Nerve cells and Electro-chemical Signaling Flashcards
what is nerves system?
a regulatory
communication network that allows an
organism to respond to environmental
stimuli and to regulate the organism’s
metabolism and activity in response to
changes in its circumstance
what is neurons made out of?
neurones
what is the fuction of efferent neuron?
transmit from the CNS to the effector organs. cell bodies and dendrites wiithin the CNS
what is the fuction of afferent neurons?
transmits form the periphery to CNS. cell bodies located outside the CNS in a ganglion
what is ganglion?
clusters of cell bodies outside the CNS
what is interneurons?
account for 99% of all neurons in the body, located within the CNS, involved in processing efferent and afferent signals
what is action potential?
a self-regenerating wave of electrochemical activity that allows nerve cells to carry signals throughout the nervous system
what is Ohm’s Law?
I(current) = V(voltage) /R(resistance)
what is responsible for the existance of Resting Membrane Potential (RMP)?
the K+ that leaks from the inside of the cell to the outside via leak K+ channels and generates a negative charge in the inside of the membrane. At rest, the membrane is impermeable to Na+, as all of the Na+ channels are closed.
what is RMP depends on?
the concentration of ions across the permeable membrane and teh presence of ion channels in the permeable membrane
what is leak channels?
non-gated channels in plasma membrane throughout neurone. always open
what is the equillibrium potential of any ion depend on?
charge and size of concentration gradient
what is sodium-potassium pump?
it’s electrogenic and helps in establishing and maintaning the chemical gradient
What causes changes in membrane potential during an action potential?
Changes in membrane potential during an action potential are due to changing membrane permeabilities to Na+ and K+ ions.
What mediates the changes in membrane permeabilities during an action potential at the biochemical level?
Voltage-gated Sodium channels and voltage-gated Potassium Channels, which undergo conformational changes.
What happens when voltage-gated Na+ channels open during an action potential?
Na+ enters the cell, leading to depolarization, making the inside of the cell positively charged.
What is the concept of threshold stimulus in action potentials?
A stimulus must reach a critical level before generating an action potential. Sub-threshold stimuli are insufficient, while supra-threshold stimuli result in action potentials of the same magnitude and duration.
How does frequency coding relate to action potentials?
Action potentials convey the intensity of stimuli. A supra-threshold stimulus can generate a burst of action potentials, increasing frequency but not amplitude
What is the concept of lateral inhibition in the context of action potentials?
Lateral inhibition refers to the mechanism where certain neurons inhibit the activity of neighboring neurons, influencing the propagation of action potentials.
Describe the structure of voltage-gated Sodium channels (Nav).
Nav channels have four domains, each composed of six transmembrane spanning alpha-helices. They include a voltage sensor in alpha-helix S4 and a pore loop acting as a selectivity filter.
What is the significance of mutations in Na+ channels?
influencing the operation of voltage-gated sodium channels and contributing to various physiological and pathological conditions.
what is synapse?
Site of information transfer between
neuron and target
examples of neurotransmitters involved in action potential.
The amino acids: glutamate, glycine, GABA
The biogenic-amines: acetylcholine, dopamine,
serotonin
