Lecture 13 and 14 Flashcards
(31 cards)
Pathway of neuronal stimulus
stimulus > sensor/integrator neuron > muscle or other effector > response
Who discovered that biological tissues have “animal electricity” within them?
Luigi Glavani
What nerve did we observe for frogs in lab?
the sciatic nerve
What units do we measure potential energy in?
volts
The individual cells the potential energy is measured in…
millivolt (mV)
In cells, this generates 20% of potential energy?
ATPase, 3Na+ ions out, 2 K+ ions in
In cells this generates 80% of potential energy?
Facilitated diffusion of ions via leak channels
There is always more (Na+ or K+) outside the cell and more (Na+ or K+) inside the cell.
Na+; K+
When is equilibrium potential reached?
when potential (electrical gradient) = potential (chemical gradient)
Potential charge for potassium
-90 mV
Potential charge for sodium
+60 mV
Potential charge for sodium potassium
-70 mV
Signals are transmitted within the neuron by two kinds of potentials
Passive: Graded potentials
Active: Action Potentials
What happens to the amplitude of the passive potentials over time?
the amplitude decreases
What happens when voltage-gated Na+ channels open?
the membrane potential depolarizes
Absolute refractory period
no amount of current injection will make an action potential
Relative refractory preiod
injecting lots of current might generate an action potential
What are ways to increase the conduction velocity of action potentials?
increase axon diameter, insulate axon (via schwann cells = oligodendrocytes
What is mutliple sclerosis?
destruction of oligodendrocytes
Signal comes from the _______ neuron and is transmitted to the ______ neuron.
presynaptic; postsynaptic
In vertebrates, the neurotransmitter at neuromuscular synapses…
Acetylcholine (Ach)
What are two neuromuscular diseases?
myasthenia gravis and muscular dystrophy
Tonix that cause muscle paralysis
tetrodotoxin and pumiliotoxin B
What does tetrodotoxin do?
Blocks the opening of Na+ channels, mainly on muscle
