Myology - Skeletal Muscle (Structure)

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for better graphics in this video we're

going to talk about skeletal muscle just

an overview sort of thing and so a

skeletal muscle cell as I mentioned in

previous in introduction video is

cylindrical shaped and multinucleated

and a skeletal muscle cell is known as a

muscle fiber and interestingly enough

skeletal muscle cell the fibers are

striated by a highly organized internal

arrangement so this muscle fiber has an

internal arrangement so if we pull one

of pull some things out from this muscle

fiber we we can find myofibrils so

muscle fiber contains many myofibrils

and if we take a portion of this

myofibril we can see that it's made out

of some interesting structures known as

the thin and thick filaments so the

myofibrils contain thick and thin

filaments the red is a thick and the

Blues of thin filaments but of course

muscle the muscle fiber the muscle cell

is actually part of a bigger um

organized structure so if we look at

this bone and a skeletal muscle which

attaches on it and we cut a

cross-section and skeletal muscle we

have the muscle the organ and so this is

what the muscle looks like as an organ

and the muscle contains if we look at

the cross section different portions of

the muscles and we'll look into this

soon but the muscle contains a outer

connective tissue layer known as the AP

Museum and how it pronounced that right

and so we take one of these portions of

the muscle here the portion of the

muscle is known as a fascicle and the

fascicle also contains other internal

structures and the outer sort of

connective member

tissue is known as a Paramecium and then

if we pull out one of these other

internal structures of this fascicle the

portion of the muscle this is where our

muscle fiber is and the muscle fiber

contains a connective tissue wrapping

around it known as the endomysium and

remember that a muscle fiber is the

muscle cell so this is this and also the

muscle fiber the muscle cell contains a

membrane known as a sacral EMA and again

if we remember if we take one of the the

internal structures of the muscle fiber

fiber we have a myofibril and the

myofibril contains the thin filaments

and the thick filaments so let's just

recap if we start off with a whole

muscle in oregon and we get a portion

under that we get the muscle fascicle

which is the portion of the muscle and

the muscle fascicle contains many muscle

fibers the actual muscle cells and then

again the muscle fiber the muscle cell

contains many internal structures the

myofibrils so muscle fiber muscle fiber

contains many myofibrils which are

specialized internals intracellular

structures and the myofibrils are the

ones that contain thick and thin

filaments also known as the cytoskeleton

elements and so we were concentrate on

the myofibrils the specialized interest

cellular structures of the muscle fiber

and will specifically look at a portion

of the myofibril and a portion of the

modifiable they all contain on the thin

filament here in blue and the thick

filament here in red and an important

terminology to know is a sacrum you and

a sacrum ear runs from one z line to

another z line so from one basically one

thin element of one thin filament z line

to another thin filament z line okay so

if we zoom into this one sacrum ear here

we have the thin filaments made up of

actin and the centre of the sacrum ear

we have what's called the M line and

from the M line on the centre we have

the thick filaments which are made up of

a protein myosin and we have other

internal structures here

orange we will look into later on but

remember sacrum ear runs from one Z disk

or Z line to another Z disk to another Z

line and this is a thin and thick

filament structure a sacrament structure

but let's have a closer look at at one

sacra beer so here we have one Sakura

with the centre being called the M line

here and the sacrum here runs from one Z

disk to another Z disk or Z line to

another Z line here and a second mirror

is a section and extends from one z disc

to the next z disk and the sacrum ear is

a smallest contractile unit of muscle so

you can say and so in a set and when a

sacrum air contracts or when a lot of

sacrum you can tracks this is when our

muscles contract when we move for

example and so again looking over the

anatomy of the sacrum and we have here

the thin filaments which are made up of

a protein called actin and then we have

the thick filaments made up of a protein

called myosin and then these orange

things which connect to the thick and

thin filaments are elastic filaments

known as made up of a protein called

tinton but the most important thing to

know from this structure is that myosin

forms thick filaments and the actin

protein forms thin fluids