Ion Channels Flashcards
A cell in your body can act like a ____. We open and close ___ channels to allow electricity to flow
Battery
Ion
Ion channels are ____ proteins across the membrane
Integral
A ____ has alternating sides opening and closing. A ____ opens to both sides of the membrane forming a pore. In a channel, substances move ____ their electrochemical gradient
Transporter
Channel
Down
Ion channels are made up of different subunits, making them ____ channels
The structure dictates the ____
Heterogenous
Function
Channels provide a means for ___ to cross the membrane which is essential to cell function. Gating refers to the ____ that opens the channel
Ions
Stimulus
Active transporters actively move selected ions ____ the concentration gradient
Against
Ion channels allow ions to ____ down concentration gradient. They are selectively permeable
Diffuse
____ ____ establish and maintain the gradients that ions use to move through ion channels
Active transporters
The Na+/K+ ATPase maintains the gradient by action of a pump that moves ____ to the extracellular fluid where ___ concentration is already high. It moves ____ to the Intracellular fluid where ____ is already high. That is why ___ is required
Na
Na
K
K
ATP
If a K+ channel opens, K+ will flow ____ the concentration gradient to the ____ of the cell
Down
Outside
If Na channels open, Na will flow ___ the concentration gradient to the ____ of the cell
Down
Inside
____ channels are always open. Help maintain resting membrane potential. Permeate ___ more than ___
Leak
K+
Na+
______ channels are activated by membrane potential, Na, Ca, K, and Cl channels
Voltage-gated
____ ____ ____ channels are regulated by ligands (neurotransmitters), glutamate, GABA, and glycine receptor channels
Extracellular ligand-activated
____ ____ channels are regulated by temperature and pain, TRP channels
Thermos-sensitive
______ and _____ channels are activated by touch, hearing, cardiovascular regulation, sensing of gravity and osmotic stress, not well classified
Mechano-sensory
Volume-regulated
____ channels include the GAP junctions, peptide ion channels like Gramicidin, venomous insect toxins like the conus toxins from cone shells
Miscellaneous
Leak channels are open ___ of the time. They have a large influence on excitable cells at ____. Na, K and Cl are the common leak channels with ___ being the most abundant and has the most influence on the ____ membrane potential
Most
Rest
K
Resting
Why is it important to monitor plasma K+ in the hospital?
Voltage gated channels are most often found in ____ cells such as neurons and muscles. They contain a ____ which is a negative and positive charge that changed shape with a change in electrical environment
Excitable
Dipole
Voltage gated Na and K channels are essential to the generation and transmission of ___ ____. Voltage gated ____ permitting signaling in many cell types- neurons, muscles, beta cells in pancreatic islets
Action potentials
Ca2+
Sensory receptors perform ____ which is the turning of a stimulus like heat, cold, vibration, touch into an electrical signal
Transduction
______ convert a temperature stimulus to electrical energy through the opening of temperature sensitive channels called ____ ____ ___ channels (TRP)
Thermoreceptors
Transient receptor potential
Glutamate receptors are examples of ___ gated channels which permit Na and Ca to ___ the cell. Glutamate is highly excitatory in the ____
Ligand
Enter
Brain
Activation of ___ ____ receptors allows influx of cations and depolarizes the membrane potential (graded potential)
Ionotropic glutamate
Examples of ionotropic glutamate receptors:
A stroke can lead to _____ toxicity
Glutamate
Cystic fibrosis transmembrane, conductance regulator (CFTR) is a ligand gated ____ channel. this channel is ____ and individuals with cystic fibrosis
Cl-
Mutated
The cystic fibrosis, transmembrane, conductance regulator is found in both the ____ and the __ ___, patience with cystic fibrosis mutation can have both respiratory and G.I. symptoms
Lungs
GI tract
_____ contain voltage gated sodium and potassium channels
Axon
_____ at the end of neurons for neurotransmitter released with voltage gated calcium channels
Terminals
______ at ligand gated ion channels and ____ at transduction channels, cause smaller potentials called graded potentials.
Neurotransmitters
Stimuli
If those smaller graded potentials some up to a threshold level, voltage gated ___ and ____ channels, generate and propagate an ___ ___
Na+
K+
Action potential
At rest, more ___ leaves a cell than ____ enters a cell. This generates a ____ potential at the membrane, that is between -90 and -70 mV
K+
Na+
Neural transmitters bind to the ___ ___ of neurons, and open channels that change the membrane potential
Cell body
This diagram shows what all three of these processes look like in terms of voltage changes
The ___ ___ is located at the first node of sensory axons
Trigger zone
Voltage gated ____ channels open first, than Voltage gated ____ channels open more slowly
Na+
K+
Fast voltage gated sodium channels open quickly and show three states:
Closed, opened, and inactivated
___ and ____ inactivation of voltage gaited sodium channels
Ball and chain
You can find multiple varieties of ____ channels within the same cell type a concept students will revisit in the cardiovascular course
K+
In neurons K+ channels open and close more ____ then do sodium channels. As the voltage gated potassium channels, open potassium ions ____ the cell, making the membrane potential more ____.
Slowly
Exit
Negative
Voltage gated states of sodium and potassium channels:
Sodium and potassium _____ changes during the action potential. ____ permeability rises, and falls with the action potential. ____ permeability rises after the action potential.
Permeability
Na+
K+
Diagram of the simulation of an action potential:
Sensory receptors respond to stimulus, ___ ___ ion channels open, influx of Na, leads to ____
Voltage gaited
Depolarization
Opening of ____ channels bring back the resting potential membrane after an action potential
K+
Potassium ____ , out of the cell, brings the membrane back to resting potential
Efflux
Opening of ____ voltage gated channels lead to further depolarization and triggers an action potential. Sodium flows ___ the cell.
Sodium
Into
Review
Review
Action potential cannot move backwards due to ____ of sodium channels
Inactivation
If Na channels are mutated, the ___ ___ can not spike as fast, leading to muscle weakness and floppy baby syndrome
Action potential
If there is extracellular hyperkalemia, more potassium outside the cell, cells will be ____ easier and fire off neurons faster. Leads to arrhythmias
Excited
Mutation in CFTR on the lumen side of the cell, will cause a ____ in chlorine into the cell. Water does not follow like it should leading to ____ mucous membranes. Causing cystic fibrosis.
Decrease
Thicker
Cause of cystic fibrosis:
If mucus membranes are thicker, ____ ___ will be impaired, bacterial pathogens will remain in the airway
Mucociliary clearance
If K channels are mutated, ____ will be slower, causing ataxia
Repolarization
If ligand gated cation channels have a gain of function mutation, they are more likely to ____, causing an easier excitable cell leading to ____
Open
Seizures
If K voltage gated channel are mutated, potassium will be ____ in the cell, leading to a more positive action potential and a more ___ excitable cell
Trapped
Easily
Voltage gated sodium channel mutation ____ the ability to close the channels, causing an excessive ____ of sodium, causing more excitable cells, and ____
Inhibiting
Influx
Seizures
