Neuroanatomy: Spinal Cord Structure Quiz
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Questions and Answers

What type of neurons are found in the posterior (dorsal) root ganglion?

  • Efferent neurons
  • Motor neurons
  • Interneurons
  • Sensory neurons (correct)

The anterior (ventral) root contains sensory axons that conduct impulses to the CNS.

False (B)

What fills the small central canal located in the middle of the spinal cord?

Cerebrospinal fluid (CSF)

The ________ gray horns contain somatic motor neurons responsible for muscle contraction.

<p>anterior (ventral)</p> Signup and view all the answers

Match the parts of the spinal cord with their function:

<p>Posterior (dorsal) gray horns = Contain sensory neurons Anterior (ventral) gray horns = Contain somatic motor neurons Lateral gray horn = Regulate autonomic functions White matter = Contains myelinated axons organized into columns</p> Signup and view all the answers

What is the role of the sensory receptor in the reflex arc?

<p>To respond to a stimulus (B)</p> Signup and view all the answers

A spinal reflex involves the brain in its processing.

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

Name one example of a deep tendon reflex.

<p>Knee jerk reflex</p> Signup and view all the answers

The component of the reflex arc that connects sensory input to motor output is the ______.

<p>integrating center</p> Signup and view all the answers

Match the following types of reflexes with their descriptions:

<p>Deep tendon reflexes = Elicited on stroking the tendon Visceral reflexes = Involves autonomic nerves Spinal reflexes = Does not involve the brain Pathological reflexes = Indicates a pathological condition</p> Signup and view all the answers

Which somatic motor pathway contains motor fibers that pass through the internal capsule?

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

What is a characteristic of pathological reflexes?

<p>They indicate an abnormal condition. (D)</p> Signup and view all the answers

The Babinski reflex is a normal reflex seen in adults.

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

Reflex actions are voluntary responses to sensory stimuli.

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

What is the final common pathway for the transmission of nerve impulses to skeletal muscles?

<p>Lower motor neuron</p> Signup and view all the answers

Which motor neuron pathway is involved in transmitting signals from the anterior horn to the spinal nerve?

<p>Ventral root</p> Signup and view all the answers

The _______ tracts are connected with multiple parts of the brain, including the basal ganglia and cerebellum.

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

Match the following components of the reflex arc with their descriptions:

<p>Stimulus = Initiates the reflex action Sensory neuron = Transmits impulse to the spinal cord Integration center = Processes the sensory input Motor neuron = Delivers impulse to the muscle Effector = Executes the motor response</p> Signup and view all the answers

At which location do the pyramidal tracts decussate?

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

The upper motor neuron cell body is located in the spinal cord.

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

What is the role of an upper motor neuron in the motor pathways?

<p>Transmits impulses from the brain to the lower motor neuron</p> Signup and view all the answers

What is the primary function of cerebrospinal fluid (CSF) surrounding the spinal cord?

<p>Acts as a cushion to protect nerve tissues (A)</p> Signup and view all the answers

The spinal cord extends from the base of the skull to the third lumbar vertebra.

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

What type of neurons transmit nerve impulses towards the brain?

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

What are the two enlargements of the spinal cord called?

<p>Cervical enlargement and lumbar enlargement</p> Signup and view all the answers

Motor neuron stimulation results in the contraction of involuntary muscle only.

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

The spinal cord is surrounded by the ___ and cerebrospinal fluid.

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

What is the pathway that carries sensory information for pain, tickle, itch, hot, and cold sensations?

<p>Spinothalamic pathways</p> Signup and view all the answers

Match the following layers of the spinal meninges with their descriptions:

<p>Dura mater = Tough, dense connective tissue Arachnoid mater = Resembles spider’s web Pia mater = Thin, delicate layer adhering to spinal cord Epidural space = Space between vertebrae and dura mater</p> Signup and view all the answers

Which part of the spinal cord is associated with the cauda equina?

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

The _____ pathway senses fine touch, proprioception, and vibrations.

<p>posterior column - medial lemniscus</p> Signup and view all the answers

Match each type of pathway with its primary function:

<p>Corticospinal = Carries motor impulses from the brain Spinothalamic = Carries sensory information about pain and temperature Posterior column - medial lemniscus = Senses fine touch and proprioception Reflex arcs = Enables fast, involuntary responses to stimuli</p> Signup and view all the answers

The white matter of the spinal cord surrounds the H-shaped mass of gray matter.

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

Which of the following describes the function of upper motor neurons?

<p>They transmit signals via corticospinal tracts. (B)</p> Signup and view all the answers

What can happen if the spinal cord is damaged?

<p>Paralysis can occur</p> Signup and view all the answers

Spinal nerves allow ___ and sensation.

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

Decussation of nerve impulses typically occurs only at the level of entry into the spinal cord.

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

How long is the spinal cord in adults?

<p>Approximately 42-45 cm (C)</p> Signup and view all the answers

What are the two main sources of sensation in somatic sensory pathways?

<p>Skin and proprioceptors (tendons, muscles, joints)</p> Signup and view all the answers

The processes involving fast, involuntary sequences of actions in response to stimuli are called _____ .

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

Which area of the brain is involved in coordinating muscle activity?

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

Flashcards

Posterior (Dorsal) Root

The posterior root of a spinal nerve carries sensory information from the body towards the central nervous system (CNS). It contains the axons of sensory neurons.

Posterior (Dorsal) Root Ganglion

A swelling on the posterior root that houses the cell bodies of sensory neurons.

Anterior (Ventral) Root

The anterior root of a spinal nerve carries motor commands from the CNS to muscles and glands.

Gray Matter

The 'H'-shaped core of the spinal cord, composed of neuron cell bodies and unmyelinated axons.

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White Matter

The outer region of the spinal cord, primarily composed of myelinated axons.

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What protects the spinal cord?

The spinal cord is encased within the vertebral canal, protected by the bony vertebrae.

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What are the layers of protection around the spinal cord?

The spinal cord is surrounded by three layers of connective tissue: dura mater, arachnoid mater, and pia mater, collectively called the spinal meninges.

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Describe the shape and location of the spinal cord.

The spinal cord is a long, cylindrical structure that extends from the base of the skull to the second lumbar vertebra.

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What is the main function of the spinal cord?

The spinal cord communicates with the brain and the peripheral nervous system (PNS), allowing for the transmission of information and control of bodily functions.

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What is the epidural space and where is it located?

The epidural space is a potential space located between the vertebral bone and the dura mater, and can be used for administering certain drugs or medications.

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What is the dura mater and what is its function?

The dura mater is the outermost layer of the spinal meninges, a thick and tough layer of connective tissue that helps protect the spinal cord.

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Where is the subarachnoid space and what is its significance?

The subarachnoid space is located between the arachnoid mater and the pia mater, and is filled with cerebrospinal fluid (CSF) which acts as a cushion and protects the spinal cord.

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What is the pia mater and what is its key function?

The pia mater is the innermost layer of the spinal meninges, a thin and delicate membrane closely adhering to the spinal cord's surface and containing blood vessels.

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What are the enlargements of the spinal cord and their functions?

The spinal cord has two enlargements, the cervical enlargement which supplies the upper limbs and the lumbar enlargement which supplies the lower limbs.

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What is the cauda equina and where is it located?

The cauda equina is a bundle of nerve roots extending from the lower end of the spinal cord, resembling a horse's tail, and it supplies the lower limbs and pelvic region.

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Descending Tracts

Nerve impulses travel from the brain to the spinal cord through descending tracts.

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Ascending Tracts

These tracts carry sensory information from the body to the brain.

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Reflexes

Quick, automatic responses to stimuli.

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Spinal Reflexes

Simple reflexes involving the spinal cord only, like a knee-jerk reaction.

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Cranial Reflexes

More complex reflexes involving the brain, like driving a car.

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Sensory Neurons

Neurons that carry impulses from the body to the brain.

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Cutaneous Receptors

Receptors in the skin that detect touch, pressure, temperature, and pain.

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Proprioceptors

Receptors in muscles, tendons, and joints that detect movement and position.

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Sensory Crossover

Sensory information from the right side of the body is sent to which side of the brain?

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Decussation

The process where sensory information crosses over to the opposite side of the brain.

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Motor Pathways

Specialized bundles of nerve fibers within the spinal cord that transmit motor commands from the brain to muscles.

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Pyramidal (corticospinal) Tracts

The motor pathways that originate in the cerebral cortex and travel through the internal capsule to the spinal cord. They control voluntary, skilled movements.

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Extrapyramidal Tracts

Motor pathways that do not pass through the internal capsule. They regulate muscle tone, posture, and balance.

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Decussation at the Medulla Oblongata

The point where the pyramidal tracts cross over from one side of the brain to the other side of the spinal cord. This allows the left hemisphere to control the right side of the body, and vice versa.

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Upper Motor Neuron

A neuron responsible for carrying motor commands from the brain to the spinal cord. It has its cell body in the primary motor area of the cerebrum.

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Lower Motor Neuron

A neuron responsible for carrying motor commands from the spinal cord to muscles. It has its cell body in the anterior horn of the spinal cord.

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Reflex Arc

The pathway that a reflex impulse travels, starting with the sensory stimulus and ending with the motor response.

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What is a reflex arc?

A reflex arc is a neural pathway that mediates a reflex, an involuntary, rapid response to a stimulus.

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What is the role of the sensory receptor in a reflex arc?

A sensory receptor detects the stimulus, converting it into a signal.

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What does the sensory neuron do in a reflex arc?

The sensory neuron carries the signal from the sensory receptor to the integrating center.

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What is the role of the integrating center in a reflex arc?

The integrating center, usually in the spinal cord, processes the signal and determines the response.

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What does the motor neuron do in a reflex arc?

The motor neuron carries the signal from the integrating center to the effector.

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What is the role of the effector in a reflex arc?

The effector, typically a muscle, carries out the response to the stimulus.

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What is a spinal reflex?

Spinal reflexes are involuntary responses that occur without the involvement of the brain, processed only within the spinal cord.

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What are pathological reflexes?

Pathological reflexes are abnormal reflexes that indicate underlying damage or disease in the nervous system.

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Study Notes

Spinal Cord Anatomy & Physiology

  • The spinal cord is a long, almost cylindrical part of the central nervous system (CNS).
  • It's located within the vertebral canal.
  • It extends from the foramen magnum at the base of the skull to the second lumbar vertebra.
  • The spinal cord is surrounded by meninges and cerebrospinal fluid (CSF).
  • Spinal nerves allow movement and sensation; damage can cause paralysis.

Spinal Cord Protection and Coverings

  • Vertebrae: Provide structural support and protection.
  • Spinal meninges: Three layers of connective tissue encasing the spinal cord:
    • Dura mater: tough, dense connective tissue, extends to vertebra S2.
    • Arachnoid mater: resembles a spider's web, extends into the subarachnoid space.
    • Pia mater: thin, delicate layer adhering to the spinal cord (and brain), contains blood vessels.
  • Cerebrospinal fluid (CSF): Acts as a cushion to protect nerve tissues. CSF circulates in the subarachnoid space.

Spinal Cord Gross Anatomy

  • The spinal cord is approximately 42-45 cm long and about the thickness of a little finger in adults.
  • The spinal cord is shorter than the vertebral column.
  • The nerves arising from the lumbar, sacral, and coccygeal regions of the spinal cord do not leave the column at the same level; this is called the cauda equina.
  • Cauda equina extends inferior to the end of the spinal cord. It consists of roots of lumbar, sacral, and coccygeal spinal nerves.

Spinal Cord Internal Structure

  • Gray matter: Forms a "butterfly" shape with three horns on each side. -Posterior (dorsal) gray horns: contain sensory neurons. -Anterior (ventral) gray horns: contain somatic motor neurons. -Lateral gray horns: contain autonomic motor neurons (for cardiac, smooth muscle, and glands control).
  • White matter: Surrounds the gray matter, organized into white columns (posterior, anterior, and lateral). -Sensory (ascending) tracts: carry impulses towards the brain. -Motor (descending) tracts: carry impulses from the brain.

Spinal Cord Nerve Tracts

  • Sensory tracts: carry impulses toward the brain.
  • Motor tracts: carry impulses from the brain.
  • Sensory and motor tracts are continuous with sensory and motor tracts in the brain.

Reflexes Activity

  • Reflexes are fast, involuntary response to stimuli, and are a basic defense mechanism of the nervous system.
  • Most reflexes occur in the spinal cord (not the brain) which happens quickly.
  • A reflex arc is the complete pathway by which a reflex action travels from the stimulus to the reflex muscle movement.
  • Five components of a reflex arc:
    • Sensory receptor
    • Sensory neuron
    • Integrating center
    • Motor neuron
    • Effector
  • Types of reflexes:
    • Deep tendon reflexes: elicited on stroking the tendon (e.g., knee-jerk).
    • Visceral reflexes: at least one part of the reflex arc is the autonomic nerve (e.g., pupillary light reflex).
    • Pathological reflexes: not present in normal conditions; presence indicates a pathological condition within the body.

Spinal Cord Clinical Significance

  • Assessing simple muscle reflexes (e.g., patellar reflex) helps evaluate potential damage to motor nerves or spinal cord.

Spinal Cord Summary

  • The spinal cord is a vital conduit for communication between the brain and the rest of the body.
  • It has complex internal structures (gray and white matter).
  • It carries signals through various tracts.
  • It controls reflexes and is the site of spinal reflexes.

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Description

Test your knowledge on the structures and functions of the spinal cord in this Neuroanatomy quiz. Questions cover the types of neurons in the dorsal root ganglion, the role of sensory axons, and the organization of gray horns. Perfect for students studying neuroscience or anatomy.

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