Spinal Cord Anatomy and Functions

Which of the following functions is NOT a primary function of the spinal cord?

If a patient has damage to the spinal cord at the L2 level, which structure might be affected?

What is the correct order of the meninges from superficial to deep?

A spinal tap (lumbar puncture) is performed to collect CSF. In what space is the needle inserted?

What is the primary component of white matter in the spinal cord, and what is its function?

Which of the following best describes the gray commissure's location and its primary function?

In the spinal cord, what distinguishes an ascending tract from a descending tract?

What is the defining characteristic of the decussation process in spinal tracts?

The gracile fasciculus carries sensory information from the lower body. Which type of information does it primarily transmit?

What is the role of the spinothalamic tract?

What is a key difference between the anterior and posterior spinocerebellar tracts?

How many motor neurons are involved in descending tracts and what are their roles?

What is the main function of the corticospinal tracts?

Which of the following is the function of the tectospinal tract?

What best describes a nerve?

What is contained in mixed nerves?

What is the role of Schwann cells in nerve fibers?

What is the function of the perineurium?

Which is the correct number of spinal nerve pairs?

Where do the first cervical nerve exit?

Where is the posterior (dorsal) root located, and what is its function?

There are two roots from which each spinal nerve is formed. What are these roots called?

Which region of the spine does NOT give rise to plexuses?

What is a dermatome?

What is the likely result if only two successive spinal nerves were anesthetized?

Which of these is NOT a characteristic of reflexes?

What type of muscle is innervated by somatic reflexes?

What is the correct pathway of a somatic reflex arc?

What is the role of muscle spindles in proprioception, and how does this contribute to motor control?

If a doctor taps the patellar tendon during a physical exam and observes no response, what might this indicate?

Why is the patellar reflex considered a monosynaptic reflex?

What is the effect of reciprocal inhibition during the stretch reflex?

What is characteristic of the flexor (withdrawal) reflex?

What term describes a reflex in which the input and output occur at different levels (segments) of the spinal cord?

What is the function of the tendon reflex?

What type of receptor is involved in Tendon reflex pathway?

The spinal cord extends from the brainstem at the olfactory bulb to the level of L3 or slightly beyond.

Neural integration is a principal function of the spinal cord, describing how spinal neurons receive input from single sources to execute appropriate output.

The spinal cord, on average, is approximately 3.8 cm thick and 65 cm long, occupying the upper two-thirds of the vertebral canal.

The medullary cone refers to the area of cervical enlargement in the spinal cord due to the increased density of nerves controlling the upper limbs.

The subarachnoid space separates the arachnoid mater from the dura mater and is filled with adipose tissue.

The filium terminale is a delicate membrane that directly adheres to the spinal cord and contains the posterior median sulcus.

The gray matter of the spinal cord, primarily composed of myelinated axons, facilitates the rapid transmission of electrical signals.

The anterior horns of the spinal cord contain both sensory and motor neurons, making them essential for integrating sensory information before motor output.

The white matter is divided into three funiculi: anterior, posterior, and lateral, each consisting of tracts that carry signals from one part of the CNS to another.

Ascending tracts in the spinal cord carry primarily motor information from the brain to the periphery, while descending tracts convey sensory input.

Decussation is a phenomenon where tracts in the spinal cord remain on the same side of the body without crossing the midline.

Ipsilateral tracts are characterized by the fact that the origin and destination of a tract are located on opposite sides of the body; these tracts always decussate.

The gracile fasciculus transmits signals for vibration, visceral pain, and precise touch from the lower limbs and trunk, terminating exclusively at the lumbar region of the spinal cord.

The cuneate fasciculus carries the same types of sensory signals as the gracile fasciculus, but its signals originate from the lower limb and abdomen.

The spinothalamic tract carries sensory signals for proprioception and muscle stretch and is part of the lateral system.

In the spinocerebellar tracts, first-order neurons synapse exclusively within the cerebral cortex, which then relays information to the cerebellum to coordinate movement.

The upper motor neurons of the corticospinal tracts originate in the brainstem and directly innervate skeletal muscles to control precise movements.

The tectospinal tract crosses to the contralateral side in the midbrain and mediates reflex responses to auditory stimuli.

Both the lateral and medial reticulospinal tracts originate in the reticular formation of the brainstem and primarily control muscles for posture and balance but do not influence pain signals.

In cases of poliomyelitis, intellectual functions are significantly impaired due to the widespread destruction of neurons throughout the brain.

ALS (Amyotrophic Lateral Sclerosis) primarily involves the loss of only sensory function, leaving motor neurons intact.

Spinal nerves can exclusively contain either sensory (afferent) or motor (efferent) fibers, but never both within the same nerve.

Epineurium wraps fascicles, which are bundles of schwann cells, while perineurium wraps the entire nerve.

The posterior root ganglion, associated with spinal nerves, houses the clusters of neurosomas located within the central nervous system.

The cervical plexus originates from the nerve roots C3–C7 and primarily innervates the lower limbs.

The phrenic nerve, originating from the coccygeal plexus, is crucial for controlling the muscles of the pelvic floor.

The brachial plexus is responsible for innervating the lower limb and arises from the lumbar region of the spinal cord.

The primary function of the lumbar plexus is somatosensory; it does not have any motor functions.

The sacral plexus innervates the pelvic region as well as the lumbar region, giving it direct control over bladder emptying.

The coccygeal plexus supplies exclusively motor fibers to the muscles of the plantar region of the foot involved in balance and plantarflexion.

Shingles is caused by the same infection that causes smallpox.

During a lumbar puncture, the spinal needle enters the spinal cord to collect CSF. This is why paralysis is a potential complication.

Following the division of spinal nerves, the posterior and anterior roots enter the vertebral canal and innervate the nervous system.

Dermatomes lack any overlapping, so damage to a singular dermatome causes total loss of sensation in the damaged dermatome's region.

Reflexes are spontaneous actions that do not require stimulation; they are simply intrinsic responses of the body.

Gamma nerve fibers carry motor impulses away from the anterior horn of the spinal cord to muscles.

The muscle spindle informs the brain of muscle length and body movement, allowing the brain to regulate coordinated movement, postural control, and muscle tone by responding with motor signals.

In a stretch reflex, there is only one synapse, making it a monosynaptic arc. A muscle spindle is required to perform the stretch reflex.

The flexor reflex involves the sensory and motor response occurring on the same side of the body.

Tendon organs can also be known as golgi tendon organs and respond to excessive pressure on the tendon.

The inferior margin of the spinal cord typically terminates at the level of L3 in most adults.

The spinal cord's neural integration function involves receiving input from multiple sources, integrating it, and executing appropriate output.

The anterior median fissure and the posterior median sulcus are superficial longitudinal grooves found on the lateral sides of the spinal cord.

The dura mater is the delicate innermost membrane that directly adheres to the surface of the spinal cord.

The lumbosacral enlargement of the spinal cord provides innervation to the pelvic region and lower limbs.

The epidural space is located between the arachnoid mater and the pia mater.

Gray matter within the spinal cord primarily consists of myelinated axons, enabling rapid signal transmission.

The central canal of the spinal cord is filled with interstitial fluid.

The anterior and lateral funiculi contain ascending and descending tracts.

Decussation refers to the process where nerve fibers in a tract remain on the same side of the body, without crossing the midline.

Ascending tracts in the spinal cord carry primarily motor information from the brain to the muscles.

The gracile fasciculus carries sensory signals from the upper limbs regarding deep touch and proprioception.

The spinothalamic tract is responsible for carrying signals related to fine touch and precise location of stimuli.

Second-order neurons in the spinoreticular tract synapse in the thalamus before projecting to the cerebral cortex.

The anterior spinocerebellar tracts cross over twice, ending in the contralateral cerebellum.

Descending tracts always involve three motor neurons: an upper motor neuron, a middle motor neuron and a lower motor neuron.

Most corticospinal tract fibers decussate in the spinal cord itself before synapsing on lower motor neurons.

Tectospinal tracts are involved in precise, voluntary movements of the distal extremities.

Lateral and Medial Reticulospinal Tracts control muscles of upper and lower limbs and reduce the transmission of pain signals to the brain.

In poliomyelitis, astrocytes fail to reabsorb glutamate from tissue fluid.

Spinal nerves are purely sensory, containing only afferent fibers to transmit information to the central nervous system

The epineurium is the loose connective tissue external to neurilemma.

Sensory nerves send signals to the CNS. Motor nerves carry signals from the CNS to muscles and glands. Mixed nerves contain both types of fibers.

Ganglia are clusters of neuron cell bodies located within the central nervous system.

There are twelve pairs of cervical spinal nerves.

The posterior root of a spinal nerve contains motor output, channeling signals from the spinal cord to effector organs.

The cauda equina is composed of nerve roots arising from levels L2 to C01.

The meningeal branch of a spinal nerve innervates the muscles of the back.

In thoracic region the anterior ramus give rise to plexus.

Shingles is caused by viral infection.

The cervical plexus supplies motor and sensory innervation to the upper limb.

The lumbar plexus provides innervation to the abdominal wall, anterior thigh, and genitalia.

The median nerve is part of the Sacral plexus

Dermatomes overlap along their edges by approximately 85%.

Somatic reflexes involve the autonomic nervous system innervating smooth and cardiac muscle.

Somatic reflexes are typically slow, voluntary and predictable responses to stimuli.

The integrating center of a reflex arc is always located within the brain.

Muscle spindles are stretch receptors embedded in skeletal muscles that monitor muscle length and activate only muscle movement.

The knee-jerk (patellar) reflex is classified as a polysynaptic reflex because it involves multiple interneurons in the spinal cord.

In a flexor reflex, the ipsilateral leg extends to maintain balance when the contralateral leg withdraws from a painful stimulus.