Introduction to neural structures and function Flashcards
Glutamate
EXCITES neurons, involved in memory and phototransduction
GABA
INHIBITS other neurons from firing
Serotonin
Affects mood
Dopamine
Involved with feeling reward, learning, and emotion
Acetylcholine
Involved with memory, attention, and muscle action
Norepinephrine
Alertness
Imbalance of glutamate (too much)
Migraines or seizures
GABA imbalance (too little)
Seizures, tremors, and insomnia
Identifiable features of bottom view of brain
Frontal lobe, olfactory bulb, olfactory tract, temporal lobe, occipital lobe
Features of the side view of the brain
Frontal lobe, parietal lobe, central sulcus, temporal lobe, lateral sulcus, preoccipital notch, occipital lobe, and cerebellum hemisphere
Where does the action potential start?
Axon hillocks
Phases of an action potential
- Activation threshold 2. Depolarization 3. Repolarization 4. Return to resting potential
Membrane potential change at activation threshold
From -70 mV to +40 mV
Refractory (def.)
Period of time where neuron is unable to fire (usually when sodium ion channel closes)
K+ ions cause…
Repolarization then hyperpolarization
Ineurons at rest (electrically speaking)
Have an electric potential between inside and outside
Usual charge of inside cell
-70mV
Depolarization
Cell becomes less negative - sodium enters cell
Hyperpolarization
Cell potential becomes more negative inside
Resting potential
Polarization level of an unstimulated neuron
Nernst equation
E = (RT/zF) on (ion outside/ion inside) Potential energy (E) depends on ionic gradient, inversely relational to charge on Ion and constants (gas constant, temperature, faraday constant)
VEP
“Visual evoked potential” - a type of non-invasive volume recording of electrophysiology. Can detect optic neuritis nerve asymmetry
Gas constant
R = 8.31 J/mol K
Standard physiological temperature
37 degrees C = 310.2 K
Faraday constant
96500 C/mol e-
Ion channels
Allow ions to cross membrane - without unable to pass due to lipid bilateral
Leakage channel
Always open ion channel
Voltage gated ion channel
Ion channels that only open at certain voltages
Receptor-linked (ligand gated) ion channel
Ion channels that open in response to the stimulus of a neurotransmitter
Cyclic nucleotide-gated ion channels
Ion channels that open in response to charges in the level of cyclic nucleotides (cGMP)
Hypernatremia
Excessive extra cellular sodium - increase size of action potential - increase muscle excitability
Hypokalemia
Loss of extracellular K+ -increase resting potential - increase muscle weakness and tremors
Na/K ATPase
Key “pump” against concentration gradient -exchange 3Na intracellular for 2K extracellular with 1 ATP
Percents of key metabolic resources distributed to the brain
25% glucose
20% oxygen
15% cardiac output
Ischemic stroke
Interruption of blood flow to the brain - loss of oxygen requires brain to switch to anaerobic respiration
Problems with anaerobic respiration in the brain
Less efficient (ion pumps compromised), lactic acid production (toxic), accumulation of free radicals
Amaurosis fugax
Temporary blindness of one or both eyes due to lack of blood flow. A symptom of an underlying problem
AION
Anterior ischemic optic neuropathy -sudden (and sustained?)loss of vision -
Arteritic AION
Sudden blindness due to inflammation of arteries supplying blood to optic nerve
N-AION
Sudden vision loss caused by reasons other than inflammation of arteries
Differentiating occipital lobe from temporal lobe
Central sulcus forms an arrow pointing towards occipital lobe
size of synaptic cleft
2 nm
requirements of synapse
production, storage, release (exocytosis), binding, generation of action potential, and removal/reuptake
structural imaging
CT and MRI
functional imaging
PET and fMRI