Nervous System and Homeostasis Quiz
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Questions and Answers

What is the primary role of the nervous system in maintaining homeostasis?

  • To reduce metabolic activity
  • To store sensory information
  • To regulate all bodily functions rapidly (correct)
  • To increase body temperature

Which structure is NOT part of the central nervous system?

  • Motor neurons (correct)
  • Brain
  • Spinal cord
  • Interneurons

What is the primary function of sensory neurons?

  • To conduct nerve impulses
  • To control voluntary movements
  • To gather information from sensory organs (correct)
  • To send information to and from the brain

Which of the following best describes glial cells?

<p>Support metabolic activities (C)</p> Signup and view all the answers

What role do interneurons play in the nervous system?

<p>Process and relay information within the CNS (C)</p> Signup and view all the answers

In the context of a reflex arc, which component processes the information received from sensory neurons?

<p>Interneurons (B)</p> Signup and view all the answers

Which of the following correctly describes the somatic division of motor neurons?

<p>Regulates voluntary muscle movement (A)</p> Signup and view all the answers

Which part of the neural pathway is involved when dodging a wayward tennis ball?

<p>Interneuron processes information (C)</p> Signup and view all the answers

What is the primary function of dendrites in a neuron?

<p>To receive information from other neurons (B)</p> Signup and view all the answers

What role does the myelin sheath play in neuron function?

<p>It allows for faster transmission of nerve impulses (A)</p> Signup and view all the answers

What is the resting membrane potential typically measured at in a neuron?

<p>-70mV (A)</p> Signup and view all the answers

Which factor significantly contributes to the establishment of the resting membrane potential?

<p>The varying concentrations of ions across the membrane (D)</p> Signup and view all the answers

During depolarization, what change occurs in the neuron's membrane potential?

<p>The inside becomes more positive due to sodium ion influx (B)</p> Signup and view all the answers

What does the 'all-or-none' response refer to in neural activity?

<p>Action potentials either occur fully or not at all (C)</p> Signup and view all the answers

What happens during the repolarization phase of an action potential?

<p>The membrane potential becomes more negative again (C)</p> Signup and view all the answers

Which of the following accurately describes the process of impulse propagation along a neuron?

<p>Action potentials rapidly travel along the axon (A)</p> Signup and view all the answers

What happens immediately after sodium gates open during depolarization?

<p>Sodium ions flow into the cell. (A)</p> Signup and view all the answers

What occurs during the refractory period?

<p>The neuron cannot respond to another stimulus. (C)</p> Signup and view all the answers

How do neurotransmitters influence the postsynaptic neuron?

<p>By binding to receptors and modifying ion channel activity. (A)</p> Signup and view all the answers

What distinguishes excitatory neurotransmitters from inhibitory neurotransmitters?

<p>Excitatory neurotransmitters depolarize the postsynaptic neuron. (C)</p> Signup and view all the answers

What is the primary role of cholinesterase in the nervous system?

<p>To break down acetylcholine after its release. (A)</p> Signup and view all the answers

What initiates the release of neurotransmitters from the presynaptic neuron?

<p>Opening of calcium gates. (C)</p> Signup and view all the answers

What type of action do cholinesterase inhibitors have in relation to acetylcholine?

<p>They reduce the breakdown of acetylcholine. (B)</p> Signup and view all the answers

What is the effect of inhibitory neurotransmitters on the postsynaptic membrane?

<p>They hyperpolarize the postsynaptic neuron. (B)</p> Signup and view all the answers

Flashcards

What is homeostasis?

A state of dynamic balance maintained by the body's systems.

Why is the nervous system vital for homeostasis?

The nervous system controls and coordinates bodily functions to maintain a stable internal environment (homeostasis).

What is the central nervous system (CNS)?

The brain and spinal cord, which receive and process information.

What is the peripheral nervous system (PNS)?

Nerves that connect the CNS to the rest of the body, carrying sensory and motor information.

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What are neurons?

Specialized cells that transmit nerve impulses.

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What are glial cells?

Cells that support and nourish neurons, providing structural and metabolic support.

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What are sensory neurons?

Neurons that carry sensory information from the body to the CNS.

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What are motor neurons?

Neurons that carry motor commands from the CNS to muscles and glands.

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Refractory Period

A brief period after an action potential where a neuron cannot respond to another stimulus.

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Depolarization

The process of the inside of a neuron's membrane becoming more positive due to sodium ions moving in.

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Repolarization

The process of the inside of a neuron's membrane becoming more negative, returning to its resting state.

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Neurotransmitters

Chemicals that transmit signals between neurons.

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Excitatory Neurotransmitters

Neurotransmitters that make the postsynaptic neuron more likely to fire an action potential.

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Inhibitory Neurotransmitters

Neurotransmitters that make the postsynaptic neuron less likely to fire an action potential.

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Acetylcholine (ACh)

A natural neurotransmitter involved in memory and muscle contraction.

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Cholinesterase

An enzyme that breaks down acetylcholine.

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Dendrites

Short, branched extensions of a neuron that receive information from other neurons or the CNS and transmit it to the cell body.

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Cell Body

The main body of a neuron containing the nucleus and the site of metabolic reactions. It processes information received from dendrites and transmits it to the axon.

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Axon

A long, slender extension of a neuron that carries information away from the cell body to other neurons, muscles, or glands.

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Myelin Sheath

A fatty, protective sheath that covers the axon of some neurons, composed of Schwann cells. It speeds up the transmission of nerve impulses by insulating the axon.

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Nodes of Ranvier

Gaps in the myelin sheath along the axon, where the signal jumps during transmission, effectively speeding up the process.

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Resting Membrane Potential

The difference in electrical charge across the cell membrane of a neuron when it is not transmitting a signal. This difference is typically around -70mV, with the inside being more negative than the outside.

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Action Potential

A brief, rapid reversal of the membrane potential across the membrane of a neuron, from negative to positive and back to negative. It is the basic unit of communication in the nervous system.

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Study Notes

Homeostasis Definition

  • Homeostasis is a state of dynamic equilibrium within the body.

Nervous System's Role in Homeostasis

  • The nervous system rapidly regulates bodily functions to maintain homeostasis.

Nervous System Structures & Functions

  • Central Nervous System (CNS):
    • Brain (processes information like thoughts, emotions, actions)
    • Spinal cord (conducts information from the brain and controls reflexes).
  • Peripheral Nervous System (PNS):
    • Sensory neurons (afferent): transmit information from sensory organs to the CNS.
    • Motor neurons (efferent): transmit information from the CNS to muscles and glands.
      • Somatic division (voluntary movements).
      • Autonomic division (involuntary movements).

Neuron and Glial Cell Comparison

  • Neurons: Basic building blocks of the nervous system, conduct nerve impulses.
  • Glial cells: Support neurons structurally and metabolically, do not conduct impulses.

Neuron Types & Functions

  • Sensory neurons: Gather information from sensory organs and transmit it to the CNS.
  • Interneurons: Located in the CNS, collect and process information, then send it to the PNS.
  • Motor neurons: Transmit information from the CNS to muscles and glands.

Neural Pathway for Dodging a Ball

  • Sensory receptors in the eyes detect the tennis ball.
  • Sensory neurons send this information to the CNS.
  • Interneurons quickly process the information in the CNS.
  • Motor neurons transmit signals to the muscles responsible for dodging the ball.
  • Muscles move the body.
  • Withdrawal reflex: Similar but automatic (involuntary) response to a painful stimulus (e.g., a hot object).

Neuron Structure and Function

  • Neurons are composed of basic structures (draw a picture to label these structures if you have one).

Myelinated Neuron Structure

  • The myelin sheath is a fatty protective layer around the axon ( composed of schwann cells, has gaps called nodes of ranvier.

Resting Membrane Potential

  • The resting membrane potential is the voltage difference across a neuron's membrane when it's not stimulated (measured at -70mV).
  • This potential is maintained by different ion concentrations inside and outside the neuron, sodium-potassium pumps (3 Na+ out, 2 K+ in), and leakiness of potassium channels.

Depolarization and Action Potential

  • Depolarization is the process of the neuron's membrane becoming more positive. Action Potential is a rapid change in membrane potential. This occurs with the opening and closing of sodium and potassium ion channels.

"All-or-None" Response

  • The action potential either occurs completely or not at all once triggered.

Repolarization

  • Repolarization is the restoration of the neuron's resting membrane potential. Sodium channels close and potassium channels open, allowing potassium ions to flow out of the cell. The sodium-potassium pumps restore ion balance. This is critical to allow for further impulses.

Impulse Propagation

  • An impulse is propagated along the length of a neuron. Resting potential reaches a threshold, sodium gates open, depolarization happens causing sodium gates to close, potassium gates open repolarization occurs, and then refractory period.

Synaptic Transmission

  • Transmission occurs from the presynaptic neuron to the postynaptic neuron. Neurotransmitters are released into the synaptic cleft to bind to post synaptic receptors to create an action potential.
  • Calcium gates open, neurotransmitters are released into the synaptic cleft. Neurotransmitters bind to receptor sites. Electrical signal is generated in postsynaptic neuron.

Neurotransmitters

  • Neurotransmitters are chemical messengers that transmit signals between neurons (and from neurons to other cells).

Neurotransmitter Effects

  • Neurotransmitters can be excitatory, increasing the likelihood of an action potential, or inhibitory, decreasing the likelihood. Different neurotransmitters can have different effects, depending on the specific receptors they bind to.

Acetylcholine and Cholinesterase

  • Acetylcholine (ACh): A neurotransmitter involved in muscle contraction and other functions.
  • Cholinesterase: Enzyme that breaks down ACh to prevent prolonged signals.

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Description

Test your knowledge on the role of the nervous system in maintaining homeostasis. This quiz covers key concepts such as the structures and functions of the central and peripheral nervous systems, as well as neuron comparisons. Dive into the essential aspects of how our body regulates its internal environment.

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