Anatomy › General Neuron Physiology
Which of the following is NOT a property of neurons?
Undergo reactive gliosis in response to injury
Permanent cells
Cells do not divide during adulthood
Compose the nervous system
Neurons are the cells that make up the nervous system. Neurons are large, permanent cells that do not divide during adulthood and spend most of their lives in the G0 phase of the cell cycle. If part of a neuron is damaged, it undergoes Wallerian degeneration, meaning that the neuron degenerates distal to the injury, and does not undergo reactive gliosis in response to injury. Astrocytes, a type of glial cell, do this.
Which of the following support cells myelinates the axons of the peripheral nervous system?
Schwann cells
Oligodendrocytes
Ependymal cells
Astrocytes
There are two types of support cells that myelinate axons in the nervous system: oligodendrocytes and Schwann cells. The difference between these two cell types is their location in the nervous system. Oligodendrocytes myelinate axons in the central nervous system, and Schwann cells myelinate axons in the peripheral nervous system.
Ependymal cells secrete cerebrospinal fluid and astrocytes help form and regulate the blood-brain barrier.
Which type of neuroglial cell is star-shaped and takes up 50% of the cells in the brain?
Astrocytes
Oligodendrocytes
Schwann Cells
Microglia cells
Ependymal cells
Astrocytes are star-shaped cells found between neurons and blood vessels. They cover almost all of the capillaries in the brain and make contact with surfaces of neurons. They make up approximately 50% of the cells in the brain. Astrocytes are responsible for supporting neurons by maintaining the extracellular fluid, facilitating nutrient delivery and waste removal to and from neurons, maintaining the blood-brain barrier, and repairing damaged cells in the central nervous system. Schwann cells and oligodendrocytes are responsible for myelinating axons in the peripheral nervous system and central nervous system, respectively. Microglia are specialized macrophages that remove cellular debris, infectious agents and damaged neurons. Ependymal cells are epithelial-like glial cells in the central nervous system that line the ventricles and produce cerebrospinal fluid.
Which of the following is NOT a property of neurons?
Undergo reactive gliosis in response to injury
Permanent cells
Cells do not divide during adulthood
Compose the nervous system
Neurons are the cells that make up the nervous system. Neurons are large, permanent cells that do not divide during adulthood and spend most of their lives in the G0 phase of the cell cycle. If part of a neuron is damaged, it undergoes Wallerian degeneration, meaning that the neuron degenerates distal to the injury, and does not undergo reactive gliosis in response to injury. Astrocytes, a type of glial cell, do this.
Which of the following support cells myelinates the axons of the peripheral nervous system?
Schwann cells
Oligodendrocytes
Ependymal cells
Astrocytes
There are two types of support cells that myelinate axons in the nervous system: oligodendrocytes and Schwann cells. The difference between these two cell types is their location in the nervous system. Oligodendrocytes myelinate axons in the central nervous system, and Schwann cells myelinate axons in the peripheral nervous system.
Ependymal cells secrete cerebrospinal fluid and astrocytes help form and regulate the blood-brain barrier.
What are the two gates of the voltage-gated channels along the axonal plasma membrane?
Activation and inactivation
Activation and reactivation
and
Positive and negative
The voltage-gated channels along the axonal plasma membrane open and close in response to changes in voltage, and may exist in three distinct states: deactivated, activated, and inactivated. While the axon is at rest, these channels are said to be deactivated; they are impermeable to sodium ions since their activation gates are closed. Once the neuron gets depolarized to the threshold of the voltage-gated sodium channels, the activation gates open, allowing the influx of sodium down its concentration gradient into the cell. During this time the channels are in their activated state. At the peak of the action potential the activation gates are still open, but the inactivation gates close, stopping the flow of sodium through the channels. The channels are in the inactivated state due to the cell becoming depolarized. Once the membrane potential drops back down towards resting, the inactivation gates open, and the activation gates close, thereby deactivating the channels again, until another action potential depolarizes the membrane.
What are the two gates of the voltage-gated channels along the axonal plasma membrane?
Activation and inactivation
Activation and reactivation
and
Positive and negative
The voltage-gated channels along the axonal plasma membrane open and close in response to changes in voltage, and may exist in three distinct states: deactivated, activated, and inactivated. While the axon is at rest, these channels are said to be deactivated; they are impermeable to sodium ions since their activation gates are closed. Once the neuron gets depolarized to the threshold of the voltage-gated sodium channels, the activation gates open, allowing the influx of sodium down its concentration gradient into the cell. During this time the channels are in their activated state. At the peak of the action potential the activation gates are still open, but the inactivation gates close, stopping the flow of sodium through the channels. The channels are in the inactivated state due to the cell becoming depolarized. Once the membrane potential drops back down towards resting, the inactivation gates open, and the activation gates close, thereby deactivating the channels again, until another action potential depolarizes the membrane.
Which type of neuroglial cell is star-shaped and takes up 50% of the cells in the brain?
Astrocytes
Oligodendrocytes
Schwann Cells
Microglia cells
Ependymal cells
Astrocytes are star-shaped cells found between neurons and blood vessels. They cover almost all of the capillaries in the brain and make contact with surfaces of neurons. They make up approximately 50% of the cells in the brain. Astrocytes are responsible for supporting neurons by maintaining the extracellular fluid, facilitating nutrient delivery and waste removal to and from neurons, maintaining the blood-brain barrier, and repairing damaged cells in the central nervous system. Schwann cells and oligodendrocytes are responsible for myelinating axons in the peripheral nervous system and central nervous system, respectively. Microglia are specialized macrophages that remove cellular debris, infectious agents and damaged neurons. Ependymal cells are epithelial-like glial cells in the central nervous system that line the ventricles and produce cerebrospinal fluid.
Which of the following is a type of acetylcholine receptor?
Muscarinic
Adrenergic
Dopaminergic
Glutaminergic
Muscarinic acetylcholine receptors (mAChRs) are found in the G protein-receptor complexes in the cell membrane of certain neurons. The suffix -ergic means exhibiting or stimulating the activity of. For example, dopaminergic receptors bind to dopamine.
A stimulus applied to a neuronal membrane that causes its potential to become more positive is __________. A stimulus that moves the potential closer to 0 is __________.
hyperpolarization . . . depolarization
hyperpolarization . . . hyperpolarization
depolarization . . . depolarization
depolarization . . . hyperpolarization
hyperpolarization . . . resting membrane potential
If an already positive membrane potential becomes more positive, it is becoming hyperpolarized because the electrical difference between the inside and outside of the cell is getting larger. On the other hand, a stimulus that moves the potential difference closer to 0 is depolarizing because it is decreasing the difference in electrical potential between the inside and outside of the cell.