Neurons and Action Potentials quiz #1 Flashcards
Neurons and Action Potentials quiz #1
You can tap to flip the card.
Control buttons has been changed to "navigation" mode.
1/40Skip to main content
What are the two main types of cells in the nervous system and their primary functions?
The two main types of cells are neurons, which transmit electrical and chemical signals, and glial cells, which support and protect neurons. What is the basic structure of a neuron?
A neuron consists of a cell body (with a nucleus), dendrites (which receive signals), an axon (which transmits signals), and axon terminals (which connect to other neurons). What is the function of dendrites in a neuron?
Dendrites receive chemical signals from other neurons and transmit them to the cell body. What is the role of the axon in a neuron?
The axon transmits electrical signals from the cell body to the axon terminals. What is a synapse?
A synapse is the junction between the axon terminal of one neuron and the dendrite of another, where signals are transmitted. What is the difference between the central and peripheral nervous systems?
The central nervous system consists of the brain and spinal cord, while the peripheral nervous system includes all other nerves in the body. What are ganglia?
Ganglia are clusters of neuron cell bodies found in the peripheral nervous system. What are the three main types of neurons and their functions?
Sensory neurons transmit sensory information to the CNS, motor neurons send signals from the CNS to muscles and glands, and interneurons connect neurons within the CNS. What is an electric current in the context of neurons?
In neurons, electric current is the flow of ions across the cell membrane. What is membrane potential?
Membrane potential is the difference in electric potential between the inside and outside of a cell, created by ion gradients across the membrane. What is resting membrane potential?
Resting membrane potential is the baseline membrane potential of a neuron when it is not transmitting a signal, typically negative inside relative to outside. What is depolarization?
Depolarization is when the membrane potential becomes more positive (less negative). What is hyperpolarization?
Hyperpolarization is when the membrane potential becomes more negative than the resting potential. What are ion channels and their significance in neurons?
Ion channels are proteins that allow specific ions to pass through the membrane, crucial for establishing membrane potentials and transmitting signals. What are leak channels?
Leak channels are ion channels that allow potassium ions to passively leak out of the cell, helping maintain the negative resting potential. What are gated ion channels?
Gated ion channels open or close in response to specific stimuli, such as ligands (ligand-gated) or changes in membrane potential (voltage-gated). What is the difference between ligand-gated and voltage-gated ion channels?
Ligand-gated channels open in response to chemical signals, while voltage-gated channels open in response to changes in membrane potential. What are the three states of voltage-gated sodium channels?
Voltage-gated sodium channels can be closed, open, or inactivated. What is the sodium-potassium pump and its function?
The sodium-potassium pump uses ATP to actively transport 3 sodium ions out of the cell and 2 potassium ions into the cell, maintaining ion gradients. What is equilibrium potential?
Equilibrium potential is the membrane potential at which there is no net movement of a particular ion across the membrane. What is an action potential?
An action potential is a rapid, all-or-nothing change in membrane potential that propagates along the axon as an electrical signal. How does a graded potential differ from an action potential?
Graded potentials vary in magnitude and can sum together, while action potentials are all-or-nothing and do not vary in size. How is the intensity of a signal coded in action potentials?
Signal intensity is coded by the frequency of action potentials, not their amplitude. What is the threshold potential?
Threshold potential is the membrane potential that must be reached to trigger an action potential. What happens during the rising phase of an action potential?
During the rising phase, voltage-gated sodium channels open, sodium rushes into the cell, and the membrane depolarizes. What causes the falling phase of an action potential?
The falling phase is caused by inactivation of sodium channels and opening of voltage-gated potassium channels, allowing potassium to exit the cell and repolarize the membrane. What is the refractory period?
The refractory period is the time after an action potential during which another action potential cannot be generated, ensuring one-way propagation. What is hyperpolarization in the context of an action potential?
Hyperpolarization is the undershoot phase where the membrane potential becomes more negative than the resting potential due to continued potassium efflux. How does axon diameter affect action potential speed?
Larger axon diameter decreases resistance and increases the speed of action potential propagation. What is myelin and its function?
Myelin is a fatty sheath that insulates axons, increasing the speed of action potential propagation. What are nodes of Ranvier?
Nodes of Ranvier are gaps in the myelin sheath where ion channels are concentrated, allowing action potentials to be regenerated. What is saltatory conduction?
Saltatory conduction is the process by which action potentials jump from one node of Ranvier to the next along a myelinated axon. Which glial cells myelinate axons in the central nervous system?
Oligodendrocytes myelinate axons in the central nervous system. Which glial cells myelinate axons in the peripheral nervous system?
Schwann cells myelinate axons in the peripheral nervous system. How does myelination affect the location of ion channels on the axon?
Ion channels are concentrated at the nodes of Ranvier in myelinated axons. What is the direction of action potential propagation and what ensures it?
Action potentials propagate in one direction due to inactivation of sodium channels behind the advancing signal. What happens when an action potential reaches the axon terminal?
When an action potential reaches the axon terminal, it triggers the release of neurotransmitters into the synapse. What is a chemical synapse?
A chemical synapse is a junction where neurotransmitters are released from one neuron to transmit a signal to another cell. What is an electrical synapse?
An electrical synapse is a direct connection between cells via gap junctions, allowing action potentials to pass directly. What role do voltage-gated calcium channels play at the synapse?
Voltage-gated calcium channels open in response to depolarization, allowing calcium to enter the axon terminal and trigger neurotransmitter release.
02:14
