Neurobiology (Exam 1) Flashcards
1
Q
Membrane Potential
A
- Voltage difference across the membrane (v or mv)
- Arises from unequal distribution of ions
- Changes w/ selective movement of ions across the membrane
- Rate of ion movement is proportional to the difference between membrane and equilibrium potential (driving force)
- The larger the difference, the stronger the driving force
2
Q
Equilibrium Potential
A
- Membrane potential when the net flow of an ion is zero
- When concentration gradient and electrochemical gradients are equal and opposite to one another
3
Q
What is the resting membrane potential of neurons?
A
~70mV
4
Q
Resting Membrane Potential
A
- Relies heavily on K+ leak current
- Neurons maintain concentration gradients via active transport
- Na/K pump, leaky channels, and ions all contribute to this
5
Q
Graded Potentials
A
- Short distance signals that occur in dendrites and cell bodies
- Vary in magnitude and duration
- Based on strength of stimulus
- Created by ligand-gated channels
- Decay over short distances
6
Q
Action Potentials
A
- Long distance all-or-none signals that maintain the same magnitude, duration, and amplitude
- Move from the axon hillock to axon terminal only
- Due to the inactivation of voltage-gated Na+ channels
- Weak stimulus leads to a low frequency of action potentials
- Strong/supra-threshold stimulus leads to high frequency of action potentials
7
Q
Types of Neurons
A
Multipolar, bipolar, unipolar, efferent, afferent, interneuron
7
Q
Steps of Neurotransmitter Release
A
- Voltage-gated Ca2+ channels open, Ca2+ flows into the cell and pushes vesicles toward the plasma membrane
- Ca2+ ions change the conformation of SNARE proteins, which causes the vesicles to fuse with the plasma membrane
- Neurotransmitter is released and binds to receptor on post-synaptic cell
8
Q
Multipolar
A
Several processes off of cell body
9
Q
Bipolar
A
Two processes off of cell body
10
Q
Unipolar
A
One process off of cell body + branches
10
Q
Efferent Neuron
A
- Carries info from CNS to PNS
- Motor neuron (multipolar)
11
Q
Afferent Neuron
A
- Carries info from PNS to CNS
- Sensory neuron (unipolar)
12
Q
Interneuron
A
- Carries info from one neuron to another
- Multipolar
13
Q
Temporal Summation
A
Converts a rapid series of weak pulses from a single source into one large signal