20 Hydrocephalus 49 50 Neuron classification Motor (Efferent) Sensory (Afferent) Interneurons (association neurons)in blu other Located mostly within the CNS Interconnect among nerve cells F Function in processing 51 PLAY From InterActive Physiology CD Nervous system I - Anatomy Review 17  6/28/20 Cells of the Nervous System üNerve cells (neurons) üElectrically active cells that process and - conduct information in the form of F = electrical signals Neuroglia (glial cells) Several kinds of cells Export PNS: Satellite cells, Schwann cells M CNS: oligodendrocytes,M astrocytes,RR microglia, ependymal cells CR 52 reptileput protein ↳ - astrocytes · ↑ nerve Neuroglia g of PNS gunglich · Schwann cells E Figure 12.6 53 Glial Cells (Neuroglia) of the Peripheral Nervous System > regulates Chemical environ Satellite cells -. in Yanglia F Surround neuron cell bodies within ganglia Schwann cells Ensheath axons and dendrites in the PNS Unmyelinated axons– Schwann cell ensheaths sections of many axons , we incomplete (simple) myeline Myelinated axon – Schwann cell ensheaths a Section of a single axon Nodes of Ranvier – gaps between Schwann cells - 54 18  6/28/20 myelinated Figure 12.6 umgelinated , exposed axon VG Nut/k + chrome a , ⑧ el smaller in diameter 55 Neuroglia of CNS & thisa immme like 56 hold cells Glial Cells (Neuroglia) of the CNS Oligodendrocytes Surround myelinated and unmyelinated CNS axons Astrocytes Largest and most numerous Structural support; scar tissue formation Regulate interstitial fluid components blood bruin barrier if nerves die , they fill w scar tissue 57 19  6/28/20 58 biochemically Blood brain barrier Isolates neural tissue from general circulation L Fi Restricts migration of cells & diffusion of molecules out of capillaries of brain Tight junctions between endothelial cells astrocytes cover capillary surfaces Restricts diffusion of CSF out of ventricles F: Tight junctions between ependymal cells incomplete barrier in areas Parts of the hypothalamus, pituitary gland, pineal gland 59 Glial Cells (Neuroglia) of the CNS Microglia F : Phagocytic cells – remove debris, pathogens, etc. by engulfing Ependymal cells Line chambers within CNS Fo Produce est in choroid plexus regions Circulate cerebrospinal fluid 60 20  6/28/20 Ependymal Cells 61 Damage repair mechanisms of the CNS and PNS Damage to nerve cell soma Ú neuron death Few if any germinative cells in adult brain Damage to nerve cell axon in CNS z not good a repairing Oligodendrocytes reabsorb myelin Astrocytes fill in area forming scar tissue Growth inhibiting factors secreted by oligodendrocytes and astrocytes Damage to nerve cell axon in PNS Schwann cell myelin pathway can guide regenerating axons and sensory dendrites 62 63 21  6/28/20 64 65 66 22  6/28/20 Disorders involving peripheral nerves and ganglia zin Herpes – latent infection of sensory neurons in peripheral ganglia Herpes varicella-zoster Chicken pox and shingles Herpes simplex 1 and 2 Hansen’s disease (leprosy) - > bacterial infection 67 23  6/28/20 Disorders involving peripheral nerves and ganglia Herpes – latent infection of sensory neurons in peripheral ganglia Herpes varicella-zoster Chicken pox and shingles Herpes simplex 1 and 2 Hansen’s disease (leprosy) 67 23