2 Structure + Function of Cells in NS

Question 1

Q: What is a neuron?

Answer 1

A: A neuron is a type of cell that makes up the nervous system and is responsible for information processing and transmission.

Question 2

Q: What are the main parts of a neuron?

Answer 2

A: The main parts of a neuron include the cell body (soma), dendrites, axon, and terminal buttons.

Question 3

Q: What are the main types of neurons based on function?

Answer 3

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).

Question 4

Q: What is a multipolar neuron?

Answer 4

A: A multipolar neuron has one axon and many dendrites attached to the soma.

Question 5

Q: What is a bipolar neuron?

Answer 5

A: A bipolar neuron has one axon and one dendrite extending in opposite directions from the soma.

Question 6

Q: What is a unipolar neuron?

Answer 6

A: A unipolar neuron has a single axon that divides, with one branch receiving sensory information and the other sending information to the CNS.

Question 7

Q: What are supporting cells in the nervous system called?

Answer 7

A: Supporting cells in the nervous system are called glial cells or neuroglia.

Question 8

Q: What are the functions of astrocytes?

Answer 8

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.

Question 9

Q: What are oligodendrocytes responsible for?

Answer 9

A: Oligodendrocytes support axons and produce the myelin sheath, which acts as insulation for nerve fibers.

Question 10

Q: What are Schwann cells?

Answer 10

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.

Question 11

Q: What is the blood-brain barrier (BBB)?

Answer 11

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.

Question 12

Q: What is the function of the blood-brain barrier?

Answer 12

A: The blood-brain barrier protects the brain from potentially harmful substances in the bloodstream while allowing essential nutrients to pass through.

Question 13

Q: What is the area postrema?

Answer 13

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.

Question 14

Q: What is membrane potential?

Answer 14

A: Membrane potential is the electrical charge across the cell membrane of a neuron, representing stored electrical energy.

Question 15

Q: What is resting potential?

Answer 15

A: Resting potential is the membrane potential of a neuron when it is not being altered by postsynaptic potentials, typically around -70 millivolts (mV).

Question 16

Q: What is depolarization?

Answer 16

A: Depolarization is the reduction of the negative charge of the membrane potential, leading to an increase in electrical potential.

Question 17

Q: What is an action potential?

Answer 17

A: An action potential is a brief electrical impulse that provides the basis for the conduction of information along the axon of a neuron.

Question 18

Q: What is the threshold of excitation?

Answer 18

A: The threshold of excitation is the value of the membrane potential that must be reached for an action potential to occur.

Question 19

Q: What is hyperpolarization?

Answer 19

A: Hyperpolarization is an increase in the membrane potential, making the inside of the neuron more negative than the resting potential.

Question 20

Q: What are the two forces that contribute to membrane potential?

Answer 20

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).

Question 21

Q: What is the role of the Na/K pump in neuron function?

Answer 21

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.

Question 22

Q: What are ion channels and what is their significance?

Answer 22

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.

Question 23

Q: What is saltatory conduction?

Answer 23

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.

Question 24

Q: What is a synapse?

Answer 24

A: A synapse is the junction between two neurons, consisting of a narrow gap called the synaptic cleft.

Question 25

Q: Why can’t action potentials cross the synaptic cleft?

Answer 25

A: Action potentials cannot cross the synaptic cleft, so nerve impulses are carried by neurotransmitters (NTs).

Question 26

Q: What are neurotransmitters?

Answer 26

A: Neurotransmitters are chemicals stored in synaptic vesicles of the presynaptic neuron, released into the synaptic cleft to transmit nerve impulses.

Question 27

Q: What are neuroreceptors?

Answer 27

A: Neuroreceptors are chemical-gated ion channels on the postsynaptic membrane, serving as specific binding sites for neurotransmitters.

Question 28

Q: What are EPSP and IPSP?

Answer 28

A: EPSP (Excitatory Postsynaptic Potential) is an excitatory depolarization of the postsynaptic membrane, while IPSP (Inhibitory Postsynaptic Potential) is an inhibitory hyperpolarization.

Question 29

Q: What determines the nature of postsynaptic potentials (PSP)?

Answer 29

A: The nature of PSP is determined by postsynaptic receptors and which ion channels they open, including sodium (Na+), potassium (K+), and chloride (Cl-).

Question 30

Q: What is neuronal integration?

Answer 30

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.

Question 31

Q: What is temporal summation?

Answer 31

A: Temporal summation is the summation of postsynaptic potentials that occur close together in time, either EPSPs or IPSPs.

Question 32

Q: What is spatial summation?

Answer 32

A: Spatial summation is the summation of postsynaptic potentials that occur simultaneously at different synapses on the same neuron, either EPSPs or IPSPs.