Central Nervous System Part 2

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Questions and Answers

What anatomical structure anchors the spinal cord to the coccyx?

Conus medullaris

Pia mater

Cauda equina

Filum terminale (correct)

Which of the following spaces is associated with the meninges surrounding the spinal cord?

Epidural space (correct)

Subdural space

Periosteal space

Intrathecal space

Which part of the spinal cord is continuous with the medulla oblongata?

Lumbar enlargement

Conus medullaris

Vertebral canal (correct)

Cervical enlargement

Where does the spinal cord typically terminate in adults?

Level of L1-L2 Signup and view all the answers

What is the primary function of the spinal cord?

Center for spinal reflexes Signup and view all the answers

At which lumbar vertebrae levels is a lumbar puncture typically performed?

L4-L5 Signup and view all the answers

Which structure contains the cell bodies of somatic motor neurons?

Ventral horn Signup and view all the answers

Which term describes the white matter tracts that carry sensory information to the brain?

Ascending tracts Signup and view all the answers

What is the arrangement of gray matter in the spinal cord?

Butterfly-shaped central core of gray matter surrounded by white matter Signup and view all the answers

What is the primary function of dorsal (posterior) horns in the spinal cord?

Sensory processing Signup and view all the answers

Which of the following accurately describes descending tracts?

They transmit motor signals from the brain to muscles. Signup and view all the answers

Where do sensory impulses generally decussate in the sensory pathways?

At the level of the 2º neurons Signup and view all the answers

Which element is NOT part of the spinal cord's white matter tracts?

Dorsal root ganglion Signup and view all the answers

Which part of the spinal cord is primarily responsible for somatic sensory functions?

Dorsal horns Signup and view all the answers

What defines the function of the ventral roots in the spinal cord?

They carry motor commands away from the spinal cord. Signup and view all the answers

What type of sensations does the medial lemniscal pathway primarily conduct?

Fine pressure and touch Signup and view all the answers

What is the role of the anterior grey horn in the somatic motor pathways?

It is the site of synapse for motor neurons. Signup and view all the answers

Which pathway is responsible for carrying crude touch and pressure sensations?

Spinothalamic pathway Signup and view all the answers

What distinguishes pyramidal tracts from extrapyramidal tracts?

Pyramidal tracts primarily control fine motor skills. Signup and view all the answers

What type of movements do extrapyramidal tracts primarily contribute to?

Complex gross movements Signup and view all the answers

How do facilitatory and inhibitory tracts act on the anterior horn?

They act in a summative manner. Signup and view all the answers

What connects the motor areas of the cerebral cortex to skeletal muscles?

Somatic motor pathways Signup and view all the answers

What is the principle of the final common pathway in motor control?

Each motor neuron controls a specific motor unit. Signup and view all the answers

Which statement correctly defines the role of the medial lemniscus?

It conducts impulses through the medulla, pons, and midbrain. Signup and view all the answers

Which of the following is NOT true about pyramidal tracts?

They involve many relays between motor areas. Signup and view all the answers

Study Notes

Spinal Cord

The spinal cord is located within the vertebral canal.
It contains 31 pairs of spinal nerves.
It connects with the medulla oblongata.
It exits the skull through the foramen magnum (occipital bone).
It extends inferiorly to the L1-L2 level.
It has cervical and lumbar enlargements.
It is the center for spinal reflexes.

Meninges

Meninges surround the spinal cord.
The meninges create spaces: epidural, potential subdural, and subarachnoid.
The dura mater does not have a periosteal layer.
Cerebrospinal fluid (CSF) circulates through the subarachnoid space around the brain and spinal cord.

Anatomical Features

The filum terminale anchors the spinal cord to the coccyx.
Understanding the level of the conus medullaris and cauda equina is clinically important.

Lumbar Puncture

Lumbar punctures are performed below the mid-lumbar region after the spinal cord terminates.
A needle is inserted into the subarachnoid space between L3-L4 or L4-L5.

Anatomy of the Spinal Cord

The spinal cord has an anterior median fissure and a posterior median sulcus.
Gray matter is centrally located, shaped like a butterfly.
White matter surrounds the gray matter in three columns.
Bundles of myelinated axons run up and down the cord (white matter).

Spinal Gray Matter

Dorsal (posterior) horns contain sensory neurons' cell bodies are in the dorsal root ganglion.
Ventral (anterior) horns contain somatic motor neuron cell bodies.
Axons exit the spinal cord through the ventral root.

White Matter Tracts

White matter tracts are classified as ascending (sensory) or descending (motor).
Tracts cross from one side of the cord to the other (commissural).
White matter tracts are found in the posterior, lateral, and anterior columns.

Somatic Sensory Pathways

Sensory pathways carry impulses from receptors to sensory areas of the cerebrum.
Impulses commonly travel through three pools: primary, secondary, and tertiary neurons.
These pathways decussate (cross) at the level of the secondary neurons.

Medial Lemniscal Pathway

Conducts fine pressure, touch, vibration, and proprioceptive information.
Fibers enter medulla and cross before synapsing in the thalamus.

Spinothalamic Pathway

Carries crude touch and pressure sensations.
Does not involve precise discrimination.

Somatic Motor Pathways

Motor function is controlled by impulses from the motor cortex.
Impulses travel to motor neurons in the anterior gray horn of the spinal cord in a somatic motor pathway.
Pathways include pyramidal (corticospinal) and extrapyramidal tracts.
Pyramidal tracts are for voluntary movements, extrapyramidal tracts for involuntary movements and posture.

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Description

This quiz covers the essential anatomy of the spinal cord and its protective structures, the meninges. It includes details about spinal nerve pairs, enlargement levels, and the clinical significance of lumbar punctures. Test your knowledge of these crucial components of the central nervous system.