University of Michigan



Anatomy of the brainThe brain is made up of two types of cells:Neurons – sending and receiving nerve impulsesGlial – provide support, nutrition, maintain homeostasis, form myelin and facilitate signal transmissionMeninges:3 layers of tissue that cover and protect the brain and spinal cord include (Dura mater, Arachnoid, and Pia mater) Cerebral Spinal fluid:Surrounds and protects the brain and spinal cord, fluid produced in ventricles (choroid plexus)Ventricular System:Four ventricles~two lateral ventricles (cerebral hemisphere) ~third ventricle (thalamus and hypothalamus) ~fourth ventricle Brainstem: (manage basic involuntary functions)Located in front of cerebellum, connects to spinal cordConsists of three structures – reticular activating system (levels of wakefulness and sleep)Midbrain - ocular motionPons – coordinating eye facial movement, facial sensation, hearing and balanceMedulla oblongata – controls breathing, blood pressure, heart rhythm, swallowing10 of 12 cranial nerves originate in brainstemCerebellum: (fine tunes body movement and maintain balance)Located in the back of the brain beneath the occipital lobesFine tunes motor activity or movementHelps maintain posture, balance, equilibrium (controls muscle tone and position of the limbs)Helps perform rapid and repetitive actions (like playing video games)In cerebellum right sided abnormalities produce symptoms on the same side of the bodyCerebrum: (high intellectual functions)2 hemispheres joined at the bottom by corpus callosumSurface of cerebrum contains neurons and glia that form the cerebral cortexMessage for movement and sensation cross to the other side of the brainDivided into lobes:Frontal – motor skills, voluntary movement, speech, intellect, behavior, memory, intelligence, concentration, temper, personality, eye and head movements, sense of orientation, Broca’s areaTemporal – visual memory, helps humans recognize objects and people’s faces, assist humans to remember and understand language, interpret other people’s emotions and reactionsParietal – interpret simultaneously, signals received from other areas of the brain such as vision, hearing, motor, sensory, and memory. A person’s memory, and the new sensory information received, give meanings to objectsOccipital – receive and process visual information, process color and shapesCranial Nerves:12 pair of nerves that originate from the brainOlfactory – smellOptic – visual fields and ability to seeOculomotor – eye movements, eyelid openingTrochlear – eye movementTrigeminal – facial sensationAbducens – eye movementsFacial – eyelid closing, facial expression, taste sensationAuditory/vestibular – hearing, sense of balanceGlossopharyngeal – taste sensation, swallowingVagus – swallowing, taste sensationAccessory – control of neck and shoulder musclesHypoglossal – tongue movementHypothalamus: Sends messages to pituitary gland & handles information from the autonomic nervous systemControls functions such as eating, sexual behavior, sleeping, regulates body temperature, emotions, secretion of hormones and movementLimbic system: emotions, hypothalamus, part of the thalamus, amygdala (aggressive behavior) and hippocampus (remember new information)Pineal Gland: Third ventricle, controls response to darkness and light, sexual maturationPituitary gland: controls secretion of hormones including growth development, function of organs, function of other glandsThalamus: Relays information, pain sensation, attention, alertness, Language and speechLeft hemisphere responsible for language and speechBroca’s – frontal lobe, damage causes expressive aphasiaWernicke’s – temporal lobe, damage causes receptive aphasiaRight hemisphere is responsible for interpreting visual information and spatial processingBrain TumorA brain tumor is an abnormal growth of tissue in the brain or central spine that can disrupt the brain function.There are over 120 types of brand and central nervous symptom tumors.Tumors are based on where the tumor originates and whether or not they are cancerousBenign:-least aggressive-originates from cells within or surrounding the brain-do not contain cancer cells, grow slowly-typically clear borders that do not spread to other tissue-usually can be removed and seldom grow back-may become malignantMalignant:- often do not have clear borders-grow rapidly and invade surrounding brain tissue-cells may break away from malignant brain tumors and spread to other parts of the brain or spinal cordPrimary: -tumors that start in the cells of the brain may spread to other parts of the brain or spine but rarely to organsMetastatic:-tumors that begin in another part of the body and then spread to the brainTumor Grade: (not the same as stage of cancer)The description of a tumor is based on the appearance of abnormal cells and the tumor tissue indicates how quickly the tumor is likely to grow and spread. Grading systems differ depending on the type of cancer.If a grading system for a tumor type is not specified, the following is generally usedGX:Grade cannot be assessed (grade cannot be determined)GI:Well differentiated (low grade), benign, grow slowlyGII:Moderately differentiated (intermediate grade), malignantGIII:Poorly differentiated (high grade), actively growing (anaplastic)CIV:Cells look most abnormal and tend to grow quickly ................
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