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Course: Health and medicine > Unit 7
Lesson 3: Diabetes- What is diabetes mellitus?
- What is diabetes mellitus?
- Breaking down diabetes
- Types of diabetes
- Pathophysiology - Type I diabetes
- Pathophysiology - Type II diabetes
- Diagnosing diabetes
- Treating type I diabetes
- Treating type II diabetes - Pharmacology
- Treating type II diabetes - A practical approach
- Acute complications of diabetes - Diabetic ketoacidosis
- Acute complications of diabetes - Hyperosmolar hyperglycemic nonketotic state
- Diabetic nephropathy - Mechanisms
- Diabetic nephropathy - Clinical presentation & treatment
- Diabetic retinopathy
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Breaking down diabetes
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These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video. Created by Matthew McPheeters.
Want to join the conversation?
- how does glucose help your muscles?(4 votes)
- Glucose is a form of sugar that gives your muscles energy to work and be used.(3 votes)
- High blood sugar is called hyperglycemia so what is low blood sugar called ?(2 votes)
- Hypoglycemia. Most diabetics (that I know) just call it "low blood sugar," though.(2 votes)
- What's the difference between diabetes mellitus and diabetes insipidus?(2 votes)
- Diabetes mellitus causes polyuria due to a problem with a lack of insulin or the function of insulin. Diabetes insipidus causes polyuria due to a lack of the hormone, ADH. Both problems cause excess urination.(4 votes)
- if you were to not have any glucose in your body and the glucose level was to low and there was no stored glucose in your pancreas then what would happen
thanks for the help(2 votes)- The body would break down amino acids to make glucose. And the body would also break down fats to make energy. The person would create keto acids causing a metabolic acidosis. The person could be starving or on the Adkins diet, which limits carbohydrates.(3 votes)
- how can glucagon abnormality cause symptoms of diabetes mallitus?(2 votes)
- By my comprehension, glucagon increases blood sugar by having the liver release it. If your body uses too much glucagon, it can result in hyperglycemia or high blood sugar. If your body uses too less, it results in hypoglycemia or low blood sugar because not as much glucose is being released from the liver. In a way, let's say you were a normal person who just checked their blood sugar because they felt drowsy or hyper and they had one of these. You should get either checked for diabetes mellitus or check the glucagon being released. With the hyperglycemia, it is more possible that you may be diabetic or that you need to get it to where your pancreas doesn't secrete too much glucagon. With the hypoglycemia, I'd suggest eating something or taking a glucagon pill or injection. But all in all, glucagon abnormality is something that shouldn't happen unless you tricked your body bad enough.
Mr. Vandiscoman
P.S. If this seems spammy or off-topic, tell me and I'll delete it.(2 votes)
- How does glucose make you stronger?(2 votes)
- Your body's cells convert glucose (sugar) to energy to fuel you. Sugar allows your cells to function.(2 votes)
- hold on! if hyperglycemia causes fatigue then how on earth can you be alright in the case of Bruce if he too has a lack of insulin(2 votes)
- He doesn't have a lack , his cells aren't exactly very sensitive to the insulin.
So glucose does go into the cells, hes not getting any symptoms much.(2 votes)
- At2:06, Matthew says glucose can't actually enter the cells. Why can't they do so without insulin?(2 votes)
- Insulin is the chemical signal that allows the cells to place the glucose transporters, protein helpers, into the plasma membrane. The cells have these proteins inside a vesicle inside the cell. By the way, why questions are impossible to answer in some ways. We can often answer 'what has been observed' but 'why' often gets answered as 'because that is the way it is'. Your questions are entering into the area that is under research and /or is at a graduate level of biology. I suggest you look at Wikipedia, which may not be perfect because anyone can edit it, but it is a place to start until you find a physiology book you like. https://en.m.wikipedia.org/wiki/Glucose_uptake(2 votes)
- At3:18, Matthew says Glucagon stimulates the liver to release the glucose stored. Then, what's the point of storing all the glucose and releasing it back again from the liver?(2 votes)
- Glucose levels are normally around 100mg per dl in the blood. Your cells need glucose so they can make ATP even when you are sleeping. The liver stores glucose so the cells that need it while you are sleeping can get it. Different cells have different requirements at different times of the day, so the liver serves as the storage depot with about 24 hours worth of glycogen.(2 votes)
- What mechanism allows the pancreas to sense the glucose build up in the blood? Does pancreas have receptor cells for this function or is there pressure or pH changes in the blood which the pancreas senses and releases insulin?(2 votes)
Video transcript
- Diabetes mellitus is a
syndrome that's caused by improper function of
insulin, and, as a result, there's disregulation of
the blood sugar levels. This results in high blood sugar, which is also known as hyperglycemia, but what exactly does this all mean? To get a better idea, let's
first go over the body's normal regulation of blood sugar. To do that, I'm gonna just
bring in a diagram here. In this diagram, you'll
see up here, you have the esophagus, that goes
into the stomach and into the beginning
portion of the intestines. Then, here in pink,
represents a blood vessel. In yellow here, is the pancreas. There are three major types of nutrients that your body uses for energy. There's fat, protein, and carbohydrates. We're gonna be focusing on carbohydrates. I'm gonna just abbreviate that CHO, which stands for carbon,
hydrogen, and oxygen, which is the chemical
makeup of carbohydrates. The carbohydrates that we
eat go through our esophagus and into our stomach and
they start to get digested. As they enter into the intestines, they're digested down into glucose. Glucose is a simple sugar, and it's very important
in the body because cells throughout the body
use glucose as energy. Glucose, like I said, is a
type of sugar, so, sometimes, people will refer to it
as blood sugar levels, and what they are referring to are the level of glucose in the blood. This glucose is absorbed
through the GI tract into the blood vessels here. Once it's in the blood, it then travels to the cells of the body,
such as muscle cells, where it can be used for energy, or the glucose in the blood
can travel to the liver, where it is stored to be
used as energy in the future, so let's see this happen. This is where the role of the
pancreas becomes important because glucose, on its own, is not able to actually enter the cells, like muscle cells, or into the liver. Without the pancreas,
glucose would just become piled up in the blood. Luckily, the pancreas here
can sense this pileup, or this increase in the blood sugar, and it releases a
hormone known as insulin. When the pancreas releases this insulin, it kinda acts like a key that unlocks the cells of the body,
such as the muscle cells and the liver, allowing the
glucose to enter the cells, so, in the case of the muscle cells, those cells can now start to do work. In the case of the liver,
the glucose can be stored. However, if this just kept going and insulin wasn't kept in check, what would happen, over time,
and as you can see here, is that that blood glucose
level would get too low. Fortunately, the pancreas can also sense when these blood glucose
levels are getting too low and it stops secreting insulin, and it starts to secrete another hormone, known as glucagon. What glucagon does is
it stimulates the liver to release this stored
glucose back into the blood to replenish the blood glucose levels, and, eventually, the blood
glucose levels return to normal. Let me draw a diagram
here to help you remember how our bodies maintain
the blood glucose levels. You can think of the maintenance
of the blood glucose level as being a balance between insulin, and if the balance is tipped in the direction of insulin
here, it will result in the unlocking of cells. It will also allow the
liver to store the glucose, then both of these things result in a lowering of the blood glucose level. Then, as this gets too
far, the pancreas reacts, and it then has glucagon
to shift the balance, by causing the release
of that stored glucose, which results in a raising
of the blood glucose level. Now that we have an
understanding of how the body normally regulates blood glucose levels with insulin and glucagon, what exactly is going
on in diabetes mellitus? Well, I mentioned at the
beginning that diabetes mellitus is a syndrome that's caused by improper functioning of
insulin, and in a sense, the insulin just doesn't work. This may be due to many
different underlying causes, such as the pancreas here not being able to produce the insulin, the pancreas just may be
producing too little insulin, or, for some reason, the
cells may not be receptive to the insulin, in a sense
that that key mechanism doesn't unlock the cells to
allow the glucose to get in. Regardless of the underlying
mechanism, though, when you don't have insulin here to balance out the blood glucose levels, this balance is gonna be tipped
in the favor of glucagon. As such, what's gonna happen is these effects of glucagon here, are going to become more predominant, so what you see in diabetes mellitus, one of the characteristic findings is that there's going to be hyperglycemia. This is because the glucagon is causing the glucose from the liver to be released, and since insulin isn't
functioning properly, this key effect here, also isn't working, so the cells aren't able
to get all of this glucose that is in the blood, so despite having all of this energy present in the blood, the cells aren't able to use it, so someone with diabetes is, oftentimes, very fatigued or tired. That's because they're not able to extract the energy from the blood. Lastly, the body tries to compensate for this increased
concentration of glucose here in the blood, and what
it tries to do is it tries to dilute the blood with water from cells. What happens is that all
this water leaves the cells, and the person becomes dehydrated, so, frequently, someone with
diabetes will be dehydrated and very thirsty. Diabetes mellitus is a syndrome that's caused by dysfunctional
insulin or a lack of insulin, resulting in an inability
of the body to maintain its normal blood sugar
balance, and you get this hyperglycemia here. Then, over time, actually,
this persistent hyperglycemia can actually cause damage to many vital organs in the body, such as the nerves, eyes, and kidneys.