Anatomy of the Spinal Cord and Meninges

Questions and Answers

What are the functions of the spinal cord?

Conducts impulses from brain, and integrates reflexes

What are the meninges?

Cover and protect CNS. Spinal and cranial.

What are the meningeal layers from superficial to deep?

Dura Mater, Arachnoid Mater, Pia Mater

What are the spaces between the meningeal layers from superficial to deep?

Epidural space, subdural space, subarachnoid space Signup and view all the answers

What is the epidural space?

On top of Dura Mater, fat layer Signup and view all the answers

What is the subdural space?

Between Dura Mater and arachnoid mater, Interstitial fluid Signup and view all the answers

What is the subarachnoid space?

Between arachnoid mater and pia mater, Cerebral Spinal fluid Signup and view all the answers

What is the denticulate ligament?

Extensions of pia mater and holds spinal cord in place Signup and view all the answers

What is the conus medullaris?

End of spinal cord, L1 and L2 Signup and view all the answers

What is the filum terminate?

Extension of the pia mater past the actual spinal cord, L4 and L5 Signup and view all the answers

What is gray matter?

Clusters of cell bodies (Nuclei) Signup and view all the answers

What are the two types of white matter?

Ascending and descending Signup and view all the answers

How many spinal nerves are there?

31 Signup and view all the answers

How many cranial nerves are there?

12 Signup and view all the answers

What are the types of nerves?

Sensory, Motor, Mixed Signup and view all the answers

What are the two roots of spinal nerves?

Dorsal root and ventral root Signup and view all the answers

What type of tissue surrounds a nerve?

Connective tissue Signup and view all the answers

What is the dorsal root responsible for?

Sensory, dorsal root ganglion Signup and view all the answers

What is the ventral root responsible for?

Motor Signup and view all the answers

What is the reflex arc?

Sensory receptor, sensory neuron, integration center, motor neuron, and effector Signup and view all the answers

What is a stretch reflex?

Monitored by muscle spindle, monosynaptic, and ipsilateral Signup and view all the answers

What is an agonist muscle?

Two things have the same function Signup and view all the answers

What is an antagonist muscle?

Having the opposite functions of each other Signup and view all the answers

Study Notes

Functions of the Spinal Cord

Conducts impulses from the brain and integrates reflexes.

Meninges

Protective coverings of the Central Nervous System (CNS), both spinal and cranial.

Meningeal Layers

Composed of three layers: Dura Mater (outer), Arachnoid Mater (middle), Pia Mater (inner).

Spaces Between Meningeal Layers

Epidural space: located above Dura Mater, filled with fat.
Subdural space: found between Dura and Arachnoid Mater, contains interstitial fluid.
Subarachnoid space: lies between Arachnoid and Pia Mater, filled with Cerebrospinal fluid.

Denticulate Ligament

Extensions of pia mater that secure the spinal cord in place.

External Anatomy of the Spinal Cord

Shape: Roughly cylindrical with cervical and lumbar enlargements, conus medullaris, and cauda equina.

Conus Medullaris

The terminus of the spinal cord, situated at lumbar vertebrae L1 and L2.

Filum Terminale

An extension of the pia mater extending below the spinal cord, located at L4 and L5; facilitates the collection of spinal fluid.

Cauda Equina

A bundle of spinal nerves resembling a horse's tail.

Internal Anatomy of the Spinal Cord

Features anterior median fissure, posterior median sulcus, gray matter (cell bodies), gray commissure, central canal, and white matter (myelinated axons).

Gray Matter

Comprises clusters of neuronal cell bodies (nuclei).

White Matter

Composed of myelinated axon groups known as tracts, with two types: ascending and descending.

Spinal Nerves

Total of 31 spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal; each connected to the spinal cord via two roots.

Nerve Roots

Dorsal root: sensory information, contains dorsal root ganglion.
Ventral root: carries motor information.

Ramus Structure

Dorsal (posterior) ramus: innervates the back.
Ventral (anterior) ramus: supplies the front torso and limbs.

Plexuses

Networks of nerves innervating specific body regions: cervical, brachial, lumbar, sacral.

Cervical Plexus

Innervates the head and neck, includes the phrenic nerve.

Phrenic Nerve

Controls the diaphragm, essential for breathing.

Brachial Plexus

Responsible for the innervation of the shoulder and upper limbs.

Lumbar Plexus

Supplies the abdominal wall, anterior, and medial thigh muscles.

Sacral Plexus

Innervates the hamstring, gluteal muscles, and lower limbs; contains the sciatic nerve.

Sciatic Nerve

Large-diameter nerve arising from the sacral plexus.

Reflex Activity of the Spinal Cord

Involuntary, rapid responses to stimuli, includes stretch reflex, tendon reflex, flexor reflex, and crossed extensor reflex.

Reflex Arc Components

Includes sensory receptor, sensory neuron, integration center, motor neuron, and effector.

Integration Centers

Can involve spinal reflexes or cranial reflexes.

Reflex Effectors

Somatic reflexes target skeletal muscles, autonomic reflexes target smooth muscle, cardiac muscle, or glands.

Types of Reflexes

Stretch reflex: Monosynaptic and ipsilateral.
Tendon reflex: Polysynaptic and ipsilateral.
Flexor (withdrawal) reflex: Triggered by a painful stimulus, polysynaptic and ipsilateral.
Crossed extensor reflex: Involves multiple synapses and is contralateral.

Synapse Types

Monosynaptic: One synapse; Polysynaptic: multiple synapses.

Body Side Effects

Ipsilateral: affects the same side; Contralateral: affects the opposite side.

Function Relationships

Agonist: functional similarities; Antagonist: functional opposites.

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Description

This quiz explores the functions and structures of the spinal cord, including its protective coverings known as meninges. You will learn about the various layers of the meninges, the spaces between them, and the anatomy of the spinal cord itself. Test your knowledge on these crucial aspects of the Central Nervous System!