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73 Cards in this Set
- Front
- Back
What makes up the forebrain?
What makes up the brainstem? What makes up the hindbrain? |
cerebrum and diencephalon
midbrain, pons, and medulla pons, medulla, and hindbrain |
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What fissure separates the two cerebral hemispheres?
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Longitudinal fissure
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What separates frontal and parietal lobes? What separates the lateral lobe form the frontal and parietal lobes?
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Central sulcus
lateral fissure |
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What gyrus is superior to the corpus callosum? What does it handle?
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cingulate gyrus
emotion |
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What occupies the cortical midline?
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limbic lobe
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What is the function of the following structures:
cerebrum thalamus hypothalamus mesencephalon pons medulla cerebellum |
conscious thought
sensory relays homeostasis consciousness and visual/auditory data sensory relay, motor (peduncles) autonomic and thalamus relay motor control |
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What are the functions of the lobes?
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Frontal lobe: personality and higher centers for voluntary motor activities (Primary motor cortex- seen in red)
Parietal lobe: peripheral sensations (primary somatosensory cortex- seen in blue) Temporal lobe: sensations of smell, taste (in insula) & hearing Occipital lobe: vision |
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What condition has slurred, slow words? Which condition has phonemic paraphrasia?
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lesions in Broca's area
lesions in Wernicke's area |
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What do right sided lesions cause in Broca's and Wenicke's area?
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dull monotone speech
inability to understand tone |
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What are basal ganglia?
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series of interconnected nuclei embedded in the subcortical white matter involved in the control of movement (plan, initiate, and maintain voluntary motor activities)
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What makes up the basal ganglia? what does damage to the area cause?
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striatum, pallidum, substantia nigra, and subthalamic nucleus
Negative signs: loss of motor function Positive signs: new motor activities, or an inability to suppress unwanted motor function |
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What are the mamillary bodies?
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olfactory pathway relay station that are part of the hypothalamus
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What are the 3 steps of sensory input?
What are the 2 steps of motor output? |
Neuron 1 carries information to the CNS
Neuron 2 carries the information to the contralateral thalamus Neuron 3 carries the information to the cortex Neuron 1 (the upper motor neuron) carries information from the cortex to a lower motor neuron on the contralateral side of the CNS Neuron 2 (the lower motor neuron) carries the information from the CNS to a muscle |
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What are the functions of the meninges?
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Cover and protect the CNS
Protect blood vessels and enclose venous sinuses Contain CSF (Keep the brains suspended in a bath of CSF) Form partitions within the skull that prevents movement within the skull |
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What layers make up the meninges?
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Dura or pachymeninx = tough mother, 2 layers
- periosteal and the menegeal Arachnoid = web like, -appears like syran wrap subarachnoid space with trabeculae (delicate collagen and elastic fibers) The Pia adheres to the brain & is rich in capillaries follows contour of the brain |
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Where are dura not fused?
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dural sinuses
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What artery and nerve supply the dura?
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middle meningeal artery
trigeminal nerve |
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What are the 4 septa?
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falx cerebri - between the cerebral hemispheres (free edge follows the corpus callosum)
tentorium cerebelli - transverse septum separating the occipital lobe from the cerebellum falx cerebelli - septum between the cerebellar hemispheres diaphragma sellae - roof of the hypophysis fossa (sella turcica), perforated by the infundibular stalk |
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What are the Arachnoid villi?
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protrude superiorly and permit
CSF to be absorbed into venous blood |
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What returns CSF to the blood via the superior sagittal sinus?
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granulations
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What are 2 potential spaces?
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epidural
subdural |
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What is a countrecoup injury?
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damage to brain during rebound collision with opposite side the skull
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What does a epidural hematoma look like? What likely tears?
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lens
middle meningeal artery |
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What shape is a subdural hematome and why?
What tears? |
crescent-shaped
bounded by dura and arachnoid bridging veins |
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What causes worst headache of life in subarachnoid hematoma? What tears? how does it look?
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meningeal irritation
arteries in pial membrane texaco star |
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Where is the blood brain barrier absent?
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the choroid plexus, hypothalamus, and pineal gland
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What are the 4 components of corpus callosum?
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rostrum
genu body splenium |
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Where does the brain receive its blood supply?
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80% of the brain’s
blood supply comes from the carotid, and the remaining 20% from the vertebral |
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What is the difference between cortical and central branches?
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Cortical (Circumferential) Branches
Supply External Brain Structures Central (Penetrating) Branches Small Penetrate ventral surface to supply internal brain structures |
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What do the anterior choroidal arteries supply?
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Anterior hippocampus &
Posterior limb of the internal capsule |
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What does an interruption in the anterior cerebral arteries cause?
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Paralysis of legs and feet
Difficulty in prefrontal lobe functions of cognitive thinking, judgment, motor initiation and self monitoring |
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what are watershed areas?
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Oerlap in arterial perfusion
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What is a transient ischemic attack?
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Transient occlusion of an intracranial artery due to thromboembolism
Symptoms resolve following rapid fragmentation and dissolution of the microemboli/thrombus |
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What is an embolism and thrombosis?
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Embolism: object/piece of a clot (from another part of the body) which travels through artery until it gets stuck
Thrombosis: object originating within a blood vessel: local buildup of fatty substances usually at a bifurcation of artery, these can rupture leading to bleeding and clotting |
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What is a lacunar infarct?
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Occlusion of small vessels (200-400 mm)
internal capsule/corona radiata, thalamus, basal ganglia, brain stem |
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What is an Arteriovenous Malformations?
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Appear tangled mass of arteries and veins
Blood vessel defects that occur before birth Can cause hemorrhagic strokes |
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What is the Monro-Kellie Doctrine?
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As an intracranial mass increases in size
CSF is displaced into the spinal canal Blood volume is reduced in the brain Displacement of brain tissue - herniation |
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What are the 4 types of herniation and the 2 types?
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Cingulate or subfalcine: compress anterior cerebral arteries)
Transtentorial herniation: ultimately the brainstem is compressed which results in death if the pressure is not removed Tonsillar (chiari malformation) can be incidental, or life threatening Cerebellar herniation (increased p2 in posterior fossa can push cerebellum up The supratentorial (occurs above the tentorial notch) Uncal, transtentorial (central), cingulate, and Transcalvarial The infratentorial (occurs below the tentorial notch) upward transtentorial and tonsillar. |
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What kind of neurons bleong in the afferent category? What neurons belong in the effernt category? CNS?
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unipolar and psuedopolar
multipolar anaxonic |
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How is interneuronal fow carried? Intraneuronal?
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Chemical
electrical |
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What is the point of the cytoskeleton?
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structural suport
compartmentilzation Guidance during development, growth, neuronal repair and regeneration Aid in the transport of substances to and from the cell body (axonal transport) |
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Which cytoskeleton elements are polar? Non-polar? Which uses ATP? Which used GTP? Nucleotide binding?
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Actin and microtubules
neurofilaments actin microtubules neurofilaments |
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What are the main 2 functions of neurofilaments?
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structure and help in axonal transport
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What is the specific funciton of actin filaments? What 3 things are they associated with?
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Help neurons interact with extracellular matrixand with other cells (tight junctions/gap junctions)
Associated with: presynaptic terminals dendritic spines growth cones |
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Which motor protein is anterograde? Retrograde?
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kinesin
dyenein |
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How does phosphorylation affect microtubules? What is this indicative of?
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destabilizes
alzheimers |
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What is transported by Component A fast anterograde?
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neurotransmitters & neuropeptides
membrane lipids & glycolipids membrane-associated enzymes (e.g. ACh-esterase) receptor proteins |
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What is transported by Component B tranport?
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Unbound materials transported (mitochondria)
does not require cell body…. or axon (just the axoplasm) |
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What is the significance of the slow anterograde axonal transport?
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cytoskeletal elements, e.g. actin, tubulin, MTs, NFs, MFs
soluble enzymes, e.g. glycolytic enzymes Primary mediator of axon growth and regeneration Limiting factor of regeneration |
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What is the purpose of fast retrogrde transport? What does it carry and in what container?
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Returns old membrane components from the axon
terminal to the cell body for recycling Transported materials are packaged into organelles materials transported include: trophic factors & growth factors used materials bound for lysosomal degradation viruses, e.g. rabies, polio, herpes simplex dyes, e.g. HRP |
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Which cells are scavengers?
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microglia
think macrophages |
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What is the difference between macorglia and microglia?
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Macroglia, which include astrocytes, oligodendrocytes,
and ependymal cells, are of ectodermal origin Microglia, the macrophages of the CNS, are of mesodermal origin. |
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What are the 4 differences between glia and neurons?
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Glial cells differ from neurons in that (1) they do not form
synapses; (2) they have only one type of process; (3) they retain the ability to divide throughout their life span; and (4) they are electrically inexcitable |
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What is the purpose of Schwann cells?
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Schwann cells supply the myelin of the PNS: Each Schwann cell commits itself to a portion of one axon
Help determine distribution of voltage-gated channels along axon Regulate synaptic communication at NMJ (neuromuscular junction), including likely release of transmitters Important in recovery from axon damage: supply growth factors, “channel” for new growth |
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How are oligodendrocytes different from Schwann cells?
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A single oligodendrocyte sends out multiple processes
Each process wraps around a portion of an axon Thus a single oligodendrocyte contributes myelin to several (40?) central axons Each Schwann cell commits itself to a portion of one axon |
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What are the most abundant and versatile glial cells?
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astrocytes
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What is the purpose of astrocytes?
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Support and brace neurons
Anchor neurons to their nutrient supplies Guide migration of young neurons Control the chemical environment |
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What are radial glial cells?
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Supply guidance to neurons during neural migration
Are progenitors for fibrous & protoplasmic astrocytes |
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What and where are ependymal cells?
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Ependymal cells – range in shape from squamous to columnar. They line the central cavities of the brain and spinal column
They line the ventricular system |
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Describe microglia?
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Arise from mesoderm not neuroectoderm
Mediate immune responses Become reactive in response to damage more microglia are recruited to the damaged area phagocytose pathogens and cell debris in the CNS release cytokines (IL-1, TNF-a) Susceptible to HIV infection |
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What causes transient loss of function?
What causes permanent loss? |
edema
constant pressure anoxia Cold neuronal degeneration |
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How is regeneration limited in the CNS?
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Oligodendrocytes inhibit neurite outgrowth
Reactive astrocytes cause glial scarring which interferes with nerve regrowth Fewer chemotropic factors available in CNS |
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What is wallerian degenration?
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Axonal degeneration distal to insult
Nerve terminal fills with clumps of Neurofilaments and disrupted mitochondria Contact Post synaptic membrane lost Glia invade and phagocytose debris |
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What are the steps of distal degneration?
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Synaptic transmission lost, terminal fills with clumps of NFs, disrupted mitochondria (Week 1)
Contact with post-synaptic membrane lost, glial cells invade, axon segment distal to injury withdraws (Week 2) Distal segment fully degenerates, myelin sheath lost, termed Wallerian degeneration (PNS: week 2-8; CNS, phagocytosis may last for months) |
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Why does retrograde degeneration occur?
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synaptic pattern dies
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What happens to a neuron during chromatolysis?
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Rearrangement of Nissl substance (arrow)
Swelling of the cell body with displacement of the nucleus (arrowhead) (Nissl, ×250) |
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How do Schwann cells promote regeneration?
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release of trophic factors
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What is the cause of crocodile tears syndrome?
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Regrowing axons are not very selective and aberrant
reinervation commonly occurs |
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where are neural stem cells found?
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walls of the
ventricles |
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How does the CNS compensate for degeneration?
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Reorganization of neuronal circuits,
Increase spine density, Dendritic arborization and by Synaptogenesis |
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What are the consequences of degeneration?
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Synaptic transmission is lost
Contact post synaptic membrane lost Nerve terminal fills up with neurofilaments and disrupted mitochondria Distal segment degenerates fully, myelin sheath lost, termed Wallerian degeneration Glia invade and phagocytose debris (PNS: week 2-8; CNS, phagocytosis may last months) |
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What are the 5 basic steps of neuron transmission?
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Synthesis of NT
Packaging (concentration of NT) in presynaptic terminal Release NT from presynaptic terminal into synapse Binding of NT to receptor in postsynaptic membrane Termination of NT action |
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What is vasogenic edema? What is it caused by? What is cytotoxic edema? What is it caused by?
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Vasogenic edema – fluid leaks from blood vessels into brain
Cause: frequent in cases of head trauma and meningitis Where: In regions bordering ischemic zones, Why: increased permeability of the blood-brain barrier Cytotoxic edema - fluid leaks into individual neurons Cause: drug poisoning, water intoxication, hypoxia from asphyxia and acute hyponatremia Result: shift of water from extracellular space to interior of brain cells |