all right um one two three one two three one two three ah yes hey guys and welcome to another video today is one of those days where i don't know i feel like I don't know, it's an off day, but anyways we're here. I'm excited because I am actually going to teach you today about the spinal cord and so, well, without further ado, let's get started! Hey guys, welcome to another video.
I'm Dr. Gonzalez and today in this video we are going to talk about the following topics but before we get started, don't forget to subscribe, like and share because in that way will never miss a video every single week when I post a new lecture. Alright, let's get started! There are hundreds of neurons and even more neuroglias composing the spinal cord. Some of the functions of the spinal cord include that that it functions independently of the brain, it controls voluntary and involuntary movement, it also processes reflexes and it integrates what we call the excitatory presynaptic cells and inhibitory postsynaptic cells, also known as EPSPs and IPSPs.
And lastly, the spinal cord can conduct sensory impulses to the brain and motor impulses to effectors like mind, body, and mind. muscles. The spinal cord begins as an extension of the medulla longata at the level of the foramen magnum and it terminates at level L2.
The spinal cord is protected by the bone like these vertebrae. It's also protected by connective tissues such as the meninges and it's protected by a fluid called the cerebrospinal fluid for short CSF. So as you can see here this area is known as the cervical area, this area is known as thoracic, this area would be lumbar, sacral and of course coccygeal. In this picture you can also observe two enlargements.
This right here is called the cervical enlargement and this right here would be the lumbar enlargement. And similarly in name these spinal nerves are going to be called depending on the region. example we have cervical spinal nerves in total we have eight of those we have also the thoracic spinal nerve in total we have twelve we have lumbar spinal nerves in total we have five and sacral spinal nerve which in total we have five there's also a coccygeal spinal nerve which is one okay so the old lady is kind of like looking side to side right it has the the the white part is the veil the brown part on top it's the her hair right and so you can see her mouth and her nose and her eye and then for the young lady she's kind of like looking away right and then what used to be the nose of the old lady it's the yaw of the young lady what you used to be the mouth of the old lady that's kind of like a necklace in the young lady right and like I said she's looking away did you spot her The internal anatomy of the spinal cord allows sensory and motor information to be processed in an organized way. The spinal cord is made up of gray and white matter. Gray matter consists of cell bodies of neurons organized into regions called horns as you can see here.
This area of the spinal cord acts as an integration and reflex processing center. So for example we have the posterior horn. lateral horn and anterior horn.
Meanwhile surrounding the gray matter is the white matter formed by myelinated and unmyelinated axons organized into columns that pass information up and down the spinal cord. So as you can see we have the posterior column, there is a lateral column and there is an anterior column. Also in this picture you can observe that coming out of the white matter and or column, columns we have these roots like the ventral root and dorsal root.
Posteriorly there's also This dorsal root ganglion and then both of these roots merge into forming a spinal nerve. We have 31 pairs of spinal nerves and these spinal nerves connect the CNS to sensory receptors, muscles, and glands and are part of peripheral nervous system. So here in this picture you can see again one more time those dorsal roots, ventral roots, and dorsally the dorsal root ganglion.
Shortly after passing through its intervertebral foramen, a spinal nerve divides into several branches known as rami. So in this picture you can observe for example the dorsal or posterior ramus and the anterior or ventral ramus. Now when nerves come together in a body region they become a plexus that innervates a specific region of the body. For example as you can see here we have the cervical plexus from C1 to C4.
We have the brachial plexus from C5 to T1. We have also a lumbar plexus from T12 to L4. And we have a sacral plexus from L4 to S4.
So this one was a little bit difficult for me because at first I was able to observe the bunny. So the bunny is, I think it's... like the easiest but the ducky it's like kind of like the hardest so if you want to see the ducky you can't have to like tilt your screen to the side because the ears of the bunny it's actually the dog's peak right and so see if you can spot it right let me know in the comments if you were able to see it the nerves that are found within the cervical plexus which is this they include the transverse cervical great auricular, lesser occipital, supraclavicular, and phrenic.
These nerves on the cervical plexus innervate neck muscles, prevertebral muscles, and the diaphragm which is innervated by the phrenic nerve. The brachial plexus innervates the upper extremity and it's divided into roots, trunks, divisions, cords, and the larynx. and branches. A good way to remember is Robert Taylor drinks cold beer.
Robert roots, Taylor trunks, drinks divisions, cold cords and beer for branches. This is a good mnemonic. And the nerves that come out of the brachial plexus would be the dorsal scapular, the suprascapular, subscapular, thoracodorsal axillary as well as the medial pectoral lateral pectoral musculo-cutaneous and nerve to subclavius and lastly there's also the median nerve radial nerve ulnar and medial antebrachial cutaneous nerve Over here we can observe the lumbar plexus nerves such as the ilio-hypogastric, ilio-inguinal, genitofemoral, femoral, and obturator.
The lumbar plexus typically innervates the anterior portion of the lower extremity. Now over here we can observe the posterior plexus which is the sacral plexus and in here we have a couple of nerves including the sciatic nerve. gluteal, pudendal, posterior femoral cutaneous, tibial, and fibular. Certain segments of the skin is supplied by spinal nerves that carry somatic sensory nerve impulses to the brain. These are known as dermatomes.
So as you can observe, almost every single spinal nerve from C2 all the way down to S5. is going to innervate this portion of the body except for c1. The area of the face is actually going to be innervated by a cranial nerve that we call the trigeminal nerve. And if you want to know more about this topic you can always click on the card on top of this video to check out similar videos regarding this lecture. Well that's it!
Thank you for watching this video. Don't forget please to subscribe, like and share because by subscribing you are helping me spread the word about human anatomy and it'll help me with the algorithm. And that's it.
Bye!