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THE NERVOUS SYSTEM By: Jennifer De Dios Pd: 4 (CRANIAL NERVES (OLFACTORY…

- - - - SOMATIC NERVOUS SYSTEM
        
        ☆Controls voluntary movements
        
        AUTONOMIC NERVOUS SYSTEM
        
        ☆Controls involuntary responses
        --conducts impulses from CNS --> skeletal muscle
        
        SYMPATHETIC DIVISION
        
        ☆Mobilizes body systems during activity
        
        PARASYMPATHETIC DIVISION
        
        ☆Conserves energy
        ☆Promotes house-keeping functions during rest
        
        COMPARE & CONTRAST
        
        ☆SYMPATHETIC: more complex, innervates more organs
        --sweat glands, arrector pili muscle of hair follicle, smooth muscle
        ☆PARASYMPATHETIC: Fibers originate from brain stem and sacral regions or cord
- - - - ☆Coordinate muscle movements, maintain posture, and balance
        ☆SUPERIOR PEDUNCLES: Carrie's neurons st cerebellar
        ☆MIDDLE PENCULES: one-way communication from the pons to the cerebellum for voluntary motor activities
        ☆SUPERIOR PEDUNCLES: convey sensory info --> cerebellum from various receptors
      - BRAIN STEM
        
        ☆Relay center connecting cerebrum and cerebellum to the spinal cord
        ☆Breathing, heart rate, body temperature, wake and sleep cycles, digestion, sneezing, coughing, vomiting, swallowing
    - - ☆PERIAQUEDUCTAL GRAY MATTER: pain suppression, links fear perceiving amygdaloid body and ANS pathways that control fight or flight
        ☆SUPERIOR COLLICULI: coordinate head and eye movement when following a moving object
        ☆INFERIOR COLLICULI: auditory relay from hearing receptors of ear --> sensory cortex
- - - - ☆Perception, object classification, spelling, knowledge of numbers, visuospacial processing
      - OCCIPITAL LOBE
        
        ☆Vision, visual processing, colouring identification
        
        TEMPORAL LOBE
        
        ☆Memory, understanding language, facial recognition, hearing, vision, speech, emotion
- - - - ☆One per hemisphere, deep, C-shaped
        --separated anteriorly by septum pellucidum
        --communicate with narrow third ventricle in diencephalon via a channel called intraventricular foramen
        --Third ventricle continuous with fourth ventricle via canal-like cerebral aqueduct that runs through midbrain
- - - - ☆Main receptive or input regions (enormous surface area)
        --collecting info
        --dendritic spines = thorny appendages for close contact with other neurons
        ☆Convey incoming messages toward cell body
        --not action potential, but short-distance = graded potentials
      - AXON
        
        ☆Arises from axon hillock
        --never more than one axon
        ☆Initial segment of axon -->slender process, uniform in diameter
        ☆Nerve fiber = long axon
        ☆Tracts in CNS, nerves in PNS = bundles
        ☆Axon collateral = branches
        ☆Axon terminals = distal ends of terminal branches
        
        ☆Conducting region -- generates nerve impulses and transmits along axolemme (conducted at secretory region)
        ☆Impulses reach axon terminal --> neurotransmitters release
        
        SYNAPSE
        
        ☆Chemical junction between axon terminals of one neuron and the dendrites of the next
        ☆Chemical interactions in this gap, not a structure
- - - - ☆Na+ rushes in --> influx of positive depolarizes --> more Na+ channels
        ☆THRESHOLD: (critical level) self generating, urged by positive feedback --> rapid depolarization and polarity reversal --> spike of ATP
      - REPOLARIZATION:
        Na+ channels are in activating, and voltage-gated K+ channels open.
        
        ☆Increasing phase of Action Potential, self-limiting --> Na+ decreases, resting level, net influx stops
        --K+ opens, rushes out --> restores internal negative charges
        
        HYPERPOLARIZATION:
        Some K+ channels remain open, and Na+ channels rest.
        
        ☆Excessige K+ reflux--> slight dip following spike, Na+ channels rest to original
- - - - ☆Cocaine blocks transporters, leaving dopamine trapped in the synaptic cleft. As a result, dopamine binds again and again to the receptors overstimulating the cell
      - ☆Speeds up brain and nerve activity, numbing/anaesthetic
        ☆Increased energy, alertness, confidence, decreased appetite and irritability
      - OPIOIDS
        
        ☆Pinpoint pupils, rush of warmth and pleasure
        ☆Drowsiness, clouded thinking, nausea, itching, vomiting, withdrawal
        
        HEROINE
        
        ☆When the body's natural opiates activate opiate receptors, the release of inhibitory neurotransmitters is shut down, without inhibition. Dopamine can be produced
        
        ☆Produces immediate feelings of sedation and well being
        
        ECSTASY
        
        ☆Serotonin transporters are responsible for removing serotonin molecules from the synaptic cleft after they have done their job
        
        ☆Affects mood, sleep, perception, and appetite
        --milder release of dopamine
        
        METHAMPHETAMINE
        
        ☆Meth enters the dopamine vesicles forcing the dopamine molecules out --> transporters start working in reverse --> pump dopamine into the synapse --> excess dopamine overstimulated the cell
        
        ☆Highly addictive because it works directly on the brain's reward pathway
        ☆Intense pleasure and exhilaration
        
        MARIJUANA
        
        ☆When activated by the body's own native cannabinoid, cannabinoid receptors turn off the release of inhibitory neurotransmitters without inhibition, dopamine can be released
        
        ☆Responsible for slowing down movement, making us feel relaxed and calm