This journey begins with a visit to the brain covers. We can find three brain covers in between the hard skull and the brain. We call them “meninges”.
The meninges are the three protective membranes that surround the brain and spinal cord, and they play a vital role in maintaining the health and function of the central nervous system. These membranes are known as the dura mater, the arachnoid mater, and the pia mater, and each of them has a unique structure and function that contribute to the overall protection of the brain.
They act as cushions while protecting the brain from friction. But, that is not their only job.
The outermost brain cover: Dura mater (“tough mother”)
The dura mater, also known as the tough mother, is the outermost layer of the meninges. It is a dense, fibrous membrane that covers the brain and spinal cord and provides a sturdy barrier against external injuries, such as blunt force trauma. The dura mater also contains a network of veins, which are important for draining blood from the brain and maintaining proper blood flow.
Figure 1 shows only the left half of the Dura mater. It is an old drawing. In reality, it contains two layers. The outer one attaches to the inner side of the skull. The inner one glistens. And, it is also transparent. Because of its transparency, we can see a network of blood vessels running inside.
Credit: Brain: dissection showing the top of the brain, with the dura mater of the left hemisphere and the gyri of the right. Watercolour after(?) W.H. Lizars, ca. 1826. Credit: Wellcome Collection. Attribution 4.0 International (CC BY 4.0)
The other two brain covers are: Arachnoid mater and Pia mater
Now, we look at the two inner covers. Inside the Dura matter, the other two thinner coverings (Figures 2 and 3) spread all over the brain surface. These covers are also transparent. Unlike the outer covering, they wrap the brain surface throughout all grooves and bumps of the brain surface. The middle layer is full of fluid, called cerebrospinal fluid.
The arachnoid mater, or spider-like mother, is a delicate, spiderweb-like layer that lies between the dura mater and the pia mater. This layer is important because it contains a fluid-filled space known as the subarachnoid space, which helps to cushion the brain and protect it from sudden movements and impacts. The arachnoid mater also contains blood vessels that help to regulate blood flow to the brain and spinal cord.
The pia mater, or soft mother, is the innermost layer of the meninges and is in direct contact with the surface of the brain. This layer is delicate and closely adheres to the surface of the brain, helping to hold it in place and protect it from external stress and pressure. The pia mater also contains blood vessels that provide nutrients to the brain and remove waste products.
source: openstax.org, RICE University
under the CC BY 4.0 license
Source: BioMed Central, a part of Springer Nature Natividad et al. under the CC BY 4.0 license.
In between the two layers harbour a fluid – named cerebrospinal fluid (in short CSF). Not only that, small branches of arteries traverse throughout the layers. They carry oxygen and food to the neuron forest and other structures.
What is the relation between meninges and stroke prevention?
The meninges help to prevent strokes by regulating blood flow to the brain. The subarachnoid space, which is located between the arachnoid mater and the pia mater, contains cerebrospinal fluid (CSF) that helps to regulate blood pressure in the brain. The CSF acts as a shock absorber, cushioning the brain and preventing it from being damaged by sudden movements or impacts. This helps to reduce the risk of blood clots forming in the blood vessels that supply the brain, which can lead to stroke.
The dura mater is also important for preventing strokes, as it contains a network of veins that drain blood from the brain. This helps to reduce the risk of blood clots forming in the veins and leading to a stroke. The dura mater also provides a sturdy barrier against external injuries, such as blunt force trauma, which can cause damage to the blood vessels in the brain and increase the risk of stroke.
The pia mater is also important for preventing strokes, as it contains blood vessels that provide nutrients to the brain and remove waste products. This helps to maintain the health of the brain and reduce the risk of strokes caused by poor blood flow or oxygenation.
The meninges play a crucial role in the prevention of strokes by regulating blood flow to the brain, cushioning it from sudden movements, providing nutrients and removing waste products. By understanding the importance of the meninges in preventing strokes, we can appreciate the vital role they play in maintaining the health and function of the central nervous system.
An excellent video clip can be found from the University of Utah through this link: https://neurologicexam.med.utah.edu/adult/html/brain-dissections.html#10
