How is cns protected

It is here where the cerebrospinal fluid bathes and cushions the brain. Blood is carried to the brain by two paired arteries, the internal carotid arteries and the vertebral arteries. The internal carotid arteries supply most of the cerebrum. The vertebral arteries supply the cerebellum , brainstem , and the underside of the cerebrum. After passing through the skull, the right and left vertebral arteries join together to form the basilar artery.

Arterial Blood Supply of the Brain The communication between the internal carotid and vertebral-basilar systems is an important safety feature of the brain. If one of the major vessels becomes blocked, it is possible for collateral blood flow to come across the Circle of Willis and prevent brain damage.

The venous circulation of the brain is very different than the rest of the body. Usually arteries and veins run together as they supply and drain specific areas of the body.

In the brain, the major vein collectors are integrated into the dura to form venous sinuses - not to be confused with the air sinuses in the face and nasal region. Venous Blood Drainage of the Brain The venous sinuses collect the blood from the brain and pass it to the internal jugular veins.

The superior and inferior sagittal sinuses drain the cerebrum, the cavernous sinuses drains the anterior skull base. All sinuses eventually drain to the sigmoid sinuses, which exit the skull and form the jugular veins. These two jugular veins are essentially the only drainage of the brain. The Blood Brain Barrier is a physiological mechanism that alters the permeability of brain capillaries so that some substances are prevented from entering brain tissue, while other substances are allowed to enter freely.

The Blood Brain Barrier A key aspect of the blood-brain barrier are the thin, flat cells known as endothelial cells which form the walls of capillaries. In most parts of the body, the endothelial cells in the capillaries overlap at what are called junctions. These junctions are leaky enough to let a lot of different materials move through the wall of the blood vessel into the tissue and back again. However, in the brain there's a different arrangement.

The endothelial cells meet at what are called tight junctions. Cells of the barrier also actively transport metabolic products such as glucose molecules. The reason for this endothelial-glial connection is unclear, but may reflect an influence of astrocytes on the formation and maintenance of the blood-brain barrier. Total views 24, On Slideshare 0. From embeds 0. Number of embeds 1, Downloads Shares 0. Comments 0. Likes 7. You just clipped your first slide!

Clipping is a handy way to collect important slides you want to go back to later. Now customize the name of a clipboard to store your clips. Visibility Others can see my Clipboard. Cancel Save. This offers physical protection and so naturally is one of the hardest bones in the body. The skull acts like a helmet for your brain, and helps to prevent damage from mechanical stress things like knocks and falls.

The spinal cord is also surrounded by some very hard bone, but this time it comes in the form of the vertebrae. Next, we have the three protective membranes - the meninges.

These are made out of connective tissue and provide a cushioning from the hard skull of the brain, jolting against the vertabrael column in the spinal cord or from any damaging impacts. You could remember this order with some sort of mnemonic or story such as - Dur -ing Dura Mater the invasion of the Arachn -ids arachnoid , Pia -nos Pia Mater were very rare. Finally, there is a special fluid, called cerebrospinal cerebro for brain, spinal for the spinal cord that circulates the entire central nervous system.

It occupies the space between the Pia Mater and Arachnoid and supplies nutrients like blood in the rest of the body , disposes of waste and acts as a shock absorber which is why I've included it as a protective structure. What four structures protect the central nervous system? Sarah C. Nor does it have a barrier between itself and the blood, leaving it exposed to toxins and mechanical injuries. The autonomic nervous system, also part of the peripheral nervous system, controls internal body functions that are not under conscious control.

For example, when a prey animal is chased by a predator, the autonomic nervous system automatically increases the rate of breathing and the heartbeat.

It dilates the blood vessels that carry blood to the muscles, releases glucose from the liver, and makes other adjustments to provide for the sudden increase in activity. When the animal has escaped and is safe once again, the nervous system slows down all these processes and resumes all the normal body activities, such as the digestion of food. Privacy Policy. Skip to main content. The Nervous System.

Search for:. The Nervous System The nervous system is composed of the central nervous system brain and spinal cord and the peripheral nervous system nerves. Learning Objectives Summarize the nervous system. Key Takeaways Key Points The central nervous system consists of the brain, which controls complex body functions, and the spinal cord, which transmits signals from the brain to the rest of the body.

The brain and spinal cord are covered by three layers of meninges, or protective coverings: the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid surrounds the brain, cushioning it and providing shock absorption to prevent damage.