00:00:06
all right engineers today what we're
00:00:09
gonna do is we're gonna talk about blood
00:00:10
vessel characteristics so what I want to
00:00:13
do is I want to go over a bunch of
00:00:15
different vessels talk about their their
00:00:18
structure their function a little bit
00:00:20
about their histology what some you know
00:00:22
special characteristics about them so
00:00:24
first thing I want to do is I want to
00:00:25
talk about the different types of
00:00:28
vessels so it's kind of let's go over
00:00:29
them we're gonna kind of label them and
00:00:31
then we're gonna try to hit each one
00:00:32
individually so the first one I want to
00:00:34
talk about within the artery department
00:00:36
is we're gonna talk about our elastic
00:00:41
conducting arteries right so this is the
00:00:47
one that we're going to talk about here
00:00:48
the elastic conducting arteries the
00:00:50
second one I want to talk about is going
00:00:53
to be called the muscular distributing
00:00:59
arteries then I want to talk about the
00:01:06
arterioles and then we're gonna discuss
00:01:10
the different types of capillaries very
00:01:13
briefly we'll go into them in more
00:01:14
detail micro circulation and then we're
00:01:17
gonna talk briefly about venules not too
00:01:20
much again and we're gonna spend more
00:01:22
time on our veins alright so the ones
00:01:26
that we're gonna spend a lot of time on
00:01:28
in this video is elastic the muscular
00:01:31
distributing we'll talk a little bit
00:01:32
about arterioles and we're gonna talk
00:01:34
about a lot about veins alright so first
00:01:37
things first let's talk about elastic
00:01:39
conducting arteries so if we take
00:01:40
elastic conducting arteries these
00:01:42
arteries are usually an example of
00:01:44
larger larger vessels right so for
00:01:47
example let's say I take here's my left
00:01:49
atrium and I got left ventricle then I
00:01:52
got the aorta right for example the
00:01:54
aorta is one of the prime examples of an
00:01:57
elastic conducting artery right and then
00:01:59
obviously think about the branches of
00:02:01
that you got the brachiocephalic which
00:02:03
gives way to the right so then after
00:02:06
that you'll get the right common carotid
00:02:07
in the right subclavian right so even
00:02:09
these guys are gonna be high pressure
00:02:10
systems they're able to take on a lot
00:02:13
and I mean a lot of pressure but if you
00:02:16
think about the aorta the thoracic and
00:02:18
abdominal they brachiocephalic artery
00:02:20
those are gonna be higher pressure
00:02:21
systems that have to be able to stretch
00:02:23
and take on that high amounts of
00:02:25
systolic pressure right so they have to
00:02:27
be able to stretch and then recoil so
00:02:29
elastic conducting arteries are again
00:02:31
good examples of like the aorta
00:02:33
ascending aortic arch thoracic abdominal
00:02:36
and the brachial cephalic right those
00:02:37
are just a couple examples and then if
00:02:39
you think about them they have a pretty
00:02:40
big diameter their diameter ranges at
00:02:43
about 1 to 1.5 centimeters in diameter
00:02:47
right so that's the elastic conducting
00:02:50
arteries the muscular distributing
00:02:51
arteries if you think about it let's see
00:02:54
here I have the aorta let's say we go
00:02:57
down you have the diaphragm here let's
00:02:59
say here's the diaphragm so then we go
00:03:01
down into the abdominal aorta you know
00:03:03
off the abdominal aorta you have a bunch
00:03:05
of different arteries one can come up
00:03:06
give way to the super renal artery one
00:03:09
could be the renal artery and we could
00:03:11
just keep going one could be the gonadal
00:03:13
and you see superior mesenteric so on
00:03:15
and so forth right so this one could go
00:03:17
and supply the adrenal gland this one
00:03:19
can go and supply the kidney but they're
00:03:21
basically arteries that are delivering
00:03:23
blood to a specific organ right so these
00:03:26
ones right here that are taking blood
00:03:27
and delivering it to the tissues these
00:03:30
ones are going to be called your
00:03:32
muscular distributing arteries right so
00:03:34
for example the renal artery the super
00:03:35
renal artery if you think about another
00:03:37
one there's the inferior phrenic artery
00:03:39
and we could just keep going on and on
00:03:40
and on all right it supplies the
00:03:41
diaphragm but the muscular distributing
00:03:44
arteries again they're gonna be high
00:03:46
pressure systems they're gonna have a
00:03:47
stream Li thick tunica media very very
00:03:50
thick tunica media and again these guys
00:03:52
diameter because of the thick tunic
00:03:54
immediate changes and it goes to about
00:03:56
six millimeters okay arterioles
00:04:01
arterioles so if I were to zoom in on
00:04:03
this part right here let's say su min on
00:04:05
the kidney and I blow that up right so
00:04:08
if I look let's say here I have an
00:04:11
arteriole right the arterioles are gonna
00:04:13
be the ones that are feeding a capillary
00:04:15
bed so let's imagine this is a capillary
00:04:17
bed here and then let's say off of this
00:04:20
obviously you have your true capillaries
00:04:22
right so let's say here's our true
00:04:24
capillaries coming off of our
00:04:27
our vascular Shawn here so again these
00:04:30
arterioles are the ones that are feeding
00:04:32
it right they're the ones that are
00:04:33
feeding this capillary bed right here
00:04:35
where arterioles are very very small
00:04:37
vessels again very very small vessels
00:04:39
they pry range in diameter about 35
00:04:44
microns so about 35 micrometers in
00:04:47
diameter so they're pretty pretty small
00:04:50
diameter right they're not very big and
00:04:52
so with these guys what's really really
00:04:54
important about arterioles one of the
00:04:55
most important things about arterioles
00:04:57
is that if you remember they have a nice
00:05:00
little smooth muscle layer here wrapping
00:05:02
around this actual med arteriole and it
00:05:07
could be the very very important and
00:05:09
that can may actually be right around
00:05:10
the bed actually there more specifically
00:05:13
right around the bed of the cat the
00:05:14
capillaries the true capillaries these
00:05:16
guys are called pre capillary shrinkers
00:05:22
and they're smooth muscle and basically
00:05:26
whenever the sympathetic nervous system
00:05:27
innervates them it causes them to
00:05:29
constrict right so one of the biggest
00:05:31
things about arterioles is that they are
00:05:33
high resistance vessels they develop the
00:05:38
most resistance to blood flow okay so
00:05:41
that's one of the big things to remember
00:05:42
about our tiers is that they're
00:05:44
extremely high resistant vessels okay
00:05:47
and then if you get into the last one
00:05:49
here for the arterial side it's going to
00:05:51
be the capillaries and the capillaries
00:05:52
are obviously extremely small they range
00:05:54
in diameter probably right around eight
00:05:57
to about 10 micrometers in diameter
00:06:01
right so if you look at a capillary here
00:06:03
let's say i zoom out on that capillary
00:06:05
now let's say I take a piece of this
00:06:06
Kapler and I zoom out on that now so if
00:06:09
I look at this capillary now you have
00:06:12
three types of capillaries and I'm not
00:06:14
going to mention too much about them
00:06:15
right now like I said we'll talk about
00:06:16
them more in microcirculation
00:06:19
but the inner lining of the capillary
00:06:22
has that Tunica intima or Tunica
00:06:25
internal lining right with the simple
00:06:27
squamous epithelial cells right and then
00:06:31
it has a tiny little basement membrane
00:06:35
here just a tiny little basement
00:06:36
membrane right
00:06:38
and then on top of that it obviously can
00:06:40
have large intercellular kanessa my
00:06:42
intercellular cleft sore some
00:06:43
fenestration pores and it might even
00:06:45
have tight junctions depending upon what
00:06:46
type of capillary it is and another
00:06:48
thing that has depending upon where it
00:06:50
is is it can even have these little like
00:06:52
types of smooth muscle cells called peri
00:06:56
sites all right like I said we'll go
00:06:58
into more detail on this and then one
00:07:00
thing wrapping all the way around that
00:07:02
is a basal lamina okay it's a basal
00:07:07
lamina which is like a connective tissue
00:07:10
layer thin little connective tissue
00:07:11
layer right
00:07:12
that's called a basal lamina but
00:07:14
basically what capillaries are designed
00:07:16
to do is they're designed for exchange
00:07:18
gas exchange nutrient exchange hormone
00:07:20
exchange waste exchange but they're
00:07:22
basically exchange vessels so what's the
00:07:25
significance of capillaries they're
00:07:27
designed to be exchange vessels like I
00:07:30
said we're gonna talk about exactly the
00:07:32
mechanisms of exchange when we get into
00:07:34
bulk flow and micro circulation all
00:07:37
right but for right now that's what I
00:07:38
just wanted to focus on so again elastic
00:07:40
conducting arteries about 1 to 1.5
00:07:42
centimeters extremely high pressure
00:07:44
systems they have to be able to be
00:07:45
extremely elastic in recoil muscular
00:07:48
distributing about 6 millimeters in
00:07:49
diameter and these are gonna be the ones
00:07:51
that are delivering blood specifically
00:07:53
to that organ for example the renal
00:07:55
artery or the super renal artery or the
00:07:57
inferior phrenic artery okay and they're
00:08:00
gonna be extremely thick tunica media
00:08:02
then we can get into the arterioles
00:08:04
which are about 35 micrometers in
00:08:06
diameter and again they have these pre
00:08:08
capillary fingers these smooth muscle
00:08:10
layers right that can control the
00:08:12
resistance and they are the resistance
00:08:13
vessels they're the highest amount of
00:08:15
resistance are and then again these true
00:08:17
capillaries their exchange vessels and
00:08:19
again they consist of a Tunica interna a
00:08:22
tiny little layer of a sub endothelial
00:08:25
layer and then after that it has these
00:08:27
tiny little parasites depending upon the
00:08:28
capillaries and then a basal lamina
00:08:31
routes on that right venules I'm not
00:08:34
gonna spend too much time about vanishes
00:08:35
again we're gonna go over that whenever
00:08:37
you're into micro circulation but if you
00:08:38
look here for right now this is an
00:08:40
arteriole it's called your terminal
00:08:42
arteriole this is your meta arteriole
00:08:44
this is your your capillary bed right
00:08:46
here and then this part right here at
00:08:48
the end of the capillary but it's called
00:08:49
the post capillary van
00:08:51
and then that drains into this
00:08:53
eventually this terminal goes into this
00:08:54
vein you'll hear this post capillary
00:08:56
manual so we go post capillary manual
00:08:57
and then eventually it'll form large
00:08:59
veins so I'm not going to talk too much
00:09:02
about venules just for right now know
00:09:04
that they're basically going to be the
00:09:07
part that the the initial parts after
00:09:08
the capillary bed and their diameter is
00:09:11
about 20 micrometers in diameter right
00:09:14
all right pains means is the ones that I
00:09:16
really want to spend some time on in
00:09:17
this video what's important about veins
00:09:20
is that they pretty they have a pretty
00:09:22
big diameter also they're about five
00:09:24
millimeters in diameter on average and
00:09:28
what's important about being so here's
00:09:29
what I want to spend some time on with
00:09:32
veins because veins are extremely
00:09:33
interesting right
00:09:35
we knew that arteries are high pressure
00:09:37
systems right they're designed to be
00:09:39
able to distribute blood to various
00:09:42
parts of the body for your systemic
00:09:43
circuits right and so in depending upon
00:09:46
your coronary circuit your pulmonary
00:09:47
circuit but they're extremely high
00:09:49
pressure systems venous blood is not
00:09:52
high pressure systems they're designed
00:09:55
to be lower pressure systems these
00:09:56
pressures usually only get to about five
00:09:59
to ten millimeters of mercury so on
00:10:02
average so that's pretty low pressure
00:10:05
system it's an extremely low pressure
00:10:06
system what's so important about veins
00:10:09
that I want to mention is if you look at
00:10:12
veins some of the characteristics of
00:10:14
veins right veins they have a very thin
00:10:19
tunica media and I'm going to get into
00:10:21
these these tunics here in a second very
00:10:23
thin tunica media all right so they have
00:10:27
a huge lumen they have a larger lumen
00:10:29
okay larger lumen and they're described
00:10:33
to be capacitance vessels or reservoirs
00:10:36
of blood so they're kind of designed to
00:10:37
be what's called capacitance vessels in
00:10:41
other words veins account for about
00:10:44
seventy percent of our total blood
00:10:45
volume and any one instant so at any one
00:10:48
instant they account for about seventy
00:10:49
percent of your total blood volume so
00:10:53
they hold a decent amount of blood
00:10:56
here's the problem though if you think
00:10:59
about it let's say I draw here I draw
00:11:00
the right side of the heart so let's say
00:11:02
here's our superior vena cava
00:11:05
right atrium and then let's say here's
00:11:07
your inferior vena cava and then there's
00:11:10
your I ventricle and the pulmonary sorry
00:11:11
or the pulmonary arteries right so if
00:11:13
you think about this what's important to
00:11:16
know is is that veins or again are not
00:11:18
very high pressure systems so how do we
00:11:21
get the blood to get back up against
00:11:24
gravity without having a not having that
00:11:26
much muscle if you don't have that much
00:11:29
muscle with inside the vessel you're
00:11:32
gonna have to cut develop a couple
00:11:34
different types of adaptations right so
00:11:37
that's what the veins do so now what I'm
00:11:38
going to do is I'm going to zoom in on a
00:11:40
vein I'm going to show a couple
00:11:40
specialties of a vein so again you have
00:11:42
your Tunica interna right such as these
00:11:45
endothelial cell lining so what's
00:11:47
important is these Tunica interna they
00:11:52
kind of fold inwards and form these
00:11:57
little valves all right so let's say
00:12:00
here's again another folding of the
00:12:01
Tunica interna another folding of the
00:12:03
Tunica interna
00:12:04
I'm gonna develop these valves here and
00:12:07
they're basically just again internal
00:12:09
folds of the Tunica interna now look at
00:12:11
what can happen here if the blood is
00:12:14
pushed up this way I'll explain how you
00:12:16
can push it right if the blood is pushed
00:12:19
up this way it's gotten into this part
00:12:20
here and then basically what can happen
00:12:22
and some of it can circulate back down
00:12:23
right and when it goes and circulates
00:12:25
back down what is it gonna do it's gonna
00:12:26
push the valves closed to prevent the
00:12:28
blood from back flowing into the
00:12:30
inferior portion of that vein and that's
00:12:32
important rice because that's what keeps
00:12:33
them with them basically the blood
00:12:35
pooling up and leading to a condition
00:12:37
we'll call later varicose veins so
00:12:39
that's one important thing for veins to
00:12:41
be able to get the blood back up to the
00:12:43
heart so again one thing is valves
00:12:47
second thing that's our extremely
00:12:49
important if you remember your veins
00:12:54
again are not very high pressure systems
00:12:56
right so if you know usually what your
00:13:00
veins are near is they're usually near
00:13:03
some muscle so let's say we take for
00:13:05
example the vein the veins inside of
00:13:08
your legs right so let's say here's some
00:13:10
skeletal muscles like you're maybe the
00:13:12
gastrocnemius soleus muscles right and
00:13:15
let's say that they're on both sides
00:13:16
actually so let's say here we have
00:13:17
another one
00:13:19
alright and here's another one and let's
00:13:27
say that these muscles contract and when
00:13:29
they contract they start squeezing on
00:13:31
the blood vessel they start squeezing on
00:13:34
to the actual blood vessel and whenever
00:13:37
they squeeze on to the blood vessel
00:13:38
whenever they shorten they push the
00:13:40
blood upwards alright so whenever they
00:13:43
push the blood upwards it's called like
00:13:45
a muscular milking because it's not very
00:13:47
fast it's a slow process but it just
00:13:50
keeps contracting and pushing the blood
00:13:51
upwards so this right here is called and
00:13:55
the second thing here which we described
00:13:57
is called a muscular milking all right
00:14:04
and it's basically again the the muscles
00:14:08
are the actual somatic muscles right the
00:14:10
skeletal muscles are going to be
00:14:11
contracting and pushing the blood
00:14:13
upwards
00:14:13
that's one another one is called a
00:14:16
respiratory pump and a respiratory pump
00:14:20
is basically whenever you ant you're
00:14:22
breathing you're increasing the thoracic
00:14:25
cavity volume right and what it does do
00:14:27
it does is it actually as you increase
00:14:28
that thoracic cavity volume it actually
00:14:30
can push on some of those actual lower
00:14:32
vessels like the inferior vena cava and
00:14:34
it can help to push that blood upwards
00:14:37
also it can help with the blood coming
00:14:38
back from the pulmonary circuit too so
00:14:40
it helps to be able to increase the
00:14:41
blood flow back to the actual heart and
00:14:44
helps to get the blood flow up from the
00:14:46
actual lower systemic circuit sorry the
00:14:48
systemic veins so that's one so again
00:14:52
respiratory pump helps to get more blood
00:14:54
from the lungs back to the heart and it
00:14:56
helps to get some of the systemic blood
00:14:58
back up to the heart right that's called
00:14:59
the respiratory pump one more thing
00:15:02
that's also important there is tunica
00:15:04
media in the blood vessel it's just not
00:15:06
that thick right so let's say here I get
00:15:08
rid of this part here and I say I draw
00:15:11
here a tunica media just a couple smooth
00:15:14
muscle cells okay
00:15:19
this is important because the tunica
00:15:21
media if you remember let's say I draw
00:15:24
here central nervous system right and
00:15:27
then out of the central nervous system
00:15:30
you know that you have your sympathetic
00:15:31
nerves right and let's say that these
00:15:34
sympathetic nerves they come over here
00:15:36
and they innervate right the intervie
00:15:41
there's tunica media and what can that
00:15:44
do that can cause Vino constriction so
00:15:47
it can also cause a Vino constriction of
00:15:49
that smooth muscle and that can also
00:15:51
help to be able to push some of the
00:15:53
blood also up there right so the fourth
00:15:55
thing that we could also say down here
00:15:57
is going to be sympathetic tone
00:16:02
sympathetic tone now you're probably
00:16:04
wondering why I'm mentioning all this
00:16:05
like what's so important about it
00:16:06
alright so what these valves these are
00:16:10
extremely important the reason why is is
00:16:11
that some people may be the pseudo B C
00:16:13
maybe it's due to standing for long
00:16:15
periods of time you know depending upon
00:16:18
what it might be these valves can become
00:16:21
incompetent and leaky and so what
00:16:23
happens is let's say it due to whatever
00:16:25
reason is these these these blood
00:16:27
vessels start expanding right because of
00:16:29
people standing for a long time and the
00:16:30
blood is pooling up in that area what
00:16:32
starts expanding and expanding and
00:16:34
expanding and then what happens is it
00:16:35
pulls so imagine here as I try to pull
00:16:39
this blood vessel away from one another
00:16:41
I'm pulling these two edges away so then
00:16:43
what starts happening to the space
00:16:44
between the vet the valves it starts
00:16:46
increasing and then blood starts moving
00:16:49
back down as the blood starts moving
00:16:52
back down it starts pooling up in one
00:16:54
area so imagine all this blood is
00:16:56
pooling up in this area here and as the
00:16:59
blood start spooling up in this area it
00:17:02
starts becoming torturous are twisting
00:17:05
right so it starts pulling up and
00:17:08
dilating and then it starts becoming
00:17:10
torturous are twisted that is called
00:17:12
varicose veins they're very common
00:17:14
within the calf right so that's one of
00:17:16
the common areas another one that
00:17:18
they're common in is in the testes there
00:17:20
it's actually called varicose eel and
00:17:22
what happens is is sometime it's
00:17:24
actually more common in the left teste
00:17:25
because the gonadal vein the left
00:17:27
gonadal vein if you look here real quick
00:17:29
let's say I draw
00:17:32
the hey let's say you have your inferior
00:17:37
vena cava here and then what happens is
00:17:39
you have your left gonadal vein it comes
00:17:41
up over here with the renal artery right
00:17:44
so what happens is it comes up here and
00:17:46
it makes this this crazy turn to put the
00:17:49
blood into the inferior vena cava
00:17:51
whereas the right gonadal goes straight
00:17:53
to the inferior vena cava so what
00:17:54
happens is the blood can actually kind
00:17:56
of lead to this backflow in to the
00:17:59
testes and whenever it back flows into
00:18:00
the testes again it can lead to this
00:18:02
tour traceur dilating or accumulation of
00:18:06
these blood vessels within the testes
00:18:07
and that can lead so it's called
00:18:09
varicose seal and that can lead to
00:18:11
infertility it can lead to dilation it
00:18:13
can lead to a pretty big scrotum so
00:18:16
again if this is the left testes and it
00:18:18
starts actually causing this dilation
00:18:19
and this torturous formation of these
00:18:22
vessels it's called
00:18:25
verrico seal and again this could be a
00:18:28
problem because it could lead to
00:18:30
inflammation it could lead to expansion
00:18:32
swelling of the left testicle and on top
00:18:35
of that it could actually lead to
00:18:36
infertility okay all right so we talked
00:18:38
about varicose seal okay and again what
00:18:40
was this problem here call whenever the
00:18:41
blood starts pulling up within this area
00:18:43
and starts becoming twisting and it
00:18:46
becomes torturous and the blood vessel
00:18:48
start dilating and it forms these ugly
00:18:49
little veins on the back of the leg
00:18:51
right that's go again it's called
00:18:52
varicose veins okay all right and then
00:18:57
another area that's gonna occur it
00:18:59
doesn't just have to happen in it within
00:19:00
the blood vessels and it doesn't just
00:19:01
have to happen here within the testes it
00:19:04
can also occur in another part which is
00:19:06
the anus right so one of the common
00:19:08
areas is the veins inside the anus
00:19:09
they're actually called the hemorrhoidal
00:19:10
veins sometimes due to high pressure
00:19:12
straining forcing to go to the bathroom
00:19:14
doing the valves office maneuver and so
00:19:16
on and so forth the pressure can
00:19:18
accumulate and again that can happen to
00:19:20
it so another form of varicose veins is
00:19:21
hemorrhoids all right and so that's
00:19:23
another example varicose veins
