Ch. 2 Structure and Function of Nervous System Flashcards
three main parts of the neuron
soma
dendrites
axon
soma
nucleus and other organelles
all proteins made here
dendrites
extensions that receive info (inputs)
shaft- main brain
spines- bumps where synaptic connections form
axon
extension that delivers outputs electrically from cell body to boutons
glial cells
not excitable cells, influence neural activity and transmission through structural support, ion concentrations around cells, reuptake, etc.
projection/principle neurons
main integrating/ processing neurons of brain region
axon usually leaves region in which soma resides (pyramidal cells)
interneurons
any neurons that are between sensory and motor neurons
OR
cells who’s axons remain within particular brain region
usually inhibitory
neurons use of ion channels
transporters and pumps used to control concentration of sodium, potassium, chloride, and calcium
what is the resting state of gated ion channels
closed
voltage gated ion channel
opens when electrical potential across membrane is altered
ligand gated ion channel
opens when a ligand binds to a receptor
second messenger ligand gated ion channel
activated by attachment of phosphate group on intracellular side of receptor
what ions have a depolarizing effect
sodium and calcium
what ions have a hyperpolarizing effect?
potassium and chloride
what is the resting membrane potential?
the voltage of the cell across the membrane determined by concentration gradients of ions
-70 mv
what causes the resting membrane potential?
higher concentration of + ions outside
higher concentration of - ions inside (mostly from intracellular proteins)
which ion is the only one that can pass through the membrane at rest?
K+
what is the threshold potential
electrical potential that causes the ion channels to open
-50 mv
what happens when sodium channels open at threshold potential?
cell depolarizes to action potential (+45 mv) because positive sodium is rushing into the cell because of electrical and chemical concentration gradient
what happens after sodium ions rush in the action potential
potassium ions move out because of the concentration gradient
repolarization causes both channels to close (-90)
what does the sodium-potassium pump do?
brings K inside and Na back outside, returning cell to resting potential
what causes initial depolarization?
synaptiv inputs from local potentials that are either excitatory (EPSP) or inhibitory (IPSP)
true or false: local potentials and action potentials are graded
false, action potentials are all or nothing
how do NTs/drugs alter neural activity through IPSPs or EPSPs
modulate impact of potemtials reaching the cell therefore change cell excitability
what are the two main parts of the nervous system?
central and peripheral nervous system
what are the components of the PNS
somatic and autonomic system
somatic system definition
voluntary control of muscles
autonomic system definition
regulate internal environment involuntarily
controls digesting, blood pressure, temperature, etc
components of the autonomic nervous system
sympathetic division
parasympathetic division
sympathetic division definition
fight or flight system, dominant in times of stress
increased heart rate, blood flow, adrenaline, etc
parasympathetic division definition
dominates when energy reserves can be conserved
digestion, glucose storage, slow heart rate, etc
what neurotransmitters does the ANS use?
norepinephrine (NE)
acetylcholine (Ach)
what kind of drugs influence the the NTs used in the ANS?
psychoactive drugs
what are some body symptoms associated with psychoactive drugs
changes in blood pressure, dry mouth, pupillary dilation/constriction, urinary problems, digestive issues, etc
what is the primary neurotransmitter(s) used by the sympathetic nervous system
Acetylcholine
norepinephrine
what receptors does acetylcholine work on in the sympathetic NS?
excitatory nicotine receptors, localized to ganglia
what is the trajectory of sympathetic signal to it’s target.
goes from brain to sympathetic ganglion/adrenal glands using acetylcholine, from here goes from ganglion/gland to target using norepinephrine
what kind of drugs increase sympathetic activation?
increase NE activity
increase Ach release
stimulate nicotine receptors
what is the primary neurotransmitter(s) used by the parasympathetic nervous system
Ach only
what receptors does acetylcholine work on in the parasympathetic NS?
muscarinic Ach receptors
what is the trajectory of parasympathetic signals to it’s target?
from spinal chord to the para-sympathetic ganglia and from here to the targets, who also release some Ach
what kind of drugs alter parasympathetic functioning?
cholinergic drugs
muscarinic agonists/antagonists
my/met/mesencephalon
older part of the brain who’s neurons use distinct NTs and have long projections throughout the brain
telencephalon
basal ganglia
limbic system
contain receptors for numerour NTs in their regions
basal ganglia function
motor control and action selection
prominent nuclei in the basal ganglia
dorsal striatum (caudate/putamen)
ventral striatum (nucleus accumbens)
dorsal striatum function
key in motor skills learning and best action selection
refines actions and decide which way of moving is best
where does the dorsal striatum receive inputs from?
sensory/motor cortex
dopamine from substancia nigra
ventral striatum function
reward/motivated behaviours
moves organisms to important of emotionally salient things
where does the ventral striatum receive inputs from?
limbic system
dopamine fom the ventral tegmental area
limbic system function
integrates emotional responses and regulates motivated behaviourand learning
parts of the limbic system
hippocampus
amygdala
hypothalamus
nucleus accumbens
prefrontal cingulate cortex
hippocampus function
establishment of new long-term memories
relational/spatial memory
tells you how to react to the environment if you know it or not
amygdala function
coordinates emotional response through connections to other brain areas
mostly fear and anxiety
Brodmann’s areas
partitioning of differnet cortical regoions based on differnet types of structures and organization of cells
prefrontal cortex function
decision making, planning, evaluating different strategies
executive functions in general
frontal lobe areas
prefrontal cortex
primar/secondary motor cortex
what brain area is most disrupted in psychiatric disorders?
PFC
primary/secondary motor cortex functions
mediates voluntary and well-learned motor sequences
what is the result of differnet regions having varying levels of differnt neurotransmitters?
they have varying sensitivities to different NTs
