lecture 5 Flashcards
write down Ohm’s law with R and g terms
V=IR ; I=gV
also R= 1/g.
g - electrical conductance
R- resistance
I- current
V-potential
what is diffusion & concentration gradient? what is electrical gradient?
diffusion- the net movement of ions from regions of higher concentration to regions of lower concentration.
concentration gradient- difference in concentration (high to low)
electrical gradient- think of opposites attracting, Na+ is a cation and Cl- is an anion; anion wants to go to cathode (plus side) and cation wants to go to cathode (neg side) electrical gradient moves from + to -
what is an example of quaternary structured protein?
different polypeptide chains can be bonded together to form a larger molecule (pg 9 lecture 5- purple subunits all together to form a molecule)
what neurotransmitters do interneurons of spinal cord release? are they projection cells? (what is their morphology?)
glycine,GABA, and GLU.
they are not projection cells.
they are multipolar
what neurotransmitter gets released by motor neurons? are they only excitatory? why? (+ what is the morphology & location)
neurotransmitter: acetylcholine & typically it IS excitatory
projection:yes
location:spinal cord/ventral
morphology: multipolar
Pyramidal cell - name the morphology, location, neurotransmitter, and whether it projects or not
- Multipolar (apical/basal dendrites)
- Hippocampus cortex
- Glutamate
- yes projects
DRG - name the morphology, location, neurotransmitter, and whether it projects or not
- Pseudo-unipolar (central/peripheral axons)
- Spinal cord (ganglia outside proper sp. cord)
- GLU
- yes projects
Hippocampal interneurons - name the morphology, location, neurotransmitter, and whether it projects or not
- Variety, mostly multipolar
- Hippocampus Cortex
- GABA
- no projections
what variable affect the equilibrium potential of ions (Eion)
it means for there to be no net movement when separated by a phospholipid membrane.
- reached w/ K+ channels in the phospholipid bilayer
- electrical potential difference that exactly balances ionic concentration gradient
how are ion channels gated?
- voltage gated
- ligand gated (receptor channels)
- mechanically gated
how is Nernst equation different from the Goldman equation
blue and yellow sticky note
why are neurons most permeable to potassium at resting membrane potential values? how is potassium regulated in extracellular fluids?
Neurons are most permeable to potassium at resting membrane potential because the cell membrane has a large number of open potassium channels at rest, allowing potassium ions to readily flow out of the cell, while sodium channels are mostly closed, making the membrane significantly more permeable to potassium than sodium; this outward movement of potassium ions is the primary factor contributing to the negative resting membrane potential of a neuron
- voltage gated (selectivity pore loop)
- these potassium channels have amino acid sequences, family of K+ channels (based on sequence similarity & function)
what is shaker fly?
fruit flies- if they have a mutation- and the voltage gated potassium channel, they start shaking and likeee the phenotype of this fly is called the shaker fly / shake of potassium channel. (Site-directed mutagenesis or SDM) which essentially alters the DNA sequence of a gene at a specific location. it results in the change of proteins)
basically, putting them through this process can determine what sequence affects certain parts of your brain and result in seizures, epilepsy, etc. - in this case, the flies resulted in shaking.
this work conducted by roderick mckinnon showed the structure of the voltage gated potassium - and that it is useful to the study of epilepsy (x ray crystallography)
what does increase in {K+}o do to the Vm?
increase (large changes in Vm caused by a minuscule change in ionic concentrations)
Define Vm-Eion
this is the rate of movement of ions across membrane
