Review! Chapter 7: The Nervous System
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Questions and Answers

List the three major functions of the nervous system.

Monitors all info about changes occurring both inside and outside the body; processes and interprets info received to solve problems; commands responses by activating muscles, glands, and other parts of the nervous system.

What does CNS stand for?

Central Nervous System

What does PNS stand for?

Peripheral Nervous System

What is the function of the autonomic nervous system?

<p>Regulates the activity of the heart and smooth muscle and of glands.</p> Signup and view all the answers

What does the somatic nervous system control?

<p>Voluntary activities such as the activation of skeletal muscles.</p> Signup and view all the answers

What is the role of neuroglia?

<p>Support, insulate, and protect cells.</p> Signup and view all the answers

What are neurons responsible for?

<p>Demonstrate irritability and conductivity, transmit electrical messages, release neurotransmitters, and are amitotic.</p> Signup and view all the answers

What is the main function of an axon?

<p>Conducts impulses away from the cell body.</p> Signup and view all the answers

What happens at the axonal terminal?

<p>Releases neurotransmitters.</p> Signup and view all the answers

What is the role of dendrites?

<p>Conducts electrical currents toward the cell body.</p> Signup and view all the answers

What does the myelin sheath do?

<p>Increases the speed of impulse transmission.</p> Signup and view all the answers

What is the cell body of a neuron?

<p>Location of the nucleus.</p> Signup and view all the answers

What is an afferent (sensory) neuron?

<p>Neuron that conducts impulses toward the CNS from the body periphery.</p> Signup and view all the answers

What is an association neuron?

<p>Neuron connecting sensory and motor neurons.</p> Signup and view all the answers

What is an efferent (motor) neuron?

<p>Neuron that conducts impulses away from the CNS to muscles and glands.</p> Signup and view all the answers

What is a ganglion?

<p>A bundle of nerve processes outside the CNS.</p> Signup and view all the answers

What are neurotransmitters?

<p>Chemicals released by axonal terminals.</p> Signup and view all the answers

What are nuclei?

<p>Collections of nerve cell bodies inside the CNS.</p> Signup and view all the answers

What is a synapse?

<p>Junction or point of close contact between neurons.</p> Signup and view all the answers

What is a tract?

<p>Communication to and from the brain, traveling up and down the spinal cord.</p> Signup and view all the answers

What are stimuli?

<p>Changes occurring within or outside the body that affect nervous system functioning.</p> Signup and view all the answers

What are cutaneous sense organs?

<p>Sensory receptors found in the skin that detect temperature, pressure changes, and pain.</p> Signup and view all the answers

What are nodes of Ranvier?

<p>Gaps in a myelin sheath.</p> Signup and view all the answers

What are proprioceptors?

<p>Sensory receptors found in muscle and tendons that detect their degree of stretch.</p> Signup and view all the answers

What are Schwann cells?

<p>Specialized cells that myelinate the fibers of neurons found in the PNS.</p> Signup and view all the answers

How is one-way conduction at synapses ensured?

<p>Axon can only release; dendrites receive.</p> Signup and view all the answers

What anatomical characteristic determines whether a particular neuron is classified as unipolar, bipolar, or multipolar?

<p>The number of processes attached to the cell body.</p> Signup and view all the answers

What is the relationship of Schwann cells to axons in the peripheral nervous system?

<p>A Schwann cell envelops an axon in a trough, rotates around it, and forms the myelin sheath.</p> Signup and view all the answers

What defines unipolar neurons?

<p>One very short process, which divides into peripheral and central processes, with the most distal portions acting as a dendrite.</p> Signup and view all the answers

What characterizes bipolar neurons?

<p>Have two processes, one axon and one dendrite, and are quite rare.</p> Signup and view all the answers

What defines multipolar neurons?

<p>They have many dendrites and one single axon.</p> Signup and view all the answers

What are potassium ions in a resting neuron?

<p>The chief positive intracellular ion.</p> Signup and view all the answers

What is meant by 'polarized' in a neuron?

<p>Electrical condition of the plasma membrane of a resting membrane.</p> Signup and view all the answers

What is depolarization?

<p>State in which the resting potential is reversed as sodium ions rush into the neuron.</p> Signup and view all the answers

What is action potential?

<p>Transmission of the depolarization wave along the neuron’s membrane.</p> Signup and view all the answers

What is repolarization?

<p>Period during which potassium ions move out of the neuron.</p> Signup and view all the answers

What is the refractory period?

<p>Period of depolarization of the neuron during which it cannot respond to a second stimulus.</p> Signup and view all the answers

Would a substance that decreases membrane permeability to sodium increase or decrease the probability of generating a nerve impulse?

<p>It would decrease the probability.</p> Signup and view all the answers

Why don't the terms depolarization and action potential mean the same thing?

<p>Force has to be great enough for an action to occur.</p> Signup and view all the answers

What does endoneurium do?

<p>Surrounds each nerve fiber.</p> Signup and view all the answers

What does perineurium do?

<p>Surrounds a group of nerve fibers.</p> Signup and view all the answers

What does epineurium do?

<p>Surrounds the bundles of fibers called fascicles.</p> Signup and view all the answers

What is the value of the connective tissue wrappings found in a nerve?

<p>Insulate.</p> Signup and view all the answers

What is a mixed nerve?

<p>Nerves carrying both sensory and motor fibers.</p> Signup and view all the answers

Study Notes

Functions of the Nervous System

  • Monitors changes inside and outside the body.
  • Processes and interprets information to solve problems.
  • Commands responses by activating muscles, glands, and other nervous system components.

Central Nervous System (CNS)

  • Comprises the brain and spinal cord.
  • Responsible for integrating and processing sensory information.

Peripheral Nervous System (PNS)

  • Consists of cranial and spinal nerves plus ganglia.
  • Connects all body parts to the CNS, functioning as a communication network.

Autonomic Nervous System

  • Regulates involuntary activities of the heart, smooth muscles, and glands.
  • Also known as the involuntary nervous system.

Somatic Nervous System

  • Controls voluntary activities, primarily activating skeletal muscles.

Neuroglia

  • Support, insulate, and protect neurons.
  • Capable of division, responsible for most brain tumors.

Neurons

  • Exhibit irritability and conductivity.
  • Facilitate electrical signal transmission and neurotransmitter release.
  • Amitotic, meaning they do not divide.

Axon

  • Conducts impulses away from the neuron cell body.

Axonal Terminal

  • Responsible for releasing neurotransmitters into the synapse.

Dendrite

  • Conducts electrical currents toward the neuron cell body.

Myelin Sheath

  • Increases the speed of impulse transmission along the axon.

Cell Body

  • Houses the nucleus of the neuron.

Afferent (Sensory) Neurons

  • Conduct impulses toward the CNS from peripheral body parts.

Association Neurons (Interneurons)

  • Connect sensory and motor neurons, processing signals within the CNS.

Efferent (Motor) Neurons

  • Carry impulses away from the CNS to activate muscles and glands.

Ganglion

  • A collection of nerve cell bodies outside the CNS.

Neurotransmitters

  • Chemicals released by axon terminals, facilitating communication between neurons.

Nuclei

  • Collections of nerve cell bodies located within the CNS.

Synapse

  • Junction where communication occurs between neurons.

Tract

  • Pathways for communication within the CNS, traveling up and down the spinal cord.

Stimuli

  • Internal or external changes that impact the nervous system's functioning.

Cutaneous Sense Organs

  • Specialized sensory receptors in the skin, detecting temperature, pressure, and pain.

Nodes of Ranvier

  • Gaps within the myelin sheath that facilitate faster signal transmission.

Proprioceptors

  • Sensory receptors located in muscles and tendons that sense stretching.

Schwann Cells

  • Cells responsible for myelinating peripheral nerve fibers.

One-Way Conduction at Synapses

  • Ensured as axons can only release neurotransmitters while dendrites receive them.

Neuron Classification

  • Based on the number of processes attached: unipolar, bipolar, or multipolar.

Unipolar Neurons

  • Characterized by a single, short process that divides into peripheral and central processes; mainly sensory neurons.

Bipolar Neurons

  • Possess one axon and one dendrite; found in specialized sensory organs (e.g., eyes, ears).

Multipolar Neurons

  • Feature multiple dendrites and a single axon; predominant in the brain and spinal cord.

Potassium Ions

  • The primary positive intracellular ion in resting neurons.

Polarized State

  • Electrical condition of the neuron when at rest, with differential charges inside and outside.

Depolarization

  • Occurs when sodium ions rush into the neuron, reversing resting potential.

Action Potential

  • The waveform of depolarization traveling along the neuron's membrane.

Repolarization

  • The process in which potassium ions exit the neuron following depolarization.

Refractory Period

  • A phase during which a neuron cannot respond to a subsequent stimulus.

Membrane Permeability and Nerve Impulses

  • Decreased sodium permeability reduces the likelihood of generating a nerve impulse.

Endoneurium, Perineurium, and Epineurium

  • Connective tissue layers surrounding individual nerve fibers (endoneurium), groups of fibers (perineurium), and entire nerve bundles (epineurium).

Mixed Nerves

  • Carry both sensory and motor fibers, facilitating bidirectional communication.

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Test your knowledge on Chapter 7 of the nervous system. This quiz covers the major functions of the nervous system, including the central nervous system and its components. Perfect for review and enhancing your understanding of this essential topic.

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