Week 5: Recorded Lectures Flashcards
What is membrane potential?
The difference in electric potential between the interior and exterior of a biological cell
What creates an electrochemical gradient in a cell?
The presence of ions inside and outside the cell
Charge of inside cell
Negative
Charge of outside cell
Positive
How is membrane potential measured?
- As voltage
- Expressed as inside relative to outside the cell
Polarized cell
A cell with any electrical gradient (not 0mV)
Depolarization
Less polarized than at rest
Hyperpolarization
More polarized than at rest
Repolarization
Returns towards its resting potential
Dendrites
Branched extensions of a neuron that receive signals from other neurons
Where do changes in cell potentials occur?
The dendrites
Agonists
- substances that bind to receptors and activate them
- Make it more likely that a neuron will reach its threshold membrane potential
Antagonists
- substances that bind to receptors but block them
- make it less likely that a neuron will reach its threshold membrane potential
Action Potential
- brief electrical impulse that travels down a neuron
- allows for the rapid transmission of electrical signals along neurons
The nature of the action potential: step 1
- Resting state
- at rest, most ion channels are closed
The nature of the action potential: step 2
- Depolarization
- some signals cause some Na channels to open
- initiates a slow depolarization
The nature of the action potential: step 3
- Rising phase of the action potential
- When depolarization reaches a certain point, Na channels open, this triggers a massive depolarization
The nature of the action potential: step 4
- Falling phase of the action potential
- Na channels close
- K channels open
The nature of the action potential: step 5
- Undershoot
- Repolarization continues past the resting potential
- This is quickly corrected
Multipolar interneurons
connect neurons together
Motor neuron
carries signals to muscles
Sensory neuron
Controls feelings
Synapse
gap between two neurons where communication occurs
Presynaptic events
- Action potential
- Presynaptic membrane
- Exocytosis of neurotransmitter
Neurotransmitters
- Each neuron produces and releases one major neurotransmitter
Postsynaptic events
- Neurotransmitter binding
- Receptor activation
- Signal transduction
Acetylcholinesterase (AChE)
Stops signaling between neuron and muscle
Central nervous system (CNS)
consists of brain and spinal cord
Peripheral nervous system (PNS)
ranial nerves, ganglia outside CNS, spinal nerves
Forebrain
collects sensory information
Midbrain
interpreter; helps hindbrain decide what to do
Hindbrain
control of movement
Pineal gland
processes info about day length
Hypothalamus
collection of neurons that receives and sends signals
Where is short term memory stored?
The hippocampus
Where is long term memory stored?
The cerebral cortex
Enteric division
controls digestion and gut function independently of the brain
Parasympathetic divisions
- Rest and digest
- slows heart
Sympathetic divisions
- fight or flight
- speeds the heart and increases contractile strength
Plasticity
bility of neurons to change their connections and functions in response to stimuli
Neural plasticity
- connections between neurons is plastic
- Weakened or strengthened in response to activity
