All About Action Potentials
What is the resting membrane potential of a neuron?
-70 mV
What are the two major divisions of the nervous system?
The central nervous system (CNS) and the peripheral nervous system (PNS).
What is the function of glia cells?
To support/nourish/protect neurons.
What is the basic function of a neuron?
To receive, process, and transmit information
What are neurotransmitters stored in before being released from the pre-synaptic neuron?
Vesicles (at the axon terminal)
Which ion rushes into the neuron during depolarization?
Sodium/Na+
What are the two structures that make up the CNS?
The brain and spinal cord
Which type of glia form myelin sheath? Hint: There are two kinds
CNS: Oligodendrocytes
PNS: Schwann cells
What are the three main parts of a neuron?
Dendrites, cell body/soma, axon
What is the main excitatory OR inhibitory neurotransmitter of the brain?
Excitatory: Glutamate
Inhibitory: GABA
What is the period called when a neuron cannot fire another action potential, no matter the stimulus strength?
Absolute refractory period (compared to distinct refractory period)
The peripheral nervous system can be broken down into autonomic and somatic divisions. What does each control?
Somatic: Voluntary movements of skeletal muscles.
Autonomic: Involuntary functions (e.g. heart rate, digestion, etc.).
Which glia act as the immune defense of the brain?
Microglia
What is the small gap between neurons called where communication occurs?
Synaptic cleft
There are two processes that remove neurotransmitters from the synapse after they have been released and induced some effect. What are these two processes called?
Reuptake and enzymatic degradation (also diffusion)
Why do action potentials only travel in one direction along the axon?
Sodium channels behind the AP are inactivated during the absolute refractory period
What is the difference between the sympathetic and parasympathetic systems?
Sympathetic arouses ("fight or flight")
Parasympathetic calms ("rest and digest")
What is the primary function of astrocytes?
To maintain the blood brain barrier (BBB)
What is the function of the axon hillock? BONUS POINTS for WHY blank is the function.
It is the "trigger zone" where action potentials are initiated.
Reason: It has a high concentration of V-G Na+ channels, making it very sensitive to changes in membrane potential.
What neurotransmitter is involved in movement and reward? Hint: Linked to Parkinson's disease
Dopamine (DA)
As individual ions, sodium has a RP of +60mV and potassium has a RP of -90mV. Why isn't the RP of the membrane the average/middle of these numbers (-10 mV)?
The membrane is more permeable to potassium than sodium, so the RMP is closer to sodium's RP.
How do sensory and motor neurons differ in direction of information flow?
Sensory (afferent) neurons carry info to the CNS
Motor (efferent) neurons carry into away from the CNS (and to muscles/glands)
Ways to remember:
AFFERENT for AWAY from environment
AFFERENT for ARRIVE at CNS
EFFERENT for EXIT CNS
In multiple sclerosis (MS), myelin is damaged. What affect does this have?
Neural communication slows/stops, leading to motor and sensory impairments.
What is the function of the axon terminal?
To release NTs into the synaptic cleft when an AP reaches the end of the axon.
What is the difference between an agonist and an antagonist?
Agonists enhance NT action, antagonists block NT it