Nervous and Endocrine Systems Quiz
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Questions and Answers

Which of the following accurately describes the relationship between the nervous and endocrine systems?

  • The nervous system provides slow, prolonged responses, while the endocrine system provides immediate responses.
  • Both systems operate independently; the nervous system controls external stimuli responses, and the endocrine system controls internal organ functions.
  • The nervous system detects and responds to changes, while the endocrine system solely maintains homeostasis.
  • Both systems work together to control bodily functions and maintain homeostasis, but the nervous system provides immediate responses, whereas the endocrine system provides slower, more prolonged responses. (correct)

An individual experiences a sudden drop in blood pressure. Which part of the hindbrain is most likely involved in regulating this immediate response?

  • Cerebellum
  • Midbrain
  • Medulla (correct)
  • Pons

A researcher is studying the effect of a drug on motor coordination in mice. Which area of the brain should they focus on to observe changes?

  • Midbrain
  • Medulla
  • Forebrain
  • Cerebellum (correct)

A patient has difficulty maintaining balance and coordinating movements. Which part of the brain is most likely affected?

<p>Cerebellum (A)</p> Signup and view all the answers

What is the primary function of the peripheral nervous system (PNS)?

<p>To process sensory information and produce responses, connecting the CNS to the rest of the body. (D)</p> Signup and view all the answers

An individual is having difficulty with alertness and maintaining a normal sleep/wake cycle. Which area of the brain is most likely affected?

<p>Midbrain (C)</p> Signup and view all the answers

What is an action potential?

<p>A rapid electrical signal along a neuron, caused by ion movement. (C)</p> Signup and view all the answers

Which of the following functions is NOT primarily associated with the hindbrain?

<p>Motor activity (A)</p> Signup and view all the answers

If a drug impairs the function of the pons, which of the following processes would be most directly affected?

<p>Regulation of breathing (A)</p> Signup and view all the answers

Damage to which area of the brain would most likely result in difficulties with planning and executing movements?

<p>Forebrain (D)</p> Signup and view all the answers

A neuron is stimulated, resulting in a change in the membrane potential from -70 mV to -60 mV. Assuming the threshold potential for this neuron is -55 mV, what type of stimulus was applied?

<p>Subthreshold stimulus (C)</p> Signup and view all the answers

During the depolarization phase of an action potential, which of the following occurs?

<p>Sodium ions (Na+) rush into the cell. (D)</p> Signup and view all the answers

What is the primary role of the sodium-potassium pump in maintaining the resting membrane potential of a neuron?

<p>To transport 3 Na+ ions out of the cell and 2 K+ ions into the cell, against their electrochemical gradients. (B)</p> Signup and view all the answers

Which of the following best describes the state of ion distribution across the neuronal membrane at rest?

<p>Higher concentration of sodium ions outside the cell and potassium ions inside the cell. (B)</p> Signup and view all the answers

During hyperpolarization, the membrane potential becomes more negative than the resting membrane potential. What causes this?

<p>Potassium channels remain open slightly longer than usual. (A)</p> Signup and view all the answers

Voltage-gated ion channels play a crucial role in action potentials. What triggers these channels to open or close?

<p>Changes in membrane potential. (D)</p> Signup and view all the answers

Which of the following sequences correctly describes the order of phases in an action potential?

<p>Hypopolarization, Depolarization, Repolarization (A)</p> Signup and view all the answers

How do ions move across the neuronal membrane through ion channels?

<p>Passive diffusion, following the electrochemical gradient (C)</p> Signup and view all the answers

What is the electrochemical gradient's primary influence on ion movement during an action potential?

<p>It drives the movement of ions based on both concentration and electrical charge. (B)</p> Signup and view all the answers

A researcher discovers a neurotoxin that specifically blocks voltage-gated potassium channels. What effect would this neurotoxin have on the action potential?

<p>Prolonged depolarization phase. (D)</p> Signup and view all the answers

During the rising phase of an action potential, what is the primary event that leads to depolarization?

<p>Influx of $Na^+$ ions into the cell. (A)</p> Signup and view all the answers

Which of the following best describes the role of myelin in neuronal signal transmission?

<p>It enables saltatory conduction, increasing the speed of action potential propagation. (D)</p> Signup and view all the answers

What is the primary mechanism by which neurotransmitters transmit a signal across a synapse?

<p>Diffusion across the synaptic cleft and binding to postsynaptic receptors. (A)</p> Signup and view all the answers

Which of the following events is most directly responsible for the repolarization phase of an action potential?

<p>Opening of $K^+$ channels. (C)</p> Signup and view all the answers

What is the significance of the membrane being 'polarized' in its resting state?

<p>It signifies a separation of oppositely charged particles, creating a potential difference. (A)</p> Signup and view all the answers

How does the entry of positive ions into the cell affect the membrane potential?

<p>It causes depolarization, making the membrane potential closer to zero. (A)</p> Signup and view all the answers

Which of the following neurotransmitters is NOT listed as a common neurotransmitter?

<p>Glutamate (C)</p> Signup and view all the answers

What must happen to an electrical impulse for it to be transmitted across a synapse?

<p>It must be converted to a chemical signal and then back to an electrical signal. (D)</p> Signup and view all the answers

In myelinated axons, where do action potentials primarily occur?

<p>Only at the nodes of Ranvier. (A)</p> Signup and view all the answers

What is the immediate effect of neurotransmitters binding to receptors on the postsynaptic cell?

<p>Change in the postsynaptic membrane potential due to ion channel activity. (B)</p> Signup and view all the answers

What primary role do dendrites play in neuronal communication?

<p>Receiving signals from other neurons and transmitting them to the soma. (B)</p> Signup and view all the answers

Which of the following accurately describes the function of myelin?

<p>Insulating the axon to prevent signal loss and speed up transmission. (A)</p> Signup and view all the answers

How do motor neurons contribute to the nervous system's function?

<p>By carrying signals away from the central nervous system to muscles or glands. (B)</p> Signup and view all the answers

What is the approximate proportion of neuroglia cells relative to neurons in nervous tissue?

<p>Neuroglia constitute the majority, accounting for about 90% of nervous tissue, while neurons account for 10%. (B)</p> Signup and view all the answers

In the central nervous system (CNS), what is the primary function of oligodendrocytes?

<p>To form the myelin sheath that insulates CNS neurons. (B)</p> Signup and view all the answers

Which type of neuroglia is responsible for removing pathogens, impurities, and dead neurons from the central nervous system?

<p>Microglia (A)</p> Signup and view all the answers

What is the primary role of ependymal cells within the brain?

<p>To line ventricles and create a barrier between nervous tissue and cerebrospinal fluid. (D)</p> Signup and view all the answers

How does the distribution of ions contribute to the resting membrane potential in a neuron?

<p>An unequal distribution of positive and negative ions inside and outside the cell creates a charge difference. (C)</p> Signup and view all the answers

Which of the following best describes the role of the axon hillock in a neuron?

<p>It channels signals from the soma to the axon, initiating an action potential if the signal is strong enough. (B)</p> Signup and view all the answers

If a signal traveling through a neuron qualifies as an action potential, what does this indicate?

<p>The signal from the dendrites was strong enough to be passed through the axon. (B)</p> Signup and view all the answers

Flashcards

Soma

The cell body of a neuron that integrates signals from dendrites.

Dendrites

Branch-like structures on neurons that receive signals from other neurons.

Action Potential

A strong enough signal that travels down the axon after being processed in the Soma.

Axon

The long thread-like part of a neuron that transmits signals away from the soma.

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Sensory Neurons

Neurons that carry impulses to the central nervous system from sensory organs.

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Motor Neurons

Neurons that transmit impulses from the central nervous system to muscles or glands.

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Neuroglia

Support cells in the nervous system that do not transmit signals.

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Astrocytes

Star-shaped glial cells that support neurons and regulate blood-brain barrier.

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Resting State

The state of a neuron at rest, with a stable membrane potential due to unequal ion distribution.

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Myelin

An insulating layer formed by glial cells that protects axons and speeds up signal transmission.

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Threshold Stimuli

Stimuli that can produce an action potential (-50 to -55 mV).

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Depolarization

Phase where sodium ions enter, making the cell's inside more positive.

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Repolarization

Phase where potassium ions exit, restoring negativity inside the cell.

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Ion Channels

Proteins that allow selective ion movement across the membrane.

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Sodium-Potassium Pump

A pump that maintains resting potential by transporting sodium and potassium ions.

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Electrochemical Gradient

The difference in ion concentration inside and outside the cell, creating potential energy.

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Overshoot

Phase where the membrane potential becomes more positive than resting potential.

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Hypopolarization

Phase that precedes depolarization, bringing potential closer to threshold.

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Hyperpolarization

Phase following repolarization, making the inside of the cell more negative.

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Nervous System

System detecting and responding to changes in the body.

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Homeostasis

The maintenance of stable internal conditions in the body.

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Central Nervous System (CNS)

Part of the nervous system that includes the brain and spinal cord.

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Peripheral Nervous System (PNS)

Nerves outside the CNS that connect limbs and organs.

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Membrane Potential

The voltage difference across a cell membrane.

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Hindbrain

Region of the brain responsible for survival functions.

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Medulla

Regulates vital functions like breathing and heart rate.

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Cerebellum

Part of the hindbrain managing balance and movement coordination.

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Forebrain

Region essential for planning, movement, and emotions.

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Rising Phase of Action Potential

The phase where a stimulus opens Na⁺ channels, causing Na⁺ ions to flow in and the membrane potential to rise.

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Falling Phase of Action Potential

The phase where K⁺ channels open, allowing K⁺ to exit, thus lowering the membrane potential back to resting value.

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Myelination

The process of axons being coated with myelin, which speeds up action potential conduction by allowing it to jump between nodes.

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Synapse

The gap between neurons where neurotransmitters transmit impulses from the axon of one neuron to the dendrites of another.

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Neurotransmitter Transmission

The process where an action potential converts electrical signals to chemical signals to cross the synapse and back to electrical.

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Neurotransmitters

Chemical signaling molecules that transmit signals across the synapse, such as norepinephrine and dopamine.

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Study Notes

Nervous System

  • Neurons are the basic units of the nervous system
  • Neurons generate and conduct signals along processes to transmit them to target tissue
  • Nerves and muscles are capable of generating an action potential
  • This capability is described as excitability
  • Subthreshold stimuli cannot cause an action potential.
  • Threshold stimuli can produce an action potential.
  • Suprathreshold stimuli can produce an action potential but have much higher strength than the threshold stimuli
  • Action potential is a sudden, fast, transitory change of the resting membrane potential
  • Action potentials are generated when a stimulus changes the membrane potential to values above threshold.
  • An action potential has three phases: depolarization, overshoot, and repolarization
  • There are two additional phases: hypopolarization and hyperpolarization
  • During depolarization, the inside of the cell becomes more positive and the membrane potential increases
  • During repolarization, the membrane potential starts to return to the resting value as positive ions leave the cell.
  • During overshoot, The inside of the cell is even more positive than the outside of the cell
  • During hyperpolarization, the inside of the cell is more negative than resting potential
  • The membrane potential is generated when a stimulus changes the membrane potential to values above threshold
  • Action potential has three phases: depolarization, overshoot, and repolarization

Types of Neurons

  • Sensory neurons (or afferent neurons) conduct impulses to the central nervous system
  • Motor neurons (or efferent neurons) carry impulses away from the central nervous system to muscles or glands
  • Interneurons (or central/association neurons) relay information from place to place within the central nervous system
  • Neurons make up approximately 10% of nervous tissue. The remaining 90% consists of support cells called neuroglia (or glial) cells. Schwann cells are an example of neuroglia

Neuroglia (or glial cells)

  • Astrocytes – star-shaped cells that serve many functions, such as physically supporting and anchoring neurons, regulating the composition of the extracellular fluid, and forming a barrier between blood and brain tissue.
  • Oligodendrocytes – form the myelin sheath of CNS neurons
  • Microglia – cells that act as phagocytes to remove pathogens, impurities, and dead neurons
  • Ependymal cells – line ventricles in the brain, forming a barrier between nervous tissue and the fluid filling the ventricles (cerebrospinal fluid)

The nervous system at work

  • In living cells, positive and negative ions are unequally distributed in the cytoplasm and extracellular fluid
  • This unequal distribution creates a charge across the membrane, known as the membrane potential

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Test your knowledge of the nervous and endocrine systems. Questions cover brain regions, functions, and interactions. Ideal for biology students studying the human body.

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