Flashcards in Intro Deck (18):
Three common elements of a response
- SENSING environmental signals
- PROCESSING the info
- PRODUCING an appropriate response
Common elements of nervous system
sensory cells - sense environment
neurons - receive, process, and transmit info over long distances
glia - support and monitoring cells
effector cells - neurons talk to these cells to create responses
Neurons are polarized or depolarized?
Parts of neuron
- somatodendritic (gray matter) - body of cell (contains nucleus) protein synthesis, receives synaptic info
- axonal (white matter) - transmit the signals over long distances to follower cells
specialized sites for signal reception at the synapse, contains receptors that convert chemical signals to electrical signals
Where do axons end?
where electrical signals are converted to chemical signals to be released onto follower cells...axons fire in "all or none" fashion
How is a membrane potential (charge difference) generated?
When positive and negative charges are separated across a lipid bilayer
Standard convention for membrane potential?
Inside potential - outside potential
What does the neuron use to transmit signals between different parts of nervous system?
Can ions move across lipid bilayer to alter elctrical signaling?
No. Must move through lipid bilayer via channel proteins
What are the two types of ion channels?
P(ore) loop channels - highly SELECTIVE cation channels. Tetrameric structure. Selectivity filter (can tell difference between Na and K ion). smaller pore
Cys-loop receptors - BROADly selective cation or ion channels - pentameric structure. Fixed rings of charge lining channel. bigger pore
Why are there multiple ion binding sites within a channel?
To increase permeation and selectivity. Think about it...one ion by itself is TOO stable and will just hang around,..having multiple ions in the channel will somewhat destabilize themselves to move faster
What is attached to ions that makes them unable to pass through membrane by themselves?
water of hydration
Negative charge rings in the CYS LOOP receptors in channels allow what to pass through?
positive charge rings do the opposite
Nernst potential for Na and K?
Na +60 mV
How does Na/K ATPase work?
ATP bond energy used NaK ATPase pumps ions against concentration gradients
3 Na out of cell, 2 K in...burns lots of ATP
At rest, which channels have the highest conductance?
Then Cl channels, then Na channels