Spinal Cord Anatomy and Function Quiz
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Questions and Answers

What does a dermatome indicate when it shows loss of sensation?

  • Injury to only the skin surface
  • Total loss of muscle function
  • Complete spinal cord injury
  • Potential damage to one or more spinal nerves (correct)

    • How is referred visceral pain connected to dermatomes?

  • It always indicates a muscle injury
  • It is unrelated to spinal nerves
  • It can travel through the same nerve pathways (correct)
  • It is only relevant for pain in the limbs

    • What effect does damage to a single spinal nerve have on muscle or skin regions?

  • Total loss of sensation in the area
  • Partial loss of innervation, preserving some function (correct)
  • Loss of innervation to the entire muscle
  • No effect whatsoever

    • Which of the following is NOT one of the main nerve plexuses?

    <p>Thoracic plexus</p> Signup and view all the answers

    What is the primary function of a nerve plexus?

    <p>To form a network of interweaving spinal nerves</p> Signup and view all the answers

    What is the function of the posterior horn in the spinal cord?

    <p>It relays sensory information to the brain.</p> Signup and view all the answers

    Which structure primarily separates the left and right sides of the spinal cord?

    <p>Anterior median fissure</p> Signup and view all the answers

    Where is the gray matter primarily located in the spinal cord?

    <p>Surrounding the central canal</p> Signup and view all the answers

    Which part of the spinal cord anatomy is involved in autonomic functions?

    <p>Lateral horn</p> Signup and view all the answers

    What does the term 'funiculus' in the spinal cord refer to?

    <p>A section of white matter containing ascending and descending fibers.</p> Signup and view all the answers

    Which anatomical structure is NOT part of the central canal's surrounding gray matter?

    <p>Lateral funiculus</p> Signup and view all the answers

    What type of matter primarily contains myelinated axons?

    <p>White matter</p> Signup and view all the answers

    Which of the following is NOT part of the gray matter in the spinal cord?

    <p>Central canal</p> Signup and view all the answers

    What structure is contacted first when performing a lumbar puncture?

    <p>Skin</p> Signup and view all the answers

    Which letter identifies the cervical plexus branch responsible for innervating the diaphragm?

    <p>C5</p> Signup and view all the answers

    Which of the following contributes to the formation of the ansa cervicalis?

    <p>C1 and C2</p> Signup and view all the answers

    What condition is characterized by reactivation of the chickenpox virus?

    <p>Shingles</p> Signup and view all the answers

    What is the primary purpose of prompt steroid administration after spinal cord injuries?

    <p>To reduce function loss</p> Signup and view all the answers

    Which of the following does NOT describe a symptom of shingles?

    <p>Muscle paralysis</p> Signup and view all the answers

    What is the advantage of using neural stem cells post-spinal cord injury?

    <p>To regenerate CNS axons</p> Signup and view all the answers

    Which nerve responsible for sensory innervation is NOT part of the cervical plexus?

    <p>Hypoglossal nerve</p> Signup and view all the answers

    What is the primary composition of gray matter in the spinal cord?

    <p>Neuron cell bodies, dendrites, and unmyelinated axons</p> Signup and view all the answers

    Which section of the spinal cord contains autonomic motor neurons?

    <p>Lateral horns only</p> Signup and view all the answers

    What do the dorsal rootlets primarily contain?

    <p>Sensory neuron axons</p> Signup and view all the answers

    What structure connects the left and right sides of the gray matter in the spinal cord?

    <p>Gray commissure</p> Signup and view all the answers

    Which type of nuclei in the posterior horn are responsible for receiving signals from skin and muscles?

    <p>Somatic sensory nuclei</p> Signup and view all the answers

    The anterior funiculus of the spinal cord contains which types of tracts?

    <p>Both ascending and descending tracts</p> Signup and view all the answers

    What shape does the gray matter in the spinal cord typically resemble?

    <p>An 'H' or butterfly shape</p> Signup and view all the answers

    What is contained within the white matter of the spinal cord?

    <p>Myelinated axons</p> Signup and view all the answers

    How many pairs of spinal nerves are present in the human body?

    <p>31 pairs</p> Signup and view all the answers

    Which spinal nerves are considered part of the cervical plexus?

    <p>C1 to C8</p> Signup and view all the answers

    Which number of thoracic nerves is present in the spinal cord?

    <p>12</p> Signup and view all the answers

    What is the correct identification for the coccygeal nerve?

    <p>Co1</p> Signup and view all the answers

    Which of the following correctly describes how C1 to C7 spinal nerves emerge?

    <p>Above their corresponding vertebrae</p> Signup and view all the answers

    What does the term 'conus medullaris' refer to in the spinal cord anatomy?

    <p>The termination of the spinal cord</p> Signup and view all the answers

    Which anatomical part is associated with lumbar plexus?

    <p>L1 to L5</p> Signup and view all the answers

    What type of axons do spinal nerves contain?

    <p>Both sensory and motor axons</p> Signup and view all the answers

    What does 'filum terminale' refer to in spinal cord anatomy?

    <p>The connective tissue that anchors the spinal cord</p> Signup and view all the answers

    Which of the following is true regarding the sacral plexus?

    <p>It includes spinal nerves S1 to S5</p> Signup and view all the answers

    Which cranial nerve is primarily responsible for sensation in the face?

    <p>Trigeminal nerve (CN V)</p> Signup and view all the answers

    Which of the following dermatomes corresponds to the C6 nerve root?

    <p>C7</p> Signup and view all the answers

    According to Hilton's Law, what does a nerve serving a muscle that produces movement at a joint also innervate?

    <p>The joint and the skin over that joint</p> Signup and view all the answers

    Which spinal nerve roots contribute to the upper limb sensation?

    <p>C3 to T2</p> Signup and view all the answers

    What is the primary function of the trigeminal nerve?

    <p>Sensation of the face and motor control of chewing</p> Signup and view all the answers

    Which nerve root does NOT correspond to the lumbar region?

    <p>S1</p> Signup and view all the answers

    Which nerve fibers are responsible for transmitting sensory information from the skin over a joint?

    <p>Somatic sensory fibers</p> Signup and view all the answers

    Which of the following best describes the innervation pattern of muscles and joints according to Hilton's Law?

    <p>A muscle's nerve also supplies the joint it acts upon</p> Signup and view all the answers

    Which spinal nerve roots are primarily involved in providing sensation to the areas of the upper arm?

    <p>C5 and C6</p> Signup and view all the answers

    Which area is NOT typically supplied by the C5 nerve root?

    <p>Medial forearm</p> Signup and view all the answers

    What region does the C8 nerve root primarily innervate?

    <p>Medial forearm and hand</p> Signup and view all the answers

    In terms of dermatome mapping, which region is primarily supplied by T10?

    <p>Abdomen</p> Signup and view all the answers

    Which of the following describes a typical consequence of an injury to the C7 nerve root?

    <p>Loss of sensation in the lateral hand</p> Signup and view all the answers

    Hilton's law implicates which type of relationship between joint, muscle, and skin innervation?

    <p>A shared nerve for all three structures</p> Signup and view all the answers

    Study Notes

    Chapter 14: Spinal Cord and Spinal Nerves

    • Spinal cord provides a vital link between the brain and body
    • Spinal cord exhibits functional independence from the brain
    • Spinal cord and spinal nerves are a pathway for sensory and motor nerve signals
    • Spinal cord and spinal nerves are responsible for reflexes and quick reactions to stimuli
    • Spinal cord extends from brain through vertebral canal to L1 vertebrae
    • Spinal cord has rootlets that form spinal nerves
    • Some spinal nerves form nerve plexuses

    Words to Know

    • Neuro = nerve
    • Epi = above
    • Sub = below
    • Inter = between
    • Myelo = spinal cord
    • -plegia = paralysis
    • Encephalo = brain
    • Duro = dura mater

    Organization of the Nervous System

    • Central nervous system (CNS): brain and spinal cord
    • Peripheral nervous system (PNS): nerves and ganglia
    • Sensory nervous system: detects stimuli and transmits information from receptors to CNS
    • Motor nervous system: initiates and transmits information from the CNS to effectors
    • Somatic sensory: consciously perceived input
    • Visceral sensory: not consciously perceived input from blood vessels and internal organs
    • Somatic motor: consciously or voluntarily controlled motor output (skeletal muscle)
    • Autonomic motor: not consciously controlled motor output; involuntary (cardiac muscle, smooth muscle, glands)

    Synapses

    • Presynaptic neuron: neuron sending signals
    • Postsynaptic neuron: neuron receiving signals
    • Chemical synapse: uses neurotransmitters (EPSP= excitatory postsynaptic potential, IPSP= inhibitory postsynaptic potential)

    Nervous System Terms

    • Ganglion: cluster of neuron cell bodies in PNS
    • Center: group of CNS neurons with common function
    • Nucleus: CNS center with distinct anatomic boundaries
    • Nerve: bundle of axons in PNS
    • Nerve plexus: nerve network
    • Tract/fasciculi: CNS axon bundle with similar function and common origin and destination
    • Funiculus: groups of tracts in the spinal cord
    • Pathway: centers with their associated tracts
    • Decussation: tract that crosses between sides of the CNS

    Spinal Cord Gross Anatomy

    • Spinal cord extends inferiorly from brain through vertebral canal
    • Ends at the level of L₁ vertebra
    • Rootlets come off spinal cord, forming spinal nerves
    • Some spinal nerves form interweaving nerves (plexuses)
    • Cervical, thoracic, lumbar, sacral, and coccygeal subdivisions
    • Cervical part: superiormost part of spinal cord; continuous with medulla oblongata; contains neurons contributing to cervical spinal nerves
    • Thoracic part: inferior to cervical part; contains neurons for thoracic spinal nerves
    • Lumbar part: short section inferior to thoracic; contains neurons for lumbar spinal nerves
    • Sacral part: inferior to lumbar; contains neurons for sacral spinal nerves
    • Coccygeal part: most inferior part of spinal cord; contains neurons for single pair of coccygeal nerves

    Spinal Cord Subdivisions (Continued)

    • Conus medullaris: tapering end marking end of spinal cord proper
    • Cauda equina: nerve roots projecting inferiorly from the cone
    • Thin strand of pia mater anchors conus medullaris to coccyx

    Spinal Nerves (31 pairs)

    • Contain sensory and motor axons
    • Identified by first letter of spinal cord part and number (e.g., C1-C8, T1-T12, L1-L5, S1-S5, Co1)

    Odd Numbering System

    • C1-C7 emerge above the vertebrae named for
    • All others emerge below their named vertebrae

    Spinal Cord Features

    • Cervical enlargement: wider part of spinal cord in cervical region, due to neurons that innervate the upper limbs
    • Lumbosacral enlargement: wider part of spinal cord in lumbar region, due to neurons that innervate the lower limbs

    Protection and Support of the Spinal Cord

    • Spinal meninges encapsulate the spinal cord (continuous with cranial meninges)
    • Vertebra
    • Epidural space
    • Dura mater
    • Subdural space
    • Arachnoid mater
    • Subarachnoid space
    • Pia mater

    Spinal Nerves

    • Dorsal/posterior root: sensory (afferent) fibers
    • Ventral/ anterior root: motor (efferent) fibers
    • Spinal nerves are short, combining dorsal/ posterior and ventral/ anterior roots

    Sectional Anatomy of Spinal Cord

    • Gray matter: neuron cell bodies, dendrites, unmyelinated axons, and glial cells
    • Looks like an "H" or butterfly
    • Masses of gray matter project from center of spinal cord (anterior horns, lateral horns, posterior horns)
    • Anterior horns house somatic motor neurons
    • Lateral horns house autonomic motor neurons
    • Posterior horns house axons of sensory neurons and cell bodies of interneurons

    Gray Matter and White Matter Organization in the Spinal Cord

    • White matter: myelinated axons to and from the brain
    • Regions of white matter: posterior funiculus, lateral funiculus, anterior funiculus

    Spinal Cord Conduction Pathways

    • Conduction pathways characteristics: includes paired tracts, composed of multiple neurons, common locations of neuronal bodies and axons, and decussation
    • Sensory pathways (ascending): signals from sensory receptors to the brain
    • Motor pathways (descending): signals from the brain to muscles or glands

    Sensory Pathways

    • Primary neuron: first neuron in sensory pathway, axon projects to secondary neuron within CNS
    • Secondary neuron: interneuron, projects to thalamus or cerebellum, axon projects to tertiary neuron
    • Tertiary neuron: interneuron residing in thalamus, axon projects to primary somatosensory cortex

    Motor Pathways

    • Upper motor neuron: within cerebral cortex or brainstem nuclei; innervates lower motor neuron
    • Lower motor neuron: within anterior horn of spinal cord or brainstem nuclei; exits CNS and projects to skeletal muscles, always excitatory

    Spinal Cord Conduction Pathways: Motor

    • Direct/pyramidal pathways: use chain of 1 or 2 motor neurons to communicate signals, lateral and anterior corticospinal tracts
    • Indirect pathways: responsible for subconscious or unconscious control, regulates and controls precise, discrete movements, related to flexor and extensor muscles

    Spinal Nerves Characteristics, Distribution, and Rami

    • Spinal nerves are formed from multiple roots.
    • Contain motor and sensory axons, enveloped in connective tissues.
    • Posterior ramus: smaller, innervates deep muscles of back, skin of back
    • Anterior ramus: larger, innervates anterior and lateral trunk, upper limbs and lower limbs
    • Rami communicantes: connect spinal nerves to sympathetic trunk ganglion and sympathetic nervous system
    • Dermatomes: specific segment of skin supplied by a single spinal nerve
    • Hilton's Law: nerve serving a muscle that produces movement also innervates the joint and skin over the joint.

    Clinical Views

    • Lumbar puncture
    • Spinal cord injuries (may lead to paralysis and loss of sensation)
    • Shingles (reactivation of chickenpox virus)

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    A&P Ch. 14 Nerves Part 1PPT PDF

    Description

    Test your knowledge on spinal cord anatomy, including the significance of dermatomes, nerve plexuses, and gray matter. This quiz covers crucial functions of different spinal structures and their impact on sensation and autonomic functions. Ideal for students or enthusiasts in anatomy and physiology!

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