Anatomy and Physiology, Nervous System PDF

ANATOMY and PHYSIOLOGY, NERVOUS SYSTEM LECTURER: G. CLYDE E. REBADULLA OD.,MD.,RN.,RM  NERVOUS SYSTEM Functions: 1. Communications between region of the body 2. Coordination of body functions 3. Orientation to environment 4. Assimilation NEURON – the basic functional u...

ANATOMY and PHYSIOLOGY, NERVOUS SYSTEM LECTURER: G. CLYDE E. REBADULLA OD.,MD.,RN.,RM  NERVOUS SYSTEM Functions: 1. Communications between region of the body 2. Coordination of body functions 3. Orientation to environment 4. Assimilation NEURON – the basic functional unit of the nervous system  NEUROGLIA AND Glial cells 1. help increase the neuron transmission, 2. provide nutrients to the neuron, 3. affect synapse 4. protect the neuron. Central nervous system a. Brain b. Spinal cords  Peripheral Nervous system A.spinal nerves B.Somatic nerves C.Dorsal root ganglia D.Cranial nerves Peripheral Nervous system Afferent or sensory division= conduct impulses to the CNS Efferent or Motor division= conduct impulses from the brain to the different parts of the body. SUB UNITS ; SOMATIC MOTOR N.S = receives impulse from the brain and innervaqte the muscles.  AUTONOMIC NERVOUS SYSTEM = innervates glands , smooth muscles , cardiac muscles and organs. Centers in the Brain for ANS ; ( subconscious directions ) Midbrain Pons medulla oblongata spinal cord  THE NEURON or nerve cell functional unit of the nervous system Dendrites – receive neural messages & transmits towards cell body/nucleus. Axon – transmits neural messages away from cell body. Axon - myelinated vs unmyelinated - nodes of Ranvier - synaptic knob/ presynaptic terminal - synapse  Nerve Body or Soma - Parts of the nerve Cells 1. Neuroplasm - cytoplasm of the nueron 2. Nissl Bodies – the endoplasmic reticulum of the nerve cell. 3. Nucleus – AXON HILLOCK – triangular region of the nerve cell body that is devoid of nissl bodies.  Mechanism for Nerve Impulse Conduction intracellular vs extracellular ions ↓ (+) stimulus ↓ change in the permeability of cell membrane ↓ influx of Na ion ↓ depolarization = action potential/ impulse ↓ synapse - to neuron to muscle/ gland  Parts of a Nerve Cell 1. cell body - has nucleus & cytoplasm 2. dendrites - small processes extending from the cell body 3. axon - long process extending from the cell body to another neuron or end organ  Function s of the neurons; 1. SENSORY OR Efferent = conducts impulses to the CNS 2. Motor or EFFEERENT = conducts impulses away from the CNS 3. ASSOCIATION OR INERNEURONS = located between sensory and motor and also transmitts impulses to the brain for processing.  Classification of Neurons based on synaps 1. MULTIPOLAR NEURONS - with single nerve cell and axons - with multiple dendrites. - majority of neurotransmitter are of this type 2. BIPOPLAR NEURONS - nerve cell bodies has two poles - has axon on one pole and a dendrite on on other pole = for vision and smell 3. UNIPOLAR OR PSEUDO UNIPOLAR - a single body with a single process attached to it - most common nerves of the body are unipolar - example is the ulnar nerve. SYNAPSE : - a space between the neurons - area of communication between neurons containing chemicals for neurotransmission. NEUROTRANSMITTERS – chemicals in the synapse NEUROGLIA OR GLIAL CELLS SWANN cell or Neurolemmocyte - these cells wrap around the axons leaving small gaps between successive cells called the Nodes of Ranvier. Myelin = these are lipoproteins which are the main component of neurolemmocyte. MYELIN SHEATH = a series of Myelin. Note ; Myelinated nerve fibers appears white that’s why its called white matter. Nmyelinated nerve fibers are called gray matter. Nodes of Ranvier : allows the nerve transmission from node to node increasing the transmission speed of the neuron. Saltatory conduction - jumping transmission in the nodes of ranvier.  Neuroglial Cells - provide support, nourishment and protection to neurons CELL TYPE: DESCRIPTION FUNCTION: ASTROCYTES Star-shaped Provide structural support; form a layer around blood vessels, contribute to BBB EPENDYMAL Squamous Line ventricles of brain, CELLS epithelial-like circulate CSF; some form choroids plexuses, part of BBB MICROGLIAL Small mobile Protect CNS from infection; CELLS cells become phagocytic in response to inflammation OLIGODENDRO Cells with Cell processes form myelin CYTES processes that sheaths around axons, or can surround enclose unmyelinated axons, several axons in the CNS SCHWANN Single cells Form myelin sheaths around CELLS surrounding axons, or enclose axons unmyelinated axons in the PNS  BRAIN AND SPINAL NERVES Lecturer : G. CLYDE E. Rebadulla OD.,MD.,RN.,RM  BRAIN : 1.4 kilograms  Procencephalon : Forebrain : 1. Cerebral hemisphere 2. Diencephalon Mesencephalon : Mid brain Rhombencephalon : Hind brain : 1. Pons 2. Medulla Oblongata 3. Cerebellum  Central Nervous System (CNS) A. BRAIN I. Cerebrum - L and R hemispheres - processing center for though, language, memory, sensory information & mvmnt - has 5 regions/lobes: 1. frontal lobe > for complex mental processes (speech thought, learning, emotion, mvmnt, judgement, reasoning 2. temporal lobe > for speech, auditory center 3. parietal lobe > for interpretation of bodily sensations 4. occipital lobe > for 1° visual center 5. limbic lobe > for emotion, learning, memory  Meninges DURA MATER - tough and fibrous membrane -Thickest ARACHNOID MATER -delicate membrane PIA MATER - very tightly bound brain and spinal cord - vascular membrane EPIDURAL SPACE SUBDURAL SPACE SUBARACHNOID SPACE Ventricles of the brain From the neural tube Lateral ventricle : Occupies each of the hemispheres  Choroid plexus : secretes the CSF Small areas in the superior portion of the ventricles  Ventricles and Cerebrospinal Fluid Circulation (CSF) - ventricles ▪ 4 fluid filled cavities that connect w/ 1 another & w/ the the spinal canal ▪ contain choroid plexus CSF analysis - cerebrospinal fluid (CSF) appearance colorless, clear - analysis of CSF composition & pressure 50-180mmHg pressure for diagnostic purposes protein 15-50mg/dl RBC negative WBC 0-5 glucose 50-80mg/dl  CSF : provides cushion and buoyancy to the brain. CSF in the lateral ventricles Foramina of Monroe Third ventricle ( located in the thalamus ) by cerebral aqueduct ( aqueduct of sylvius ) Fourth ventricle Central canal Spinal cord CSF  CSF : 150 ml goes to the dura matter, to the venous sinuses, and the fluid goes to the cardiovascular system thru the internal Jugular vein. CSF Circulation FOREBRAIN CEREBRUM Convolutions : Folds and ridges in the cerebrum Gyri = ridges Sulci = Depressions : Fissures LOBES : Frontal Parietal Occipital Temnporal  Lateral Fissure : Separates the temporal lobe from the frontal and Parietal lobes of the brain. Frontal Lobe : Central sulcus : responsible for higher functions = Intellect Abstract reasoning Creativity Social awareness Language BROCCA’S area : Motor speech Area = responsible for speech formation Precentral Gyrus Primary Motor Cortex : This cortex is important for directing a part of the body to move. Motor Homunculus : Construct s the image of the body on the brain and produces the image of the person.  PARIETAL LOBE : Post Central Gyrus or Primary sensory cortex - Receives sensory information from the body. - Pinpoints the sensory part of the body that is affected. - Sensory Homunculus - ASSOCIATION AREAS : Interprets the sensation - Pain, cold and etc. WERNICKE’S area : responsible for Language development. ; for Written and spoken Language and coherent sentences.  OCCIPITAL LOBE : = responsible for Vision = Shapes, color, Distant vision, and recollection of past visual images. Transverse Fissure : Separates the area between the occipital lobe and the cerebellum.  TEMPORAL LOBE: - Contains the Primary Auditory Cortex : - Interprets hearing, interpretes the nature of sound, location, rhythm and distance. - Translate words into thoughts - Also contains 1. Olfactory center : smell 2. Gustatory center : taste. INSULA - a small mass of cortical material in the temporal lobe.  CEREBRAL HEMESPHERES Longitudinal fissure = Separates the 2 brain hemispheres LEFT Cerebral : involves in Language and reasoning RIGHT : For space, pattern, Perception artistic awareness, imagination and music Comprehension. Cerebral Dominance : also known as Cerebral Symmetry. Especialization of cerebral hemispheres to different tasks.  FOREBRAIN - Pituitary gland - Optic chiasm – transmits visual impulses from the optic nerve to the brain - Mammillary bodies : two small process posterior to the pituitary which function for olfactory reflexes  HIND BRAIN CEREBellum - PONS = relay center for information - Medulla Oblongata = Connects the brain to the spinal cord  FOREBRAIN : Corpus callosum = C – shaped structure that connects the cerebral hemispheres. Genu ; Anterior portion Splenium : Posterior portion  Septum Pellucidum : separates the two lateral ventricles  III. Brainstem 1. midbrain - reticular activating system (RAS) - relay station for auditory & visual information - control of body movement 2. pons - cardiac acceleration & vasoconstriction centers 3. medulla - cardiac slowing, respiratory, vomiting, vasomotor, swallowing centers  IV. Cerebellum - receives info from muscles, joints and tendons - coordinates voluntary movement and maintains trunk stability & equilibrium  Diencephalon : consist of Thalamus Hypothalamus Thalamus : Relay center that receives all the sensory information from the body and serves and sends it to the cerebral cortex. HYPOTHALAMUS : directs some parts of ANS : Involved in the endocrine function of the Pituitary gland. = center for water balance, thirst, pleasure hunger, sleep pattern, Temperature regulation sexual desire, rage, aggression.  II. Diencephalon 1. thalamus - major relay center/ “central switchboard” 2. hypothalamus - regulates endocrine (e.g. hormonal activity) autonomic functions (e.g. stress response, appetite, body tempfluid balance, emotions) PINEAL GLAND = located in the thalamus = endocrine glands that secretes Melatonin = A hormone that regulates daily rhythm  MID brain : is a small area posterior to the diencepahlon Cerebral peduncles : occupies an area superior to the pons. Cerebral Aquiduct : a canal that passes through the midbrain. Corpora Quadrigemina : Consist of : Superior Colliculi : For Visual Reflexes Inferior Colliculi. Substancia Nigra : Causes Parkinsons disease if not functioning Properly.,  HIND BRAIN : consist : a. PONS : Anterior : relay center : Respiratory Center b. Medulla oblongata : Center for Respiration BP Control Area of transfer of information from right to left hemispheres. terminates in the Foramen magnum and continue as a cervical region of the spinal cord. c. Cerebellum : For maintenance of Posture For Balance. Muscle Coordination.  Cerebellum ; Consist of : Outer cerebellar cortex : Inner Arbor Vitae ( White Matter ) FOURTH Ventricle : Triangular space anterior to the cerebellum. BRAIN Consist of Gray Matter : Myelinated. This forms the cerebral cortex. Cerbral cortex : area for active integrative process - Located in the superficial region of the brain - Main metabolic area - Thinking Area of the brain.  WHITE matter : Unmyelibnated. - Consists of tracts that take information from one region of the brain to the cerebral cortex for processing ant integration. - Brings the sensory information from the spinal cord to the cortex o r back from the cor4tex to the spinal cord..  BASAL NUCLEI - deep islands of gray matter in the brain. - involved in the subconcious process ex. Swinging of the arms while walking. - - also for regulation of Muscle tone  LIMBIC SYSTEM : - involved in formation of mood, emotions, memory, - center for feeding, sexual desire, fear and satisfaction.  Cranial Nerves - 12 pairs  Peripheral Nervous System (PNS) A. Cranial nerves - 12 paired nerves that exit the cranial cavity - cranial nerve: * Oh Oh Oh To Touch And Feel Very Good Velvet Ah Heaven. * Some Say Marry Money But My Brother Says Big Business Makes Money 1.OLFACTORY – Nose smell Sensory S 2. OPTIC - eyes Vision Sensory S 3. OCULOMOTOR Eyes All eye muscles M Except those supplied by CN. 4 & 6 Ciliary and Iris Sphincter 4. THROCHLEAR Eyes Superior Oblique M 6. ABDUCENS Eye lateral rectus M 5. TRIGEMINAL B Sensory to Face, Nose, sinuses Motor : To Muscles for mastication 7. FACIAL Face Muscles of the face B Nervus Intermedius Motor for :Submaxillart, Sublingual, Lacrimal gland Sensory: Anterior part of the tongue Soft Palate 8.VESTIBULOCOCHLEAR S Ears Hearing and Balance 9. GLOSSOPHARYNGEAL B Sensory : Posterior part of the toungue, Tonsils, Pharynx, Middle Ear Motor : Stylopharyngeus Pharyngeal musculature 10. VAGUS B Motor: Pharynx, Heart, Lungs,Bronchi, GI Tract Sensory : Heart, Lung, Bronchi, Trachea Larynx, Pharynx. GI Tract, External Ear 11. ACCESSORY M Sternocliedomastoid, Trapezius 12. HYPOGLOSSAL M Tongue Musculature PERIPHERAL AND CENTRAL NERVOUS SYSTEM  Nervous system -Divisions of the Nervous System: - CNS -PNS ▪ brain ▪ nerves & ganglia ▪ spinal cord >sensory division >motor division - Somatic Motor Nervous System - Autonomic Nervous System > Sympathetic Nervous System > Parasympathetic Nervous System Organization of Nervous Tissue - CNS - PNS ▪ cortex & nuclei ▪ ganglia ▪ pathway or tracts ▪ nerves  Nervous System Cells A. Neuron - basic unit of the nervous system - characteristics: 1. ability to generate nerve impulse 2. transmit impulse w/in the cells 3. transmit impulse to other cells  SPINAL CORD = major communication link between the brain and PNS. = Integration of stimulus and \response = from the foramen magnum to the level L1 and L2. =31 pairs  B. Spinal Nerves - 31 paired nerves that exit the spinal cord - each nerve has ventral (anterior) and dorsal (posterior) branch  Enlagrerments CERVICAL ENLARGEMANT = supplies the upper limbs ( T3 to T2 ) LUMBOSACRAL ENLARGEMENTS = Supplies the lower limbs. ( T 7 to T11 ) CONUS MEDULLARIS = tapered end of SC to form a conelike regions at L2  FILUM TERMINALE - a thin thread like connective tissue that attaches the Sc to the coccyx  CAUDA EQUINA = the end\ part of the SC that resembles a horse tail. - parallel cluster of nerves  Cross section of the spinal cord GRAY MATTER - H shaped or butterfly WHITE Matter – located on the periphery  Gray Matter - two NARROW HORNS ( posterior horns) for SENSORY information from the somatic nerves - Two rounded horns sends MOTOR signals to the spinal nerves Lateral horns = additional section of the gray matter.  Gray commissure = connection on each side of the gray matter. CENTRAL CANAL = runs the length of the spinal cord.  WHITE Matter – located on the periphery Tracts or Fasciculi ASCENDING TRACTS = takes sensory information to the brain DESCENDINF TRACTS = receive MOTOR information from the brain  COLUMNS = bundles of tracts in larger units Posterior median sulcus depression in the posterior surface of the spinal cord Anterior Median Fissure = deeper depression the anterior side of the spinal cord.  Spinal Cord - anatomically: from C1 – L2 - functionally: carries sensory and motor info. : involuntary response to pain - x-section: gray matter : white matter - dermatome: area of skin innervated by the sensory fibers of a single dorsal root of a spinal nerve B. Spinal Cord – Ascending Tracts B. Spinal Cord – Descending Tracts  Meninges of the Spinal Cord - DURA MATTER = superficial Thecal sac = the membrane that covers or sorrounds the spinal cord. EPIDURAL SPACE = the space that separates the spinal cord from the periosteum = area for epidural anesthesia  Meninges DURA MATER - tough and fibrous membrane -Thickest ARACHNOID MATER -delicate membrane PIA MATER - very tightly bound brain and spinal cord - vascular membrane EPIDURAL SPACE SUBDURAL SPACE SUBARACHNOID SPACE  ARACHNOID SPACE - the thin spiderlike, cobweb like membrane Subdural space – space between the Dura and arachnoid PIA matter – third deepest layer. Subarachnoid space the space between the archnoid and Pia matter.  Subarachnoid - contains blood vessels and CSF.  NERVES: Parallel neuron fibers that carry information from one area to to onother. Nerve wrappings : -ENDONEURON wraps a single nerve fibers. PERINEURON - the sheath that wrps around groups of nerve fibers. EPINEURON - the wrapping that that covers the entire nerve. SPINAL NERVES AND PLEXUSES Periphery >> Dorsal ramus ( S and M ) >> Ventral ramus >> NERVE.. SPINAL NERVE = Location : Intervertebral foramen Divisiosn ; Dorsal Root gangleon ( Sensory nerves) ventral root Gangleon ( Motor nerves )  Spinal merves 31 pairs Exists from the spinal cord. Mixed nerves ( S and M ) –8 cervical –12 thoracic –5 lumbar –5 sacral –1 coccygeal  PLEXUSES - Brancing network of spinal nerves. CERVICAL PLEXUS - from upper spinal nerves of the neck - Phrenic nerve - stimulates diaghragm - for breathing - for muscles and skin of the neck and skin and ears. ( pinch clients ears for sensory ) Brachial Plexus = C5 to T 1 - innervates the upper extremities - AXILLary NERVE the major nerve for upper shoulders RADIAL nerve : for the extensors of the hand Musculocutaneos nerve - extensors of the hand Ulnar nerve – flexors of hand muscles Median nerve - hand and fprearm flexors BRACHIAL PLEXUS THORACIC NERVES - Exits through the foramina of the vertebral column - for ribs, muscles and the thoracic wall.  Lumbar and Sacral plexus LUmbosacral plexus) - For the lower limbs EXAMPLE : OBTURATOR nerves - Innervates the adductor muscle of the thigh. Pinch your medial thigh FEMORAL nerve ; Innervates the muscle of the anterior thigh Pinch your anterior thigh  Nerves innervating the leg and foot Tibial nerve Common fibular ( peroneal nerve ) SCIATIC NERVE TEST ; pinch the posterior aspect of the thigh,