- [Instructor] Alrighty, so we're talking about cartilage,
and cartilage is, at the most basic level,
a connective tissue that can be found
throughout the entire human body.
And so cartilage is an extracellular tissue
secreted by cells called chondrocytes,
which are derived from the same precursor cells as bone,
the fibroblast.
Now chondrocytes secrete fibrous materials
such as collagen, which is a strong fibrous protein,
and elastin, which as it's name sort of sounds like,
is an elastic protein that provides
a rubbery, elastic component to cartilage.
And one thing that I just wanted to touch on briefly
is something that I personally sort of struggled with
for a little while before I realized,
ah that's what it is.
So cartilage basically is, as I said,
a connective tissue, just like bone,
just like fat and other connective tissues
that you find in the body.
Collagen, on the other hand,
is one of the building blocks of cartilage.
So, I feel like sometimes it was easy for me
to confuse these two terms,
but realize that cartilage is actually referring
to the type of tissue and collagen is referring
to the type of protein that is found in cartilage.
Now the key thing to remember about collagen and elastin,
that make up cartilage,
is that it gives cartilage strength and flexibility.
And a couple of other key points to remember
about cartilage is that it is not innervated,
meaning it doesn't have nerve cells,
and it is also avascular,
meaning it doesn't have any vasculature
that runs through it.
In other words, it doesn't have
arteries and veins and blood vessels that run through.
Instead, cartilage receives nutrition
and immune protection from the surrounding fluid.
So, there are three main types of cartilage
found within the body.
The first type is called hyaline cartilage.
So, you can find hyaline cartilage
in the larynx and trachea in the throat portion of the body,
and then also in all of the joints
where the surfaces of bones are articulating each other.
So this is called articular cartilage.
And, the main purpose of hyaline cartilage
is to reduce friction and absorb shock.
The second type of cartilage
that you will find in the human body
is called elastic cartilage,
which can be found in the shape of the outer ear,
and also the epiglottis which is the structure
that protects your airway whenever you are swallowing food.
And so the main purpose of elastic cartilage
is to provide shape and support.
And then finally we have fibrous cartilage.
And you can find fibrous cartilage
in the intervertebral discs in the spine
and also in an area of the pelvis
called the pubic symphysis
which is where the two halves of your pelvic bones
come together to form a joint there.
And the main purpose of fibrous cartilage
is to provide rigidity and to absorb the shock
that is transmitted between these joints.