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Questions and Answers
What protects the spinal cord within the vertebral canal?
What protects the spinal cord within the vertebral canal?
Which pairs of spinal nerves are associated with the thoracic vertebrae?
Which pairs of spinal nerves are associated with the thoracic vertebrae?
How many cervical spinal nerves are present in the human body?
How many cervical spinal nerves are present in the human body?
What structure carries both sensory and motor fibers?
What structure carries both sensory and motor fibers?
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Which part of the spinal nerve supplies the anterolateral parts of the trunk and limbs?
Which part of the spinal nerve supplies the anterolateral parts of the trunk and limbs?
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What is the fate of the 5 sacral vertebrae in the human body?
What is the fate of the 5 sacral vertebrae in the human body?
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Which of the following accurately describes the structure of spinal nerves?
Which of the following accurately describes the structure of spinal nerves?
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How many total vertebrae make up the human vertebral column?
How many total vertebrae make up the human vertebral column?
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What type of neurons are responsible for transmitting signals to internal organs and glands?
What type of neurons are responsible for transmitting signals to internal organs and glands?
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Which division of the autonomic nervous system is responsible for preparing the body for emergencies?
Which division of the autonomic nervous system is responsible for preparing the body for emergencies?
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What is primarily indicated by dermatomes?
What is primarily indicated by dermatomes?
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Which spinal nerves contribute to the formation of the phrenic nerve?
Which spinal nerves contribute to the formation of the phrenic nerve?
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What is the main function of somatic motor neurons?
What is the main function of somatic motor neurons?
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Which of the following best describes mixed spinal nerves?
Which of the following best describes mixed spinal nerves?
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Which plexus does not have a corresponding formation of peripheral nerves for the thoracic spinal nerves?
Which plexus does not have a corresponding formation of peripheral nerves for the thoracic spinal nerves?
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What function does temporal summation relate to in neural transmission?
What function does temporal summation relate to in neural transmission?
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What is the primary function of the brachial plexus?
What is the primary function of the brachial plexus?
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Which of the following nerves is NOT part of the lumbar plexus?
Which of the following nerves is NOT part of the lumbar plexus?
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What movement is associated with myotome C5?
What movement is associated with myotome C5?
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Which part of the nervous system integrates and commands the entire nervous function?
Which part of the nervous system integrates and commands the entire nervous function?
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What do autonomic sensory neurons primarily transmit information about?
What do autonomic sensory neurons primarily transmit information about?
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Which of the following defines a dermatome?
Which of the following defines a dermatome?
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Which plexus innervates the back of the thigh and all structures below the knee?
Which plexus innervates the back of the thigh and all structures below the knee?
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Which of the following nerves originates from the sacral plexus?
Which of the following nerves originates from the sacral plexus?
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Which myotome is responsible for knee extension?
Which myotome is responsible for knee extension?
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What does impaired sensation along a specific dermatome indicate?
What does impaired sensation along a specific dermatome indicate?
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What is the primary innervation area of the cervical plexus?
What is the primary innervation area of the cervical plexus?
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Which spinal nerves are responsible for forming the lumbar plexus?
Which spinal nerves are responsible for forming the lumbar plexus?
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Which movement is linked with myotome C6?
Which movement is linked with myotome C6?
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What is the purpose of forming a plexus from ventral rami of spinal nerves?
What is the purpose of forming a plexus from ventral rami of spinal nerves?
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The area of skin supplied by a specific spinal nerve's sensory fibers is referred to as a:
The area of skin supplied by a specific spinal nerve's sensory fibers is referred to as a:
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What is the primary component of the epineurium in a peripheral nerve?
What is the primary component of the epineurium in a peripheral nerve?
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Which peripheral nerve is innervated by the spinal root values C5 and C6?
Which peripheral nerve is innervated by the spinal root values C5 and C6?
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What type of connective tissue surrounds a fascicle within a peripheral nerve?
What type of connective tissue surrounds a fascicle within a peripheral nerve?
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Which nerve is associated with the spinal root values L2, L3, and L4?
Which nerve is associated with the spinal root values L2, L3, and L4?
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What is the primary function of afferent fibers within the peripheral nervous system?
What is the primary function of afferent fibers within the peripheral nervous system?
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Which of the following nerves does NOT primarily consist of fibers from the lumbar spinal cord?
Which of the following nerves does NOT primarily consist of fibers from the lumbar spinal cord?
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What component of a peripheral nerve provides a nutrient supply to the individual axons?
What component of a peripheral nerve provides a nutrient supply to the individual axons?
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Which nervous system component primarily includes the Sciatic Nerve?
Which nervous system component primarily includes the Sciatic Nerve?
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Study Notes
Nervous Tissue 2: Peripheral Nerves
- Peripheral nerves comprise afferent (sensory), efferent (motor), and mixed nerves.
- Afferent nerves transmit sensory information from sensory receptors to the central nervous system (CNS).
- Efferent nerves transmit motor commands from the central nervous system to muscles and glands.
- Mixed nerves contain both afferent and efferent fibers.
Peripheral Nerve Structure
- A peripheral nerve's structure:
- Epineurium: Dense, irregular connective tissue surrounding the entire nerve.
- Perineurium: Cell layer surrounding a fascicle (bundle of nerve fibers).
- Endoneurium: Connective tissue surrounding individual nerve fibers.
- Fascicle: Bundle of individual axons.
- Axons: Individual myelinated nerve fibers.
Spinal Nerves
- 31 pairs of spinal nerves in the peripheral nervous system (PNS)
- Each spinal nerve emerges from the spinal cord and emerges from the spinal canal at corresponding vertebral levels.
- Spinal nerves form plexuses, which are complex networks of nerves composed of anterior rami.
- Plexuses include cervical, brachial, lumbar, and sacral plexuses.
- These plexuses give rise to named peripheral nerves innervating specific regions of the body.
- Spinal nerves are “mixed”, containing both sensory and motor fibers.
Dermatomes
- A dermatome is an area of skin innervated by a single spinal nerve's sensory fibers.
- Dermatomal patterns provide clinical utility in assessing nerve damage.
- Examining sensory loss may aid in diagnosis of potential spinal injury or nerve root irritation.
Myotomes
- A myotome is a group of muscles innervated by a single spinal nerve's motor fibers.
- Myotomes assist in assessment of motor function within a spinal region, providing additional evidence of possible nerve impairment.
- Evaluating muscle strength in myotomes assists in diagnosis.
Spinal Nerve Formation: Mixed Nerves
- Spinal nerves are formed from the dorsal and ventral roots.
- Dorsal root: Sensory fibers (afferent).
- Dorsal root ganglion: Sensory neuron cell bodies are housed here.
- Ventral root: Motor fibers (efferent).
- Joining of the ventral and dorsal roots forms the spinal nerve.
- Ramus: Branch of a spinal nerve.
- Dorsal ramus: Supplies skin and deep muscles of the back.
- Ventral ramus: Supplies the rest of the trunk, limbs, and anterior body wall.
Nerve Plexuses
- Cervical plexus: Formed by ventral rami; it innervates the back of the head, neck, and shoulders.
- Brachial plexus: Formed by ventral rami of C5-T1; it innervates the upper limbs.
- Lumbar plexus: Formed by ventral rami of L1-L4; it innervates the lower anterior abdominal wall, hip, and anterior thigh.
- Sacral plexus: Formed by ventral rami of L4-S4; it innervates the posterior thigh, leg, and foot.
Common Peripheral Nerves
- Numerous peripheral nerves and their corresponding spinal nerve roots are given.
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Description
Test your knowledge on peripheral nerves with this quiz. You'll explore afferent and efferent nerves, their structure, and the role of spinal nerves in the peripheral nervous system. Perfect for students studying nervous system anatomy!
