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Block 5 - Week 1
Week 1
51
Biology
Graduate
04/27/2009

Additional Biology Flashcards

 


 

Cards

Term
Which parts of the neuron has abundant RER and nissl bodies?
Definition
Dendrites and body; axons have abundant SER
Term
Which microtubule associated proteins are found in what specific parts of the neuron?
Definition
Dendrites- MAP2, Soma-MAP1,5, Axon-MAP1,3,5
Term
Which part of the neuron is devoid of nissl bodies(RER equivalents) and unmyelinated and initiates action potentials?
Definition
Axon hillock or intial segment
Term
_____________ is a motorneuron disease eventually causing death from respiratory paralysis.
Definition
Amyotrophic lateral sclerosis (ALS)
Term
Loss of dopaminergic neurons in the substantia nigra results in which disease?
Definition
Parkinson’s
Term
What is the function of astrocytes and where are they found in grey and white matter?
Definition
They help maintain the BBB, maintain extracellular environment, coupled by gap junctions and respond to injury by becoming a reactive astocyte that are glassy pink and GFAP+; protoplasmic are found in gray matter, and fibrous are found in white
Term
What is the name of the cell that is the macrophage of the CNS, that is derived from blood monocytes, and become enlarged and motile when damage occurs?
Definition
Microglia
Term
The _______ __________ is formed by the envagination of pia matter and ependymal cells in ventricular spaces
Definition
choroid plexus
Term
What are satellite cells?
Definition
They are found in both sensory and autonomic ganglia, they are multipotent glial cells that support the neuron cell body yet do not contain myelin
Term
Differentiate epi/peri/endonuerium connective tissue that cover peripheral nerves.
Definition
Epi- dense irregular CT, peri- dense CT joined by tight junctions that isolate blood-nerve barrier, endo- loose CT with fixed macrophages, capillaries, and mast cells that surround Schwann cells
Term
True or False: sensory cells have different diameters but have uniform shape and receive synaptic contacts.
Definition
False, sensory cells receive no synaptic contacts
Term
True or False: autonomic postganglionic cells are multipolar cells, receive synaptic contact, and have cell bodies that are surrounded by satellite cells.
Definition
True
Term
What is the name of the cell that lines the cerbellar cortex, has numerous dendritic projections, and is involved in the refinement of motor activities?
Definition
Purkinje cell
Term
How are the thalamus and the cerebral cortex related?
Definition
The thalamus receives and processes specific types of incoming info then sends it to the cortex; damage to the thalamus does not occur in isolation and damage to specific regions of the thalamus and cortex reveals characteristic clinical motor and sensory signs
Term
Degeneration of the basal ganglia results in disorders like Huntington’s and Parkinson’s, what does this area of the brain do?
Definition
It is associated with motor control and motor planning
Term
The hippocampus, located deep in the temporal lobe, is responsible for what processes?
Definition
Learning and memory; degeneration leads to epilepsy or Alzheimer’s
Term
What is a SNARE complex and how does BOTOX affect them?
Definition
SNARE is a series of vesicle bound proteins that when bound to calcium (synaptotagmin) induces the vesicle to release its neurotransmitters by exocytosis; BOTOX works to cleave these proteins (synaptobrevin) thereby preventing neuro release
Term
The NMJ has a high safety factor, what does that mean?
Definition
It means its resting potential is far enough away from the depolarization limit to prevent spontaneous signal transmission; it also refers to the excess of neurotransmitters used to conduct signals across the synapse
Term
What role do Schwann cells play for axons in the PNS if they don’t myelinate them?
Definition
They support the axonal tissues
Term
True or False: decreasing diameter increases the speed of conduction in myelinated axons.
Definition
False, increasing diameter increases speed linearly in myelinated axons, and to the square root of diameter in unmyelinated
Term
What is the difference between CMAP and SNAP?
Definition
CMAP measures the activation of many muscle fibers through a synapse by taking the difference in latency; SNAP measures sensory nerve conduction without a synapse, have smaller voltage; both are useful for detecting defecits
Term
How does myelination increase AP?
Definition
It reduces membrane capacitance and lowers current leak laterally
Term
How does demyelination interrupt signaling?
Definition
Current is lost to charge the capacitance of the membrane through the few sodium channels that exist at nodes, so conduction is either slowed or stopped while the amplitude should remain the same.
Term
Describe the process of nerve injury and regeneration.
Definition
In the proximal cell the nissl bodies and RER disappear (chromolysis) or move to the periphery and the distal axon undergoes degeneration via enzymes; the proximal axonal stump starts a sprouting cone and distal schwann cells form tube, so if connection remade then function resumes, otherwise both atrophy over time
Term
What are the two types of cholinesterases and where are they located?
Definition
Ach-E is located in cholinergic synapses and erythrocytes; Psuedo-E occurs in the plasma, liver, and glia and it breaks down succinylcholine
Term
What is the difference between Lambert-Eaton Myasthenic syndrome and Mysthenia gravis?
Definition
LEMS is due Ab against presynaptic Ca channels, MG is due to Ab against postsynaptic nicotinic receptors at NMJ
Term
What are the 3 therapies for myasthenia gravis?
Definition
Immunotherapy with gamma globulin, plasmapheresis, thymectomy
Term
What is the dibucaine number used for?
Definition
To assess the effectiveness of a patients Pseudo-AchE, where 80 is normal and 20 is homozygous mutant
Term
What is the difference between GABA-A and GABA-B receptors?
Definition
A is a ligand gated Cl channel that hyperpolarizes membranes, B is a G-protein receptor that increases K conductance and inhibits cAMP
Term
How do you grade deep tendon reflexes?
Definition
Scale of 0 to 4 with 2 being normal, rated as follows - absent, minimal, normal, brisk, brisk with clonus
Term
What is the Babinski sign?
Definition
Normal response to stroking the bottom of foot is big toe flexion, damage to corticospinal pathways causes extension of the big toe
Term
ID whether each of these is a sign that a problem is located either peripherally or centrally - deep tendon reflexes decreased or normal, babinski sign present, muscle atrophy, muscle fatigue (MG), increased tone/spasticity, fasciculations, crossed finding, deep tendon reflexes increased, babinski absent?
Definition
P, C, P, P, C, P, C, C, P
Term
List the grades of muscle strength.
Definition
0-no contraction, 1-trace contraction, 2-active w/o gravity, 3-active w/ gravity, 4-active with some resistance, 5-active with full resistance
Term
ID which type of nerve injury has the following “positive” effects - 1. fasciculations/cramps 2. paresthesias 3.dysesthesias/allodynia 4. increased sweating/hypertension
Definition
1-motor, 2-sensory large fiber, 3-sensory small fiber, 4-autonomic nerves
Term
When looking at a nerve conduction study in polyneuropathy what difference will you notice in the waveforms in demyelinated nerves versus axonal degradation?
Definition
Demylination will show a slow conduction while the axonal will show low amplitude CMAP/SNAP
Term
When looking at EMG interference pattern in neuropathy what will you notice in a denervation or conduction block versus a reinnervation?
Definition
Conduction block will show reduced interference pattern whereas reinnervation will show motor unit potentials of increased amp and duration
Term
What is the name of the common demyelinating polyneuropathy that results in rapid paralysis, is post-infectious 60% of the time, and causes paresthesias and lost reflexes?
Definition
Guillain-Barre Syndrome
Term
What are the 6 D’s used to make an etiologic diagnosis for neuropathy?
Definition
Distribution, duration, deficits (involved fibers), disease pathology(axonal or demy), developmental, drug
Term
Axonopathy or Myelinopathy: majority are toxic/metabolic causes, CMAP 80% of normal or distal motor latency, legs>arms, EMG shows signs of denervation and reinnervation
Definition
axonopathy
Term
Axonopathy or Myelinopathy: hypertrophic nerves, arreflexia, motor>sensory, NCS shows slowed conduction velocity or distal motor latency prolonged, EMG shows reduced recruitment without much denervation
Definition
myelinopathy
Term
When thinking of diseases causing deficits in predominantly motor fibers you think of what 3?
Definition
Guillain Barre, Lead Toxicity, or Charcot-Marie-Tooth (demy)
Term
When thinking of diseases causing deficits in sensory/proprio fibers you think of what 2?
Definition
Carcinoma, B6 toxicity
Term
When thinking of diseases causing deficits in autonomic small fibers you think of what 3?
Definition
Diabetes, amyloid, drugs like vincristine/DDL/DDC
Term
What is the difference between primary and secondary demyelination?
Definition
Primary-degeneration of myelin in the presence of intact axon, secondary- degeneration as a result of degeneration of the axon
Term
Differentiate retrograde degeneration versus trans-synaptic degeneration.
Definition
Retro- neuron cell bodies atrophy if there is progressive injury to the distal axon, trans-syn- neuron atrophies if major synaptic input is lost due to infarct/trauma/injury
Term
What is excitotoxicity?
Definition
Neurons become overstim’d due to excessive glutamate on iontropic cell receptors causing cell death
Term
What is the most common primary tumor within the CNS?
Definition
Astrocytoma
Term
Which responds to injury in the brain - microglia or astrocytes?
Definition
Both, astocytes are more slow and stain GFAP+, while microglia are quicker to respond and are GFAP-, CD68+
Term
In the ventral horn of the spinal chord alpha motor neuron cell bodies innervate striated muscle, what does the gamma motor neuron innervate?
Definition
Muscle spindle fibers which help regulate tone
Term
Identify the motor pool organization in the ventral horn of the spinal chord.
Definition
Neurons that are more medial are for proximal muscles, lateral=distal muscles, dorsal=flexor, ventral=extensor
Term
Intermediate grey matter from T1 to L2/3 is composed of interneurons that link sensory and motor function as well as mediate visceral function, what is the name of the pre-ganglionic sympathetic neurons that form a column of cells in this region?
Definition
Intermediolateral cell column
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