Welcome to today’s lesson on the brain. In this lesson today, you are going to learn about the three main areas of the brain, their functions, and also some of the brain's protective barriers. Specifically, you will look at:
The brain is the control center of our nervous system and it's divided into three main regions. We have our forebrain, midbrain, and hindbrain.
Take a look at the image below as you learn about the three main regions of the brain.
The forebrain is colored green. The forebrain is the most highly developed part of your brain, and it includes the two hemispheres of the cerebrum, the thalamus, and the hypothalamus.
The midbrain, which is the little part labeled in blue, is the smallest region of our brain. And the function of the midbrain is to relate information from the body's sensory organs to the forebrain, where that information can then be processed.
The hindbrain, in pink, is located just above the spinal cord and it includes the parts of the brain such as the medulla oblongata, the cerebellum, and the pons.
The brain is composed of three layers of meninges, and meninges are just membranes of connective tissue located between the skull and the brain.
The purpose of these three layers is to cover the central nervous system's neurons and blood vessels. It's protecting the brain, protecting those neurons and blood vessels associated with the brain.
Take a look at the diagram below to see these layers.
The first layer on the top is not one of the meninges, just skin. Below the skin, you have bone and then below that, you have the three layers of meninges.
The first layer is called the dura matter. This is a thick, leathery layer that composes the first layer of meninges found right underneath your skull. The next layer is the arachnoid matter, followed by the pia matter.
The layers of the meninges get thinner and more delicate as we move down. The first layer is very thick and leathery, the next layer is a little bit thinner and a little bit more delicate, and then the pia matter is very thin and very delicate.
Those are the protective layers and features of the brain. Some other features of the brain that serve as protective barriers are the cerebral spinal fluid, which acts to cushion the brain. Cerebral spinal fluid is actually formed from blood plasma.
The blood-brain barrier controls what blood-borne substances are allowed to enter the cerebral spinal fluid.
The reason the blood-brain barrier is protective and can control what substances can enter the cerebral spinal fluid is because the capillary walls of the barrier are much less permeable to substances than other capillaries found in your body. It helps to control the spread of viruses, toxins, bacteria from having contact with the brain. You don't want those materials entering your cerebral spinal fluid because your brain is such an important part of our nervous system, and of your entire body, that you need to make sure that whatever is entering is controlled.
However, the blood brain barrier doesn't protect your hypothalamus, and the reason for that is because your hypothalamus needs to be exposed to your bloodstream so it can monitor the chemical makeup and the temperature of your blood in order to help maintain homeostasis.
This lesson has been an overview on the brain's three regions: the forebrain, the midbrain, and the hindbrain. It has also been an overview of the brain’s protective areas and the blood brain barrier.
Keep up the learning and have a great day!
Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND
A barrier created by a glial cell called astrocytes; the blood-brain-barrier only allows a small amount of materials from the blood to enter the inside of the brain; plays a role in protecting neurons and creating a stable environment inside of the brain.
A fluid similar to plasma that is created by the brain; it washes the internal brain of metabolic waste and plays a minor role in cushioning the brain.
The largest part of the brain that consists of the cerebral hemispheres and all of the structures contained within them.
The area of the brain that consists of the cerebellum, pons, and medulla oblongata.
The protective connective tissue found on the outside of the brain and spinal cord; consists of three layers: dura mater, arachnoid mater, pia mater.
The area of the brain that connects the hindbrain to the forebrain; also the top structure of the brain stem.