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87 Cards in this Set
- Front
- Back
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GLIAL CELLS
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IN THE CNS, SUPPORTING CELLS, DIVIDE BY MITOSIS
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CELL BODY OF NEURON
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(PERIKARYON), NUTRITION CENTER, CELL BODIES WITHIN CNS CLUSTERED INTO NUCLEI AND IN PNS IN GANGLIA.
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DENDRITES
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PROVIDE RECEPTIVE AREA, TRANSMIT ELECTRICAL IMPULSES TO CELL BODY
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AXON
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CONDUCTS IMPULSES AWAY FROM CELL BODY
AXOPLASMIC FLOW-SLOWER, PROTEINS AND OTHER MOLECULES ARE TRANSPORTED BY RHYTHMIC CONTRATIONS TO NERVE ENDINGS |
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AXONAL TRANSPORT
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MORE RAPID, EMPLOYS MICTROTUBLE FOR TRANSPORT, MAY OCCURIN ORTHOGRADE OR RETROGRADE DIRECTION, VERY SELECTIVE
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AXON HILLOCK
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ORIGIN OF AXON NEAR CELL BODY IS EXPANDED REGION WHERE NERVE IMPULSES ORIGINAT.
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FUNCTIONS OF NEURONS
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BASED UPON DIRECTION IMPULSES CONDUCTED. SENSORY OR AFFERENT-CONDUCT IMPULSES FROM SENSORY RECEPTORS INTO CNS. MOTOR OR EFFERENT-CONDUCT IMPULSES OUTOF CNS TO EFFECTOR ORGANS. EX-MUSCLES AND GLANDS
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2 TYPES OF MOTOR NEURONS: SOMATIC AND AUTONOMIC
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SOMATIC-REFLEX AND VOLUNTARY CONTROL OF SKELETAL MUSCLES.
AUTONOMIC-INNERVATE (SEND AXONS TO) THE INVOLUNTARY EFFECTORS (SMOOTH MUSCLE, CARDIAC M., GLANDS) |
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SYMPATHETIC..."FIGHT OR FLIGHT"
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-INCREASE E EXPENDITURE. EX. WHEN YOURE SCARED...PUPILS GET BIGGER, INCREASE HEART RATE
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PARASYMPATHETIC
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STOPS CARING WHEN YOURE SCARED. WHEN YOURE NOT SCARED ANYMORE, YOU HAVE TO P. CAUSES YOUR MOUTH TO BE DRY.
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STRUCTURAL CLASSIFICATION OF NEURONS
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BASED ON THE # OF PROCESSES THAT WXTEND FROM CELL BODY.
PSEUDOUNIPOLAR:SHORT SINGLE PROCESS THAT BRANCHES LIKE A T(SENSORY n.) BIPOLAR NEURONS:HAVE 2 PROCESSESS (RETINA OF EYE) MULTIPOLAR:HAVE SEVERAL DENDRITES AND 1 AXON (MOTOR NEURON) |
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PNS SUPPORTING CELLS
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SCHWAAN CELLS: ACT AS PHAGOCYTES, AS THE DISTAL NEURONAL PORTION DEGENERATES. SURROUNDED BY BASEMENT MEMBRANE, FORM REGENERATION TUBE:SERVE AS GUIDE FOR AXON, SEND OUT CHMICALS THAT ATTRACT THE GROWIN AXON, AXON TIP CONNECTED TO CELL BODY BEGINS TO GROW OWARDS DESTINATION.
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M.S.
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CAUSED BY DEGENERATED MYELIN SHEATHS ON AXONS.
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CNS SUPPORTING CELLS
OLIGODENDROCYTES: |
PROCESS OCCURS MOSTLY POSTNATALLY, EACH HAS EXTENSIONS THAT FORM MYELIN SHEATHS AROUND SEVERAL AXONS...INSULATION
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NEUTROTROPHINS
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PROMOTE NEURON GROWTH
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NODES OF RANVIER
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GAPS IN MYELINATED SHEATH, THRY PRODUCE NERVE IMPULSES
MYELINATED AXONS CONDUCT IMPULSES MORE RAPIDLY |
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CNS SUPPORTING CELLS
ASTROCYTES- |
MOST ABUNDANT GLIAL CELL, VASCULAR PROCESSES TERMINATE IN END-FEET THAT SURROUND TE CAPILLARIES, STIMULATE TIGHT JUNCTIONS, CONTRIBUTING TO BLOOD-BARRIER, REGULATE
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EXTERNAL ENVIRONMENT OF K AND pH, TAKE UP K FROM ECF(EXTRA CELL. FLUID), NTs RELEASED FROM AXONS, AND LACTIC ACID (CONVERT FOR ATP PRODUCTION). OTHER
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EXTENSIONS ADJACENT TO SYNPSES-FEW SYNAPSES FORM IN THE ABSENSE OF ASTROCYTES, THOSE THAT DO ARE DEFECTIVE.
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ASTROCYTE END FEET
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SURROUNDIGN BLOOD CAPILLARIES TAKE UP GLUCOSE FROM THE BLOOD. GLUCOSE IS METABOLIZED INTO LACTIC ACID OR LACTATE(RELEASED AND USED AS E...ATP.)
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CNS SUPPORTING CELLS
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MICROGLIA-PHAGOCYTES, MIGRATORY
EPENDYMAL CELLS-SECRETE CSF, LINE VENTRICLES, FUNCTION AS NEURAL STEM CELLS, CAN DIVIDE AND PROGENY DIFFERENTIATE. |
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LIVING SHEATH OF SCHWANN CELLS
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AKA- neurilemma, found in PNS. myelin sheathsin cns are formed by oligodendrocytes. they have extensions lide an octopus, they form myelin sheaths around several axons.
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ACh as a NT
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ACh is bot an exc. and inhib. NB, depending on organ. opens the chem. gated ion chanels.
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Nicotinic ACh receptor
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found in auton. ganglia and sdeletal muscle. stimulates muschle contraction
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Muscarinic ACh receptors
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found in the plasma memb. of smooth and cardia muscle cells
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Ligand operated ACh channels
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nost direct mechanism, ion channel runs through receptor. Receptro has 5 polypeptide subunits that enclose ion channel. 2 subunits contain Ach. Channel opens when both sites bind to Ach. permits diffusionof Na into and K out of postsyn. cell, inward flow on Na dominates . Produces EPSPs
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G protein poerated ACh channel
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only 1 subunit. ion channes are separate proteins located away from the receptors. binding of Ach activates alpha G protein subunit. Alpha subunit dissociates. alpha subunit or the beta gamma complex diffuses throught membrane until it binds to ion channel, opening it.
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AChE
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enzyme that inactvates ACh. present on post memb or immediatley outside the memb. prevent continued stimulation
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ACh in CNS
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Cholinergic neurons use ACh as NT, axon bouton synapses with dendrites or cell body of anothyer neuron, 1st VG channels are located at axon hillock.
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Curar
ACh in Pns |
used as muscle relaxant by competing with ACh for attachment tothe nicotinic ACh receptor and thus reduces the size of hte end-plate potentials
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monoamines as NT
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EP-adrenalin, NEP, Serotonin-released from blood (derived from tryptophan) vessels, dopamine-effects kidneys...derived from tyrosine
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monomines as NT
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released by exocytosis from presynaptic vesicles, diffuse across the synaptic cleft, interact with specific receptors in postsyn. memb
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inhibition of monoamines as NT
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reuptake of monoamines into presyn. memb. Enzymatic degradation of monoamines in presyn. memb. by MAO (used to break down Ep and NEp in postsn.
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MAO inhibitors
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treat depression, block NT breakdown, keep NTs in synapse longer
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Mechanism of MAO Action
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monoamine NT do not directly open ion channels, act thru 2nd messenger (cAMP). Binding of NEP stimulates dissociation of G protein alpha subunit. Alpha subunit binds to adenylate cyclase, converting ATP to cAMP, this activates protein kinase, phosphorylating other proteins. open ion channels
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Seratonin as NT
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NT (derived from L tryptophen), fro neurons with cell bodies in raphe nuclei, regulation of mood behavior appetite and cerebral circulation, SSRIs (seratonin specific reuptake inhibitors)-inhibit reuptake and destrucion of seratonin, prolonging the action of NT, used as an antidepressant
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Dopamine as NT
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NT for neurons with cell bodies in midbrain. Axons project into Nigrostriatal dopamine syst. and Mesolimbic dopamine syst.
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Nigrostriatal dopamine syst.
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neurons in substantia nigra send fiber to corpus straitum, inhibition of skel. muschle movement, Parkinsons-degeneration of neurons in substantia nigra
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mesolimbic dopamine syst.
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neurons originate in midbrain, send axons to limbic (forbrain) syst., involvedin behavior and reward, addictive drugs
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NE (norepinephren) as NT
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NT in both PNS and CNS (just like ACh), PNS-smooth muscle, cardiac, and glands-increase in blood pressure, contricions of arteries. CNS-general behav.
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Amino Acids as NT
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glutamic acid and aspartic acid: major exc. NT in CNS. Glutamic acid:NMDA receptor involved in memory. Glycine: inhibitory (IPSP), helps control sk. muscle, opening of Cl channels in post.
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Amino Acids as NT cont.
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GABA: most prevalent NT in brain, inhibitory, produces IPSPs. involved in motor control
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Benzodiazepines
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increase GABA activity, ingibits musc. spasms, treat anxiety and insmnia. ex...valum
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Polypeptides an NT
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CCK-secreted from Sm. intestin, promotes satiety. Substance P: major NT in sensations of pain. Synaptic plasticity (neuromod. effects): neurons can release classical NT or the polypeptide NT
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Polypeptides as NT:
Endogenous opiods |
brain produces its own analgesic endogenous morphine like compounds, blocking release of substance P. Ex: the joggers high
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Poly as NT:
Neuropeptide Y |
most abundant neuropeptide in brain
ingibits lutamate in hippocampus powerful stimulator of appetite |
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Poly as NT
NO |
exerts its effects by stimulaton of cGMP(acts like 2 messenger), macrophages release NO to help kill bacteria, inbolbed in memory and learning, smooth muscle relaxation (penis erection)
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Synaptic integration
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ESPS can summate, producing AP
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Synaptic integration
Spatial Summation |
numerous boutons converge on a single post. neuron (distance).
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Synaptic Integration
Temporal summation |
successive waves of neurotransmitter release (time)
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AP
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produced by an increase in Na permeability. After short delay, increase in K permeability
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depol and repol
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occur thru diffusion
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long term potentiation
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transmission along frequently used neuralpathways, high frequency stimulation: enhancing excitability of synapse, improves efficacy of synaptic transmission, neuaral pathwasy in hippocampus use glutamate (memory and learning)
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Gray matter
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consists of neuron cell bodies and dendrites
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white matter
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myelin, consists of axon tracts
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cerebrum
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(telencephalon), 80% of brain, high mental functons
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corpus collasum (found in cerebrum)
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major tract of axons that functionlly interconnects right and left
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cerebral cortex
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numerous convolutions (gyri and sulci) contains the 4 lobes
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insula
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memory encoding, cardiovascular response to stress
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parietal
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perception of somatestetic sensation, highest densiities or receptors
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temporal
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auditory centers receive sensory fibers from coclea, interpretation and association of auditory and visual info
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Electroencephalogram (EEG)
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measures synaptic porentials produced at cell bodies and dendrites, create elect. currents. Used clinically to diagnose epilepsy and brain death
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EEG Patterns
Alpha |
recorded from parietal and occ gegions, person is wake eyes closed. 10-12 cylces/sec
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Beta
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strongest fro mfrontal lobes, produced by visual stimuli and mental activity, evoked activity 13-25
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Theta
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emitted from temporal and occ obes, common in newborn, adult indicates emotional stress 5-8
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Delta
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Emitted in a gen. pattern, common drug slep and awake infanst . in adult indicates braind damage 1-5
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EEG, 2 types
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REM
dreams,low amplitude, high frequency oscilations (beta) |
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reward and punishmeht
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hypoth and frontal cortex
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hippocampus
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critical component of memory. acquisition of new info reqires temp. lobe and hippocmapus.
NT is glutamate and glycine |
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BRAIN REGIONS
Forebrain |
Telencephalon-Cerebrum
Diencephalon-thalamus:acts primarily as a relya center for sensory info to get to cerebrum |
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Midbrain
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Mesencephalan-s. nigra, red nucleus,
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Hindbrain
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Metencephanlon-pons and cerebellum
Myelencephalon-medulla oblongata |
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Thalamus
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acts as a relay center thru which all snesory info except olfactory (smell) passes to cerebrum
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Epithalamus
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contains choroid plexus where CSF is formed, Pineal gland whch secretes melatonin
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Hypothalamus
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neural centers for hunger, thirst and body temp., contributes to teh reg. of sleep, wakefulness, emotionss, sex arousal, fear, pain, produces ADH and oxytocin, coordinates sym and para reflexes
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PITUITARY GLAND
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posterior piruitary:(neurohypophysis), stores and releases ADH and oxytocin
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Hypothalamus
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produces realeasing and ingibiting hormones tha are transported to anterior pituitary, reg. secretions of anterior hormones
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Anterior Pit.
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regulates secretion of hormones of other endocrine glands.
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midbrain
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Substantia Nigra-required for motor coordination
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HINDBRAIN
Pons |
surface fibers connect to cerebellum adn deeper fibers are part of motor and sensory tracts, contains the resp. centers.
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Cerebellum
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receive input from proprioceptors , participates in cordination of movement...bringing a fork to mouth
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Myelencephalon (medulla oblongata)
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all descending and ascending fiber tracts betw. sp. cord and brain must pass thru the medulla
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CRANIAL AND SPINAL NERVES
Cranial |
2 pairs from neuron cell bodies in forbrain, 10 pairs arise from mid brain dn hinbrain, most are mixed nerves (sensory and motor)
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Spinal
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31 pairs, produces 2 roots to each nerve:dorsal root composed of sensory fibersand vetral root composed of motor fibers
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Division of ANS
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sympathetic nervous syst. and parasympathetic have preganglionic neurons that originate in CNS and postganglionic neurons that originate outside of the CNS in ganglia
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Sympathetic
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preganglionic neuron are short and release Ach.
Postganglionic are long, nicotinic receptor, release NE at smooth muscle and glands, and ACh at sweat glands |
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Parasympathetic
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preganglionic neurons are short, release Ach to adrenal medulla, no postganglionic neuron
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Adrenal medulla
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secretes EP, and NE into circulation
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