Chapter 12 Flashcards
What are the two main components of the central nervous system (CNS)?
a) Brain and ganglia
b) Spinal cord and nerves
c) Brain and spinal cord
d) Nerves and ganglia
c) Brain and spinal cord
Explanation: The central nervous system (CNS) consists of the brain and the spinal cord, which are the primary structures contained within the cranial cavity of the skull and the vertebral cavity of the vertebral column, respectively.
The peripheral nervous system (PNS) includes all nervous tissue outside the central nervous system.
A) True
B) False
A) True
Explanation: The peripheral nervous system (PNS) comprises all the nervous tissue outside the CNS, including nerves and ganglia.
The two major regions of the nervous system are the central nervous system (CNS) and the ________ nervous system (PNS).
peripheral
Explanation: The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS).
What type of cell provides a framework of tissue that supports the neurons in the nervous system?
a) Neurons
b) Axons
c) Glial cells
d) Dendrites
c) Glial cells
Explanation: Glial cells are a variety of cells that provide a supportive framework for neurons and their activities.
White matter in the brain and spinal cord appears white because it is insulated by a lipid-rich substance called myelin.
A) True
B) False
A) True
Explanation: White matter appears white due to the presence of myelin, a lipid-rich substance that insulates axons.
The fiber that connects a neuron with its target is called an ________.
axon
Explanation: An axon is the fiber that connects a neuron with its target, transmitting signals to other neurons or tissues.
Which of the following regions predominantly contain cell bodies and regions composed of just axons in the nervous system?
a) Gray matter
b) White matter
c) Both a and b
d) Neither a nor b
c) Both a and b
Explanation: Gray matter consists mainly of cell bodies and dendrites, while white matter predominantly contains axons.
Gray matter in the nervous system is always gray in color.
A) True
B) False
B) False
Explanation: Gray matter is not necessarily gray; it can appear pinkish or even slightly tan, depending on blood content and how long the tissue has been preserved.
In the nervous system, the regions with many axons are often referred to as ________ matter.
white
Explanation: White matter is composed of regions with many axons, which appear white due to the myelin sheath that insulates them.
Which of the following is NOT a correct statement about the peripheral nervous system (PNS)?
a) It includes ganglia and nerves.
b) It is entirely outside the central nervous system.
c) It is responsible for processing information within the brain.
d) It connects the CNS to limbs and organs.
c) It is responsible for processing information within the brain.
Explanation: The PNS connects the CNS to limbs and organs and includes ganglia and nerves, but it does not process information within the brain; this is the function of the CNS.
What is the term for a localized collection of neuron cell bodies in the central nervous system (CNS)?
a) Ganglion
b) Nerve
c) Nucleus
d) Axon
c) Nucleus
Explanation: In the CNS, a localized collection of neuron cell bodies is referred to as a nucleus.
In the peripheral nervous system (PNS), a cluster of neuron cell bodies is referred to as a ganglion.
A) True
B) False
A) True
Explanation: A cluster of neuron cell bodies in the PNS is called a ganglion.
The ________ is the outer cortex of the brain composed primarily of neuron cell bodies.
gray matter
Explanation: Gray matter makes up the outer cortex of the brain and is composed primarily of neuron cell bodies.
What does the white matter in the brain primarily consist of?
a) Cell bodies
b) Dendrites
c) Axons
d) Nuclei
c) Axons
Explanation: White matter consists mainly of axons, which are insulated by myelin.
The terms “tract” and “nerve” refer to the same structures but differ in their locations within the nervous system.
A) True
B) False
A) True
Explanation: “Tract” refers to a bundle of axons in the CNS, while “nerve” refers to a similar structure in the PNS
The optic nerve becomes the optic ________ when it passes through the optic chiasma into the brain.
tract
Explanation: The optic nerve becomes the optic tract when it continues into the brain past the optic chiasma.
Which of the following structures is NOT found in the PNS?
a) Ganglia
b) Nuclei
c) Nerves
d) Axons
b) Nuclei
Explanation: Nuclei are localized collections of neuron cell bodies found in the CNS, not the PNS.
White matter in the CNS appears white because of the myelin sheath.
A) True
B) False
A) True
Explanation: The white appearance of white matter is due to the myelin sheath that insulates the axons.
The term for a bundle of axons found in the CNS is a ________.
tract
Explanation: A bundle of axons in the CNS is called a tract.
What term describes a group of nuclei in the CNS that are connected together?
a) Ganglia
b) Tract
c) Basal nuclei
d) Optic tract
c) Basal nuclei
Explanation: A group of connected nuclei in the CNS is often referred to as the basal nuclei
What is the main function of the somatic nervous system (SNS)?
a) Involuntary control of body functions
b) Conscious perception and voluntary motor responses
c) Regulation of the internal environment
d) Control of digestive system functions
b) Conscious perception and voluntary motor responses
Explanation: The somatic nervous system (SNS) is responsible for conscious perception and voluntary motor responses, including the contraction of skeletal muscles.
The autonomic nervous system (ANS) is responsible for voluntary control of the body’s functions.
A) True
B) False
B) False
Explanation: The autonomic nervous system (ANS) is responsible for involuntary control of body functions, usually for the sake of homeostasis.
The ________ nervous system is responsible for controlling the smooth muscle and glandular tissue in the digestive system.
enteric
Explanation: The enteric nervous system is responsible for controlling the smooth muscle and glandular tissue in the digestive system and is considered a part of the PNS.
Which division of the nervous system is involved in receiving information about the environment and generating responses to that information?
a) Sensory functions
b) Motor functions
c) Integration functions
d) All of the above
d) All of the above
Explanation: The nervous system is involved in sensory functions (receiving information), motor functions (generating responses), and integration functions (processing information).
Sensory functions of the nervous system register the presence of a change in homeostasis or a particular event in the environment.
A) True
B) False
A) True
Explanation: Sensory functions of the nervous system detect changes in homeostasis or specific events in the environment, known as stimuli.
The sensory input that causes the nervous system to respond is referred to as a ________.
stimulus
Explanation: A stimulus is the sensory input that triggers a response from the nervous system.
What type of response does the nervous system produce based on the stimuli perceived by sensory structures?
a) Only voluntary responses
b) Only involuntary responses
c) Both voluntary and involuntary responses
d) Neither voluntary nor involuntary responses
c) Both voluntary and involuntary responses
Explanation: The nervous system produces both voluntary (conscious) and involuntary (unconscious) responses based on sensory input.
The enteric nervous system (ENS) is entirely dependent on the CNS for its functions.
A) True
B) False
B) False
Explanation: The enteric nervous system (ENS) is a large part of the PNS and is not dependent on the CNS for its functions.
The three major functions of the nervous system are sensation, response, and ________.
integration
Explanation: The three major functions of the nervous system are sensation (receiving information), response (generating actions), and integration (processing and integrating sensory input).
Which of the following is NOT a function of the autonomic nervous system (ANS)?
a) Regulation of internal environment
b) Control of voluntary motor responses
c) Involuntary control of smooth and cardiac muscle
d) Regulation of glandular activity
b) Control of voluntary motor responses
Explanation: The autonomic nervous system (ANS) is responsible for involuntary control of smooth and cardiac muscle and glandular activity, not voluntary motor responses.
Which part of the nervous system is responsible for the execution of voluntary motor responses?
a) Spinal cord
b) Brain
c) Nerves
d) Ganglia
b) Brain
Explanation: The brain is responsible for the perception and processing of sensory stimuli, execution of voluntary motor responses, and regulation of homeostatic mechanisms.
The enteric nervous system (ENS) operates independently of the brain and spinal cord.
A) True
B) False
A) True
Explanation: The ENS, located in the digestive tract, is responsible for autonomous functions and can operate independently of the brain and spinal cord.
The ________ nervous system includes the fibers of sensory and motor neurons and is part of the peripheral nervous system.
somatic
Explanation: The somatic nervous system includes the fibers of sensory and motor neurons and is part of the PNS.
What is the primary function of ganglia in the PNS?
a) Initiation of reflexes
b) Relay of motor responses
c) Reception of sensory stimuli
d) Both b and c
d) Both b and c
Explanation: Ganglia in the PNS are responsible for the reception of sensory stimuli and the relay of visceral motor responses.
The claim that humans only use 10 percent of their brains is scientifically accurate.
A) True
B) False
B) False
Explanation: The claim that humans only use 10 percent of their brains is not true. Functional MRI (fMRI) shows that much more of the brain is active during various tasks.
Functional MRI (fMRI) is a technique used to measure ________ in the brain by detecting changes in blood flow.
activity
Explanation: fMRI measures brain activity by detecting changes in blood flow, indicating active regions of the brain.
During an fMRI experiment, which areas of the brain would be active when a subject is asked to recognize a photograph of a face?
a) Visual sensory areas
b) Integrating areas
c) Motor areas
d) All of the above
d) All of the above
Explanation: In such an experiment, visual sensory areas, integrating areas, and motor areas responsible for moving the eyes and pressing a button would all be active.
The autonomic nervous system (ANS) controls involuntary responses such as heart rate and digestion.
A) True
B) False
A) True
Explanation: The ANS is responsible for involuntary control of body functions, including heart rate, digestion, and glandular activity.
The ________ nervous system is responsible for regulating homeostatic mechanisms such as body temperature and hydration.
autonomic
Explanation: The autonomic nervous system regulates homeostatic mechanisms like body temperature and hydration.
Which nervous system structure is involved in the initiation of reflexes from the ventral horn and lateral horn gray matter?
a) Brain
b) Spinal cord
c) Nerves
d) Ganglia
b) Spinal cord
Explanation: The spinal cord initiates reflexes from the ventral horn (somatic) and lateral horn (autonomic) gray matter.
What are the primary types of cells that compose nervous tissue?
a) Neurons and muscle cells
b) Neurons and glial cells
c) Glial cells and epithelial cells
d) Muscle cells and epithelial cells
b) Neurons and glial cells
Explanation: Nervous tissue is composed of neurons, which are electrically active and communicate signals, and glial cells, which provide support for neurons.
Neurons are considered the basis of nervous tissue because they are responsible for the computation and communication functions.
A) True
B) False
A) True
Explanation: Neurons are electrically active and responsible for the communication and computation functions of the nervous system.
The main part of a neuron that contains the nucleus and most organelles is called the ________.
soma (cell body)
Explanation: The soma, or cell body, contains the nucleus and most of the major organelles of a neuron.
What is the function of dendrites in a neuron?
a) Transmitting electrical impulses to target cells
b) Receiving information from other neurons
c) Insulating axons
d) Supporting neuron structure
b) Receiving information from other neurons
Explanation: Dendrites are highly branched processes that receive information from other neurons at specialized areas called synapses.
Myelin, produced by glial cells, acts as insulation for axons, similar to how plastic insulates electrical wires.
A) True
B) False
A) True
Explanation: Myelin insulates axons to help electrical signals travel faster, much like plastic insulates electrical wires.
The gaps between myelin sheaths along an axon are called ________.
nodes of Ranvier
Explanation: Nodes of Ranvier are gaps between the myelin sheaths along an axon, important for the propagation of electrical signals.
What part of the neuron is responsible for propagating the nerve impulse?
a) Soma
b) Dendrites
c) Axon
d) Synapse
c) Axon
Explanation: The axon is the process of a neuron that propagates the nerve impulse to target cells.
Unipolar neurons have two processes attached to the cell body.
A) True
B) False
B) False
Explanation: Unipolar neurons have one process attached to the cell body, while bipolar neurons have two processes.
At the end of the axon, the enlarged area that makes the connection with the target cell is called the ________.
synaptic end bulb
Explanation: Synaptic end bulbs are enlargements at the end of axons that form connections with target cells at synapses.
Which type of neuron has more than two processes, including one axon and two or more dendrites?
a) Unipolar neuron
b) Bipolar neuron
c) Multipolar neuron
d) None of the above
c) Multipolar neuron
Explanation: Multipolar neurons have more than two processes, including one axon and two or more dendrites.
What distinguishes unipolar neurons from other types of neurons?
a) They have no dendrites.
b) They have two axons.
c) They have one axon and one dendrite.
d) They are exclusively found in the CNS.
a) They have no dendrites.
Explanation: Unipolar neurons have one process that includes the axon and no dendrites.
Bipolar neurons have two processes: one axon and one dendrite.
A) True
B) False
A) True
Explanation: Bipolar neurons have two processes extending from each end of the cell body, one axon and one dendrite.
Neurons that have one axon and two or more dendrites are classified as ________ neurons.
multipolar
Explanation: Multipolar neurons have one axon and two or more dendrites, making them the most common type of neuron in the CNS.
Which type of neuron is typically found in sensory ganglia and has a cell body located in the periphery?
a) Multipolar neuron
b) Bipolar neuron
c) Unipolar neuron
d) Anaxonic neuron
c) Unipolar neuron
Explanation: Unipolar neurons are typically found in sensory ganglia with cell bodies located in the periphery.
Glial cells are known as the “glue” of the nervous system because they provide support and insulation for neurons.
A) True
B) False
A) True
Explanation: Glial cells, or neuroglia, provide support and insulation for neurons and are often referred to as the “glue” of the nervous system.
The glial cell type responsible for creating the blood-brain barrier in the CNS is the ________.
astrocyte
Explanation: Astrocytes are the glial cells responsible for maintaining the blood-brain barrier and providing support to neurons in the CNS.
What is the primary function of oligodendrocytes in the CNS?
a) Phagocytosis
b) Creating cerebrospinal fluid (CSF)
c) Insulation and myelination
d) Supporting blood vessels
c) Insulation and myelination
Explanation: Oligodendrocytes are responsible for insulating axons and creating the myelin sheath in the CNS.
Microglia are the glial cells responsible for immune surveillance and phagocytosis in the CNS.
A) True
B) False
A) True
Explanation: Microglia are responsible for immune surveillance and phagocytosis, helping to maintain the health of the CNS.
The glial cells that produce cerebrospinal fluid (CSF) in the CNS are called ________ cells.
ependymal
Explanation: Ependymal cells are responsible for producing cerebrospinal fluid (CSF) in the CNS.
Which glial cell type in the PNS provides support similar to astrocytes in the CNS?
a) Schwann cells
b) Satellite cells
c) Oligodendrocytes
d) Microglia
b) Satellite cells
Explanation: Satellite cells in the PNS provide support to neurons, similar to the function of astrocytes in the CNS.
Which glial cell type in the CNS is responsible for forming the blood-brain barrier (BBB)?
a) Microglia
b) Oligodendrocytes
c) Astrocytes
d) Ependymal cells
c) Astrocytes
Explanation: Astrocytes maintain the blood-brain barrier (BBB) and support neurons in the CNS.
Oligodendrocytes in the CNS are responsible for insulating axons with myelin.
A) True
B) False
A) True
Explanation: Oligodendrocytes insulate axons in the CNS by wrapping them in myelin.
The glial cells responsible for immune surveillance and phagocytosis in the CNS are called ________.
microglia
Explanation: Microglia perform immune surveillance and phagocytosis, acting as the CNS’s resident macrophages.
What is the main function of ependymal cells in the CNS?
a) Insulating axons
b) Creating cerebrospinal fluid (CSF)
c) Supporting neurons
d) Phagocytosis
b) Creating cerebrospinal fluid (CSF)
Explanation: Ependymal cells filter blood to make cerebrospinal fluid (CSF) that circulates in the CNS.
Satellite cells in the PNS provide similar support to neurons as astrocytes do in the CNS.
A) True
B) False
A) True
Explanation: Satellite cells support neurons in the PNS, similar to the role of astrocytes in the CNS.
In the PNS, the cells that insulate axons with myelin are called ________ cells.
Schwann
Explanation: Schwann cells insulate axons with myelin in the PNS.
What is the primary function of the myelin sheath?
a) Supporting neuron cell bodies
b) Facilitating transmission of electrical signals along the axon
c) Creating cerebrospinal fluid
d) Engaging in phagocytosis
b) Facilitating transmission of electrical signals along the axon
Explanation: The myelin sheath insulates axons and speeds up the transmission of electrical signals.
Oligodendrocytes can myelinate multiple segments of the same axon or separate axons.
A) True
B) False
A) True
Explanation: Oligodendrocytes can myelinate multiple axon segments, either on the same axon or different axons.
The gaps between myelinated segments along an axon are called ________.
nodes of Ranvier
Explanation: Nodes of Ranvier are gaps between myelinated segments where action potentials are generated.
Which glial cell type lines the ventricles of the brain and helps circulate CSF?
a) Microglia
b) Astrocytes
c) Ependymal cells
d) Schwann cells
c) Ependymal cells
Explanation: Ependymal cells line the ventricles of the brain and help circulate cerebrospinal fluid (CSF).
What is the function of the myelin sheath?
a) Supporting neuron cell bodies
b) Facilitating the transmission of electrical signals along the axon
c) Creating cerebrospinal fluid
d) Engaging in phagocytosis
b) Facilitating the transmission of electrical signals along the axon
Explanation: The myelin sheath insulates axons and speeds up the transmission of electrical signals.
Myelin sheaths can extend for one or two millimeters, depending on the diameter of the axon.
A) True
B) False
A) True
Explanation: The length of myelin sheaths can vary, typically extending for one or two millimeters, depending on the axon’s diameter.
The gaps between myelinated segments along an axon are called ________.
nodes of Ranvier
Explanation: Nodes of Ranvier are gaps between myelinated segments where action potentials are generated.
Which glial cell type is responsible for myelinating axons in the CNS?
a) Schwann cells
b) Astrocytes
c) Oligodendrocytes
d) Ependymal cells
c) Oligodendrocytes
Explanation: Oligodendrocytes are responsible for myelinating axons in the CNS.
Multiple sclerosis (MS) is an autoimmune disease that affects the myelin in the central nervous system.
A) True
B) False
A) True
Explanation: MS is an autoimmune disease where antibodies attack the myelin in the CNS, leading to inflammation and destruction of the myelin sheath.
The autoimmune disease affecting the peripheral nervous system and causing demyelination is known as ________.
Guillain-Barré syndrome
Explanation: Guillain-Barré syndrome is an autoimmune disease that causes demyelination in the peripheral nervous system.
What are the typical symptoms of multiple sclerosis (MS)?
a) Only sensory deficits
b) Only motor deficits
c) Both somatic and autonomic deficits
d) None of the above
c) Both somatic and autonomic deficits
Explanation: MS can cause both somatic and autonomic deficits, including motor control issues and problems with autonomic functions like bladder control.
Schwann cells myelinate axons in the PNS by wrapping around a portion of the axon.
A) True
B) False
A) True
Explanation: Schwann cells in the PNS wrap around portions of axons to create the myelin sheath.
The process of myelination in the CNS involves the wrapping of axons by ________.
oligodendrocytes
Explanation: Oligodendrocytes wrap around axons in the CNS to form the myelin sheath.
Which of the following diseases involves demyelination caused by an autoimmune reaction?
a) Multiple sclerosis
b) Guillain-Barré syndrome
c) Both a and b
d) Neither a nor b
c) Both a and b
Explanation: Both multiple sclerosis and Guillain-Barré syndrome involve demyelination due to autoimmune reactions.
What type of receptor is sensitive to temperature in the skin?
A. Mechanoreceptor
B. Thermoreceptor
C. Photoreceptor
D. Nociceptor
B. Thermoreceptor
Explanation: Thermoreceptors are specialized nerve endings in the skin that detect temperature changes.
Where does the sensory pathway reach for conscious perception?
A. Spinal Cord
B. Thalamus
C. Cerebral Cortex
D. Brainstem
C. Cerebral Cortex
Explanation: The sensory pathway reaches the cerebral cortex for conscious perception of sensory information.
The voltage at which an electrical signal is generated is called the __________.
Threshold
Explanation: The threshold is the critical level to which the membrane potential must be depolarized to initiate an action potential.
The neurotransmitter causes the release of a signaling molecule called a __________.
Neurotransmitter
Explanation: Neurotransmitters are chemicals released by neurons to transmit signals to other cells.
The thalamus is involved in relaying sensory information to the cerebral cortex.
A) True
B) False
A) True
Explanation: The thalamus acts as a relay station for sensory information, directing it to the cerebral cortex.
Action potentials can travel both towards and away from the central nervous system.
A) True
B) False
B) False
Explanation: Action potentials typically travel in one direction, from the sensory receptors towards the central nervous system.
What region of the brain is responsible for sending signals down to the spinal cord for movement?
A. Thalamus
B. Precentral Gyrus of the Frontal Cortex
C. Occipital Lobe
D. Temporal Lobe
B. Precentral Gyrus of the Frontal Cortex
Explanation: The precentral gyrus of the frontal cortex is where upper motor neurons are located, which send signals to the spinal cord for movement.
What neurotransmitter is released at the neuromuscular junction to cause muscle contraction?
A. Dopamine
B. Serotonin
C. Acetylcholine
D. GABA
C. Acetylcholine
Explanation: Acetylcholine is released at the neuromuscular junction, causing the muscle fibers to contract.
The axon of the upper motor neuron extends all the way down the __________.
Spinal Cord
Explanation: The axon of the upper motor neuron extends down the spinal cord and synapses with a lower motor neuron.
Following a large potential known as an __________ potential, the muscle fiber contracts.
End Plate
Explanation: The end plate potential is the depolarization of the muscle membrane, leading to contraction.
The lower motor neuron terminates on muscle fibers at the neuromuscular junction.
A) True
B) False
A) True
Explanation: The lower motor neuron’s axon terminates on muscle fibers at the neuromuscular junction, where it releases acetylcholine to initiate contraction.
Neurophysiology solely focuses on the academic study of the nervous system.
A) True
B) False
B) False
Explanation: Neurophysiology also includes clinical applications, biotechnology research, and medical practices such as psychiatry and neuropsychology.
What type of membrane is essential for generating action potentials in neurons?
A. Inactive Membrane
B. Excitable Membrane
C. Semi-permeable Membrane
D. Impermeable Membrane
B. Excitable Membrane
Explanation: An excitable membrane can generate action potentials, which are essential for neuron communication.
Which protein is primarily responsible for maintaining the concentration gradients of sodium and potassium ions across the cell membrane?
A. Calcium Pump
B. Sodium/Chloride Pump
C. Sodium/Potassium Pump
D. Potassium/Calcium Pump
C. Sodium/Potassium Pump
Explanation: The sodium/potassium pump actively moves sodium ions out and potassium ions into the cell, maintaining their concentration gradients.
The cell membrane is composed of a __________ bilayer with hydrophobic cores.
phospholipid
Explanation: The cell membrane consists of a phospholipid bilayer, allowing it to regulate what enters and exits the cell.
The process by which ions move across the cell membrane through ion channels in response to a concentration gradient is known as __________.
Electrochemical Exclusion
Explanation: Electrochemical exclusion describes the movement of ions based on charge and concentration gradients.
Ion channels can be gated, meaning they can open or close in response to specific stimuli.
A) True
B) False
A) True
Ion channels can be gated, opening or closing in response to chemical, mechanical, or voltage changes.
Ligand-gated channels open due to physical distortion of the cell membrane.
A) True
B) False
B) False
Explanation: Ligand-gated channels open in response to the binding of a signaling molecule (ligand) to the channel protein.
What type of ion channel opens and closes at random without a specific triggering event?
A. Voltage-Gated Channel
B. Ligand-Gated Channel
C. Mechanically Gated Channel
D. Leakage Channel
D. Leakage Channel
Explanation: Leakage channels open and close randomly and contribute to the resting membrane potential.
What is the standard membrane potential typically measured in neurons at rest?
A. +30 mV
B. 0 mV
C. -70 mV
D. -30 mV
C. -70 mV
Explanation: The resting membrane potential in neurons is commonly measured at -70 mV.
The difference in charge across the cell membrane, measured in millivolts (mV), is known as the __________.
Membrane Potential
Explanation: Membrane potential refers to the distribution of electrical charge across the cell membrane.
The process of the membrane potential becoming more positive, moving towards zero, is called __________.
Depolarization
Explanation: Depolarization occurs when the membrane potential becomes less negative, moving towards zero.
Leakage channels contribute to the generation of action potentials.
A) True
B) False
B) False
Explanation: Leakage channels primarily contribute to the resting membrane potential, not the generation of action potentials.
The concentration of potassium ions is higher inside the cell than outside.
A) True
B) False
A) True
Explanation: The concentration of potassium ions (K+) is higher inside the cell compared to outside.
What is the typical threshold membrane potential required to initiate an action potential?
A. -70 mV
B. -55 mV
C. 0 mV
D. +30 mV
B. -55 mV
Explanation: The threshold potential at which an action potential is initiated is typically -55 mV.
What happens during the depolarization phase of an action potential?
A. Sodium ions leave the cell
B. Potassium ions enter the cell
C. Sodium ions enter the cell
D. Chloride ions enter the cell
C. Sodium ions enter the cell
Explanation: During depolarization, sodium ions rush into the cell, making the membrane potential more positive.
The process of the membrane potential becoming more negative than the resting potential after an action potential is called __________.
Hyperpolarization
Explanation: Hyperpolarization occurs when the membrane potential becomes more negative than the resting potential.
The period during which no new action potential can be initiated, regardless of the strength of the stimulus, is called the __________ refractory period.
Absolute
Explanation: During the absolute refractory period, a new action potential cannot be initiated.
Action potentials are all-or-none events.
A) True
B) False
A) True
Explanation: Action potentials either occur fully or not at all; they do not vary in size or strength.
The voltage-gated potassium (K+) channel has two gates: activation and inactivation gates.
A) True
B) False
B) False
Explanation: The voltage-gated potassium channel has only one gate, while the voltage-gated sodium channel has two gates (activation and inactivation).
What term describes the process of action potential jumping from one node of Ranvier to the next in myelinated axons?
A. Continuous Conduction
B. Saltatory Conduction
C. Depolarization
D. Repolarization
B. Saltatory Conduction
Explanation: Saltatory conduction is the process where the action potential jumps from one node of Ranvier to the next, which occurs in myelinated axons.
What ion concentration is higher inside the neuron compared to the outside, playing a critical role in repolarization?
A. Sodium (Na+)
B. Calcium (Ca2+)
C. Chloride (Cl-)
D. Potassium (K+)
D. Potassium (K+)
Explanation: The concentration of potassium ions (K+) is higher inside the neuron, which is critical for the process of repolarization.
The resting membrane potential of a neuron is typically around __________ mV.
-70 mV
Explanation: The resting membrane potential of a neuron is generally about -70 mV.
The rapid increase in membrane potential to +30 mV during an action potential is known as __________.
Depolarization
Explanation: Depolarization is the rapid rise in membrane potential, making the inside of the cell more positive.
The absolute refractory period is the time during which a new action potential can be initiated if the stimulus is strong enough.
A) True
B) False
B) False
Explanation: During the absolute refractory period, no new action potential can be initiated regardless of the stimulus strength.
Astrocytes play a key role in maintaining the chemical environment of CNS tissue.
A) True
B) False
A) True
Explanation: Astrocytes are responsible for maintaining the chemical environment in the central nervous system (CNS).
