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Cell Membrane Functions

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120 Questions

Which type of cell-cell adhesion protein is responsible for the adhesion of white blood cells?

Selectins

What is the primary role of the glycocalyx or cell coat on the cell surface?

To allow cells to recognize and interact with each other

Which type of specialized cell junction is responsible for allowing the unrestricted passage of small nutrient molecules between cells?

Gap junctions

What is the primary function of the resting membrane potential in nerve and muscle cells?

To generate electrical signals for communication

Which type of cell-cell adhesion protein is responsible for anchoring the cytoskeleton to the cell membrane?

Cadherins

What type of signal is required for releasing secretory materials outside the cell in regulative exocytosis?

External signal

What type of endocytosis involves the transfer of large solid particles into the cell?

Phagocytosis

What protein covers the area where the pit forms during clathrin-mediated endocytosis?

Clathrin

Which enzyme acts as a molecular scissor during clathrin-mediated endocytosis?

Dynamin

What specific function does the adaptin protein perform in clathrin-mediated endocytosis?

Recognition by cargo receptor

What is the main function of the phospholipid bilayer in a cell?

Controlling entry and exit of molecules

Which component establishes and maintains the electrical charge difference across the plasma membrane?

Electrochemical gradients

What is the role of glycocalyx in cell communication?

Creating a molecular fingerprint for cell identification

How do intercellular connections contribute to cell physiology?

Controlling communication with other cells

Which term refers to the collective carbohydrates molecules attached to the plasma membrane?

Oligosaccharide chains

What is the major lipid component of the plasma membrane according to the Fluid Mosaic Model?

Phospholipid

How does cholesterol contribute to regulating membrane fluidity during temperature changes?

By stabilizing the membrane at high temperatures and preventing aggregation at low temperatures

Where do transmembrane proteins typically reside in the plasma membrane?

Embedded across the entire cell membrane

Which group of proteins completely spans the cell membrane according to the Fluid Mosaic Model?

Transmembrane proteins

In what way does cholesterol help in preventing phospholipid aggregation at low temperatures?

By inserting into phospholipids and preventing interference

What is the main function of lipid rafts in the plasma membrane?

Facilitate cell signaling

Which type of proteins embedded in the plasma membrane allows the entry and exit of molecules?

Channels

What is the role of integrins in cell physiology?

Cell migration and attachment to the extracellular matrix

Which type of proteins are essential for exocytosis by recognizing vesicles at docking sites?

Docking marker acceptors

What is the primary function of CDC markers in intercellular communication?

Cell adhesion

What is the primary role of Inhibitory Postsynaptic Potential (IPSP) in the context of neuron communication?

Decreases the permeability of the subsynaptic membrane to K+ and Cl− ions

What is the specialized portion of the muscle cell membrane where the axon terminal innervates the muscle cell known as?

Motor end plate

What is the main outcome of Excitatory Postsynaptic Potential (EPSP) in a neuron?

Promotes the depolarization of the postsynaptic neuron

What structures typically innervate muscle cells at neuromuscular junctions?

Only one muscle cell is innervated by one axon terminal

Which type of potentials allow for the creation of graded potentials in postsynaptic neurons?

Excitatory Postsynaptic Potentials (EPSP)

Which of the following statements accurately describes the role of glucagon in maintaining blood glucose homeostasis?

Glucagon stimulates the conversion of glycogen to glucose in the liver and its subsequent release into the bloodstream.

Which of the following processes is primarily responsible for maintaining the resting membrane potential in nerve and muscle cells?

The selective permeability of the plasma membrane to potassium ions over sodium ions.

Which type of cell junction is responsible for facilitating the intercellular communication and passage of small molecules between adjacent cells?

Gap junctions

What is the primary function of the glycocalyx, or cell coat, on the surface of cells?

Protecting cells from mechanical stress and regulating cell-cell interactions.

Which type of cell-cell adhesion protein is responsible for anchoring the cytoskeleton to the plasma membrane, providing mechanical strength and stability to cells?

Integrins

Which of the following statements accurately describes the concept of enantiostasis in the context of physiological processes?

Enantiostasis describes the antagonistic control of physiological processes by opposing mechanisms or systems.

Which of the following statements accurately describes the role of hemocyanin in the blue crab's (Callinectes sapidus) ability to live in both high and low salinity environments?

Hemocyanin is a respiratory pigment that allows efficient oxygen binding and release, enabling adaptation to varying salinity levels.

Which of the following transport mechanisms is primarily responsible for the movement of large molecules, such as proteins, across the plasma membrane?

Endocytosis and exocytosis

Which of the following statements accurately describes the role of pathophysiology in the context of disease and wellness?

Pathophysiology is the study of disturbances in physiological processes that can lead to diseases.

Which of the following statements accurately describes the relationship between input and output in maintaining wellness or homeostasis?

If output is greater than input, it leads to illness or disease.

In the propagation of action potential, the influx of Na+ ions in the active area triggers depolarization.

True

The refractory period ensures that another action potential can be initiated at any point along the axon.

False

Schwann cells are the myelin-forming cells found in the Central Nervous System (CNS).

False

The action potential is initially produced at the axon hillock.

True

During the relative refractory period, a stronger stimulus is needed to produce another action potential due to hyperpolarization.

True

Excitatory Postsynaptic Potential (EPSP) causes hyperpolarization of the postsynaptic neuron.

False

The axon hillock is the site where action potentials are initiated in a neuron.

True

Myelin-forming cells, like oligodendrocytes in the central nervous system, wrap around axons to increase the speed of action potential propagation.

True

During the absolute refractory period, it is impossible for an action potential to be initiated, regardless of the stimulus strength.

True

Schwann cells are myelin-forming cells found in the central nervous system.

False

During the peak of the action potential, the Na+ inactivation gate opens, allowing Na+ to enter the cell.

False

K+ leaves the cell during the repolarization phase, causing it to return to its resting potential.

True

The action potential falling phase is primarily initiated by the closure of the K+ activation gate.

False

The Na+ activation gate opens during the action potential falling phase.

False

Myelin-forming cells play a crucial role in increasing the speed of action potential propagation by promoting saltatory conduction.

True

Saltatory conduction occurs when the impulse travels smoothly along the axon without interruptions.

False

In saltatory conduction, the action potential leaps over myelinated sections, slowing down the propagation of action potentials.

False

Myelination decreases the speed of conduction of action potentials and consumes more energy in the process.

False

The nodes of Ranvier contain a rich number of voltage-gated K+ channels.

False

Oligodendrocytes and Schwann cells are responsible for forming the myelin sheath around axons in the nervous system.

True

The axon hillock is the initial segment of the axon where action potentials are generated.

True

During action potential propagation, the membrane potential returns to its resting state through the influx of potassium ions.

False

The absolute refractory period occurs when the voltage-gated sodium channels are recovering from inactivation and cannot be reopened.

True

Oligodendrocytes are myelin-forming cells found in the peripheral nervous system.

False

Nodes of Ranvier are the gaps between adjacent Schwann cells or oligodendrocytes where action potentials are regenerated.

True

During the relative refractory period, a weaker stimulus is needed to produce another action potential due to depolarization.

False

Schwann cells are the myelin-forming cells found in the Central Nervous System (CNS).

False

The action potential is initially produced at the dendrites.

False

The absolute refractory period is a time when another action potential can be triggered, regardless of the stimulus strength.

False

Myelin sheaths increase the speed of action potential propagation by decreasing membrane resistance.

True

The action potential is initiated at the axon hillock.

True

During the absolute refractory period, a second action potential can be initiated regardless of the stimulus strength.

False

Schwann cells are the myelin-forming cells found in the Central Nervous System (CNS).

False

The relative refractory period is characterized by hyperpolarization of the cell membrane.

True

Myelin sheath is a continuous covering along the entire length of an axon, with no interruptions.

False

Conduction velocity is slower in myelinated axons compared to unmyelinated axons.

False

The myelin sheath is formed by a fatty substance called cerebrospinal fluid.

False

Nodes of Ranvier are regions of the axon covered by myelin sheath.

False

Saltatory conduction allows an action potential to travel continuously along an axon.

False

The absolute refractory period is shorter than the relative refractory period.

True

Saltatory conduction is a type of nerve impulse propagation where the impulse 'jumps' from node to node, skipping over the myelinated sections of the axon, thus increasing conduction ________

speed

The axon hillock is the site where action potentials are initiated in a neuron, serving as the trigger zone for generating an ________ potential

action

During the absolute refractory period, it is impossible for an action potential to be initiated, regardless of the ________ strength

stimulus

Non-specific ion channels in the subsynaptic membrane permit simultaneous passage of Na+ and K+ ions, causing a change in membrane ________

permeability

Schwann cells are the primary myelin-forming cells found in the peripheral nervous system, while oligodendrocytes fulfill this role in the ________ nervous system

central

The spread of action potential occurs along every patch of the membrane down the length of the ______

axon

Action potential is produced at the ______, the initial active area where AP is produced

axon hillock

Voltage-gated Na+ channels will never open unless action potential is done, ensuring the one-way propagation of action potential through ______

refractory periods

Schwann cells in PNS and Oligodendrocytes in CNS are two important ______-forming cells

myelin

After the Absolute Refractory Period, the portion of the membrane can be stimulated to produce an action potential; however, it needs a stronger stimulus during the ______ Refractory Period

Relative

During action potential propagation, the membrane potential returns to its resting state through the efflux of _______ ions.

potassium

After the Absolute Refractory Period, the portion of the membrane can be stimulated to produce an action potential; however, it needs a stronger stimulus during the _______ Refractory Period.

relative

Action potential is produced at the ______, the initial active area where AP is produced.

axon hillock

Myelin sheaths increase the speed of action potential propagation by decreasing ______ resistance.

membrane

Schwann cells are myelin-forming cells found in the ______ Nervous System (CNS).

peripheral

During the absolute refractory period, it is impossible for an action potential to be initiated, regardless of the stimulus strength. This period ensures that the neuron has time to recover before firing another action potential. The absolute refractory period is essential for maintaining the ______ of action potential propagation.

directionality

The ______ is the site in a neuron where action potentials are initiated. It acts as a trigger zone due to its high density of voltage-gated ion channels.

axon hillock

Saltatory conduction, which occurs in myelinated axons, allows the action potential to 'jump' between the nodes of Ranvier. This process significantly speeds up the propagation of action potentials compared to continuous conduction in unmyelinated axons. Myelin-forming cells, such as Schwann cells in the peripheral nervous system, play a crucial role in promoting ______ conduction.

saltatory

The relative refractory period follows the absolute refractory period and is characterized by hyperpolarization of the cell membrane. During this period, a stronger stimulus is needed to generate another action potential due to the increased threshold caused by the hyperpolarization. This phenomenon contributes to the ______ of action potential propagation.

regulation

Inhibitory Postsynaptic Potentials (IPSPs) and Excitatory Postsynaptic Potentials (EPSPs) are crucial in modulating neuronal activity. IPSPs lead to hyperpolarization of the postsynaptic neuron, making it less likely to generate an action potential, while EPSPs induce depolarization, increasing the chances of an action potential. This modulation of membrane potential and ______ is essential for proper neuronal function.

permeability

The direction of flow of current is established by the flow of positive ions. Excitable cells such as neurons and muscles evolved for rapid signaling, coordination, and movement. Allow changes in membrane electrical state. Every cell has a certain membrane potential that is important for rapid signaling, coordination, and movement. Communication is an important part of homeostasis. Communication is critical for the survival of the cells that compose the body. Polarization— the value of the membrane potential is not 0 mV. May either be positive or negative longer the duration of the graded potential. Local changes in membrane potential that occur in varying grades or degrees of magnitude or strength. When the area of the cell membrane is triggered by a stimulus, a graded potential may happen; decrease decrementally. Initial active area → graded potential travels(example: 14 mV) → *example: 7 mV on both sides. OUTLINE Introduction IV. Synapses and Integration A. Overview A. Subtopic 1 Graded Potentials V. Neural Signaling and A. Graded Potential External Agents Action Potential A. Subtopic 1 A. Introduction B. Axon Hillock C. Action Potential Propagation D. Axon terminal. DIFFERENT MEMBRANE ELECTRICAL STATES 1.

Angela

Synapses and Integration A. Overview A. Subtopic 1 Graded Potentials V. Neural Signaling and A. Graded Potential External Agents Action Potential A. Subtopic 1 A. Introduction B. Axon Hillock C. Action Potential Propagation D. Axon terminal. DIFFERENT MEMBRANE ELECTRICAL STATES 1.

Antonio

The direction of flow of current is established by the flow of positive ions. Excitable cells such as neurons and muscles evolved for rapid signaling, coordination, and movement. Allow changes in membrane electrical state. Every cell has a certain membrane potential that is important for rapid signaling, coordination and movement. Communication is an important part of homeostasis. Communication is critical for the survival of the cells that compose the body. Polarization— the value of the membrane potential is not 0 mV. May either be positive or negative longer the duration of the graded potential. Local changes in membrane potential that occur in varying grades or degrees of magnitude or strength. When the area of the cell membrane is triggered by a stimulus, a graded potential may happen; decrease decrementally. Initial active area → graded potential travels(example: 14 mV) → *example: 7 mV on both sides. OUTLINE Introduction IV. Synapses and Integration A. Overview A. Subtopic 1 Graded Potentials V. Neural Signaling and A. Graded Potential External Agents Action Potential A. Subtopic 1 A. Introduction B. Axon Hillock C. Action Potential Propagation D. Axon terminal.

Jana

Neural Signaling and A. Graded Potential External Agents Action Potential A. Subtopic 1 A. Introduction B. Axon Hillock C. Action Potential Propagation D. Axon terminal. DIFFERENT MEMBRANE ELECTRICAL STATES 1.

Antonio

Neural Signaling and Graded Potential External Agents Action Potential A. Subtopic 1 Introduction Axon Hillock Action Potential Propagation Axon terminal DIFFERENT MEMBRANE ELECTRICAL STATES 1.

Jana

Connective tissue is composed primarily of an extracellular matrix and a limited number of ______.

cells

Adipose or fat tissues store ______ in the form of adipose tissues.

fat

The action potential falling phase is primarily initiated by the closure of the K+ activation ______.

gate

Saltatory conduction is a type of nerve impulse propagation where the impulse 'jumps' from node to node, skipping over the ______ sections of the axon, thus increasing conduction speed.

myelinated

Schwann cells are the ______ cells found in the Central Nervous System (CNS).

myelin-forming

The axon hillock is the site where action potentials are initiated in a ______.

neuron

During the relative refractory period, a stronger stimulus is needed to produce another action potential due to ______.

hyperpolarization

Myelin sheaths increase the speed of action potential propagation by decreasing membrane ______.

resistance

During the absolute refractory period, it is impossible for an action potential to be initiated, regardless of the stimulus ______.

strength

K+ leaves the cell during the repolarization phase, causing it to return to its resting ______.

potential

During the peak of the action potential, the Na+ inactivation gate closes and PNa+ falls, ending the net movement of Na+ into the cell. At the same time, the K+ activation gate opens and PK+ rises. K+ leaves the cell, causing its repolarization to resting potential, which generates a falling phase of action potential. On return to resting potential, the Na+ activation gate closes and inactivation gate opens, resetting the channel to respond to another depolarizing triggering event. Further outward movement of K+ through a still-open K+ channel briefly hyperpolarizes the membrane, which generates after hyperpolarization. K+ activation gate closes, and the membrane returns to resting potential. This sequence of events describes the process of ________ potential propagation.

action

The site where action potentials are triggered by a graded potential if it is of sufficient magnitude is known as the neuron’s ________ zone.

trigger

The ________ is the initial segment of the axon where action potentials are generated.

axon hillock

During the absolute refractory period, it is impossible for an action potential to be initiated, regardless of the ________ strength.

stimulus

Myelin-forming cells, like oligodendrocytes in the central nervous system, wrap around axons to increase the speed of ________ propagation.

action

Explore the various functions of the cell membrane such as selective permeability, electrochemical gradients, communication, and intercellular connections. Understand how these functions play a crucial role in maintaining the cell's internal environment and responding to external signals.

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