Central Nervous System part B

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Questions and Answers

What composes the protective layers surrounding the brain?

Adipose tissue, fascia, and tendons

Blood vessels, nerves, and connective tissue

Bone, meninges, and cerebrospinal fluid (correct)

Skin, muscle, and ligaments

What is one function of the cerebrospinal fluid (CSF)?

Acts as a barrier against all chemicals

Serves as a nutrient supply for bones

Prevents the brain from crushing under its own weight (correct)

Increases brain weight

Which layer of the meninges is the outermost and the strongest?

Subdural layer

Dura mater (correct)

Pia mater

Arachnoid mater

What role do the choroid plexuses play in the central nervous system?

Alter ion concentrations and cleanse cerebrospinal fluid Signup and view all the answers

What is the primary function of the cerebrospinal fluid (CSF)?

To protect the brain and spinal cord Signup and view all the answers

What structure is formed when the two layers of the dura mater separate?

Dural sinuses Signup and view all the answers

How does the blood-brain barrier contribute to brain health?

It separates bloodborne substances from neurons Signup and view all the answers

Which meninx is described as a delicate layer that closely adheres to the surface of the brain?

Pia mater Signup and view all the answers

What structure anchors the spinal cord to the coccyx?

Filum terminale Signup and view all the answers

Which feature is found at the inferior end of the vertebral canal?

Cauda equina Signup and view all the answers

How does the blood-brain barrier function in relation to harmful substances?

It prevents harmful substances from entering the brain. Signup and view all the answers

What is the purpose of arachnoid villi in the central nervous system?

To absorb cerebrospinal fluid into venous blood Signup and view all the answers

What is the primary purpose of the epidural space?

It is filled with fat and a network of veins Signup and view all the answers

Which of the following characteristics distinguishes cerebrospinal fluid from blood plasma?

CSF has a different ion concentration. Signup and view all the answers

What mechanism allows the blood-brain barrier to selectively permit some substances to cross?

Chemical diffusion through plasma membranes Signup and view all the answers

What are the cervical and lumbar enlargements responsible for?

They serve as attachment points for spinal nerves connected to limbs Signup and view all the answers

Study Notes

Brain Protection

The brain is safeguarded by bone, meninges, and cerebrospinal fluid (CSF).
The blood-brain barrier shields the brain from harmful substances.

Meninges

The CNS is covered in three connective tissue membranes:
- Dura mater
- Arachnoid mater
- Pia mater
These membranes serve several functions:
- Cover and protect the CNS
- Protect blood vessels and enclose venous sinuses
- Contain cerebrospinal fluid (CSF)
- Form partitions within the skull

Dura Mater

Leathery, strong meninx made up of two layers of fibrous connective tissue.
The layers separate in specific areas to form dural sinuses.

Arachnoid Mater

The middle meninx, loosely enveloping the brain.
There is a subdural space between arachnoid mater and dura mater.
Below the arachnoid is the subarachnoid space, filled with CSF and large blood vessels.
Arachnoid villi protrude superiorly, allowing CSF absorption into venous blood.

Pia Mater

The innermost meninx, composed of delicate connective tissue that clings tightly to the brain.

Cerebrospinal Fluid (CSF)

A watery solution similar to blood plasma, but with less protein and different ion concentrations.
It acts as a liquid cushion, providing buoyancy for CNS organs.
This prevents the brain from being crushed under its own weight.
It offers protection from blows and other traumas.
It nourishes the brain and carries chemical signals throughout it.

Choroid Plexuses

Capillary clusters forming tissue fluid filters, hanging from the roof of each ventricle.
They have ion pumps that regulate CSF ion concentrations.
They assist in cleansing CSF by removing waste products.

Blood-Brain Barrier Functions

A protective mechanism maintaining a stable environment for the brain.
It separates bloodborne substances from neurons.
This selective barrier allows free passage of nutrients.
It is ineffective against substances diffusing through plasma membranes
Stress enhances the ability of chemicals to pass through the blood-brain barrier.

Spinal Cord

CNS tissue confined within the vertebral column from the foramen magnum to L1.
Provides bi-directional communication between the brain and the body.
It is protected by bone, meninges, and CSF.
The space between the vertebrae and the dural sheath (dura mater) is called the epidural space; it is filled with fat and a network of veins.

Spinal Cord Features

Conus medullaris: the terminal portion of the spinal cord.
Filum terminale: a fibrous extension of the pia mater anchoring the spinal cord to the coccyx.
Denticulate ligaments: delicate shelves of pia mater attaching the spinal cord to the vertebrae.

Spinal Cord Connections

31 pairs of spinal nerves connect to the cord via paired roots.
Cervical and lumbar enlargements: regions where nerves serving upper and lower limbs emerge.
Cauda equina: a collection of nerve roots at the inferior end of the vertebral canal.

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Description

This quiz covers the protective structures surrounding the brain, including the bones, meninges, and cerebrospinal fluid (CSF). Furthermore, it delves into the individual layers of the meninges: dura mater, arachnoid mater, and pia mater, highlighting their roles and characteristics.