Transcription
What is going on, wonderful people? It's Medicosis Perfectos, where medicine makes perfect sense. This is the beginning of a new review series on psychology. Let's break this word down. What does "-ology" mean? It means the study of. The study of what? The "psychi," the soul. And this is the Greek word "psyche."
In today's video, we'll start talking about the biological basis of psychology, i.e., biology. Welcome to an interesting review of the nervous system. Remember that the building unit of your body is the cell. When a group of cells join together, they form a tissue. When a group of tissues join together, they form an organ. When a group of organs join together, they form a system. Case in point: the nervous system.
Click the like button, click the Subscribe button, and let's dive deep into the human psyche. This is my psychology playlist. Please watch these videos in order for maximum sensation, perception, and conception. And if you're studying for the MCAT, the iMat, the DAT, the COMLEX, or the AP exams, oh boy, do I have a playlist for every subject that you can imagine.
Now let's start by talking about the anatomy of the nervous system. For a more robust discussion, refer to my neuroanatomy playlist. These are my ten commandments of neuroanatomy, and I've talked about them before in my neuroanatomy playlist.
Commandment number one: Thou shalt draw your line in the sand between the motor (anterior) and the sensory (posterior). The motor is efferent and descending, whereas the sensory is afferent and ascending.
Commandment number two: Thou shalt understand the difference between the central nervous system and the peripheral nervous system; the difference between the brain and the spinal cord; cranial versus spinal; somatic versus autonomic. Oh, by the way, the word "autonomic" is synonymous with the word "visceral," which is synonymous with the word "splanchnic," which should be a brand name for an aftershave for men.
Next, thou shalt understand the difference between myelinated and unmyelinated; the white ramus versus the gray ramus. Then you need to know the definitions of the following: the nucleus, the ganglion, tract, nerve, and lemniscus. Then, the differences among prosencephalon, mesencephalon, and rhombencephalon. Then you need to understand the organization of the nuclei in the brainstem and the difference between the anterior 2/3 of the tongue and the posterior 1/3 of the tongue, because one has nothing to do with the other neurologically speaking.
Now let's start with commandment number one. Look, this right here—all of this is the brain. Unfortunately, most people think of the brain as only this part. That's not true. If you happen to think that the brain is only this part right here, then this means that your accomplishments in life are like the square root of a negative number—imaginary. Look, my friend, all of this is your brain. This part, just this part, is called the cerebrum or the cerebral cortex, which is made of two cerebral hemispheres: right and left. Deep to that, we have basal nuclei, commonly referred to as basal ganglia. We have a diencephalon hidden within. Then we have a midbrain, followed by a pons, followed by the medulla, and then the cerebellum. All of what I've just discussed is the brain. What is the central nervous system, then? The central nervous system is the brain—all of this plus the spinal cord down below. So, CNS = brain + spinal cord.
This is the cerebral cortex or the cerebrum. It has a frontal lobe, a temporal lobe, an occipital lobe, and a parietal lobe. Thou shalt draw your line in the sand. This is the first commandment. You draw it parallel to something called the central sulcus, okay? And then, what's anterior is here; posterior is there. This is front; this is back. Anterior is mostly motor, and posterior is mostly sensory. If you are motor, then you are efferent and descending. What does "efferent" mean? It means that you will start in the brain and go somewhere else, such as to your biceps or triceps or quadriceps muscles. So, motor is descending, efferent, and anterior (in front of the line). On the other hand, sensory is ascending, okay, which means afferent. It starts somewhere else, such as your fingertips when you feel something, and these sensations will travel up until they end up in the brain, behind the line. I repeat: anterior is mostly motor; posterior is mostly sensory.
Case in point: let's say that you want to move your biceps. You'll contract your biceps muscle to move your arm. This impulse has to start here in the primary motor cortex. Notice that this is in front of the line. Let me tell you something: the primary motor cortex on the left controls your right arm, and the cortex on the right controls your left arm. It's some crisscross action. Similarly, the primary somatosensory cortex on the left receives sensation from your right arm, and the somatosensory cortex on the right receives sensations from the left half of the body.
Next, what if I want to move my eyes right and left, up and down? This is the frontal eye field. Notice it's in front of the line. But what if I want to see? Oh, vision—vision is a sensation. Primary visual cortex in the occipital lobe. Notice this is behind the line. Next, what if I want to speak and talk, talk, talk, talk? This is Broca's area—to articulate my thoughts. Notice it's in front of the line. But what if I want to hear you and then understand you? This is Wernicke's area, which is, surprise, surprise, behind the line. See, medicine makes so much sense once you understand what the French toast you're talking about.
Now let's say that I have a lesion in my Broca's area. What's going to happen? I'll not be able to talk, and we call this non-fluent aphasia. Usually, the patient is so upset and aware that he has a problem, so this is called egodystonic. I am upset, and I know that I have a problem. But patients with Wernicke's aphasia, or damage to Wernicke's area, tend to speak, although their speech does not make so much sense; it's a word salad. They cannot understand you, but they feel amazing; they feel that they have no problem whatsoever, and that you, as a doctor, you are the problem. And this is called egosyntonic. A mnemonic to help you remember which is which is that Broca's is broken. "Boca" means mouth in Spanish. So if I have Broca's aphasia, I cannot talk.
Again, the central nervous system is made of the brain, which is here, and the spinal cord. If you wish to see more videos like this in the future, please drop a brain emoji in the comments, which is here. This is your spinal cord. Again, you draw your line in the sand like this: anterior is mostly motor; posterior is mostly sensory. This is efferent; this is afferent. Efferent is motor, okay? It starts here and goes somewhere else, but afferent is sensory. Cool. So we call this the motor or the efferent or the ventral root. On the other hand, this is the sensory, afferent, or dorsal root. You can say ventral or anterior; you can say dorsal or posterior. Let's say that I touch a hot stove. I will feel the warm temperature through the dorsal root, which is posterior. Then I will move my hand away from the stove. To move, I need the ventral or anterior root. Keep in mind that the dorsal root has a ganglion, but the ventral one does not. Then you have sensory fibers here and motor fibers there, and they join together here in a spinal nerve, which has sensory fibers and motor fibers. And then the spinal nerve is going to divide again into dorsal ramus and ventral ramus. The dorsal ramus is also known as posterior primary ramus, and the ventral ramus is otherwise known as anterior primary ramus. No one—literally no one—cares about the posterior primary ramus. This is just for the skin of your back and the muscles of your back; that's it. But all the drama, all the action, is carried by the ventral ramus or the anterior primary ramus. You want to talk about the cervical plexus? Anterior primary ramus. How about brachial plexus? Anterior primary ramus. How about lumbar plexus? Anterior primary ramus. How about the sacral plexus? Anterior primary ramus.
If you wish to download these doozy colorful notes, go to medicosisperfectos.com. I help you learn, understand, and pass exams. If you want me to personally tutor you, reach out to me on my website. So we're done with the first commandment.
Next: CNS versus PNS. Central nervous system includes the brain and the spinal cord. Peripheral nervous system, however, is cranial nerves and spinal nerves—what comes out of the brain and what comes out of the spinal cord. There is a disease that causes demyelination, or loss of myelin, in the CNS, and this is called multiple sclerosis, or MS. But there is another disease called Guillain-Barré syndrome, or GBS, which causes demyelination of the PNS. How many cranial nerves do you have? The answer is 12 pairs. And how many spinal nerves do you have? The answer is 31 pairs.
Next: brain versus spinal cord. Again, the CNS is brain and spinal cord; PNS is cranial nerves and spinal nerves. The brain is made of the cerebrum, which you see here, the cerebellum, and the brainstem. Then the brainstem is further subdivided into midbrain, pons, and medulla. As for the spinal cord, it's divided into certain areas: there is cervical, there is thoracic, there is lumbar, there is sacral, and coccygeal. The cervical region of the spinal cord has eight segments; the thoracic has 12 thoracic segments; lumbar, five segments; sacral, five segments; coccygeal, one spinal segment.
Next, the peripheral nervous system: cranial nerves. These are 12 pairs. The spinal nerves are 31 pairs. Some of your cranial nerves are purely sensory; others are purely motor; some are mixed, meaning both sensory and motor. As for the spinal nerves, they are all mixed; all of them contain sensory fibers and motor fibers together. Remember when we talked about the posterior or dorsal root and the anterior or ventral root, and then they join together to give me a spinal nerve? So the spinal nerve has both sensory and motor.
Next, what is the structural unit of your nervous system? It's the neuron, which is made of soma, which has a bunch of dendrites and an axon. But what is the functional unit of the nervous system? It's the reflex arc. The reflex arc consists of: S—the stimulus, such as the hot candle; R—receptors, temperature receptors in my fingertips; A—the afferent; this is the sensory or the afferent root; C—the center; it's part of the central nervous system; in this case, it's the spinal cord; E—the efferent; these are the motor fibers in the efferent ventral root; E—effector organ, such as the muscles of my arm or the muscles of the forearm or the hand; R—the response, which is to remove my hand away from this hot stimulus. This is a reflex arc. It happens very quickly before you think about anything. After you remove your finger, then you can think, "Oh, that hurt. I better not repeat this again." So the reflex arc is S-A-R-C-E-R, which in Arabic means cockroaches. Again, the reflex arc contains the stimulus, receptor, afferent, center, efferent, effector, response. How many neurons do we see here? There is one; there is a second one; and there is the third one. So how many synapses? There is one connector synapse here between the first and the second neurons, and there is another synapse here between the second and the third neurons. A synapse is a connection or union between two neurons. So we have two synapses here. So we can call this disynaptic or bisynaptic, or because it's more than one, polysynaptic. So we divide the reflexes into monosynaptic and polysynaptic. The example of the candle and flexing the muscle—this is polysynaptic. The monosynaptic reflex that you need to know is the stretch reflex, otherwise known as the myotatic reflex.
Next, let's talk about some definitions. First, this is the soma, and this is the axon. If we have a collection of somas, a bunch of somas gathering together in the CNS, we call this a nucleus, such as the nucleus of the facial nerve. How about if we have a bunch of somas gathering together in the peripheral nervous system? We call this a ganglion. But what if we have a collection of axons in the central nervous system? This is called a tract. How about a collection of axons in the peripheral nervous system? This is called the nerve.
Next, some embryology action. The trilaminar embryo is made of endoderm on the inside, ectoderm on the outside, and mesoderm in between. By the way, the word "meso" means in the middle. Later, I'm going to tell you about the midbrain, also known as mesencephalon. "Meso" means mid, such as midbrain, or the layer in the middle. Where does the nervous system come from? The nervous system is ectodermal, okay? But let's be specific. Which part of the ectoderm are we talking about? Is the nervous system derived from the surface ectoderm or from the neuroectoderm? The answer is neuroectoderm. This neuroectoderm is further subdivided into neural tube and neural crest. The neural tube is going to give you the CNS, whereas the neural crest will give you the PNS—central nervous system and peripheral nervous system. What are the names of the cells that myelinate the axons of the CNS? The answer: oligodendrocytes. So they are derived from the neural tube. How about the cells that myelinate the peripheral nervous system? These are Schwann cells, and they are derived from the neural crest cells. Do you remember the definition of a ganglion? Oh, yeah, the ganglion is a collection of somas in the PNS. Oh, PNS—that's why all the ganglia are derived from the neural crest, including your adrenal medulla, which is a special kind of a ganglion; it's also derived from the neural crest.
Next, the ependymal cells that make cerebrospinal fluid are derived from the neural tube. But be careful, because the microglial cells or microglia, which are the macrophages of the brain or the nervous system, they start with an "m," so they are mesodermal in origin. Next, how about the meninges—the coverings that cover the brain and the spinal cord? Well, you have three meninges: there is the dura mater, the arachnoid mater, and the pia mater. The dura mater is mesodermal in origin, but the pia and the arachnoid maters are ectodermal in origin, especially from the neural crest.
Next, let's talk about myelinated versus unmyelinated fibers. Keep in mind that myelinated fibers appear white, and they form white matter. But unmyelinated fibers appear gray, so we call them the gray matter. So when you see the word "white ramus," it has "white," so it is myelinated. But gray ramus is gray because it's unmyelinated. If we're talking about the brain, as you see, the fibers on the outside are unmyelinated, and that's why they are the gray matter. But in the spinal cord, it's the other way around: the gray matter (unmyelinated fibers) are on the inside, whereas the white matter (myelinated) is on the outside.
Next, a note on the origin of cranial nerves. How many cranial nerves do we have? The answer is 12 pairs. Cranial nerves I and II are attached to the forebrain; cranial nerves III and IV are attached to the midbrain; cranial nerves V, VI, VII, and VIII are attached to the pons; IX, X, XI, XII are attached to the medulla. The first cranial nerve is the olfactory nerve; the second one is the optic nerve; III is the oculomotor; IV is the trochlear; V is the trigeminal; VI is the abducens; VII is the facial; VIII is the vestibulocochlear; IX is the glossopharyngeal; X is the vagus; XI is the accessory nerve; and XII is the hypoglossal nerve. What is a nucleus? A bunch of somas in the CNS. Ganglion? A bunch of somas in the PNS. Tract? A bunch of axons in the CNS. Nerve? A bunch of axons in the PNS. Lemniscus? A collection of ascending sensory fibers in the brainstem headed towards the thalamus; after that, they are headed towards the sensory cortex. How many lemnisci do we have in the brain? The answer is four. If you know their names, please let me know in the comments.
Coming up next: the differences among prosencephalon, mesencephalon, and rhombencephalon. Remember that the CNS is made of what? It's made of brain and spinal cord. The brain starts as three vesicles. We call them the three primary brain vesicles. The first one is the prosencephalon or forebrain; the second one is the mesencephalon or midbrain; again, the word "meso" means mid; the third one is the rhombencephalon or the hindbrain. The prosencephalon is divided into telencephalon and diencephalon. The telencephalon, with the "t," is on the outside, with a "T"; it's the outer one, and you see it on the edges here, whereas the diencephalon, with the "d," is deep inside, within. What is the telencephalon? It has the cerebral hemispheres, also known as the cerebral cortex. It also has the basal ganglia. As for the diencephalon, it includes any word that has "thalamus" in the name, including thalamus, hypothalamus, epithalamus, subthalamus, and metathalamus. And the mesencephalon—the mesencephalon is subdivided into pons and cerebellum, whereas the myelencephalon is just the medulla. What does the word "myelo" mean? "Myelo" means core, because the medulla is in the core of the foramen magnum, and the spinal cord, which is the continuation of the medulla, is in the core of the vertebral column. And that's why we refer to spinal cord diseases as myelopathies or pathologies in the myelo. What's the myelo? The core, which could mean the spinal cord or the midbrain.
Some quick notes: why do I need the cerebral cortex for? Well, it has motor functions; it has sensory functions. The primary motor cortex is here in the frontal lobe; the primary somatosensory cortex is here in the parietal lobe. If you want to move your eyes, the frontal eye field is in the frontal lobe; the visual cortex is in the occipital lobe; the auditory cortex is in the temporal lobe. Higher functions: execution, rational thinking, accounting, maths, etc.—cerebral cortex. Next, the basal ganglia. What's the basal ganglia? The basal ganglia is like the co-pilot. So if there is a pilot for movement, then we also need a co-pilot for movement. The co-pilot is the basal ganglion. Why do we need a hypothalamus? It has many functions, including: it's a thermostat, glucostat, and osmostat. What does "thermostat" mean? A regulator of temperature. Glucostat? A regulator of glucose in your bloodstream. And osmostat? A regulator of your appetite. Most of the eye reflexes have their center in the midbrain. The cerebellum is very important for balance, equilibrium, coordination, and gait. The medulla has four vital centers that you should never forget. I should be able to wake you up from a coma, and you should still be able to tell me that the medulla oblongata has the cardiovascular center, respiratory center, swallowing center, and vomiting center. Pneumonic: heart and lungs—get it in, get it out. Cardiovascular center, respiratory center, swallowing center, and vomiting center. Emotions and behaviors: limbic system, otherwise known as rhiencephalon. You know why we call it rhiencephalon? Oh, yes, because it's related to olfaction. If you want to know what the limbic system is, just imagine that you went to a restaurant, and the chef cooked a meal that smelled so good, which did remind you of the meal that your late grandmother used to cook for you. You smelled the food, you remembered your grandmother, and experienced some emotions. This is the limbic system in a nutshell. Thermostat, glucostat, osmostat—that's the hypothalamus. Eye reflexes—midbrain. Heart and lungs—get it in, get it out—medulla oblongata. Micturation reflex, which is urination, defecation reflex, and erection—these have their centers in the sacral segments of the spinal cord. The pneumonic is sacral 2, 3, 4: keep the penis off the floor.
Now, if you want to dig deeper and learn about the organization of the nuclei in the brainstem, if you want to learn about the differences between the anterior tongue and the posterior tongue, as well as all of this gibberish, please watch my neuroanatomy playlist. But there is one more thing that we need to talk about, which is somatic versus autonomic. Your nervous system is divided into somatic and autonomic. What's the difference? Somatic is what you can control, such as me contracting my muscles and punching you in the face. This is a voluntary action. Of course, I will never do this because I love you. This was a somatic function. But on the other hand, we have autonomic functions. Autonomic means automatic—something that you cannot control; it's involuntary. It is autonomic; it is visceral; it is splanchnic, such as sweating. That's an autonomic function; it's something that you cannot control. How about regulating your blood pressure? Oh, this is something that you do, but you cannot control; you do so involuntarily. How about dilating or constricting your pupil? Involuntary action. Somatic is divided into motor or sensory; same thing with autonomic: we have motor autonomic and sensory autonomic. But what does the word "mixed" mean? "Mixed" means motor and sensory together. Sometimes you even add some autonomic. If you ask the average doctor or medical student what's the autonomic nervous system, they will say without hesitation, "Oh, it's the sympathetic and the parasympathetic," which is true but incomplete. The autonomic also includes the enteric nervous system. Enteric means in your gut, in your gastrointestinal system. These include the myenteric plexus for motility and the submucosal plexus for secretions. Again, the word "autonomic" means involuntary, means visceral, means splanchnic. And that's it for the ten commandments.
What are the meninges? These include the dura mater, arachnoid mater, and pia mater. From the outside inwards, the outer covering is the dura mater; it covers the brain and the spinal cord, followed by the arachnoid mater, which covers the brain and the spinal cord as well, and the inner one is the pia mater, which covers the brain and the spinal cord as well. For the pros, we call the meninges "maters"—dura mater, arachnoid mater, pia mater—because the word "mater" is Greek for mother. It's not "matter" with two Ts; it's "mater" with one T. You have three mothers hugging your brain and the spinal cord. Isn't that lovely? Yes, it is lovely, until these meninges get inflamed; then it's painful and rigid AF. The dura mater is the toughest layer, and we call it the pachymeninx, which means the tough mother. The arachnoid mater means spider-like mother; pia mater means tender, affectionate mother. "He who hasn't known a mother's love has no reason being infatuated with the world"—Will Durant. The arachnoid and the pia mater are thin, so we call them leptomeninges. "Meninges" is the plural; "meninx" is the singular. The dural sheath becomes continuous with the epineurium of the nerve. Also, these meninges cover some nerves, such as the optic nerve. The optic nerve is covered by these meninges as well. And let me tell you something that will blow your mind: the dura that surrounds the optic nerve becomes the sclera that surrounds the eye. The dura and the sclera are the same layer. And that's why when you have meningitis, you suffer from photophobia—fear of light—because the same meninges that cover the brain also cover the optic nerve and the eye. Something that your mediocre professor will never tell you.
In the next video in this playlist, you'll learn about the sympathetic and the parasympathetic nervous systems. Some quick notes on the cerebral cortex: motor is anterior; sensory is posterior. The left cerebral cortex controls the right half of the body, and the right cerebral cortex controls the left half of the body. If you are right-handed, then your dominant cerebral hemisphere is the left one. And if you are left-handed, then the dominant hemisphere is the right one. Let's suppose I'm right-handed, which means that my dominant cerebral hemisphere is the left one. So, therefore, the left hemisphere will be responsible for seeing and visualizing letters and words; hearing and understanding language-related sounds; performing speech, reading, writing, and arithmetic, because that's my dominant hemisphere. But again, I'm right-handed, so therefore my right hemisphere is the non-dominant one, and that right hemisphere will do what? It will see faces rather than letters or words; it will hear music rather than language; and it will emote rather than think and calculate. And it will also be responsible for visual-spatial function, such as geometry, the sense of direction, navigating while driving a car, etc. Those are the functions of the non-dominant hemisphere. Of course, it's not that clear-cut; it's not black and white, but this is largely true. How do we know that this is largely true? The answer is when there is a disease; when there is a stroke. Strokes in the non-dominant hemisphere present slightly different from strokes in the dominant hemisphere. That's how you know they are different.
The cerebral cortex—well, it's part of the CNS, of course, because it's part of the brain. Which part of the brain? Forebrain, which is prosencephalon. Which part of the forebrain are we talking about? Telencephalon or diencephalon? This is telencephalon. Is this cerebral cortex or basal ganglia? We're talking cerebral cortex. The cerebral hemispheres—left and right—contain what? They have surfaces, such as the lateral surface here, medial surface hidden behind here, and inferior surface. It has lobes: there is the frontal lobe; there is the parietal lobe; there is the temporal lobe; and this is the occipital lobe. We have poles, such…
As the anterior pole, the posterior pole, it has sulci such as this famous Central sulcus, and it has gyri such as this one pre-Central gyrus and this one post-Central gyrus. A sulcus is a depression, whereas a gyrus is an elevation. So the sulcus looks like this—that's a depression—and then a gyrus looks like that—that's an elevation—and then sulcus, and then another gyrus, and then sulcus, and then another gyrus. This is the lateral surface of the cortex; this is the medial surface; and this is the inferior surface, seen from below. To learn more about the arteries that supply the brain, please refer to my neuroanatomy playlist. Sulci and gyri: here is the central sulcus of Rolando; here is the lateral sulcus of Sylvius; and this is the parieto-occipital sulcus. This is the frontal lobe; this is the parietal lobe; this is the temporal lobe; and this is the occipital lobe. What surface is this? This is the lateral surface. How about the medial surface? Well, that's the remaining part of the central sulcus. This is called the cingulate sulcus and the cingulate gyrus. This is the parieto-occipital sulcus, and this is the Corpus callosum, which connects the right cerebral hemisphere to the left cerebral hemisphere. The Corpus callosum has a rostrum, a genu (which means a knee), a body, and a splenium. For the pros out there, did you know that the splenium can help you differentiate between the male brain and the female brain? But that's a story for another time.
Let's move my arm; let's feel whatever is touching my fingertips. Let me move my eyes; let me see; let me see; let me hear; let me understand; and let me talk. Then there is something called the homunculus. So we're going to suppose that from here to here, that's about your medial aspect of the cerebral cortex, and this is the lateral aspect of the cerebral cortex. So this is the representation of the homunculus: your toes, then your foot, then your leg, then your thigh, then the abdomen, the back, the shoulder, the arm, the forearm, the hand, the fingers, the head, and the lips. And it looks like this: here's the lateral aspect; here's the medial aspect. Your upper extremity and your head are more lateral, whereas your bladder and your lower extremities are more medial. By the way, the genitalia are represented close to the feet, and that's why, for some people, rubbing their feet can turn them on, if you know what I'm saying.
What is the diencephalon? It's anything that has the word "thalamus" in the name, including thalamus, epithalamus, hypothalamus, subthalamus, and metathalamus. Metathalamus is part of the thalamus. What does the thalamus do? The thalamus is the secretary of sensations, and who's the boss? The boss of sensations is the primary somatosensory cortex. So if you are a sensation, let's say coming from my fingertips and trying to reach the brain first, you'll have to pass by the secretary, which is the thalamus, and then after you reach the secretary, you will go to the primary somatosensory cortex—the secretary first, then the boss. How many thalami do you have? The answer is two: you have two thalami, one on the right and one on the left. But how many hypothalami do you have? The answer is one, in the midline. The hypothalamus is related to the mammillary body for memory, to the optic chiasm for vision, and to the pituitary gland for secretions. #endocrine system. To learn more about the endocrine system, please refer to my biology playlist and my physiology playlist. I have the best endocrine physiology videos on the face of the planet. To learn more about the thalamus, I have a special video called "Thalamus," which you can find in this psychology playlist. But how about the hypothalamus? The hypothalamus has many functions, including endocrine functions. The hypothalamus is the CEO; the anterior pituitary is the general manager; and then we have the employees that have to listen to the manager. These employees include the adrenal cortex, the thyroid gland, and the gonads. To learn more about all of this, please refer to my physiology playlist. The hypothalamus also makes ADH and oxytocin. ADH, or antidiuretic hormone, reabsorbs water in the kidney to prevent the water from being lost in the urine. Oxytocin has many functions, including milk let-down from the breast, contraction of the uterus during labor or during coitus. The hypothalamus has another function, which is it has the feeding center and the satiety center. The feeding center wants me to eat; the satiety center wants me to stop eating. If I have damage to the feeding center of my hypothalamus, what's going to happen? I will stop feeding, and I will become anorexic. But what if I have an injury in the satiety center in the hypothalamus? I will never be satiated; I'll keep eating and eating and eating until I become morbidly obese. You can learn more about all of these functions in my video on the hypothalamus, which you can find in this psychology playlist as well as in my neuroanatomy playlist.
Basal ganglia: What are the functions of the basal ganglia? Again, the basal ganglia is the co-pilot for movement. The basal ganglia helps with movement. The basal ganglia has a very important neurotransmitter known as dopamine. Dopamine has many functions in the brain, depending on the location, but dopamine in the nigrostriatal pathway helps with movement, and that's why if I have a disease in the basal ganglia, such as Parkinson's disease, I will have a movement disorder. Symptoms include rigidity, tremors, postural instability, gait problems, and mask-like face with no muscle contractions in the facial muscles. To learn more about the different functions of dopamine, I have a special video titled "Dopamine," which you can find in this psychology playlist. To learn about anti-epileptics, antidepressants, antipsychotics, and antiparkinsonian medications, download my neuropharmacology course at medicosisperfect.com. And don't forget to take a look at my other playlists as well. If you value what I do, help me make more videos by supporting the channel. Go to buymeacoffee.com/medicosis. There are more than 600 premium videos available on this channel when you click the join button and choose the highest tier. Please subscribe, hit the bell, smash like, support my channel on Patreon, PayPal, or Venmo. Go to my website to download my courses, notes, and cases, or if you would like me to personally tutor you. Be safe, stay happy, study hard. This is Medicosis Perfectis, where medicine, chemistry, math, and physics make perfect sense.