transmission within a neuron Flashcards
(26 cards)
What are the two main parts of the nervous system?
Central Nervous System (CNS) and Peripheral Nervous System (PNS)
label the neuron
What is the function of sensory neurons?
Carry information from the body to the CNS
What is the function of motor neurons?
Carry information from the CNS to the body
What is the role of interneurons?
Connect sensory and motor neurons
What is the function of dendrites?
Receive messages from other neurons
What does the axon do?
Carries action potentials away from the soma
What is the soma?
The cell body of a neuron containing the nucleus
What is the myelin sheath and what does it do?
Insulating layer that speeds up action potential conduction
What are terminal buttons?
Ends of the axon that release neurotransmitters
Name three types of glial cells.
Astrocytes, oligodendrocytes, and microglia
What is the function of oligodendrocytes?
Produce the myelin sheath in the CNS
What are nodes of Ranvier?
Gaps in the myelin sheath where action potentials regenerate
What is the resting membrane potential of a neuron?
-70 mV
Which ions are concentrated inside the neuron at rest?
Potassium (K⁺) and anions (A⁻)
Which ions are concentrated outside the neuron at rest?
Sodium (Na⁺) and chloride (Cl⁻)
What two forces maintain ion balance?
Diffusion and electrostatic pressure
What does the sodium-potassium pump do?
Pumps 3 Na⁺ out and 2 K⁺ into the neuron
What triggers an action potential?
Threshold of excitation is reached (~ -55 mV)
What happens during depolarization?
Sodium channels open, and Na⁺ rushes in
What happens during repolarization?
Potassium channels open, and K⁺ exits the cell
What is hyperpolarization?
The membrane potential becomes more negative than the resting potential
What is meant by “all-or-none” in action potentials?
The neuron either fires completely or not at all
What is propagation?
The process of the action potential moving down the axon
