Midterm 1 Flashcards
What does physiology mean?
study of normal functioning of a living organism and its component parts, including all it’s chemical and physical processes
What are emergent properties?
greater than the simple sum of individual parts
What is homeostasis?
similar condition | output must equal input and vice versa
What are the environmental factors of homeostasis?
osmolarity, pH, temperature
Which feedback control (positive or negative) is homeostatic?
negative feedback
What are the 5 types of active transport across the membrane?
exocytosis | endocytosis | phagocytosis | direct/primary active transport | indirect/secondary active transport
What are the 4 types of passive transport across the membrane?
simple diffusion | facilitated diffusion | ion channel | aquaporin channel (osmosis)
Which active transport types are protein-mediated?
direct/primary active transport | indirect/secondary active transport
Which passive transport types are protein-mediated?
facilitated diffusion | ion channel | aquaporin channel
What are channel proteins?
creates a water-filled pore
What are 2 kinds of channel proteins?
gated and open
What are open channel proteins?
pores - usually open
What are gated channel proteins?
open and close in response to signals
What are carrier proteins?
never form an open channel between the two sides of the membrane
What are the 3 kinds of carrier proteins?
uniport | symport | antiport
What are uniport carrier proteins?
transport only one kind of substrate
What are symport carrier proteins?
moves 2 or more substrates in the same direction across the membrane
What are antiport carrier proteins?
move substrates in opposite directions
Which ions make up most of the extracellular fluid (Na+ or K+)?
Na+
Which ions make up most of the intracellular fluid (Na+ or K+)?
K+
What are the 2 types of gated channels?
voltage-gated | ligand-gated
What are voltage-gated channels?
channels that respond to changes in intracellular voltage
What are ligand-gated channels?
channels that respond to binding of molecules
What are carrier proteins also called?
transporters
What are 3 amino acid transporters commonly spoken about?
GABA | Glutamate | Glycine
What are 3 types of transporters?
amino acid | carbohydrate | neurotransmitter
How do carrier proteins work?
changes conformation to let things in or out | can be modulated by voltage but not gated
What is the specificity of the molecules to channels and carrier proteins?
will allow some things in but has a high preference to specific molecules
What is cooperative binding?
as binding of specific/preferred molecule increases = affinity of more of those molecules increases
What is primary transport?
direct active transport | ATP hydrolyzed directly
What is secondary transport?
indirect active transport | concentration gradient created by ATP
What are tight junctions?
proteins that hold membrane together
What cells are excitable cells?
neurons and muscle cells
What cells are non-excitable cells?
all other cell types in body
What does it mean by “excitable cells”?
the ability of cells to be electrically excited = generating an action potential
What are the 3 basic structural components of neuronal cells?
cell body | axon | axon terminal
Which of the 3 parts of neuronal cells have the ability to affect the next cell (post-synaptic cell)?
axon and axon terminal
Which component of a neuron cell triggers a post-synaptic effect?
axon terminal
What is a synapse?
area where pre-synaptic and post-synaptic cell communicate
What is synaptic cleft?
the gap between pre-synaptic and post-synaptic cell
What are neurotransmitters?
molecules released at axon terminal to affect post-synaptic cell
What are purkinje cells?
specialized neuron cells lining the surface of the cerebellum
What is voltage?
force that drives movement of charge = dictates how much charge can be pulled/pushed
What is the avg charge of cells? (intracellular)
-50mv
What is the Nerst equation?
measure membrane potential of a cell based on ONE ion
What is the cell voltage when there is an equal concentration of K+?
-90mV
What will the movement of potassium (K+) be if the cell ‘s voltage is -90mV?
no movement because it is at equal concentration = no driving force
What affects the movement of ions in or out of cells?
charge and concentration difference
What is the Goldman-Hodgkin-Katz equation?
measure membrane potential of a cell based on MULTIPLE ions
What are the 2 factors that influence the membrane potential?
uneven distribution of ions across membrane | different membrane permeability of ions
What is the equilibrium concentration of Na+?
+60mV
What is the equilibrium concentration of Cl-?
-63mV
What is depolarization?
cell voltage going towards (+) voltage
What is hyperpolarization?
cell voltage going towards (-) voltage
What is sub-threshold graded potential?
below threshold = not enough charge to drive post-synaptic cell because signal strength decreased
What is supra-threshold graded potential?
above threshold = a lot of charge to drive psot-synaptic cell | strong signal strength could stimulate more cells
How is an action potential generated from a stimulus?
axon hillock converts stimulus into an impulse
During an action potential, which ion channel (Na+ or K+) opens first?
Na+
During an action potential, why does the K+ channel have a delay in opening?
to prevent charges from cancelling out
What gives you current?
electrons moving
What is an electrochemical gradient?
the chemical (concentration) gradient and the difference in charge across the membrane
What happens when voltage inside the cell increases?
drives current as long as resistance doesn’t change | more charge will flow through axon | more ions will flow in/out cell
What dictates how much current goes in and out of the cell?
rate of movement of ions
What is a negative (-) current?
when the positive charge moves into the cell
What is a positive (+) current?
when positive charge moves out of the cell
Which equation (GHK or Nernst) can tell you the equilibrium potential of an ion based on its concentration in/out of the cell?
Nernst
What type of ion channels are densely found more towards/near the cell body? (K+, Na+, Cl-, or Ca2+)
Na+
What is an absolute refractory period?
during depolarization and hyperpolarization | no stimulus can trigger another AP
What is a relative refractory period?
after absolute refractory period, second AP potential can be produced if the stimulus strength is greater
What is the triggering zone?
contains high density of voltage-gated Na+ channels
Where is the triggering zone found?
near cell body, at start of axon
Why do squid axons not need myelination?
axons are so big (1mL in diameter)
Where in animals are axons myelinated?
in the brain
What is the purpose of myelin sheaths?
prevents AP from leaking out since channels along axon causes APs to leak out = myelin sheaths blocks these leakage points = increase om signal strength
What is saltatory conduction?
nerve impusles will jump from one node of Ranvier to another = faster conduction of APs
What are nodes of Ranvier?
gaps between the myelin sheaths on an axon
What is multiple sclerosis?
myelin sheaths are dying off = cannot conduct APs as fast = uncoordinated movements
What is hypokalemia?
low in potassium
What is hyperkalemia?
high in potassium
What happens if potassium ions are not in the right concentration?
neurons won’t function correctly
What are electrical synapses?
the presynaptic neuron is DIRECTLY connected to the post-synaptic neuron || gap junctions
Why are electrical synapses more effective and efficient?
They are direct
What are gap junctions?
channels joining pre-synaptic terminal and post-synaptic membrane
What is a disadvantage of electrical synapses?
post-synaptic cell will have the same effect (excited or inhibited) as the pre-synaptic cell
What are chemical synapses?
use neurotransmitters to communicate = INDIRECTLY connected
What are excitatory neurotransmitters? Example?
excites post-synaptic cell to generate AP »_space;> depolarizes the post-synaptic cell | ex: Glutamate
What are inhibitory neurotransmitters? Example?
inhibits post-synaptic cell from generating AP | ex: GABA and glycine
What are 3 places on the neuron can pre-synaptic terminals attach to and release a signal?
dendritic tree | cell body | terminal
What 2 voltage-gated channels are important?
Na+ and K+
What does “activation” mean when referring to the Na+ voltage-gated ion channel?
gate is open
What does “deactivation” mean when referring to the Na+ voltage-gated ion channel?
gate is closed
What does “inactivation” mean when referring to the Na+ voltage-gated ion channel?
inactivation gate (the ball) is in the channel thus inactivating it
Why are mitochondria needed in chemical synapses?
for energy in order to be able to fuse the vesicles to the membrane to release the NTs
What is a complex AP?
a very strong stimulus such as falling or tripping
What does it mean by “APs are all or nothing”?
means that once the (+) charge is initiated into the cell and passes threshold = there will either be an AP generated or not
How can neurons spontaneously or continuously fire APs?
if there are a lot of NTs present around the synaptic cleft
How can spontaneously firing cells stop firing APs?
if it is given an inhibitory signal
How are silent neurons excited?
by receiving an input signal
Why is oxygen needed for neuron firing and sustaining high-frequency APs?
provides energy | hypoxia level affects amount of APs fired
What kind of receptor are G-protein coupled receptors?
metabotropic receptor (as it metabolizes GTP)
How can inputs into the cell cancel each other out?
if one is excitatory and one is inhibitory
What are 2 types of glutamate receptor channels?
AMPA and NMDA
What happens when glutamate binds to AMPA?
allows Na+ to enter = depolarization of cell
What happens when glutamate binds to NMDA?
release of Mg2+ block »_space;> allows Ca2+ to enter »_space;> turns on gene expression of AMPA receptors
How is Mg2+ released from the NMDA channel?
when intracellular voltage is (+) »_space;> Mg2+ disengages out of the NMDA pore = NMDA activated
What are coincidence inputs?
2 inputs coming in at the same time on the same neuron
What are the 2 types of coincidence inputs?
spatial summation | temporal summation
What is spatial summation?
simultaneous inputs to different places on neuron are added together
What is temporal summation?
two or more inputs occurring at different times are added together
Excitatory Postsynaptic Potentials (EPSP)
depolarizing graded potential in postsynaptic neuron due to activated excitatory synapse
Inhibitory Postsynaptic Potentials (IPSP)
hyperpolarizing graded potential in postsynaptic neuron due to activated inhibitory synapse
What is the threshold level? (mV)
-55mV
What is the resting membrane potential? (mV)
-70mV
What is the purpose of the refractory period?
help prevent signals from traveling in both directions down the axon at once
What is the effect of myelination?
reduces the amount of current “leaking” through membrane = improves electrotonic conduction
What is the main role of calcium ions at chemical synapses?
cause fusion of synaptic vesicles with the plasma membrane of the axon terminal
How does fast axonal transport work?
use motor proteins that walk down microtubules to transport organelles and vesicles anterograde and retrograde with use of ATP = need a lot of mitochondria
What are basket cells?
GABAergic interneurons
What is the function of basket cells?
make inhibitory synapses and control potentials of target cells
What are glial cells?
support cells that glue and hold the nervous system together
What is the function of glia cells?
hold nervous system together and provide nutrition and maintenance for cells
What are astrocytes?
highly branched (star-like) found near synapses
What are the functions of astrocytes?
take up release chemicals (cleans up NTs) | provide substrate for ATP production | help maintain electrolyte homeostasis
What are microglia?
specialized immune cells for the nervous system
What are satellite cells?
non-myelin forming Schwann cells that support cell body clusters
What are Schwann cells?
form meylin in PNS
What are Oligodendrocytes?
form myelin in CNS
What is ganglia?
cell body clusters
What are the chemicals that guide axon growth during development?
neurotrophic factors
How do growth cones respond chemotropically?
by retracting or extending the axon
What are the 2 types of synaptic plasticity?
long term potentiation | long term depression
What is long term potentiation?
synapses are functioning stronger
What is long term depression?
synapses are functioning weaker
What is synaptic plasticity?
basis of learning and memory
What was the Morris-Water Maze?
tests the function of NMDA in relation to synaptic plasticity
What was the finding from the Morris-Water Maze?
rat cannot remember his way because its NMDA receptors are blocked = shows NMDA and AMPA receptors are necessary for learning and memory
What is synaptic potentiation
strength of synapse
What is the S4 segment on the voltage-gated channels?
charged subunit that goes across the membrane | responsible for making these channels voltage-gated
Why is the S4 segment important?
it has (+) charged amino acids = when membrane changes voltage = these amino acids will move
What will happen if there was a mutation in S4 gene?
removes voltage capability
What is the difference between the K+ and Na+ voltage-gated channel?
K+ = 4 proteins (4 genes) | Na+ = 1 protein (1 gene)
What type of channels are inhibition and excitation channels?
ligand-gated
What are the physiological differences between electrical synapses and chemical synapses?
electrical synapses = no mitochonria, no vesicles | chemical synapses = mitochondria and vesicles with NTs are present
What makes up the synaptic density?
aggregation of membrane proteins
What is synaptic density?
all of the aggregation of proteins involved in vesicle fusion
What does “kiss and run” mean in terms of NT release?
vesicle kisses membrane »_space;> release contents »_space;> vesicle gets taken up by pre-synaptic cell to be filled with more NTs
What is the function of the NT vesicles?
to be filled with NTs (not terminate signal)
What do NT vesicles have on their membranes that allow NTs to come in?
tranporter proteins
What are SNARE proteins?
proteins involved with the docking of NT vesicles for fusion
How do the NT vesicles fuse?h
AP comes down axon »_space;> depolarize axon terminal »_space;> activates voltage-gated Ca2+ channel
What happens if intracellular level of Ca2+ is high?
cell starts dying because proteins are constantly activated in the cell
What is post-synaptic density?
all of the proteins on the membrane of the post-synaptic cell
What is perisynaptic zone?
close to the synapse
What is the extrasynaptic zone?
outside/far from synapse
What do glutamatergic synapses have?
glutamate transporters
What do GABAergic synapses have?
GABA transporters
What do glycinergic synapses have?
glycine transporters
What is EAAT?
excitatory amino acid transporter = glutamate transporter
What is the driving force of glutamate transporters?
K+ and protons
What is the driving force of GABA transporters?
Na+ gradient and Cl-
What are ventricles?
spaces in brain filled with CSF, no blood but constant movement and production of CSF
How is O2 supplied to the brain to make energy?
via blood supply
What happens if major vessels burst in the brain?
neurons start dying
What is the blood-brain barrier?
junctions between cells lining cells = separates brain from rest of body
What is AMPA?
sodium channels
What is the purpose of NDMA receptors?
increase cell response to glutamate
In which part of the brain is long term potentiation (LTP) found?
hippocampus
Which NT is associated with long term potentiation (LTP)?
glutamate (AMPA and NMDA)
In which part of the brain is long term depression (LTD) found?
cerebellum (hind brain)
What are parallel fibers?
axons of granule cells innervating (making synapses) with Purkinje cells
What are granule cells?
cell which axons become part of the parallel fibers which constantly stimulate Purkinje cell
What is significant of granule cells?
each cell represents a part of your body | most numerous types of neurons in the brain
Which cell decides which synapse to weaken in long term depression (LTD)
Purkinje cell = coincidence detector
Is NMDA used in long term depression (LTD)?
no, LTD is NMDAR-independent
What kind of memory is associated with the hippocampus?
short term
What is the cerebellum highly involved with?
motor learning
What was the Rotarod test?
tests if LTD is damaged or not working
What was the Rotarod test findings?
if mice cannot stay on rod = LTD is not working
What are the 2 main branches of the nervous system?
Central and Peripheral
What are the 2 pathways of the peripheral nervous system (PNS)?
sensory and motor
What is the sensory component of the PNS?
all info coming from environment into the nervous system to the brain
What is the motor component of the PNS?
info coming from brain to induce a motor response to sensory info
What are the 3 parts of the brainstem?
mid-brain | pons | medulla oblongata
What is contained within the brainstem (what functions)?
basic functions and controls such as breathing and heart rate
What is the cerebrum?
where most executive decisions are made
What are the 4 lobes of the cerebrum?
frontal, parietal, occipital, temporal
What is grey matter?
where the cell bodies are
What is white matter?
where all the axons are
What is the corpus callosum?
connects left and right sides = allows those sides to communicate
What is basal ganglia?
initiation of motion in the CNS | generates new movement
What type of NT and transporters are associated with the basal ganglia of the CNS?
dopaminergic transporters and dopamine
What role does dopamine play in?
intiating movement
What is important for movement to start?
neurons need to fire an AP
What structure is damaged in Parkinson’s disease patients?
basal ganglia
What problem do Parkinson’s patients have? Why?
hard time initiating motions = b/c dopaminergic neurons are dying off = basal ganglia cannot command initiation of motion
What is the treatment for Parkinson’s disease?
dopamine supplements
What is a problem with the treatment for Parkinson’s disease and how is it solved?
dopamine supplement cannot cross blood-brain barrier | solution = L-dopa = can cross blood-brain barrier (enzyme in brain cuts it to dopamine)
How is the grey and white matter organized in the spinal cord and in the cerebrum?
spinal cord: grey = inner / white = outer | cerebrum: grey = outer / white = inner
What is the dorsal root ganglia (DRG) of the spinal cord?
sensory input to the CNS
What is the bulge on the dorsal root ganglia of the spinal cord?
where all the cell bodies are coming from different parts of the body
What is the ventral root of the spinal cord?
motor output, no bulge
What is decussation?
fibers shift control from one side of the brain to the other (left side can control left and switches to right side)
What do the different layers of cell bodies in the grey matter of the cortex correspond to?
different functions
Where is the limbic system located?
inside of the cerebrum
What are the 3 parts of the limbic system?
hippocampus, thalamus, amygdala
What is the hippocampus involved with?
short term memory
What is the thalamus involved with?
gateway of information, accumulation of neurons (in CNS-nuclei and in PNS-ganglia
What is the amygdala involved with?
emotions and memory
What is the prefrontal cortex?
involved in high executive function
What enhances the structure of receptors part of LTP to provide support?
actin
How does the NMDA receptor aid in forming short-term memory?
the potentiation in the NMDA receptors
What is habituation?
gets used to stimulus over time
What is sensitization?
encourages stronger reflex
How is EPSP affected in habituation?
decreases
What is an example of long-term depression?
cerebellar - motor learning
What happens if cerebellar LTD is disrupted?
motor learning is disrupted
What are the 4 neuromuscular disorders associated with synapses?
parkinson’s | schizophrenia | depression | myasthenia gravis
What is Myasthenia gravis?
autoimmune disease targeting acetylcholine receptors and severely impacts neuromuscular activity
What are 2 diseases that are associated with single mutations in ion channels?
cystic fibrosis, myotonia, hyperekplexia
What is cystic fibrosis? What mutation does it have?
mucus build-up in lungs and pancreas | mutation in Cl- channel
What is myotonia, hyperekplexia? What mutation does it have?
fainting goats | mutation in glycine receptors
Where are specialized synapses found?
visual and auditory systems
What is an example of a specialized synapse?
ribbon synapses (vesicles attach to protein and closer to membrane)
What are meninges?
brain covering
What are the 3 layers of meninges?
dura mater (outermost layer) | arachnoid membrane | pia mater
What does cauda equina mean?
spinal cord in lumbar vertebrae
What are the 2 functions of the blood-brain barrier?
prevents solutes coming between epithelial cells in brain | protects nervous system from toxins in circulation
What is the Circle of Willis?
blood supply to the brain
