Gross Anatomy of the Human Brain: Major Anatomical Structures and Terminology
- Track Progress
- 0:05 The Importance of Anatomical…
- 1:43 The Brain's Hemispheres
- 3:05 The Sulci
- 4:41 The Gyri
- 5:19 Lesson Summary
In this video you'll find out how and why we divide our brain into major sections. It's not just random names and games. You'll learn about where these divisions occur, what we call them, and what they separate.
The Importance of Anatomical Terminology
Your brain is a very complex and amazing structure. As humankind began to explore this intricate organ, we had to make it somehow easier for ourselves to not only be able to memorize the different parts of the brain but also reference them among ourselves with some level of consistency. In order to do this, we came up with some terms to help us out.
Let's use a metaphor to illustrate this. Say you are looking at a football and are pretending it's our brain. You notice that the football has these strange ridges. But the ridges are in every single football that you have ever encountered. You decide to name the ridges 'laces' so that everyone can call it the same thing without confusion.
But in one particular football, you notice that there is a little bump to the left of the ridges. You need to figure out if this is just an accident or something others have encountered before. Therefore, you decide to call up a friend who also studies footballs. Knowing that the ridges are properly called laces, you'll be able to quickly ask your friend, using laces as a reference point, if he sees anything similar to the left of any laces on his footballs.
This is precisely one reason why we name different parts of the brain with different names. We use them as reference points for major divisions of the brain, such as the brain lobes, and for proper communication between colleagues.
Now that you understand that, we'll get into learning about the brain's:
The Brain's Hemispheres
Imagine that your brain is nothing more than a globe. You probably know that our world, Earth, is divided into more than one part. We know these parts individually as hemispheres. Likewise, our brain is divided into two hemispheres as well. The left hemisphere is a region of your brain on the left side of your body, and the right hemisphere is a region of your brain on the right side of your body.
It's important to note that when referencing the left hemisphere vs. the right hemisphere, we are talking about your own body's perspective. This means that just like your left arm is on the left side of your body, your left hemisphere is on the left side of your body, too. The same goes for your right arm and right hemisphere - they're both on your right side.
When you hear the phrase 'left brain vs. right brain,' you now know that we are referring to the hemispheres of our brain. We stereotypically think of right-brained people as creative types and left-brained people as the scientific and nerdy ones. However, it's not that cut and dry. Every hemisphere has a little bit of creative and scientific power, and they usually work together at the same time to complete any given task.
When you look at the brain from the top down, you'll also notice that there are a bunch of squiggly-looking lines all over it. These lines actually have a name. They are actually crevices on the surface of your brain that we call sulci, the word sulci being plural for the word sulcus, which is a crevice on the surface of your brain.
The brain of each individual person has so many different little sulci in a lot of different patterns that a lot of these indentations have no actual name. However, there are some consistencies between the brains of individuals, like the laces on a football, that are so big and so identifiable that people actually have names for them.
One of these big indentations crossing the entire brain, from side to side, is called the central sulcus. The central sulcus is a really big groove that separates the frontal lobe from the parietal lobe.
Another really big landmark that we have in the brain is called the lateral sulcus. This is another groove in the brain that occurs separately on each hemisphere. The lateral sulcus separates the frontal and parietal lobe from the temporal lobe on each hemisphere.
As you can tell, a sulcus is nothing more than a deep line, or groove, in the brain that we have identified as something either large or significant enough to separate other important structures in the brain. One or more of these lines, no matter how big or small, are called sulci.
In between every little sulcus is a piece of brain tissue. When looking at the brain from the side, it looks like there are little bumps, folds, or ridges separated by sulci. These folds of tissues that are separated by grooves called sulci are themselves called gyri. One of these bumps is called a gyrus, and a gyrus is nothing more than an elevation on the surface of your brain surrounded by one or more sulci. Therefore, one bump is a gyrus, and two or more bumps are called gyri.
Now let's review all of the important points we covered in this lesson.
Our brain is separated into two equal halves. Each half of our brain is called a hemisphere. We have two hemispheres; one is called the right hemisphere, which is a region of your brain located on the right side of your body, and the other is called the left hemisphere, which is a region of your brain located on the left side of your body.
There are a lot of little lines of indentation all over the brain that we call sulci. The singular form of this word is known as a sulcus. There are two really big sulci that separate certain lobes of our brain. The central sulcus runs from across our entire brain from side to side and separates the frontal lobe from the parietal lobe. In addition, there is one lateral sulcus located on each hemisphere. The lateral sulcus separates the frontal and parietal lobe from the temporal lobe.
Finally, an elevation on the surface of your brain surrounded by one or more sulci is known as a gyrus. The plural form of this word is gyri.
At this point, you should have gathered that the main point in this lesson is that we have words for very large and obvious structures in our brain that are found in virtually every human. We have set names for these words so that we can easily reference them, and these structures either function to separate large areas of the brain, like the central sulcus does, or are themselves centers of functionality, like your left and right hemispheres are.
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