Module 3: Neural Functioning Flashcards
molecules–organelles
–cells–tissue–organs–organ systems–organisms
four types of molecules
lipids (fats); proteins (amino acids); carbohydrates (sugar, energy); nucleic acids (DNA, RNA)
bilipid membrane
surrounds cell; keeps things away from each other and maintains resting potential
nucleus
center of cell
nucleolus
RNA in nucleus
cytosol
intracellular soup with organelles
mitochondria
metabolism/food storage for cell
cytoskeleton
structural protein; for shape and transportation
endosplasmic reticulum
proteins to build larger molecules
Golgi apparatus
move materials out of cells
lysosomes
break down and recycle old materials
microtubulues and filaments
maintain structure and are cytoskeletal tracks for axonal transport (anterograde and retrograde)
electrochemical gradient
make equal
concentration gradient
high sodium on the outside, lower on the inside; passive process for producing electrical current
positive and negative ions
pos: sodium/calcium/potassium; neg: chloride
selective permeability
only allows (chloride) through passively due to shape
globular proteins
channels that let things in and out
ATP
energy in cell
sodium potassium pump
voltage regulated gate; moves from low to high (against gradient); allows for change in resting potential by providing energy to the cell; exchange of sodium and potassium (uses ATP for energy)
multipolar neurons (several dendrites, one axon)
Golgi Type I projections: long axons; myelinated; motor. Golgi Type II: local, unmyelinated, thalamic loops, interneurons
bipolar neurons (one dendrite and one axon)
rare; auditory and olfactory
unipolar neurons (one axon)
sensory information from PNS to CNS
axondendritic synapse
normal connection
axomsomatic synapse
inhibition
axoaxonic synapse
modulate pattern generators
Nissl susbstance
special protein in rough ER for membrane upkeep (maintains negativity) and info processing; needs constant supply of oxygen
axon hillock
connection of axon to soma
teledendrion terminate in
terminal boutons
resting potential
difference in potential across the membrane at rest: -70 mV; cytosol is negative compared to extracellular space so that reaction can occur; depolarization occurs when differences reaches -55mV
graded potential
mechanical or chemical perturbation (generated by sensory input) that effects the plasma membrane; travels along dendrites in small decrements and can accumulate to create AP OR decrease as it spreads
depolarization
cell becomes less negative; excitatory; positive ions in (Na), negative out; RP decreased
hyperpolarization
cell becomes more negative; inhibitory; positive ions out, negative in; back to -70mV; RP increased
action potential (nerve impulse)
all or nothing; at axon hillock to terminal bouton; if cell membrane reaches -55mV, the electrical gate opens; depolarization opens Na+ channels and floods cell with positive ions; sets of negative waves down the axon; decremental; sodium channel opens at -55mV and Na+ enters cell until it gets to +40mV; then K+ leaves cell, potential returns to resting; recovery period
synaptic transmission
AP reaches boutons; opens voltage-gated Ca++ channels; activates synaptic vessicles to release neurotransmitter
neurotransmitter
causes ion channels or post-synaptic membrane to open; synthesized in soma or cytoplasm; largely chemical process
Ligand Channel
electrical gates on one side, chemical on other; opens when dopamine hits (chemical gate)
Nodes of Ranvier
unmyelinated areas; more common in PNS; saltatory transmission; faster for shorter axons, and more efficient
convergence
1 neuron receives impulse from multiple neurons; inhibitory or excitatory; summative strong response (from graded potential to AP)
divergence
1 neuron activates multiple proximal synapses; increases amplification; branching into limitless pathways; common in cerebellum due to sensory afferent to thalamus and cortical areas
degeneration of cell
primary neuronal loss: immediate neuronal loss (CVA, anoxia, trauma)–loss of all blood flow; secondary neuronal loss: region adjacent to primary injury
retrograde axonal reactions
degeneration changes to cell body in response to injury down the axon
regeneration
PNS: injured axon can regrow due to trophic factors that cause axonal sprouting (in Schwann cells); CNS: no growth, or if limited, then rapid scar tissue produced
retrograde transneural degeneration
death that affects proximal cells
excessive neurotransmitter removed in three ways
1: reuptake 2: degradation (used up in opening channels and changes into other substance) 3: diffusion (into extracellular space)
excitatory
resting potential decreases (less neg.), causes depolarization EPSP: muscle, gland, other neurons. Example: glutamate
inhibitory
resting potential increases (more neg.), causes hyperpolarization IPSP. Example: GABA
neuropeptide
neurotransmitter for modulation/regulation of other neurotransmitters
examples of neurotransmitters
ACh, norepinephrine, neuropeptides, dopamine, serotonin, GABA
synaptic transmission process
synthesis of neurotransmitter; concentration and packing of neurotransmitter; release of n. into synaptic cleft; binding to receptor molecule post-synaptically; termination of action (exocytosis: closing of vesicle)
Parkinson’s
Not enough inhibitory dopamine produced in basal ganglia, so Ach exitatory is unopposed and keeps firing; hypokinetic (rigid/dysarthria); masked face; monopitch; rapid articulation; stuttering. Tx: reduce ACh, make dopamine last longer, add more
myasthenia gravis
disorder at gap junction; progressive weakness of muscles; autoimmune response as enzymes attack neurotransmitter and prevent synapse; ptosis (eyelid dropping), blurred vision, dysphagia, slurred speech. Tx: medication
