Do today is I'm gonna tell you some details about the format of the exam.
You just exam then I'll go through and review section that I put together based on questions that I got asked. I'll ask you don't ask questions during that period. So I can make it clean.
Morning group, then open it up and you can ask questions, you chat, or you can unmute yourself and ask a question. Okay. So let's first talk about the format of the exam.
Your exam has forty five, multiple choice questions that you'll have thirty five minutes, multiple choice questions are shuffled and they appear one at a time and they lock after you answer the question.
This is to prevent people. If you happened to be communicating with someone else, while you were taking an exam, you wouldn't be able to help each other because you would only you'd each have one question in front of you. And it would be a different question.
This again is to make it an independent exam, they do lock after you answer it, so you can't go back. So, do your best giving your best guess forty five multiple choice questions thirty five minutes for this section.
Those questions will open up ten, ten, and we'll close at about ten fifty. Once you start the timer starts with those thirty five minutes.
You will then download the short answer document and I'll go onto canvas. I'll show you where all that is. And you will have it should only take you about ten minutes for two short answer questions. I believe. I have it open from ten, thirty five to ten, fifty five.
So, assuming you use your thirty five minutes you would have ten minutes, but if you finish early, you have a little bit earlier starting. You could take for the short answer questions and I'll show you on campus all.
That is the idea behind the exam. Is that I'm not gonna make you pay for proctoring or online? Proctoring person brokering is no longer a thing but online proctoring cost money.
I'm not gonna make you do that so instead I made it, I made the exams so that I'm assuming you're gonna study like, you normally would, and you're not going to use any resources we take the test. So, you're just going to open up your laptop or tablet.
Take the exam without any notes in front of you without Googling things about working together. So it'll be a normal independent exam when you submit the short answer questions. I put them through their site, which is a plagiarism detection software.
That will tell me if you copy and paste anything, I'm going to assume.
You are, you will not you will take it from your brain. Okay. Let me show you where all this stuff is on this.
So, if you your canvas page against your homepage, scroll down a reminder, the muscle worksheet is due in forty five minutes. You should do that. You'll also put up this review session right here.
Okay. You go to assignments. You will see me up again that muscle work. She did at eleven, answering this muscle questions you can at midnight.
This will be available starting at ten, ten click on this.
Currently locked, I opened it at ten, five, ten, five. You can answer that. You'll do that for thirty five minutes. Then you'll come here. You'll do your short answer, walked into ten, thirty five. You will answer that.
That one again do a ten, fifty five. That's gonna be your test. The other thing I want you to to bring your attention to a quizzes tab.
I put up a technology survey that just gonna tell me have you been able to use WebEx? Is it helpful?
Have you not been able to hear because WebEx has not been helpful I mean, you just look at YouTube I just wanna get a better idea of where everyone is. Okay. So that is gonna be how we do that. Okay.
With that being said, are there any questions about the format of the exam? So please put them in the chat.
But that being said, I'm gonna now switch gears and do a short review set to spend a day, a short review session. Okay. Let's share content.
Okay, our point here and again, this I posted so your exam covers chapters, five and six bones and muscles. Are you going to post this recording? Yes.
I will,
I will post is recording to a fun thing is happening from the instructor and WebEx when we do the WebEx recordings,
they go onto the WebEx com server system.
And then when I first started doing this, like, last week, when I was practicing, and on Monday, I was able to download the videos within about ten minutes after class ended and posted to YouTube.
Yesterday the video or the video, Wednesday afternoons, video, talk about twenty hours to do that as opposed to ten minutes. So I may not be able to post it.
Like, immediately I will post as soon as I can. Yeah, I will. I'll post as soon as I can. Okay. Let's talk about the review session. Bones and muscles.
I'm gonna go just based on the question I have. And then I'll open it up for questions at the end.
So, I got the majority of the questions in the thing that most you want to talk about with muscle contraction and there were a variety of different questions that I think all go under this umbrella of muscle cell contraction. How does a muscle cell contract? How does a muscle fiber contract?
Remember cells and fibers are synonyms. How to motor neurons? Signal muscle cells? Why are the bands of the sarcomere important? Why is the sarcomere important? How do we label the sarcomere?
What does the or or or calcium do.
In muscle contraction, so I'm going to hopefully answer all of those questions here first.
So keep in mind skeletal muscle is Sal is also called the skeletal muscle fiber those are center, and it contains plasma membrane that we call a sarcolemma.
The cell has in it, a few key things. The major thing you would notice if you were to look under a microscope at skeletal muscle cell, is that it's filled with Cisco.
We also call those site skeletons, elements, mile filaments.
And what you would see is that they alternate, dark and light bands, they look striated or striped, and the dark bands we call a bands and the light bands we call as we know because we now understand structure from here.
Dark bands are dark, because they're full of mice and they film, it makes the a band start and the light bands are light because that's where you only see the light bands are white because that's where you only see active.
My five roles are made of contract units called sarcomeres. Why? The second is important they are, what does the contraction of the muscle?
So they are, what contracts and what mean back contraction is when the filaments will slide past each other and the two will come together. So, sarcomere is measured Z disc.
It has a van in the middle,
and again,
those islands in the middle of the whole thing we call the H zone and there's an empty area called the M line where you won't find any,
as soon as the middle actin is anchored to our mass shown here again,
then filaments are actin filaments anchored to the at rest and the muscles not contracting.
There is no acting in that zone. At the middle of the sarcomere. The thick filaments are myosin there. What do the action of muscle contraction.
Inadvertently right. Okay at some point, make sure you can draw a circle here. Now, let's talk about how the muscle contracts keep in mind our vocab words excitable, contractual, extensible in the last muscles need to be stimulated.
By skeletal muscles are voluntary.
So,
they need a signal from your brain that says,
hey,
tracked tracked by our motor neurons one motor non,
stimulate several muscle cells and we call it a motor unit and they meet an Eric called the neural muscular junction where the motor neuron will release a into the gap what we call the synaptic cleft and will
bind to that muscle cell.
The motor neurons come from the spinal cord, come from the spinal cord, and they go and they innervate make junctions with all of our skeletal muscles.
We're gonna release a cedar calling to see to calling again, is that chemical?
We caught a neurotransmitter and they release it into the synaptic cleft, you know, calling is released because of a signal that comes down the motor neurons, the motor, and we'll get a signal from the brain down the spinal cord.
That signal will cause calcium to fill the motor.
The calcium is what tells and wandering around hey, about your Colleen and it will it will dump into the synaptic cleft and that a, will bind to the muscle cell plasma membrane.
What this does is it opens up a CAD ion channel can ion remember means a positively charged, catch a positive, positive things in your life and there are two flavors of CAD ions here that we're gonna look at. First is sodium.
Sodium is our sprinter, the sodium is going to rush into the South fast. This means the cell has a positive charge.
Now we call this change and electrical potential this change in electrical signal a depolarization. So that Russia positive charge the depolarization. It's followed by potassium potassium.
Is our tortoise it's a little slower and it will eventually leave our muscle. So creating this wave a positive coming in and positive.
Positive going out. Okay. If this moves down our muscle fiber, that isn't action potential.
So the acetal calming binds to a Caroline and channels sodium rushes in making this up positively charged potassium Ilium meaning negatively charged. This is the depolarization.
How does an end? acetal calling is broken down. It's broken down by an enzyme called. We. Abbreviate. Ach.
E,
this will end our contraction and that positively charged way that depolarization will spread,
like,
fire on a tweak down or muscle fiber on our muscle fiber all this,
an action potential flow of depolarization.
Hello of decolorization. Okay. What is the muscle cell do in response? So the muscle cell is going to contract the sarcomere specifically. sarcomere is going to contract.
And how it contracts is, the myosin will reach up and it will grab the actin and it will pull it to the center. We call this a sliding filament model because none of the fibers are gonna be destroyed or created.
They're just going to slide past each other. They're going to take a plus space.
This sliding requires calcium calcium comes from an area and the cell called the sarcoplasmic Reticulum, which is just a store of calcium.
So, the calcium is required, because the myosin at rest is blocked touching the app and it wants to it wants to grab the action. But it cannot.
And when calcium comes, that releases the block and allows the myosin to grab the actin, and it uses to do this. So the mixing needs two things it needs calcium and it needs in order to contract.
Okay.
So,
if we put it all together,
put it all together,
we have a cedar calling being released from our motor neurons calling will bind to the circle will open up a Caroline channel sodium,
rushing to the cell chassis and will slowly leave,
creating a wave of positive charge called depolarization a depolarization will move down the muscle fiber as an action potential and the action potential opens up the calcium stores from the sarcoplasmic.
Reticulum calcium is still our muscle cell and that calcium will release the block that is on actin and allow myosin to grab up and pull action to the middle actin.
And myosin will use as the energy source for this. And it will keep going until a signal.
Is stopped by acetylcholinesterase breaking down acetylcholine, or the muscle runs out of which we'll talk about in a little bit muscle can run out of ATV.
A lot of other people wanted to know about you blasts and Nancy a class or other questions about bone growth, bone remodeling, the function of muscles and bones all that I'm gonna put together here.
So,
ossification is the process by which we replace cartilage with bone as an embryo and as a fetus,
all of our skeletal system is present first as cartilage and cartilage needs to be replaced by bone and the cells that do this are last.
So, the osteoblasts are gonna cover the cartilage with the bony Matrix, and it will dissolve and digest that hyaline cartilage, leaving the bone behind. So, we then are replacing the cartilage with bone at birth. Almost all.
This is complete, except for a few key areas. You have those functionals in the skull that allow the child's head to be kinda mushy. So, if it fits through the birth canal, and we also have our or our growth points, which are present in our long bones.
Bones grow length wise from those growth plates. The cartilage is added to the top and then on the bottom the distill in the cartilage is replaced by bone again by those blast speed for building cells.
Those are builders they add bone.
Bone remodeling is where the bone changes shape in response to something, whether that is muscle activity or hormones. Okay.
While modeling is when that muscle that bone will change shape and to do this, the bone is gonna be reabsorbed or destroyed in some areas by our osteoclasts.
With the or chaos cells, and it will be added to other areas by the osteoblasts or builder ourselves.
Again, bone remodeling, the blasts are gonna add bone. The class are gonna destroy bone. If we had an increase in this conference in the width of our bones, we call it appositional growth. And this whole process is controlled by growth hormones.
What when would we need to do this?
So, if calcium in the blood is low, your body does not care about your bones, your body thinks in the short term and so your body needs to maintain homeostasis of blood, calcium set point a happy medium for blood calcium.
So, blood calcium is low. The parathyroid is gonna release parathyroid hormone, which is going to stimulate those destroying cells and osteoclasts, and it will take calcium away from the bones and put it in the bloodstream. So that blood calcium is back to normal.
Phones can also increase insights and this is where muscles come in. So we've talked about with muscles we learned about origins and insertions right landmarks on the bone.
We're the muscles attach those areas exert a lot of force. So the muscles going to exert force on the bone and the bone willing to get stronger and thicker to deal with that increase for.
So, if you're working out your deltoid muscles, you're working on your deltoid muscles. You're doing some of those abduction and adduction exercises right?
You're increasing the force of the deltoid that's going to add force onto your humorous insertion of the deltoid. And so the humerus is gonna want to add bone to try to deal with that increase of force.
And so we'd like to think that calcium tells us when we need to have bone remodeling. If calcium is low bones going to be destroyed calcium is high, we're gonna add to our bony matrix and the muscles tell us where the muscles say.
Hey, we got a lot of calcium in the blood put them over here. I'm bringing that extra calcium and put it here because this person every day is arm day and so the humerus needs more calcium. Okay.
People ask about how his were generated, there are three ways, are generated muscles need to contract. However, there's only enough stored in our muscles for a few seconds of contraction.
And so we have to make more we have to turn identity dye phosphate with the D into identity and try phosphate tea after we use it up.
First, we can regenerated directly, so our muscles can use something called create team, creatine, phosphate, phosphate group. It's stored in our muscles. We can take the phosphate from creatine phosphate and add it to a diagnostic making it a try.
We make one every creatine phosphate molecule. We don't need to use oxygen, but the issue is that store creating phosphates still goes fast even if we're taking a bunch of supplements.
So it's only going to give you fifteen seconds of energy approximately you can also make without oxygen without oxygen.
This is called anaerobic respiration you can take glucose and make two molecules issue with this, is that you're gonna build up lactic acid. It's causes muscle soreness and we use a lot of glucose for not a lot of return.
The best way is to make in our mitochondria, using aerobic respiration, uses oxygen. We get thirty two for every glucose, and we can go hours and hours out promoting muscle says how we regenerate.
If you ever want to know about the pelvic girdle was function has a different males and females. The pelvic girdle is made of a few different bones.
The main of are two coxal bones or hip bones as well as our sacred do not confuse the coxal.
And the coccyx bones,
the capsule bones are this,
the anatomical term for our hipbones,
whereas the toxic bone that is our tailbone center,
but these are large,
heavy bones are attached via ligaments and they have deep sockets for five bones for the femur to articulate the function of our pelvis is to bear weight.
These are big, strong bones, because they hold a lot of weight and for females especially these are gonna protect some very delicate reproductive organs. They're made of a fusion of three bones Ilium, ischium and pubis some key things.
You need to know you need to know what the iliac crest that comes down to our iliac spine. That's where you can feel when you put your hands on your hips. The issue is, what is our sit phone?
We have a tuberosity that holds the weight more sitting down and the spine helps form. The narrowest spot in the hips for childbirth is the deep socket for our.
When we talk about measurement, we can measure week two weighing all pelvis. We can also measure the inlet true pelvis. And for comparing males versus females you just wanna think about childbirth. The female coxal bone.
The female pelvis is designed for childbirth. So this means that the Ilya are more laterally flared to create more space. There's a larger more circular, pelvic inlet. There's a shorter sacral.
The whole thing is around, or it has a larger pubic arch to create more space for childbirth whereas with males the opposite, right? There are more vertically flared.
They have a longer sacral they're less round and their pubic arch is smaller. They have a smaller true pelvis.
People want a muscle tetanus so with muscle contraction, the muscle cell, the individual. So either contract or not. But the whole muscle can have a creative response.
So, strength is related to the number of muscle cells that are contracted and the characterization of that muscle contraction depends on the stimulation.
So, if we just get one motor neuron firing onto a muscle cell, that's gonna create a muscle Twitch, severance habit island twitches.
Right. You can feel that little bit that little bit of contraction. Okay the muscle needs to contract in a complete way.
So a complete a smooth movement, we call that a fuse complete tendance a smooth movement. And that occurs when the motor neurons aspiring rapidly on the muscle.
If the motor not is not firing rapidly, either because of damage or some sort of injury is usually the case. That's where we can get that is usually visualize by tremors.
So if you look at Parkinson's patients, for example, they have a resting tremor, their hands are shaking that's caused by abnormal firing from the motor. So you want the motor to fire very, very quickly upon the muscle to give us that fuse complete ten minutes.
Increased frequency will lead to a smooth contraction and again, force comes from the number of.
People who last motor muscle disorders muscular dystrophy again this is the inherited muscle.
Destroying one is the one I talked about there are multiple times, but is diagnosed in early childhood ages, two to seven, usually fatal, but the person or persons in their twenties or thirties, because the sarcomere itself starts to fall apart.
Whereas miscellaneous Gravis is diagnosed. Onset is in adults and also fatal, but this is from a destruction of receptors. So in muscular dystrophy, the sarcomere itself is falling apart. The muscle can't contract.
And in miscellaneous Gravis the muscle is fine. It's just that it's not receiving input for the motor. Because it doesn't have working acetal calling receptors.
Aging muscle atrophy associated aging we call sarcopenia circle meeting muscle again. This is where we see a decrease in muscle mass, a decrease in overall body, mass decrease strength. But this is reversible.
So you can maintain and rebuild your strength. The majority of your strength. If you maintain your exercise programs, so again, muscles use it or lose it.
I want to know about synovial joints,
synovial joints again,
you want to think of examples so we have planed joints these are in the inner carpals or risks they spread your hands these are a sliding or gliding motion non Axio.
We have a hinge joint. The classical example here is the elbow. It's a uniaxial joint move a one direction.
Have a joint pivot join is also uniaxial of this think of the pronation supination that we see at our road radio owner joint, right?
So our arm bones can move and that wrote in that pivoting motion around each other for pronation supination because of that pivot joint.
We think of our nipples of our fingers,
these are by axial so they can move back and forth and side to side,
but they can't make a full circle and this is similar to our saddle joints,
but saddens can be the bigger circles and fingers versus the saddle joint is the carpal metacarpal trainer with them when you get close to a full circle because of that saddle joint.
And finally, we have a multi axial joint is their ball and socket or shoulders and our hips. They have a wide range of motions.
Okay, so that is the end of slide show that I hired for you guys on.
Are there any questions people have.
I'm gonna stop the recording classes now actually.
