The Heart and Major Vessels – PART 1 – Anatomy Tutorial

This is a tutorial on the heart and some of
the major vessels that lead to the heart and from the heart. So here, we’re looking at an anterior view
of the chest with the thoracic cage and the muscles dissected away. So you can see the
heart sitting centrally in the mediastinum, which is this central compartment of the chest
separating the pleural cavities on either side. The heart, as you can see, is angled
to the left. So the apex of the heart is angled down into the left. You can see it sitting
on top of the diaphragm, which is this flat muscle here. So in the anatomical position, which we’re
looking at now, the heart has several surfaces. The surface that’s in contact with the diaphragm,
the inferior surface of the heart is known as the diaphragmatic surface. This right side
of the heart which is in contact with the right lung is called the right pulmonary surface.
Conversely, the left side which is in contact with the left lung is called the left pulmonary
surface. The anterior surface of the heart, which is
in contact with the sternum is called the costosternal surface. The back of the heart,
which you can’t see in this particular view is known as the base of the heart. This point
here is the apex of the heart. So it’s important to note the orientation
of the heart in this position. So when you’re looking at it from this view, front on, you’re
seeing mostly the right side of the heart. So from this view, you’re seeing mainly the
right ventricle. So just to quickly go over the basic structure
of the heart and the function of the heart, the heart can be thought of as a dual pump.
So you’ve got a pump to the lungs and a pump to the body. Deoxygenated blood is received
from the rest of the body into the right atrium. It is then pumped into the right ventricle,
which then contracts to send blood out through the pulmonary trunk into the lungs where it
receives oxygen. Once oxygenated, the blood is returned to
the heart via pulmonary veins into the left atrium. The left atrium contracts and sends
blood into left ventricle, which then sends blood out via the aorta to the rest of the
body. This blood is oxygenated because it’s been received from the lungs. So just when you’re watching this tutorial,
the blue-colored vessels are veins and the red-colored vessels are arteries. So the color
of the vessel doesn’t actually relates to whether or not the blood is oxygenated in
this model. The blood that is sent out of the right side of the heart to the lungs is
deoxygenated, but on this model, you can see that the pulmonary arteries are actually red
because they’re arteries. This is the only artery that carries deoxygenated blood in
the body. And also, you can see the pulmonary veins
which are returning from the lungs into the left side of the heart, the left atrium are
blue in this model because they’re veins. But again, these are the only veins in the
body that carry oxygenated blood. So just to point that out. So between the atrium and the ventricles,
you have valves, which prevent the backflow of blood. So between the right atrium and
the right ventricle, you’ve got a valve known as the tricuspid valve. I remember the tricuspid
valve as being on the right because tricuspid contains the letters ri. So tri, ri, right
if you know what I mean. If not, just try and remember that the tricuspid valve is on
the right. And on the left, between the left atrium and
left ventricle, you’ve got the mitral valve. You’ve also got valves between the vessels
that lead away from the heart and the ventricles. So between the pulmonary trunk and the right
ventricle, you’ve got a valve called pulmonary valve. And between the aorta and the left
ventricle, you’ve got the aortic valve. So these are four valves that you need to
remember — the tricuspid one on the right between the right atrium and the right ventricle,
the mitral valve between the left atrium and the left ventricle and you’ve got the pulmonary
and aortic valves. Don’t worry too much about what these look
like and the structures of them because I will be doing a more detailed tutorial on
the structure of the heart including blood supply to the heart, all the different bits
of the hearts and I’ll be looking at the hearts in more detail. So in this tutorial, what
I want you to remember is you’ve got the two atrium which pump blood to the two ventricles
and the ventricles pump blood through the major vessels. And between the atrium and
ventricles, you’ve got the mitral and tricuspid valves and between the ventricles and these
great vessels, you’ve got the pulmonary and aortic valves. So the great vessels are those vessels which
take blood directly to the heart, and take blood directly from the heart. So you’ve got
four great vessels, you’ve got the vena cava, you’ve got the pulmonary trunk, the aorta,
and you’ve got the pulmonary veins. So blood is brought to the heart by the vena cava,
you’ve got the superior vena cava and the inferior vena cava. So you’ve got these veins
which drain into the vena cava, called the brachiocephalic veins, so you’ve got one on
each side.