Puzzle Piece 10: Spinal Cord and Spinal Nerves

What are the two main components of the Central Nervous System (CNS)?

The brain and the spinal cord.

What is the primary function of the spinal cord?

To transmit sensory and motor information between the brain and the rest of the body.

What analogy is used to describe the spinal cord's function?

It is likened to a highway for sensory information to reach the brain and for motor information to leave the brain.

What structures protect the nervous tissue of the CNS?

Bony structures (cranial bones and vertebral column) and membranes (meninges).

What are the three layers of the meninges?

Dura mater, arachnoid mater, and pia mater.

What is the epidural space and where is it located?

The epidural space is between the dura mater and the vertebra and contains fat.

What is the function of cerebrospinal fluid (CSF)?

CSF provides buoyancy, nutrient delivery, and waste removal.

Which meningeal layer is the outermost and toughest?

The dura mater.

What is found in the subdural space?

Interstitial fluid.

Describe the arachnoid mater.

It is the middle layer of the meninges and resembles a spider web.

What is the function of the pia mater?

It is the innermost layer that hugs the spinal cord and contains blood vessels supplying oxygen and nutrients.

What is the vertebral canal?

A canal formed by the alignment of vertebral foramina that houses the spinal cord.

What are denticulate ligaments?

Extensions of the pia mater that provide lateral anchoring for the spinal cord.

What is the filum terminale?

An extension of the pia mater that anchors the spinal cord to the coccyx.

What is the subarachnoid space?

The space beneath the arachnoid mater that contains cerebrospinal fluid.

What is the significance of the vertebral foramen?

It forms the vertebral canal when aligned, allowing the spinal cord to pass through.

What is the role of the cranial nerves in relation to the CNS?

They serve as additional communication routes between the brain and the body.

How does the body protect the spinal cord during movement?

By having multiple layers of protection, including fat in the epidural space and the tough dura mater.

What does the term 'sub' in subdural space indicate?

It means 'below' the dura mater.

What does the term 'epi' in epidural space indicate?

It means 'above' the dura mater.

Why is the spinal cord considered delicate?

Because it is composed of nerve tissue that requires multiple layers of protection.

What happens to the blood vessels in the pia mater?

They are anchored in place by the web-like columns of the arachnoid mater.

What is the role of the arachnoid mater in relation to the pia mater?

It provides a protective layer above the pia mater and helps anchor blood vessels.

What is the filum terminale and its function?

The filum terminale is an extension of the pia mater that anchors the spinal cord to the coccyx, preventing it from moving inferiorly.

What surrounds the spinal cord and is filled with cerebrospinal fluid (CSF)?

The subarachnoid space surrounds the spinal cord and is filled with cerebrospinal fluid (CSF).

Between which vertebrae does the spinal cord typically end?

The spinal cord typically ends between the L1 and L2 vertebrae.

What are denticulate ligaments and their role?

Denticulate ligaments are lateral extensions of the pia mater that anchor the spinal cord laterally, preventing side-to-side movement.

What is the central canal in the spinal cord?

The central canal is a canal in the center of the spinal cord through which cerebrospinal fluid (CSF) flows.

How is the spinal cord divided into right and left sides?

The spinal cord is divided into right and left sides by the posterior median sulcus and anterior median fissure.

What is the difference between the anterior median fissure and the posterior median sulcus?

The anterior median fissure is wider than the posterior median sulcus.

What are the two types of mater found in the spinal cord?

The spinal cord contains gray mater and white mater.

What surrounds the gray mater in the spinal cord?

The white mater surrounds the gray mater in the spinal cord.

What are the three regions of gray mater in the spinal cord?

The three regions of gray mater are the posterior gray horn, lateral gray horn, and anterior gray horn.

What is contained within the posterior gray horn?

The posterior gray horn contains the neuronal cell bodies of interneurons that receive sensory information.

What is the function of the lateral gray horn?

The lateral gray horn contains the neuronal cell bodies of autonomic motor neurons.

What does the anterior gray horn contain?

The anterior gray horn contains the neuronal cell bodies of somatic motor neurons.

What are the three regions of white mater in the spinal cord?

The three regions of white mater are the anterior white column, lateral white column, and posterior white column.

What is the role of the white mater columns?

Each white mater column is formed by bundles of nerve fibers responsible for transmitting sensory (ascending) and motor (descending) information.

What is the anterior white commissure?

The anterior white commissure is located in the white mater between the anterior median fissure and the gray commissure, aiding communication between the right and left sides of the central nervous system.

What is the gray commissure?

The gray commissure is located within the gray mater and connects the gray mater on both sides of the spinal cord.

What runs through the center of the gray commissure?

The central canal runs through the center of the gray commissure.

Why is white mater described as 'white'?

White mater is described as 'white' because it is packed with nerve fibers that transmit signals, often surrounded by a fatty layer (myelin sheath), giving them a whitish appearance.

Why is gray mater described as 'gray'?

Gray mater is described as 'gray' because it houses numerous neuronal cell bodies in one place.

What is the function of commissures in the spinal cord?

Commissures are bundles of nerve fibers that connect the right and left sides of the spinal cord, facilitating communication between them.

What is a witty tip to remember the difference between the anterior median fissure and posterior median sulcus?

Remember: Skinny Sulcus, Fat Fissure! The posterior median sulcus is skinny, while the anterior median fissure is wider.

What is the anterior white commissure and its function?

The anterior white commissure is located in the white matter between the anterior median fissure and the gray commissure, made of nerve fibers that cross from one side of the spinal cord to the other, allowing communication between the white matter columns.

What does the term 'decussation' refer to in the context of the spinal cord?

Decussation refers to the crossing of nerve fibers from one side of the spinal cord to the other.

What are the two roots that emerge from the spinal cord?

The two roots are the dorsal root and the ventral root.

What is the primary function of the dorsal root?

The dorsal root consists of axons of sensory neurons and is responsible for conveying sensory information to the spinal cord.

What is contained within the dorsal root ganglion?

The dorsal root ganglion contains neuronal cell bodies of unipolar neurons involved with general senses.

What does the ventral root consist of and its primary function?

The ventral root consists of axons of motor neurons and is responsible for conveying motor information away from the spinal cord.

How can you visualize the dorsal and ventral roots of the spinal cord?

Picture the dorsal and ventral roots as cables with lots of wires; the dorsal root consists of sensory neuron axons, while the ventral root consists of motor neuron axons.

What is the significance of the term 'ganglion' in the context of the dorsal root ganglion?

A ganglion is a group of neuronal cell bodies located outside of the central nervous system.

How do sensory stimuli travel from the periphery to the spinal cord?

Sensory stimuli are brought by dendrites towards the neuronal cell body in the dorsal root ganglion and then travel away via axons that form the dorsal root.

What is the role of the dorsal gray horn in the spinal cord?

The dorsal gray horn is where sensory stimuli arrive after traveling through the dorsal root.

What shape do general sensory neurons have, and where are their cell bodies located?

General sensory neurons are unipolar in shape, and their cell bodies are located within the dorsal root ganglion.

What shape do neurons involved with special senses have?

Neurons involved with special senses have a bipolar shape.

What mnemonic can help remember the functions of the dorsal and ventral aspects of the spinal cord?

The 'S' in Dorsal/Posterior stands for Sensory, while Ventral/Anterior has no 'S', indicating it is not sensory but motor.

What happens when the dendrites of dorsal root sensory neurons meet the axons of ventral root motor neurons?

They come together to form a spinal nerve, which contains both sensory and motor nerve fibers.

What type of nerves are spinal nerves classified as?

Spinal nerves are classified as mixed nerves because they transmit both sensory information and motor information.

What aspect of the spinal cord is related to sensory information?

The dorsal aspect of the spinal cord is related to sensory information.

What aspect of the spinal cord is related to motor information?

The ventral aspect of the spinal cord is related to motor information.

What is the function of the axons in the ventral root?

The axons in the ventral root carry motor information away from the spinal cord towards effectors.

What is the significance of the dorsal root ganglia being located on both sides of the spinal cord?

Each dorsal root ganglion houses neuronal cell bodies of sensory neurons, indicating a symmetrical arrangement on both sides of the spinal cord.

What is the relationship between the dorsal root and sensory neurons?

The dorsal root is formed by the axons of sensory neurons that bring sensory stimuli to the spinal cord.

How does the structure of the spinal cord facilitate its functions?

The distinct arrangement of dorsal and ventral roots allows for the separation of sensory and motor pathways, facilitating efficient communication between the body and the central nervous system.

What is the role of dendrites in sensory neurons?

Dendrites bring sensory stimuli from the periphery towards the neuronal cell body.

What is the role of axons in sensory neurons?

Axons carry the sensory stimulus away from the neuronal cell body.

What is a witty tip to remember the functions of the dorsal and ventral roots?

Remember 'Vroom, Vroom' for ventral (motor) and 'S' for sensory in dorsal.

What forms a spinal nerve?

A spinal nerve is formed when the dorsal and ventral roots come together.

What are the two main branches of a spinal nerve?

The two main branches are the posterior ramus and the anterior ramus.

What does the dorsal ramus innervate?

The dorsal ramus innervates the skin and muscles of the back.

What does the ventral ramus innervate?

The ventral ramus innervates the lateral and anterior trunk, as well as the limbs.

What is the function of the dorsal root ganglion?

The dorsal root ganglion contains unipolar neurons that receive sensory information from the periphery.

How do unipolar neurons transmit sensory information?

The dendrites of unipolar neurons receive a stimulus, converting it into an action potential that travels to the neuronal cell body and then through the axon to the terminal buttons.

What is the role of interneurons in the posterior gray horn?

Interneurons in the posterior gray horn receive sensory information from the dorsal roots and transfer it to motor neurons or send it upwards to the brain.

What do the lateral gray horns contain?

The lateral gray horns contain neuronal cell bodies of autonomic motor neurons.

What do autonomic motor neurons control?

Autonomic motor neurons control involuntary functions in cardiac muscle, smooth muscle, and glands.

What is the significance of autonomic motor control?

Autonomic motor control is crucial for the functioning of internal organs and visceral functions, and malfunctions can pose serious risks.

What is the intervertebral foramen?

The intervertebral foramen is the hole between vertebrae through which spinal nerves pass.

What analogy is used to describe the formation of the spinal nerve?

The spinal nerve is compared to a thick cable formed by merging the dorsal and ventral root 'cables'.

What happens to the spinal nerve after it forms?

After forming, the spinal nerve splits into branches called rami.

What is the function of the posterior ramus?

The posterior ramus contains both sensory and motor nerve fibers and innervates the back.

What is the function of the anterior ramus?

The anterior ramus contains both sensory and motor nerve fibers and innervates everything that is not the back.

What is the role of sensory neurons in the spinal cord?

Sensory neurons transmit sensory information from the periphery to the spinal cord.

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

Unipolar neurons are found in the dorsal root ganglion.

What is the purpose of the terminal buttons of sensory neurons?

The terminal buttons synapse with neurons in the gray matter of the spinal cord.

What is the function of interneurons?

Interneurons transfer sensory information to motor neurons and send information to the brain.

What does the term 'ramus' mean in Latin?

Ramus means 'branch' in Latin.

What are the two types of gray horns in the spinal cord mentioned?

The two types of gray horns are the posterior gray horn and the lateral gray horn.

What is the primary role of the posterior gray horn?

The posterior gray horn contains interneurons that process sensory information.

What is the function of the lateral gray horn in the spinal cord?

It safeguards precious neurons and protects autonomic motor neurons from potential injuries.

Where are autonomic motor neurons primarily concentrated in the spinal cord?

In the thoracic region.

What is contained within the anterior gray horn of the spinal cord?

Neuronal cell bodies of somatic motor neurons that reach skeletal muscles, related to voluntary control.

What are the components that form a spinal nerve?

Axons of motor neurons and dendrites of sensory neurons, comprised of myelinated nerve fibers wrapped in connective tissue layers.

What are the three connective tissue layers surrounding a spinal nerve?

Endoneurium, perineurium, and epineurium.

What is the role of the epineurium in the spinal nerve?

It provides tensile strength, enabling the spinal nerve to resist movements and stretching.

Where does the spinal cord end?

Between the L1 and L2 vertebrae.

What is the conus medullaris?

The cone-shaped end of the spinal cord.

What is the cauda equina?

A collection of lower spinal nerves (lumbar, sacral, and coccygeal) that hang down from the end of the spinal cord.