Neurophysiology - Special topics Flashcards
Nerve cell type that are non-permanent cells?
Neuroglia/glial cells/supporting cells
Nerve cell type that are permanent cells?
Neurons
Cell type that produces CSF
Ependymal cells
Macrophage of the brain
Microglia
Regulates ECF ion levels, gives mechanical support forms BBB
Astrocyte (nurse cells)
Creates myelin in the CSF
Oligodendrocytes
Creates myelin in the PNS
Schwann cells
Receiving portion of the neuron
Dendrites and cell body
Where action potential of the neuron starts
Axon hillock
Unmyelinated portion of the axon
Nodes of Ranvier
Branches of the axons
Neural fibril
Terminal portion of neural fibril that contains NT-containing vesicles
Axon terminal/Boutons/end-feet
Space between two neurons
Synapse
Causes saltatory nerve conduction
Nodes of Ranvier
Death of axon distal to the site of injury after an axon is transected
Wallerian degeneration/ anterograde/orthograde degeneration
Changes in the soma after axon is transected
Axonal reaction/chromatolysis
Used by the neuron to communicate with another neuron across a synapse
Neurotransmitter
Acetylcholine is secreted from?
Basal ganglia, Nucleus Basalis of Meynert
ACh deficiency results to what?
Alzhiemer’s disease - mc cause of elderly dementia
Dopamine is found mainly in?
Substantia Nigra Pars Compacta and ventral Tegmental Area
Dopamine is degraded by what enzyme?
MAO (in presynaptic terminals and COMT (in tissues including liver)
Dopamine deficiency?
Parkinson’s disease
Dopamine excess
Schizophrenia
Classic problem in Parkinson’s disease
Akinesia
Secretes norepinephrine and epinephrine
Locus ceruleus in the pons
B2 is more on epinephrine
Tryptophan derivatives
Melatonin, serotonin and niacin
Serotonin is mainly secreted by
Median raphe of the brain
Inhibitor of pain pathwAys in spinal cord, “happy hormone”, low levels seen in depression
Serotonin
Serotonin is converted to ____ in the pineal gland
Melatonin
Secreted in the brain areas responsible for long - term behavior and memory
Nitric oxide - short acting inhibitory neurotransmitter
Neurotransmitter not preformed and stored in vesicles, synthesized almost instantly as needed
Nitric oxide
Histamine is secreted from?
Tuberomammillary nucleus of the hypothalamus
Neurotransmitter involved in control of arousal, sleep and circadian rhythm
Histamine
Two inhibitory neurotransmitter
Glycine - in spinal interneurons (spinal cord)
GABA - number one inhibitory in the brain
Comes from Glutamate: causes increase chloride influx or potassium efflux in the brain
GABA
Increases chloride influx in the spinal interneurons (spinal cord)
Glycine
Number one excitatory neurotransmitter of the brain
Glutamate
Exhibited by almost all cells, its the potential difference that exist across the membrane
Resting membrane potential (RMP) - intracellular charge
RMP is -70mV caused by?
- Nernst potential for Na and K diffusion
- Na-K leak channels or K leak channel
- Na-K ATPase (-4mV)
Basis for resting membrane potential and action potential
Ion channels
Making the membrane potential less negative
Depolarization
Making the MP more negative
Hyperpolarization
Positive charges flowing into the cell
Inward current
Positive charges flowing out of the cell
Outward current
Membrane potential in which AP is inevitable
Threshold
Portion of AP where MP is positive
Overshoot
Portion of the AP where MP is <RMP
Undershoot (hyperpolarizing after potential)
Undershoot results from _____
Prolonged opening of K+ channels
Refers to opening of the Na-activation gates causes sodium influx
Depolarization
Refers to closure of Na-inactivation gates (stops sodium influx) and opening of potassium gates (causes potassium efflux)
Repolarization
Tetradotoxin and Saxitoxin are examples of _____
Sodium channel blockers of neurons
An example of potassium channel blocker of neurons
Tetraethylammonium
Time periods in an action potential during which a new stimulus cannot be readily elicited
Refractory period
another action potential cannot be elicited, no matter how large the stimulus is. Coincides with almost the entire duration of the action Potential
Absolute refractory period
Action potential can be elicited only if a larger than usual inward current is provided
Relative refractory period
Slow depolarization that the threshold potential is passed without firing an action potential
Accommodation
Synaptic inputs that depolarize the post synaptic cell
Excitatory post-synaptic potential (EPSP)
Synaptic inputs that hyperpolarize the post-synaptic cell
Inhibitory post-synaptic potential (IPSP)
Two or more presynaptic inputs arrive at postsynaptic cell simultaneously
Spatial summation
Two or more presynaptic inputs arrive at postsynaptic cell in rapid succession
Temporal summation
Repeated stimulation causes response of postsynaptic cell to be greater than expected
Nerve facilitation
Increased released of NT and increased sensitivity to the NT
Long-Term Potentiation
Repeated stimulation causes decreased response of postsynaptic cell
Synaptic fatigue
All sensory nerves pass through the thalamus except for
Olfactory nerve
Vasomotor center, respiratory center, swallowing, coughing and vomiting centers
Medulla
Micturition center, pneumotaxic, apneustic centers
Pons
Relay center for almost all sensation
Thalamus
Contributes to balance
Cerebellum
Connects the two brain hemispheres
Corpus callosum
Motor, personality and calculation
Frontal lobe
Somatosensory cortex
Parietal lobe
Vision center
Occipital lobe
Hearing, vestibular processing and face recognition
Temporal lobe
Lesion to Broca’s area results to broken speech or ____ aphasia
Expressive aphasia
Types of memory
- Short term memory - chemical changes
- Intermediate memory - days to weeks
- Long term memory - physical changes
Refers to conversion of short memory to long memory
Consolidation - accelerated and potentiated by rehearsal and learning by trauma
Hippocampal lesions will result to what type of amnesia?
Anterograde amnesia - loss of short term memory
Thalamic lesion will cause what type of amnesia?
Retrograde amnesia - loss of pre-existing memories to conscious recollection
Limbic system: produces mainly oxytocin
Paraventricular nuclei
Limbic system: produces mainly vasopressin
Supra optic nuclei
Limbic system: satiety center
Ventromedial nuclei
Limbic system: hunger center
Lateral nuclei
Limbic system: sweating - heat release
Anterior hypothalamus
Limbic system: shivering - heat conservation
Posterior hypothalamus
Limbic system: punishment center
Central gray area around Aqueduct of Sylvius
Limbic system: reward center
Medial forebrain bundle
Limbic system: social inhibition
Amygdala
Bilateral destruction of the amygdala results to a condition presenting with Hyperorality, Hyperphagia and Hypersexuality
Kluver-Buche syndrome
Master clock, modify the biological clock in the human body. Destruction causes loss of circadian functions
Suprachiasmatic nucleus (SCN)
EEG: wave during deep sleep
Delta
EEG: wave during awake, eyes closed
Alpha
EEG:wave when awake, eyes open
Beta
Secretion of this peptide could be the possible cause of sleep
Muramyl peptide
Two types of sleep
Slow wave sleep
Paradoxical sleep
Sleep type associated with memory stimulation
Slow - wave sleep
Most metabolic organ of the body
Brain - 15% of total metabolism
Main source of brain metabolism
Glucose and ketones only
Most efficient extractor of oxygen in the body
Heart - 97%
Amount of CSF produced per day
500ml - 150ml total amount of CSF in the brain
CSF pathway: connects the lateral to third ventricle
Foramen of Monroe
CSF pathway: fourth ventricle to subarachnoid space passing through the ______
Foramen of Magendie and Foramen of Luschka
CSF pathway: connects the third and fourth ventricle
Aqueduct of Sylvius
Sympathetic or parasympathetic: serous salivation
Parasympathetic
Sympathetic or parasympathetic: Mucoid salivation
Sympathetic
Sympathetic or parasympathetic: glandular secretion
Parasympathetic
Most potent heat generating mechanism
Shivering
Most of the body heat is loss through which way?
Radiation>evaporation> conduction to air> conduction to objects
High temp secondary to use of succinylcholine and halothane
Malignant hyperthermia - treated with PGE2
Energy system: in 100m dash, jumping, diving
Phosphagen energy system
Energy system: tennis and soccer
Glycogen - lactic acid system : anaerobic, reconstitute ATP and phosphocreatinine
Energy system: for unlimited time as long as with energy supply, long distance jogging
Aerobic system
Basis of muscle endurance
Glycogen in the body
What organ is the limiting factor for maximal exercise
Heart and not the lungs
At level of ____altitude, person may experience twitching / seizures
18,000 feet
Condition that manifest with acute pulmonary edema, acute cerebral edema
Acute mountain sickness
Manifest as pulmonary vasoconstriction, right sided heart failure
Chronic mountain sickness
More dangerous G force, blood shunted to the lower extremities
Positive G - at +20G vertebral fracture
Manifest as pain in the joints and muscles and dyspnea
Decompression sickness