00:01
Today we will have a look at the motor unit.
00:05
This image illustrates what motor unit looks like.
00:08
They are the basic functional units of skeletal muscle.
00:11
Each muscle is composed of a large number of muscle cells.
00:15
In mammals, each muscle cell receives only one synapse.
00:20
I have written it down because it is a very important point.
00:23
In mammals, each muscle cell receives only one synapse.
00:26
The motor unit, now we're defining it, is one motor neuron and all of the muscle cell is a innervates and don't be confused by the word innovates it just means supplying neurons sometimes a motor neuron will innervate only one muscle cell and sometimes many as we can see here there's one motor neuron and one muscle fiber and there's multiple motor neurons and many muscle fibers but as we can notice here that each each modern neuron is going to one one muscle fiber.
01:27
And this brings us back to the main important point that i mentioned over here.
01:31
Each muscle cell receives only one synapse.
01:34
Now moving on to the three types of modern units.
01:38
There's the slow twitch oxidative, fast oxidative glycolytic, and fast twitch glycolatic.
01:47
Fast twitch oxidative is a slow fatigue resistant tissue.
01:53
It builds small amount of tension slowly, increases cross -bridge formation between myazine inactive, if you remember from before, very slowly, and holds the tension for a very long time.
02:05
So again, it builds tension slowly, but it can hold it for a very long time due to high oxygen supply.
02:12
They're capable of generating tension for long periods of time without burning down energy stores.
02:17
This is why they have large number of mitochondria.
02:21
They're very small fibers and they're well vascularized.
02:24
That means they have a high level of blood vessels...