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158 Cards in this Set
- Front
- Back
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WHEN DOES action potential OCCUR
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occurs when a neuron sends information down an axon, away from the cell body.
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WHAT IS action potential
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is an explosion of electrical activity that is created by a depolarizing current.
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WHAT IS RESTING POTENTIAL
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WHEN NEURONAL MEMBRANE ISN'T SENDING A SIGNAL
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WHAT STARTS ACTION POTENTIAL
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WHEN A THRESHOLD STIMULUS IS RECEIVED
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WHAT IF NEURON DOES NOT REACH THRESHOLD
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the neuron does not reach this critical threshold level, then no action potential will fire.
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what happens when a stimulus is first received
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A stimulus first causes sodium channels to open
Na+ |
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what does influx of Na+ cause
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influx of Na+ causes depolaization ((sodium has a positive charge, so the neuron becomes more positive and becomes depolarized.))
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what does depolarization of Na+ cause
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potassium K+ channels open When they do open, potassium rushes out of the cell, reversing the depolarization.
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K+ Na+
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when K+ opens na+ closes
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What happens when K+ channels close
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depolarazation begins again in an adjacent section og membrane
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where is action potential occuring
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down the axon
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what restores ion distribution
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Na+/K+ pump
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what is refractory period
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after action potential the neuron has to recover to reset
resting period |
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how does action pontential move
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moves in one direction
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how do neurons send messages
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Neurons send messages electrochemically. This means that chemicals cause an electrical signal. Chemicals in the body are "electrically-charged" -- when they have an electrical charge, they are called "ions.
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what are neurotransmitters
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Chemicals, called neurotransmitters, are released from one neuron at the presynaptic nerve terminal.
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what is the chemical at the neuromuscular junction
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acetytcholine
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what are chemicals at synapse between neurons
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epineprine (adrenaline) and norepineprine (non adrenaline)
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depolarization
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(an excitatory postsynaptic potential) or
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hyperpolarization
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(an inhibitory postsynaptic potential
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does action potential occur during depolarization or hyperpolarization
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depolarization
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Inactivation of Neurotransmitters
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1. degraded by enzymes in synapse
2. defuses out of synapse and degrades else where 3. pumped back in axon terminal |
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what is synapse
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synapse is a small gap separating neurons
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What are targets of neurons
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other neurons
muscles glands |
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What are sensory receptors
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specialized cells in special sense organs
have modified nerve endings |
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what do sensory receptors react to
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pressure, temperature,
pain cutaneous and deep |
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where do sensory receptors stretch
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muscles and tendons
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another name for action potential
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nerve impulse
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at rest ( unstimulated) what is the neural membranes charge
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neurons have build up of positive charge outside
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neuronal membrane is polarized. what does this mean
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has a positive side and negitive side
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What chemicals cause polarization
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K+ potassium
Na+ sodium |
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How is a neuronal membrane polarizes
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greater concentration of Na+ outside and K+ inside
outside is positive compared to inside |
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What is depolarization
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loss of polarity caused by influx of Na+
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how does sodium get into the cells
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*neuronal cell membranes contain channels
*channels are closed until stimulus opens them *stimulus can be neurotransmitter for another neuron *Na+ defusses thru chsannel |
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thresholds
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all or nothing..either stimulus reaches threshold (is strong enough) or doesn't
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nerve cells stimulated
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stimulus causes Na+ channels to open
*Na* rusheds in and Na+ channels close (membrane is depolarized) *this causes K+ channels to open *K+ rushes out *K+ channels close * |
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what is propagation of action potential
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action potential in 1 region stimulates adjacent region
nerve impulse travels down axon |
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pre synaptic neuron
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conducts impulse toward synapse
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synaptic cleft
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space between 2 neurons at synapse
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post synaptic neuron
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conducts impulse away from synapse
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how does synapse work
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*neurotransmitter is released by pre synaptic cleft
*defuses across synapse *binds to receptors on post synapse neurons |
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synapsetic transmission
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many presynaptic neurons from synapses with same post synaptic neuron
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excitatory synapses
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stimulate the post synaptic neuron to fire on action potential
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inhibitory synapses
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prevent the post synaptic neuron from firing a n action potential
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what makes up CNS
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brain and spinal cord
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responsible for higher order of mental function
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cerebrum
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examples of higher order of thinking
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memory learning speech
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largest part of brain
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cerebrum
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how many hemispheres in cerebrum
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2
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parts of cerebrum
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gyrus-ridge
sulcus- shallow groove fissure-deep grove longitudinal fissure-seperates the 2 hemispheres |
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what is corpus collosum
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bridge of nerve fibers connecting the 2 hemispheres
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how many lobes does each hemisphere have
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frontal
parietal temporal occipital |
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cerebral cortex
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thin outer layer of gray matter
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gray matter
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cell bodies and unmyelinated fibers
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white matter
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tracts of myelinated nervefibers
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tracts
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bundles of nerve fibers in cns
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nuclei
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clusters of nerve cell bodies in cns
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basal nuclei
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subcortical regions of gray matter
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what are special senses
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receptors located in special sense organs
ex visual receptoers in eye |
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somatic senses
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receptors scattered thru bodie
ex pain receptors |
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5 special senses
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sight, smell, touch(equilibrium), hearing, taste
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where do receptors of sense organs send signal to
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each receptor sends signals to specific area of cortex
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what are somatic senses
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temp, pressure, pain, body portion?????
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where do receptors of somatic senses send signals
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to somatosensory area in parietal lobe
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where is somatosensory area in parietal lobe
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located in the central sulcus
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central sulcus
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groove between frontal lobe and parietal
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where is the primary somatosensory area
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post central area of parietal lobe
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where doed each part of body send sensory input to
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each part has a specific area
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where is primary motor cortex
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precentral gyrus of central lobe
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where are neurons that control skeletal system
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primary motor cortex
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diencephalon area
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part of forebrain between cerebral hemisphere and midbrain
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what is in the area diencephalon
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thalmus, hypothalmus and epithalmus pituitary gland choradal plexis
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thalmus
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relay station for sensory input
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hypothalmus
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endocrine gland
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epithalmus
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contains pineal body
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chorad plexus
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knot of capillaries producing cfs
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pituitary gland
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endocrine gland inferior to cerebral spinal fluid and hypothalmus
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co ordianates voluntary muscle movement
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cerebellum
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maintains posture and balance
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cerebellum
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conatains nuclei for visceral function
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cerebellum
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conatains nuclei for origination of craniel nerves
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cerebellum
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midbrain
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vision and hearing
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pons
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controls breathing
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medulla oblongata
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heart rate blood pressure and rate of breathing
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nervous tissue is protected by
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*bones-skull and vertebrae
*membranes- meninges *fluid-cerebrospinal *meninges-membranes covering the brain and spinal cord |
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kinds of matter
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duramater-outer layer of connective tissue
arachnoid-2nd layer pia mate inner layer, very thin,and closely attached to spinal cord and many blood vessels |
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ventricles
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cavities in the brain continuous with spinal cord
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what is in the ventricles
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csf
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how is csf produced
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blood by endothelial cells in choroid plexis
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endothelial cells
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simple squamous epithelial cells that form lining of blood vessels
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subarachnoid space
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between arachnoid and pia mater
filled with csf |
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where do you find csf
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circulated throught subarachnoid space, ventricles,and central canal then drains back intoblood
*acts as shock absorber |
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what is blood brain barrier
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formed by tight junction between epithelial cella in capillary walls
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what does blood barrier do
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prevent difussion of many substances out of blood into brain tissue
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what crosses blood barrier
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O2 water glucose essential amino acids
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what can't cross
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metabolic wastes, nonessential amino acids
K+ most drugs |
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Limbic system
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not a specific area
* functional groups of gray and white matter in the cerebrum |
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what does limbic system control
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emotional state, pleassuresensation,motivation
neurons are targets of drug abuse |
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reticular formation
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scattered areas of gray matter in brain
K+ most drugs |
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what is reticular formation responsible for
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responsible for reticular activating system--
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reticular activating system
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conciousness, awake sleep cycles
coma |
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where is reticular formation located
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extension of brain stem, exits skull at foramen magnum
goes through vertebral column to L2 |
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what is foramen magnum
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large opening on inferior aspect of skull,
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what is cauda equina
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formed from spinal nerves at inferior end of spinal cord
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cross section of spinal cord
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gray commissure, central copal, nerve tracts, ascending tracts descending tracts, decussation
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gray commissure
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band of gray matter connecting the 2 sides
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central copal
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opening thru center where spinal cord goes
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nerve tracts
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major nerve pathways
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ascending tracts
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relay info to the brain
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descending tracts
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carries impulses from brain to effector organs
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decussation
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crossing of nerve tracts from one side to the other
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function of spinal cord
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*conduct nerve impulses
*serves as center for reflexes |
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reflexes
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responds to stimuli
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3 types of reflexes
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involunatary, rapid, predictable
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reflex arc
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nerve pathways for reflexes
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somatic reflex
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contraction of a skeletal muscle
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autonomic reflex
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contraction of smooth or cardiac muscle , secretion from a gland
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pupillary light reflex
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pupil gets smaller in response to light
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what happns if no pupil response to light
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poss brain damage
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5 special sense receptors location
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in brain
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what do special sense receptors do
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read indo about vision, hearing, equillibrum, taste, smell
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photoreceptors
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responds to light
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mechanoreceptors
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responds to movement
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chemoreceptors
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resond to chemicals
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orbit
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cavity that houses eye
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conjunctiva
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mucus membrane covering inner surface of eyelids
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conjunctivitis
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inflamation of conjunctiva
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lacrimal glands
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produce tears
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6 muscles of eye
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superior and inferior rectus
superior and inferior oblique medial and lateral rectus |
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3 layers of wall of eye
or tunics(covering) |
outer--scalera
middle--vascular inner |
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fibrous tunic
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center, transparent--cornea
posterior-scalera |
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vascular tunic
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choroid
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choroid
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contains __________that absorb stray light waves.
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cillary body
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ring of smooth muscle that changes shape of lens
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superior____ligament
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attaches cillary body to lens
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iris
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color part of eye between cornea and lens- controls amt of light entering the eye
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???????
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opening in iris
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retina
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contains photoreceptors
sensory receptors for vision |
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what gives us depth perception
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sensory input from each eye goes to both sides of the brain
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lens
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focuses light onto the retina
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far point of vision
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farthest distance with clear vision
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near point
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closest distance of clear focu
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when does normal vision occor
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when light is focused already on the retina rather then in front or behind
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what happens when nearsighted
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myopic--elongated eyebal, image focus infront of retina
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far sighted
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shortened eyeball...image focus behind eyeball
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somatic reflex
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contraction of a skeletal muscle
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autonomic reflex
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contraction of smooth or cardiac muscle , secretion from a gland
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pupillary light reflex
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pupil gets smaller in response to light
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what happns if no pupil response to light
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poss brain damage
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5 special sense receptors location
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in brain
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what do special sense receptors do
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read indo about vision, hearing, equillibrum, taste, smell
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photoreceptors
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responds to light
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mechanoreceptors
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responds to movement
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chemoreceptors
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resond to chemicals
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orbit
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cavity that houses eye
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conjunctiva
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mucus membrane covering inner surface of eyelids
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conjunctivitis
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inflamation of conjunctiva
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lacrimal glands
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produce tears
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