2 Structure + Function of Cells in NS Flashcards
Q: What is a neuron?
A: A neuron is a type of cell that makes up the nervous system and is responsible for information processing and transmission.
Q: What are the main parts of a neuron?
A: The main parts of a neuron include the cell body (soma), dendrites, axon, and terminal buttons.
Q: What are the main types of neurons based on function?
A: The main types of neurons are sensory neurons (detect changes in the environment), motor neurons (control muscle contraction and gland secretion), and interneurons (involved in cognition, entirely within the CNS).
Q: What is a multipolar neuron?
A: A multipolar neuron has one axon and many dendrites attached to the soma.
Q: What is a bipolar neuron?
A: A bipolar neuron has one axon and one dendrite extending in opposite directions from the soma.
Q: What is a unipolar neuron?
A: A unipolar neuron has a single axon that divides, with one branch receiving sensory information and the other sending information to the CNS.
Q: What are supporting cells in the nervous system called?
A: Supporting cells in the nervous system are called glial cells or neuroglia.
Q: What are the functions of astrocytes?
A: Astrocytes, or star cells, provide physical support to neurons, nourishment, clean up debris when neurons die, form scar tissue, and control the chemical composition of the fluid surrounding neurons.
Q: What are oligodendrocytes responsible for?
A: Oligodendrocytes support axons and produce the myelin sheath, which acts as insulation for nerve fibers.
Q: What are Schwann cells?
A: Schwann cells are a type of glial cell found in the PNS responsible for wrapping around a single axon to form the myelin sheath.
Q: What is the blood-brain barrier (BBB)?
A: The blood-brain barrier is a semipermeable barrier between the central nervous system (CNS) and the circulatory system, regulating the flow of nutrient-rich fluid into the brain.
Q: What is the function of the blood-brain barrier?
A: The blood-brain barrier protects the brain from potentially harmful substances in the bloodstream while allowing essential nutrients to pass through.
Q: What is the area postrema?
A: The area postrema is a region of the medulla oblongata where the blood-brain barrier is weak. It allows toxins in the blood to stimulate this area, which triggers vomiting as a protective mechanism to expel the poison.
Q: What is membrane potential?
A: Membrane potential is the electrical charge across the cell membrane of a neuron, representing stored electrical energy.
Q: What is resting potential?
A: Resting potential is the membrane potential of a neuron when it is not being altered by postsynaptic potentials, typically around -70 millivolts (mV).
Q: What is depolarization?
A: Depolarization is the reduction of the negative charge of the membrane potential, leading to an increase in electrical potential.
Q: What is an action potential?
A: An action potential is a brief electrical impulse that provides the basis for the conduction of information along the axon of a neuron.
Q: What is the threshold of excitation?
A: The threshold of excitation is the value of the membrane potential that must be reached for an action potential to occur.
Q: What is hyperpolarization?
A: Hyperpolarization is an increase in the membrane potential, making the inside of the neuron more negative than the resting potential.
Q: What are the two forces that contribute to membrane potential?
A: The two forces that contribute to membrane potential are diffusion (movement of molecules from high concentration to low) and electrostatic pressure (attraction of oppositely charged ions).
Q: What is the role of the Na/K pump in neuron function?
A: The Na/K pump pushes sodium ions out of the neuron and potassium ions into the neuron, maintaining the concentration gradients necessary for neuron function.
Q: What are ion channels and what is their significance?
A: Ion channels are proteins that open and close, allowing ions to pass through the cell membrane. Voltage-gated ion channels play a crucial role in generating and propagating action potentials.
Q: What is saltatory conduction?
A: Saltatory conduction is the process by which an action potential jumps from one node of Ranvier to the next along a myelinated axon, increasing conduction speed and reducing energy consumption.
Q: What is a synapse?
A: A synapse is the junction between two neurons, consisting of a narrow gap called the synaptic cleft.
Q: Why can’t action potentials cross the synaptic cleft?
A: Action potentials cannot cross the synaptic cleft, so nerve impulses are carried by neurotransmitters (NTs).
Q: What are neurotransmitters?
A: Neurotransmitters are chemicals stored in synaptic vesicles of the presynaptic neuron, released into the synaptic cleft to transmit nerve impulses.
Q: What are neuroreceptors?
A: Neuroreceptors are chemical-gated ion channels on the postsynaptic membrane, serving as specific binding sites for neurotransmitters.
Q: What are EPSP and IPSP?
A: EPSP (Excitatory Postsynaptic Potential) is an excitatory depolarization of the postsynaptic membrane, while IPSP (Inhibitory Postsynaptic Potential) is an inhibitory hyperpolarization.
Q: What determines the nature of postsynaptic potentials (PSP)?
A: The nature of PSP is determined by postsynaptic receptors and which ion channels they open, including sodium (Na+), potassium (K+), and chloride (Cl-).
Q: What is neuronal integration?
A: Neuronal integration is the process by which excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) summate and control the rate of firing in a neuron.
Q: What is temporal summation?
A: Temporal summation is the summation of postsynaptic potentials that occur close together in time, either EPSPs or IPSPs.
Q: What is spatial summation?
A: Spatial summation is the summation of postsynaptic potentials that occur simultaneously at different synapses on the same neuron, either EPSPs or IPSPs.
