Cardiovascular System—Anatomy of the Heart
Lecture 1
Now, most courses on the subject begin with a big overview, de nitions,
relationships of the systems, and we’re not going to do that here because
I think that can be easily done as we move along through the lectures.
Rather we’re going to go literally to the heart of the matter and start
with the anatomy of the human heart.
T
his introductory lecture examines this st-sized muscle that pumps
blood throughout the body. After reviewing the distinction between
arteries and veins and discussing the location of the heart, the lecture
examines in detail the coverings, layers, and subdivisions of the heart.
Finally, it examines the valves that control blood ow into, through, and out
of the heart, as well as the conduction system that controls the beating of the
heart.
Lecture 1: Cardiovascular System—Anatomy of the Heart
The heart as a mechanical pump
The heart pumps 1.3 gallons of blood per minute, or 700,000 gallons per
year [editor’s note: professor correction], at rest and four times that amount
at peak exercise. It weighs less than a pound and is the size of a closed st.
Types of circulation in the anatomy
In systemic circulation, arteries carry oxygenated blood from the
heart to the rest of the body. Veins then return oxygen-depleted
blood to the heart.
In pulmonary circulation, pulmonary arteries carry oxygen-depleted
blood to the lungs, where it is oxygenated and returned to the heart
through pulmonary veins.
Arteries have thick walls and carry blood away from the heart.
Veins have thin walls and return blood to the heart.
4
, Location of the heart
Contrary to common belief, the heart is not located on the left side but in the
center of the chest in the thoracic cavity, which is bounded by the ribs and
the diaphragm. CPR uses the exible ribs to compress the heart between the
sternum and backbone and pump blood in cases of cardiac arrest. Before the
advent of CPR, open cardiac massage was used.
The thoracic cavity contains three separate enclosures, one for each lung
and one for the heart. The mediastinum is the
heart’s enclosure and is the space between the
In the old days,
right and left lungs, between the sternum and
the vertebral column, and between the clavicles [pacemakers] had a
and the diaphragm. The heart’s right-to-left axis xed rate and you
is between the lungs. Its front-to-back axis is had to come in for
between the sternum and backbone. Its up-and-
battery changes, just
down axis is between the diaphragm and neck.
It sits on the diaphragm. like you had to come
in for an oil and lube
The heart’s covering is the pericardium job.
(“around the heart”). The pericardium is a
saccular structure of tough brous tissue that
holds the heart in place and protects it from overexpansion. The parietal
(“wall”) pericardium lines the walls of the heart’s enclosure. The visceral
pericardium is a thin layer that covers and adheres to the heart. The space
between the parietal and visceral pericardia is lled with lubricating uid.
Clinical applications: Infections and in ammations of the pericardium
(pericarditis) can cause friction between the heart and pericardial surfaces,
causing severe pain. Trauma can cause blood to ll the pericardium, resulting
in pericardial tamponade (blood pressing on the heart). Emergency surgery
is necessary to relieve pressure on the heart.
The heart wall
The heart wall has three layers. The outer layer is the epicardium (epi means
“outer”), which is actually the visceral pericardium. It is a shiny, transparent,
lubricating layer that is an integral part of the heart wall. The thin inner layer
is the endocardium (endo means “inner”). It covers the muscle and valves,
and it continues out into the vessels, where it becomes the endothelium.
5
Lecture 1
Now, most courses on the subject begin with a big overview, de nitions,
relationships of the systems, and we’re not going to do that here because
I think that can be easily done as we move along through the lectures.
Rather we’re going to go literally to the heart of the matter and start
with the anatomy of the human heart.
T
his introductory lecture examines this st-sized muscle that pumps
blood throughout the body. After reviewing the distinction between
arteries and veins and discussing the location of the heart, the lecture
examines in detail the coverings, layers, and subdivisions of the heart.
Finally, it examines the valves that control blood ow into, through, and out
of the heart, as well as the conduction system that controls the beating of the
heart.
Lecture 1: Cardiovascular System—Anatomy of the Heart
The heart as a mechanical pump
The heart pumps 1.3 gallons of blood per minute, or 700,000 gallons per
year [editor’s note: professor correction], at rest and four times that amount
at peak exercise. It weighs less than a pound and is the size of a closed st.
Types of circulation in the anatomy
In systemic circulation, arteries carry oxygenated blood from the
heart to the rest of the body. Veins then return oxygen-depleted
blood to the heart.
In pulmonary circulation, pulmonary arteries carry oxygen-depleted
blood to the lungs, where it is oxygenated and returned to the heart
through pulmonary veins.
Arteries have thick walls and carry blood away from the heart.
Veins have thin walls and return blood to the heart.
4
, Location of the heart
Contrary to common belief, the heart is not located on the left side but in the
center of the chest in the thoracic cavity, which is bounded by the ribs and
the diaphragm. CPR uses the exible ribs to compress the heart between the
sternum and backbone and pump blood in cases of cardiac arrest. Before the
advent of CPR, open cardiac massage was used.
The thoracic cavity contains three separate enclosures, one for each lung
and one for the heart. The mediastinum is the
heart’s enclosure and is the space between the
In the old days,
right and left lungs, between the sternum and
the vertebral column, and between the clavicles [pacemakers] had a
and the diaphragm. The heart’s right-to-left axis xed rate and you
is between the lungs. Its front-to-back axis is had to come in for
between the sternum and backbone. Its up-and-
battery changes, just
down axis is between the diaphragm and neck.
It sits on the diaphragm. like you had to come
in for an oil and lube
The heart’s covering is the pericardium job.
(“around the heart”). The pericardium is a
saccular structure of tough brous tissue that
holds the heart in place and protects it from overexpansion. The parietal
(“wall”) pericardium lines the walls of the heart’s enclosure. The visceral
pericardium is a thin layer that covers and adheres to the heart. The space
between the parietal and visceral pericardia is lled with lubricating uid.
Clinical applications: Infections and in ammations of the pericardium
(pericarditis) can cause friction between the heart and pericardial surfaces,
causing severe pain. Trauma can cause blood to ll the pericardium, resulting
in pericardial tamponade (blood pressing on the heart). Emergency surgery
is necessary to relieve pressure on the heart.
The heart wall
The heart wall has three layers. The outer layer is the epicardium (epi means
“outer”), which is actually the visceral pericardium. It is a shiny, transparent,
lubricating layer that is an integral part of the heart wall. The thin inner layer
is the endocardium (endo means “inner”). It covers the muscle and valves,
and it continues out into the vessels, where it becomes the endothelium.
5
