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Resting membrane potential
which kinds of cells
potential diff that exist across membrane of EXCITABLE cells (muscle/neuron cells)
What is the range cells like to be at? Close/far to which ions?
- -70 and -80 mV
- close to Cl and K
- far from Na and Ca
How does a cell get excited?
- by moving the potential (+/-)
- more permeable the great you change the RMP
Chord conductance equation
evaluates the contribution of each ion
How can you calculate contribution of each ion
Nernst or Goldmans
What is action potential?
excitable cells of RAPID DEPOLARIZATION (upstroke) then REPOLARIZATION
What are the characteristics of AP
- size and shape
- all-or-nothing response
What is depolarization?
making the MP less negative (more +)
What is hyperpolarization?
making the MP more negative
What is inward current?
+ charge INTO the cell -> depolarizes MP
What is outward current?
+ charge OUT of cell -> hyperpolarization MP
What is threshold potential?
the MP becomes excitable by the current and it fires at a certain point
What is overshoot?
- moving ions in/out =overshoot
- the MP in cell interior is suppose to be - but it turns + because of too much
What is undershoot?
cells went back to rest (it is -)
What is the refractory period?
cell not capable of anything until it recovers
Nerve Na channel AP
integral membrane protein means that it is activated by two ways (IG and AG)
In Na channel which gates is open/close?
- Activation is closed
- Inactivation is open
What is absolute RP?
depolarization happens and nothing else will happen
What is relative RP
only if excitation is way more positive than when it was initially given in what it has to overcome
What is accommodation?
- holds cell in a depolarized state
- shuts back down->never reaches AP
Conduction velocity is influenced by what?
- time-how quickly is depolarizes
- length-how far a current will spread
What changes occur in conduction velocity?
- resistance (inhibits or promotes movement)
- capacitance (can membrane respond approp)
- How long will it take to get from head to toe
What increases resistance?
- increase depolarization much quicker
- capacitance makes it goes faster bc of jumping
What are the empty spaces on nerves?
- Nodes of Ranvier and "jump" instead of going through
- AKA saltatory conduction
What does demyelination cause?
decrease in conduction velocity
Excitable cells reach synapse (new areas) how?
some will reach destination by chemical or electrical
If synapse is reached by electrical it has what?
At what rate are electrical synapses? Direction?
- very fast
- simultaneous conduction (cell-to-cell)
Where are electrical synapses found?
- in the heart
- some smooth muscle
If synapse is reached by chemical it has what?
synaptic cleft -> neurotransmitter
At what rate are chemical synapses? Direction
- synaptic delay, slow
Where are chemical synapses found?
- in the muscle
- neuromuscular junction (a nerve connected to a muscle)
- activates a skeletal muscle
What is a motor neuron?
- turns on the motor and the
- acriavtes nerve to tell neruon
What links Choline and Acetyl CoA
- an enzyme esterase
- synthesis and degradation of ACh
- Choline needs to be brought back into nerve to make more ACh
What are the types of synaptic arrangements?
- one-to-one (1 nerve to 1 muscle)
- one-to-many (entire region get amplified, uncommon)
- many-to-one (most common, summut)
Synaptic input (Excitatory postsynaptic potentials)
- work at Ach level
- Always make the next thing turn on
- excitatory at the postsynaptic potential
- happen on the membrane on the other side
Synaptic input (Inhibitory postsynaptic potentials)
What kind of integration synaptic types are there? (multiple inputs)
- spatial-2+ arrive at postsyn cell at SAME SPACE
- temporal-2+ arrive at post syn cell at SAME TIME
What is long term potentiation
alter the nerve (so long so many times)
What is synaptic fatigue
needs to go to recovery no matter how many times its poked
Ach is the only NT where? Which cells
- All preganglionic cells in parasym and symp NS
- most postganglionic cells
Everything that is autonomic has how many relays?
Which are the only postganglionic cells that do not use ACh?
What are the catacholamines? Where are the derived from?
What do all 3 have in common?
they are made from the AA Tyrosine
How to turn off (degrade) Dopamine, NE and E?
Where does Serotonin come from?
What is serotonin a precursor for?
What are other neurotransmitters?
Which NT are AAs?
glutamine and glycine
Which type of NT is Histamine?
Which NT is the major excitatory NT in the CNS?
Ionotrophic receptor means what?
- have to wait for the right ion to activate
- has ion
Metabotropic receptor means what?
Glycine is what kind of NT unlike the others
- brainstem and spinal cord
GABA is the transmitter to find which receptors?
- GABA-A (Cl channel ionotrophic) Benzos and barbiturates
- GABA-B (K+/G protein) metabotrophic
What is disease is GABA highly linked to
Nitric oxide (NO)
short-acting inhibitory in CNS and GI tract
Neuropeptides have what 3 kind
- neuromodulators- modulate presynaptic cells
- neurohormones- secrete blood
- neuropeptide- syn in nerve cell body
What are the thick filament of muscle called? They create what?
- myosin (heavy/light chains)
What are the thin filaments of muscle called? They create what?
- actins (globular)
- tropomyosin and troponin
What needs to happen to the two filaments
actin needs to touch myosin for contraction to take place
What is considered one contraction
Z-Z (one sarcomere) for a contraction to occur
What is stored in the sarcoplasmic reticulum?
What are the Ca releasing channels on SR?