Nervous 1 Flashcards
what is a ganglion?
a centralized group of electrically active cells
what is a brain?
a centralized command over the entire body, two lobes, more interneurons than direct primary neurons
when does a ganglion become a brain?
when there are two lobes, if it has more interneurons than primary ones, and if it has centralized command
what is the neocortex?
part of the cerebral cortex, highly organized and complex, has 6 layers
does having more neurons mean you’re smarter?
NO! whales have very complex neocortex, birds don’t have one but are very smart
frontal lobe is for
motor cortex, planning, long term memories, higher functions
temporal lobe is for
auditory cortex, memory formation, communication, facial recognition
pareital lobe does what
sensory integration from multiple modalities (somatosensory cortex)
what cations and anions do neurons use?
Na+, K+, Ca2+, Cl- and other anions
resting membrane potential is around
-60-70 mV due to a negative charge built up on the interior of the neuron
ions always want to flow _____ to eliminate electrical potentials.
down concentration gradients
resting membrane potential is maintained by _____
ion pumps, sodium potassium pumps
maintaining resting membrane potential is ______
an energy intensive process, 1 ATP per 3 Na+ ions
what are the two types of passive transport channels?
ligand-gated channels and voltage-gated channels
voltage gated sodium channels open at _____ and inactivate at
-50 to -55 mV
over 0
voltage-gated potassium channels open at and inactivate at
0mV
-90mV
action potentials are initiated at the
axon hillock
rate of propagation is determined by
axon diameter: larger diameter means faster impulse
presence of myelin sheath: myelin means faster
what are the two mechanisms of propagation?
continuous (unmyelinated) and saltatory (myelinated)
what is the threshold level for an action potential?
-55mV
what is a graded potential?
small fluctuations in membrane potential due to the opening of ion channels
depolarization has ___ potential and hyperpolarization has ____ potential
excitatory
inhibitory
ionotropic receptors are ______. when the receptor is activated, the ion channel ____. can be either _____ or ____. they signal ____
ligand-gated ion channels
opens
excitatory
inhibitory
quickly
metabotropic receptors are often _____. this signaling ____ and this is a _____
linked to an ion channel via signaling cascade
persists longer
G coupled protein receptor
