- So to continue our discussion of appendages
I'll come to this palm side right here
and so I'll draw this little water droplet
to indicate this person has a very sweaty palm
and the reason why it's so sweaty
is because this guy has a lot of sweat glands
so a lot of sweat glands that are on his palm
or maybe elsewhere in his body.
And as I mentioned in an earlier video
our glands are situated in the reticular dermis.
They're in the reticular dermis
and they have ducts that lead out
into the external environment
to help coat our skin with their secretions.
And now we have three types of glands
that exist in our skin.
They are called the holocrine gland.
There's the apocrine gland
and finally the merocrine gland.
So I'll kind of compare and contrast them here
The first thing to realize is
that the way we name these types of glands
indicate how they release their secretions.
The holocrine gland releases its secretions
by disintegrating the whole cell
So the entire cell breaks down
to release what's called sebum,
sebum,
and so another name for holocrine glands
are sebaceous glands
sebaceous because they release sebum.
Now apocrine glands release secretions
from the apex of the cell
or the top of the cell breaks off
So the top of your cell breaks off
to release a mixture of proteins, lipids, and steroids
so proteins, lipids, and steroids
so a whole bunch of things right here
And finally merocrine secretion
or merocrine glands
release their secretions
which is mostly the watery sweat we think of
these are the main sweat glands we talk about
they release watery sweat
by a process you may be familiar with
it's called exocytosis.
That's the budding off of the cell membrane
with contents from inside the cell
which in this case would just be watery salty contents
that would be sweat.
Now it's got a little more room right here
and talk about where
each of these types of sweat glands are found.
Holocrine sweat glands are found on
the face, the chest, and the back,
the face, the chest, and the back.
It looks like I didn't write it here
but I want to make sure you know that
sebum is mostly an oily substance
so it's more lipid concentrated
than say something you're apocrine secretions
so it's very oily
and now your apocrine glands are mostly concentrated
in your armpits, the groin, and around the nipples
the armpits, the groin, and around the nipples
and the main thing here that's unique
about the apocrine sweat glands
is that they release their contents into the hair follicle
so they release their contents into the hair follicle
which is unique from the other types of sweat glands
we're talking about
and then finally our merocrine glands
which are our bread and butter sweat glands,
are found literally everywhere else
everywhere else in the body
and they're mostly concentrated
in our palms of our hands like with this guy up here.
palms in our hands and even the sols of our feet
our palms and our soles
and then finally what are the functions
of these three types of glands.
Well for our holocrine or our sebaceous glands
this oily or lipid-rich sebum
is meant to lubricate the skin
so it lubricates our skin
and in doing so that also slows bacterial growth
so it slows bacterial growth
by making it difficult for bacteria
to move around and divide.
So slows bacteria growth.
Now for apocrine glands
the interesting thing about them
is that they even don't really begin to release secretions
until after puberty hits.
until after puberty
and the reason why
could be better understood when we talk about animals
because apocrine glands in animals
release things like pheromones and warning signals
and even territorial marking signs
that we don't really practice as human beings.
So the interesting thing about apocrine glands
is that they're involved in what's called
emotional sweating
and they're an ongoing topic of research
emotional sweating meaning that these glands
are most active during times of great anxiety
stress, fear, and even pain.
And finally our merocrine glands are
actually I'd say our most important glands
because they help us cool down
through evaporative cooling
we talk about that in a separate video
so they help us cool down with our sweat.
They help us eliminate waste products as well.
so any extra nitrogenous waste products that we might have
or water or electrolytes we don't need
we release through our merocrine glands in our sweat
and finally merocrine glands also release things like
lysozymes
lysozymes which are enzymes that will lyse bacteria
and even antibodies
which are immunologic proteins
so antibodies that will help tag bacteria
and other foreign pathogens or bad stuff
that could cause damage to our skin and our bodies
tag these things for elimination.
So your sweat is far more important
than just cooling you down.
It even helps your livelihood
in addition to all the other things we talked about here
So there's a lot going on
when we talk about our glands
and the rest of the appendages we've appreciated here.