Student Gross Anatomy of the Nervous System PDF

INTRODUCTION TO THE NERVOUS SYSTEM DR. JACQUELINE MOBLEY AHS 2202:  TODAY WE WILL LEARN ABOUT THE MAJOR STRUCTURES OF THE CENTRAL NERVOUS SYSTEM BRAIN & SPINAL CORD COVERINGS OF THE SPINAL CORD THE GENERAL THE NERVOUS SYSTEM  INTRO...

INTRODUCTION TO THE NERVOUS SYSTEM DR. JACQUELINE MOBLEY AHS 2202:  TODAY WE WILL LEARN ABOUT THE MAJOR STRUCTURES OF THE CENTRAL NERVOUS SYSTEM BRAIN & SPINAL CORD COVERINGS OF THE SPINAL CORD THE GENERAL THE NERVOUS SYSTEM  INTRODUCTION THE NERVOUS SYSTEM IS THE COMMUNICATION AND CONTROL SYSTEM OF THE BODY RECEIVES INPUT THE OUTSIDE WORLD ALLOWS COMMUNICATION BETWEEN THE CELLS, TISSUES, ORGANS COORDINATES MOVEMENTS “NEUROLOGY” THE STUDY OF THE NERVOUS SYSTEM “NEUROLOGIST” A DOCTOR SPECIALIZING IN NEUROLOGY  NERVOUS SYSTEM FUNCTION ORGANIZATION 1) SENSORY FUNCTIONS 2) INTEGRATING FUNCTIONS 3) MOTOR FUNCTIONS  Nervous system senses a change Information is sent to the brain & spinal NERVOUS cord from peripheral nerves SYSTEM Information is analyzed, stored & SIGNALING integrated to form a response A motor response response instructs the body to do something  NERVOUS SYSTEM ORGANIZATION CENTRAL NERVOUS SYSTEM BRAIN AND SPINAL CORD PERIPHERAL NERVOUS SYSTEM NERVES INCLUDES CRANIAL NERVOUS (THOUGH THEY ORIGINATE FROM THE BRAIN)  HOW DO NERVES SEND SIGNALS? NEURONS ARE THE BASIC FUNCTIONAL UNIT OF THE NERVOUS SYSTEM CELL BODY DENDRITES RECEIVE IMPULSES FROM THE BODY AXONS CONDUCT IMPULSES TO THE BODY AKA “NERVE FIBER” CHEMICAL ARE RELEASED FROM THE ENDS OF AXONS TO BRING ABOUT A CHANGE (USUALLY A MUSCLE MOVEMENT OR GLAND RELEASING CONTENTS) THE CENTRAL NERVOUS SYSTEM (CNS)  BRAIN & SPINAL CORD BRAIN & SPINAL CORD MAKE UP THE CNS GRAY MATTER NEURON CELL BODIES GIVE THE GRAY APPEARANCE WHITE MATTER MYELINATED NERVE FIBERS MYELIN IS THE FATTY COVERING OF NERVE FIBERS (AXONS) 100,000 NERVE FIBERS  THE BRAIN DIVIDED INTO LEFT AND RIGHT HEMISPHERES CEREBRUM AREA OF HIGHER LEARNING & INTELLIGENCE CEREBELLUM COORDINATION OF MOTOR CONTROL DIENCEPHALON PRIMITIVE BRAIN BRAINSTEM PRIMITIVE BRAIN  THE CEREBRUM THE CEREBRUM IS THE LARGEST PART OF THE BRAIN IN DOMESTIC ANIMALS WHAT IS THE CEREBRUM MADE OF? CEREBRAL CORTEX (OUTER LAYER) → GRAY MATTER DEEP TO THE CEREBRAL CORTEX (INNER LAYER) → WHITE MATTER This Photo by Unkn own Auth or is licensed under CC BY-SA INCLUDES THE CORPUS CALLOSUM → MADE OF WHITE MATTER & CONNECTS THE HEMISPHERES  FUNCTIONS OF THE CEREBRUM LEARNING, REASONING, INTELLIGENCE RECEIVES AND INTERPRETS SENSORY INFORMATION CONTROLS CONSCIOUS (VOLUNTARY) NERVE IMPULSES TO SKELETAL MUSCLES INTEGRATES NEURON ACTIVITY ASSOCIATED WITH CONSCIOUS ACTIVITY COMMUNICATION, EXPRESSION OF EMOTIONAL RESPONSES LEARNING, MEMORY, RECALL  CEREBRUM STRUCTURE WRINKLES INCREASE SURFACE AREA GYRUS (GYRI): CEREBRUM FOLD FISSURES: DEEP GROOVES IN THE CEREBRUM SULCUS (SULCI): SHALLOW GROOVES LONGITUDINAL FISSURE: SEPARATES THE BRAIN INTO LEFT & RIGHT HEMISPHERES EACH HEMISPHERE IS SEPARATED INTO LOBES EACH LOBE HAS A DIFFERENT FUNCTION This Photo by Unkn own Auth or is licensed under CC BY-SA  DAMAGE TO THE CEREBRUM DAMAGE CAN OCCUR SECONDARY TO TRAUMA, HYPOXIA, DRUGS, TOXINS, STROKE POSSIBLE CONSEQUENCES SEIZURES DECREASED OR ABSENT VOLUNTARY MOVEMENT MEMORY ISSUES BEHAVIORAL CHANGES This Photo by Unknown Author is licensed under CC BY  CLINICAL CASE: TRAUMATIC BRAIN INJURY TRAUMATIC BRAIN INJURY IS COMMON WITH HBC, BBD, OTHER INJURIES TO THE HEAD DIAGNOSIS: NEUROLOGIC EVALUATION CLINICAL SIGNS: SEIZURES, ABNORMAL MENTATION, ABNORMAL CRANIAL NERVE FUNCTION, ATAXIA, BEHAVIORAL CHANGES TREATMENT: OXYGEN!, TREAT PAIN, ELEVATE HEAD, REDUCE EXTERNAL STIMULI, MAINTAIN & SUPPORT GENERAL BODY This Photo by Unkn own Auth or is licensed under CC BY-SA FUNCTIONS, ANTICONVULSANTS PROGNOSIS: DEPENDS….  THE CEREBELLUM THE SECOND LARGEST COMPONENT OF THE BRAIN LOCATED CAUDAL TO THE CEREBRUM PHYSICAL QUALITIES: GRAY MATTER CORTEX WHITE MATTER DEEP TO THE CORTEX This Photo by Unkn own Auth or is licensed under CC BY-SA-NC WRINKLED APPEARANCE  FUNCTIONS OF THE CEREBELLUM Coordinated Balance Posture Complex reflexes movement Fine-tunes movements ordered by the cerebral cortex  Hypermetria: exaggerated movements DAMAGE TO THE Jerky movement CEREBELLUM Lack of coordination  CLINICAL CASE: CEREBELLAR HYPOPLASIA IN CATS DISEASE INVOLVING FAILURE OF THE CEREBELLUM TO DEVELOP NORMALLY COMMONLY SEEN IN KITTENS BORN TO MOTHER’S INFECTED WITH FELINE PANLEUKOPENIA DURING GESTATION CLINICAL SIGNS: JERKY, UNCOORDINATED, SPASTIC MOVEMENTS LACK OF FINE MOTOR MOVEMENT HEAT TREMORS WIDE-LEGGED STANCE PROGNOSIS: EXCELLENT! THEY ARE NOT IN PAIN. THERE IS NO CURE. CEREBELLAR HYPOPLASIA  LOCATED BETWEEN THE BRAINSTEM & THE CEREBRUM (“DI” = BETWEEN) DIENCEPHALON DOES NOT HAVE CLEAR AREAS OF GREY & WHITE MATTER COMPONENTS OF THE DIENCEPHALON 1) THALAMUS RELAY STATION FOR REGULATING SENSORY INPUT TO THE CEREBRUM 2) HYPOTHALAMUS INTERFACE BETWEEN THE NERVOUS SYSTEM AND ENDOCRINE SYSTEM 3) PITUITARY REGULATES HORMONES THROUGHOUT THE BODY  DIENCEPHALON – THE HYPOTHALAMUS VERY IMPORTANT STRUCTURE! FUNCTIONS: TEMPERATURE REGULATION HUNGER THIRST This Photo by Unkn own Auth or is licensed under CC BY-SA-NC RAGE & ANGER RESPONSES  THE BRAINSTEM THE BRAINSTEM IS THE CONNECTION BETWEEN THE BRAIN & THE SPINAL CORD THE MOST PRIMITIVE PART OF THE BRAIN COMPONENTS OF THE BRAINSTEM: MEDULLA OBLONGATA PONS MIDBRAIN MANY CRANIAL NERVES COME OFF THE BRAINSTEM  Supports BASIC life-sustaining functions of the body FUNCTIONS Autonomic control of OF THE BRAINSTEM The heart Breathing Blood vessel diameter Swallowing vomiting  RARE THIS AREA IS WELL-PROTECTED IF DAMAGED CAN RESULT IN RAPID DEATH INJURY TO THE BRAINSTEM OTHER IMPORTANT BRAIN STRUCTURES  THE MENINGES CONNECTIVE TISSUE LAYERS AROUND THE BRAIN AND SPINAL CORD 1) PIA MATTER (INNER MOST LAYER, LIES DIRECTLY ON THE SURFACE OF THE BRAIN & SPINAL CORD) 2) ARACHNOID LAYER (DELICATE, SPIDER-WEB LIKE) 3) DURA MATTER (TOUGH, FIBROUS OUTER LAYER) “PAD” THE BRAIN FUNCTION OF THE MENINGES PROTECTION BLOOD SUPPLY FOR O2 & NUTRIENTS FLUID, FAT & CONNECTIVE TISSUE PROVIDES CUSHION  CLINICAL CASE: MENINGITIS MENINGITIS IS INFLAMMATION OF THE MENINGES PATHOPHYSIOLOGY: INFECTIOUS OR IMMUNE-MEDIATED DISEASE CLINICAL SIGNS: SPINAL PAIN AND NECK RIGIDITY, ABNORMAL GAIT, LETHARGY, FEVER DIAGNOSIS: CSF TAP, MINIMUM DATABASE, IMAGING TREATMENT: STEROIDS (AUTOIMMUNE FORM), ANTIBIOTICS (BACTERIAL, TICK-BORNE), SUPPORTIVE CARE PROGNOSIS: GOOD FOR AUTOIMMUNE, GUARDED FOR INFECTIOUS https://vcahospitals.com/know-your-pet/meningitis-in-dogs  CEREBROSPINAL FLUID (CSF) CSF PROTECTS THE BRAIN AND SPINAL CORD FROM ITS BONY CASINGS WHERE IS CSF LOCATED? BETWEEN MENINGES THE VENTRICLES OF THE BRAIN THE CENTRAL CANAL OF THE SPINAL CORD CSF CONTINUOUSLY CIRCULATES THROUGH THE CNS  CLINICAL INFO: DIAGNOSTIC TESTS FOR NEUROLOGIC DISEASE WAYS TO EVALUATE NEUROLOGIC DISEASE NEUROLOGIC EXAM MENTATION, CRANIAL NERVES, POSTURE, SPINAL REFLEXES, SPINAL PAIN, GAIT, POSTURAL REACTIONS RADIOLOGY ….RADIOGRAPHS OF THE SPINE MAY BE USEFUL, RADIOGRAPHS OF THE HEAD…? MRI OR CT SCAN – BETTER IMAGING CSF TAP: GOOD FOR COLLECTING A FLUID SAMPLE OF POTENTIAL INFECTIOUS AGENTS OR CANCER CELLS IN THE CNS  The blood-brain barrier separates the brain from the blood BLOOD- Why is this so critically important? BRAIN BARRIER How is the BBB formed? Capillaries of the brain do not have fenestrations (openings) (BBB) Brain capillaries are covered by the cell membranes of glial cells Prevents drugs, proteins, ions, What does the bbb do? infectious agents from passing through  Includes nerves I-XII THE Cranial nerves may be motor, sensory or both CRANIAL CN I (olfactory nerve) – sensory (smell) NERVES CN II (optic nerve) – sensory (sight/vision) CN III (oculomotor nerve) – motor (controls eye movement) CN V (trigeminal) – mixed sensory & motor (chewing, facial sensation)  THE CRANIAL NERVES This Photo by Unknown Author is licensed under CC BY-SA-NC  The spinal cord continues caudally from the brainstem Contains grey (nerve cell bodies) & white SPINAL matter (nerve fibers) CORD Function Conducts nerve impulses to and from the brain to the periphery of the body Processing and modification of nerve impulses  SPINAL CORD STRUCTURE GREY MATTER IS INSIDE AND IS SHAPED LIKE A BUTTERFLY WHITE MATTER (MYELINATED FIBERS) IS OUTSIDE DORSAL & VENTRAL SPINAL NERVE ROOTS COME TOGETHER TO FORM THE SPINAL NERVE DORSAL NERVE ROOT SENSORY (AFFERENT) FIBERS VENTRAL NERVE ROOT MOTOR (EFFERENT) FIBERS ACRONYM “DAVE”: DORSAL AFFERENT VENTRAL EFFERENT THE SPINAL NERVE EXITS BETWEEN EACH VERTEBRAE  Afferent neurons are located in the dorsal horns SPINAL of the “butterfly” CORD STRUCTURE Efferent neurons are located in the ventral horns THE END