Chapter 13 2
Terms
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- Star shape, support fibers, from scar tissue, and form blood-brain barrier in brain capillaries.
- Astrocytes (90%)
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Information management, storage, and retrieval as well as forgetting trivial
- Memory
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Respiratory center
Cardiac center
Vasomotor center
Other areas control swallowing, vomiting, coughing, hiccuping, sweating - Vital Centers
- Brain tumors composed of glial cells
- Brain tumors
- Three CT layers, cover the brain & spinal cord, CSF flows between them forms a protective fibrous membrane.
- Meninges
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STM, few seconds - few hours, limited bites of info
Working memo: holds info long enough to carry out an action (like remembering a phone #)
- Short-term memory
- General senses of the kin, muscle, tendon, organs
- Somatosensory or somesthetic
- Ability to hold info in mind a few seconds (re-echo of what just happened)
- Immediate memory
- Produce & circulate CSF in brain.
- Ependymal.
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Result of aneurysm in brain causing brain damage usually in 1 hemisphere and loss of
motor on one function to some or all of the opposite side of the body
- Stroke
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Most posterior part of brain,
Relay center from brain & SC to cerebellum
Contains vital
- Medulla oblongata
- Destruction of motor neurons caused by poliovirus
- Poliomyelitis
- Motor end plate - between motor neurons and muscle cell.
- Neuromuscular Junction
- Control emotions Limbic System - Affects emotional aspects of behavior & motivation and evaluates rewards - plays a role in sexual behavior, biological rhythms, and autonomic responses - Extreme rage
- Emotions
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Location - 3rd ventricle to optic chiasma below thalamus
Regulates pituitary hormone activity and is the major control center for ANS
- Hypothalamus
- Thought disorder involving delusions, hallucinations, incoherent speech, withdraw from society, inappropriate response to stimuli, etc. Due to heredity or developmental NS development.
- Schizophrenia
- Brain and spinal cord. Protected by cranium & vertabrate.
- CNS (central nervous system)
- State of unconsciousness which no amount of stimulus can awaken
- Coma
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large mass of fibers forms a bulge on the anterior of brain stem
Connects signals from spinal cord and medulla to upper brain regions
center for incoming sensory / outgoing motor signals & regulates respirations
- Pons
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Atrophy in gyri folds and hippocampus, plaques tangles accumulate in
nerve cells memory loss and later loss of brain function
- Alzheimers Disease
- Unexcited state - a change in resting state in excitable cells may generat an AP.
- Resting State
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75% of brain - areas concerned with cognition, integration of information
between sensory and motor components. - Association Areas
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About 83% of total brain mass - most prominent part of brain in mammals
All higher brain functions occur here
- Cerebrum
- Lack of muscular coordination due to motor area damage during prenatal, birth, or infancy caused by rubella injection, drugs, or radiation exposure, or lack of O2 at birth & hydrocephalus
- Cerebral Palsy
- Many arms from myelin sheath around several nerve fibers using white matter, insulate nerve and increase AP rate.
- Oligodendrocytes
- Recurring headaches often accompanied by nausea, vomiting, dizziness, and aversion to light. Due to such things as diet, food additives, stress, hunger, red wine, noise, and yet unknown causes. More common in women.
- Migraine Headache
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Develops from the embryonic neural tube which is composed of three main parts:
Neural tube begins as: Neural plate „³ neural groove „³ neural tube „³ brain & SC
- BRAIN
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Reduced dopamine levels cause - muscle movements like hand shaking
& loss of some motor function. Pts develop shuffling gait, stooped posture, & slurred speech.
- Parkinsons Disease
- Delicate innermost layer that rests directly on the surface.
- Pia Mater
- Inflammation of the brain usually accompanied by fever. Due to mosquito-borne virus or herpes virus. Causes neuron degeneration and necrosis leading to delirium, seizures, & death.
- Encephalitis
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Largest part of hindbrain - 2nd largest region of brain = 10% of brain
Coordinates voluntary muscle movements in limbs & maintains muscle tone and posture by
monitoring learning motor skills - Cerebellum
- Degeneration of motor neurons & muscles. Sensory and intellect remain in tact
- Amyotrophic lateral sclerosis - Lou Gehrigs disease
- Ony schwann cells from neurolemma - from myelin sheath, wraps around axons.
- Schwann Cells
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Lasts a lifetime and can store info in STM (recall name, address, routes)
Declarative - retention of facts you can put into words - #, dates, names, places
Procedural - retention of motor skills - walking, running, et
- Long-term memory
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Functions as relay center for information entering brain from the spinal cord
Includes visual, auditory, and tactile reflex center
- Midbrain
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Temporary state of unconsciousness. Deprivation tests indicate improper brain
function, altered mental state, and psychosis occurs when sleep deprived.
- Sleep
- During AP and msec after it is difficult or impossible to stimulate another AP.
- Refractory Period
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Loss of memory or inability to store memory
Antegrade amnesia - cant store new information or make new memories
Retrograde amnesia - Cant recall events before the brain injury
- Amnesia
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Gateway of most sensory input to the cerebrum
Main input and output center for sensory and motor information to cerebrum
- Thalamus
- Degeneration of the myelin sheath and oligodendrocytes
- Multiple sclerosis
- Carry incoming sensory signals toward CNS (brain & spinal cord) Detect changs in environment called stimula - Begin on skin or in organ as sensory receptors.
- Sensory (Afferent)
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Accumulation of glycolipids in myelin that disrupts conduction of signals
- Tay-Sachs
- Carry signas away from soma to synapse. Distal end branchs to form syaptic knob - contains neurotransmitters released to send signal across gab (synaptic cleft) neuron, gland, or muscle.
- Axon
- Damage to brain due usually due to blow to head causing altered LOC (level of consciousness), blurred vision, nausea, altered equilibrium
- Concussion
- Nerve Impulse generation created by voltage-regulated ion channels. Only neurons and muscle cells have the ability to change their membrane potentials.
- Action Potential (AP)
- Mental processes like awareness, perception, thinking, knowledge, memory
- COGNITION
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Convolutions (gyri) = thick folds
Sulci = shallow groove between the folds in the surface of the brain
Fissures = few deep furrows into the brain folds E.g. Longitudinal fold separates R & L hem.
- Features of Cerebum
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Neural tube defect causing bulge or sac to develop on exterior of spine containing
spinal cord, meninges, and fluid. May cause paralysis to lower body.
- Spina Bifida
- 90% of all neurons in body, in CNS, receive signals from other neurons and integrate signals. Connect sensory and motor nerve pathways.
- Interneurons (association)
- Disorder causing sudden massive discharge of neurons (seizures) resulting in motor convulsions, mental & psychic disturbances, and altered LOC. Due to trauma, tumors, drugs & alcohol abuse, or congenital brain defects
- Epilepsy
- Specialized glands/tissue that make & send chemicals through blood to target cells. Have a slower, longer lasting effect than NS.
- Endocrine (Hormone) System
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Controlled in different areas of cerebral cortex - read, write, speak, understand words
Wernickes Area - complex thought
Brocas area - muscle movement
- Language
- Bundles of myelinated (insuulated) axons called tracts in CNS located beneath the gray matter in brain and outside gray matter in spinal cord.
- White Matter
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Inflammation of the meninges caused by bacterial or viral infection
Bacterial = spreads to adjacent nerves and ventricles and brainstem enlarges
- Meningitis
- Thick band of white matter (bundle of nerves) that holds hemispheres together
- Corpus Collosum
- Relatively long-lasting change in behavior; result of remembering what we experience
- Learning
- 12 pair of cranial nerves (exit from the brain) and 31 pair of spinal nerves (one pair exits from between each vertebrate of the spine) Makes up the rest of the NS.
- PNS (peripheral nervous system)
- Due to short-term loss of O2 to brain
- TIA (transient ischemic attack) (mini-strokes)
- Accessory cells that support the neurons.
- Neurons and Neuroglia
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4 internal chambers at center of brain, make & secrete CSF brain and spinal cord and is reabsorbed by sinuses in dura matter.
Bouyancy, Protection, and Chemical Stability. - CSF
- Vision association area Fx: sight
- Occipital
- Somatic and autonomic motor & sensory fibers. 31 spinal and 12 cranial nerves ANS=sympathetic & parasympathetic.
- Cells of PNS
- Do no cell division but are long-lived.
- Mature Neurons
- Insulating layer around nerve - Made by oligodendrocytes (CNS) and Schwann cells 9 PNS)
- Myelin Sheath
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Allows signals to pass to thalamus - gateway to
cerebrum. Consists of 100+ nucleii running through midbrain, pons, and medulla
- Reticular formation -gatekeeper
- 50 X's more gliam cells than neurons. Protect and aid neurons. Provide support direct movement in embryo, prevent unwanted synapses, create barriers.
- Neuroglia
- Dendrite-Cell Body(Soma)-Axon-Synaptic Knob
- Neuron Structure
- Contains the cell bodies of sensory neuron cell bodies - sends signals into spinal cord to inteneuron.
- Dorsal Root Ganglion
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Primary somatosensory cortex receives & interprets signals from sensory receptors.
- Parietal
- Carry signals away from CNS to effector cell - Effector=cells and organs.
- Motor (efferent neurons)
- Mitochondria, lysosomes, Golgi, inclusions, rER, etc.
- Neuroplasm
- Demyelinating disease in CNS which prevents AP conductions.
- Multiple Sclerosis
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Deep between the fold between the temporal and parietal lobes
Fx: ? Spoken language, sense of taste integrates other sensory information
- Insula
- WBS that [hagocytize debris, concentrate on damaged or infected areas.
- Microglia
- Control center, contains organelles and nucleus.
- Cell Body(Soma)
- Like a vertical stalk with cerebrum perched on top of it - includes diencephalon, midbrain, pons, medulla oblongata. Ends at foreman magnum where CNS continues as spinal cord.
- Brainstem
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Hearing and smell, auditory association area
Fx. Learning, hearing, smell, visual recognition, memory, emotional behavior
- Temporal
- Surround soma in ganglia - unknown fx.
- Satellite Cells
- Nerve Cell, functioning unit of NS. Electrically excitable cells specialized for transmitting signals from one location in the body to another.
- Neuron
- Middle layer, sticks to inner surface of dura mater superficially. Works with choroid plexus to form a blook-brain barrier beween CSF and blood.
- Arachnoid Layer
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Motor cortex
Sensory cortex
Association Areas - Cerebral Cortex Three Regions
- Ropelike bundles of 100-1000 nerve fibers (axon) wrapped in CT - Emerge from CNS through foramina in the vertebrate and skull and innervate body.
- Nerves (tracts)
- (1+ branched fibers) receive signal from receptor or another neuron.
- Dendrite
- Decides to transmit or store information.
- Interneurons
- Other than somesthetic refers to ears, eyes, nose, taste
- Special Senses
- Tubular cord extending from the base of the brain to the level of the second lumbar vertebrate that conveys signals to/from brain and serves as a reflect center.
- Spinal Cord
- Rapid Transmission of signals from cell to cell, but short-lived effect.
- Nervous System
- Ventrolateral surface & meet ventral root of spinal nerve - send efferent messages out to effector cells.
- Ventral (anterior) Horns
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Primary motor cortex sends commands to skeletal muscle signaling appropriate
responses to sensory stimuli, speech center
Fx: motivation, planning, foresight, mood, memory, social judgement, aggression
- Frontal
- Nerve cord from brain which lies within central canal of vertebrate - coordinates nerve impulses passing between brain and PNS.
- Spinal Cord
- Fiber-Like extensions attached to cell body.
- Neuron Fibers
- Difference in ions inside vs. outside of the neuron cell membrane - potential enery that polarizes cell. Stimulus creats a current as ions flow in and out or neuron cell membranes.
- Electrical Potential
- Controlled by hypothalamus and brain stem
- Sleep cycle
- Charge difference between inside & outside surface - 70 mV means there are more negatively charged ions inside of membrane thatn out.
- RMP (resting membrane potential)
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Electroencephalogram records brain wave activity. Lack of brain waves = death
- EEG
- Unmyelinated nerve cell bodies and dendrites located on the surface of brain, deeper, and in core of spinal cord.
- Gray Matter
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Sleep and wake cycles of daily routine, biological clock
Brain of a sleeping adult passes up and down through above stages of brain activity.
- Circadian Rhythm
- Tracts - Nerves
- Axons in Clusters.
- Neurons - Gangila
- Cell Bodies
- Amount of stimulus required to depolarize a nerve membrane.
- Threshold
- If axon is damaged, end of axon dies, new sprouts seek out neurolemma tube - guides growing axon to original destination - only in PNS. No repair occurs in CNS.
- Regeneration Tube
- Abnormal accumulation of CSF due to blockage of CSF flow-ventricles expand & compress tissue, infants entire head enlarges sice cranial bones are not fused yet - may insert a shunt.
- Hydrocephalus
- A cleft created at the distal end of axon knob and next cell - most cases AP triggers release of neurotransmitter across cleft starting AP in next cell.
- Synapse
- Outer, tough fibrous layer (texture like rubber gloves)under skull bones.
- Dura Mater
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1. Resting State
2. Depolarization Phase
3. Repolarization Phase
4. Undershoot
5. Refractory Period -
Propagation steps to an AP
- Reduction in the electrical gradient across a membrane.
- Depolarization
- Forms from folding of anterior end of the neural tube in embryo. Higher center that coordinate activities in the body in response to stimuli and connects to spinal cord.
- Brain
- 83% of brain, has two hemispheres right and left.
- Cerebrum
- Maintans resting charge by pulling Na out and K neuron.
- Sodium-Potassium Pump
- Gaps between the cells are found along a single axon.
- Nodes of Ranvier
- Inferior to cerebrum, it occupies posterior cranial fossa.
- Cerebellum