PGY 300 Lecture 1Introduction to central nervous system -Inside the bony structure-Brain and spinal cord-All the nerves that enter and leaves the central nervous system-12 sets of cranial nerves -Spinal nerve that enter and leave spinal cord -Protecting: dura, pia, arachnoid (up until nerve)oPhysical protection and cushioningoProtect soft bony structure from hard bony structure -Gray matter: enter-Dorsal root: enter/sensory neuron enter SC form periphery through dorsal root AFFERENT -> Send information to dorsal horn -Leave SC, sending message to periphery EFFERENT information to muscles and glands -> Ventral horn leave SC to periphery, EFFERENT neuron 12 cranial nervesEnter and leave to the brainSpinal cord, every vertebrae another set of nerve that enter and leavesProtecting: dura, pia, arachnoid (up until nerve)Physical protectionCushioningAny bony structure in skull -Gray matterDorsal root: into SC from periphery, sensory afferent neuron to the SC Sen information to white matter, dorsal horn -Ventral hornVentral root: leave SC and efferent, motor neuron stimulate muscles and glands -Efferent autonomic neuron, GI tract control, internal organ (not aware)-Somatic motor neurons, aware, ventral root neuron control skeletal muscle -Grey matter SC cord-White matter surrounding grey matter: neurons sending signal up to the brain or from brain to go region of SC-Spinal reflexes (hot stove)Initiates a response without input from the brainStimulusSensory informamtion -Ascending fibers, sensory information to the brain-Descending fibers come down from the brain -Glial cells cover neurons, Meningeal layers of the brain cushion and protect delicate neural tissueCraniumDura materVenous sinusArachnoid membranePia materBrainMeningitis: inflammation of meninges, bacterial infection particularly dangerous CSF: fluid provide nutrients, waste product remove, cushion and protection In subarachnoid space, and ventricles in various region in brain Constantly change content with bloodThis is done in Choroid plexus, which transports ions and nutrients from the blood into theCSF Hydrocephalus: elevated CSF CSF goes down into SC as well to brain. Procedures to drain thisLumbar Puncture: Sample CSF from subarachnoid space, test for meningitis Blood supply regulated in terms of what to get and what is needed. Restricted flow of material BLOOD BRAIN BARRIER-Many pharmacy work hard to get through the barrier, created by tight junction of cells lining the endothelial cellsAstrocytes forms this, secrete paracrines that promote tight junction formationTight junction prevents solute movement between endothelial cells Ex) Imodium is an opiate used to treat diarrhea but does not cross blood-brain barrier Discovered:Paul Ehrlich systemic injection of vital stains filled all organs except brain and spinal cord Brain Cerebellum have the most neurons Cerebrum, cover top of brain, viewed as aspect of brain counts for our intelligence and important function Cerebellum, large structure, has about half of nerve cells of entire brainThought to be involved with controlled of motions. Reach out and touch something, how good at job you are doing (far/close distant) Not initiate process of movement. Also behavior as well! Pons, region between cerebellum and cerebrum, communication between cerebrum and cerebellum, autonomic: respiratory Medullae, lowest part of brain, connection between SC and brain, CVD function and control of respiration Frontal lobe: Prefrontal lobe: involved in executive function (what to do, behavior, appropriate or not, plan to do something) higher level function with brainTemporal lobeParietal lobeOccipital lobe Sensory information goes through thalamus and then occipital, if visual Somatic sensory area: primary sensory area, poke skin, for example, relate through primary somatic sensory cortex Then Sent to a sensory association area, coordinating information from primary area. Have a concept of what you have sensed, that produced these stimuli, motor response to stimuli. Send information to motor area motor association area combined information of what is going on with your body (standing, lay down) response differently based on what the sensory information you are getting Send information to various muscles of the body, to tell the what to doPrimary motor cortex, efferent nerve going through the body Homonculus (representation of you) of primary somatosensory cortex in blue: hands, face, tongueMotor map in precentral gyrus: (out to send information) face control, hand Example of cortical association areas: wernicke's and broca's areaWernicke's area damage: fluent word use but with little meaningCannot figure out what does it mean, speak very well, but does not make senseHear wordsSensory Broca's area damage: telegraphic speechUnderstand but you cannot speak to respond to your understandingSee wordsMotor Example) Wernicke's Aphasia Hemisphere of cerebral cortexLeft: analytical language mathematicRight: Artistic ability Suppress each other, left hemisphere dominant suppressing artistic hemisphere Right side of body, left hemisphereLeft side of the body, right hemisphere Corpus Callosum: connect hemisphere Damage to one hemisphere, fire and become too active cause epilepticExtreme cases, corpus callosum gets cut to prevent firing Basal ganglia: action selection by disinhibition, linked to Tourette syndrome, obsessive-compulsive disorder, Parkinson's and Huntington's disease. Suppress parts of the brain, until you need them, not all active: inhibit neuronsBasal ganglia you want certain activity, it removes inhibitionMotor activity is allowed to function while you have inhibited that. (Parkinson's disease) loss of dopamine in basal ganglia Limbic systemMemory mechanismHippocampus: memory short-term memories into long-term memories, involved in learning and memory Amygdala: involve in memories associated with emotion, response with emotional events.Stimulate amygdala spank child example. Cingulate gyrus: plays a role in emotion Thalamus: all sensory information, expect olfactory (smell) first goes through thalamus and then gets into cortex. Also process the information, evaluatingRelay and integrating sensory and motor information Diencephalon Below thalamus, we have hypothalamus.Hypothalamus: homeostasis, function important for body. Diffuse modulatory systemsNot cause anything, not mediating responseOriginate in reticular formation in brain stemSerotonin, depression, people who are depressed do