Cardiovascular System
The pulmonary circuit takes deoxygenated blood from the heart to
the lungs to receive oxygen and remove carbon dioxide.
Pathway
Right ventricle of heart pulmonary artery lungs pulmonary vein left atrium of heart
In the pulmonary system, arteries carry oxygen POOR blood and veins
carry oxygen RICH blood, opposite that of the systemic circuit.
The systemic circuit takes oxygenated lungs from the heart to the
body to provide oxygen and remove carbon dioxide.
Pathway
Left ventricle of heart aorta body vena cava right atrium
Note, there are several steps between aorta and vena cava that it is
not included because they relate to specific areas of the body. For example,
if we wanted to write about the path of blood to the head, the path would
be:
Left ventricle of heart aorta carotid artery head jugular vein superior vena cava right atrium
For more information, refer to page 87 and 88 of your lab manual.
Major Blood Vessels
Body Part
Heart
Head
Arms
Kidney
Legs
Intestines
Artery
Coronary
Carotid
Subclavian
Renal
Iliac
Mesenteric
Vein
Cardiac
Jugular
Subclavian
Renal
Iliac
Hepatic Portal
Coronary artery – takes blood from the aorta to the heart
Cardiac vein – takes blood from the heart to the vena cava
Carotid artery – takes blood from the aorta to the head
Jugular vein – takes blood from the head to the vena cava
Subclavian artery – takes blood from the aorta to the arms
Subclavian vein – takes blood from the arms to the vena cava
Renal artery – takes blood from the aorta to the kidneys
Renal vein – takes blood from the kidneys to the vena cava
Iliac artery – takes blood from the aorta to the legs
Iliac vein – takes blood from the legs to the vena cava
Path of Blood through the Heart
Vena Cava right atrium atrioventricular (AV) valve right ventricle semilunar valve pulmonary artery lungs pulmonary vein left atrium
atrioventricular (AV) valve left ventricle semilunar valve aorta
Blood Vessel Comparison
Arteries carry blood at high pressure (the high pressure being from
the heart) and have think walls. Veins move blood via skeletal muscle
contractions and require valves to ensure that blood does not backflow, as
there is no more pressure from the heart. Veins are more superficial in the
body because they require muscle movement to provide pressure to move
blood. Arteries already have pressure from the heart, so they do not need
to be closer to skeletal muscle. In addition, if a vein is cut, the lower
pressure will result in less blood loss than if an artery is severed.
For more information, refer to pages 85 and 86 of your lab manual.
Blood Cell Comparison
Red blood cells (erythrocytes) carry oxygen from the heart to the
rest of the body. Hemoglobin is the protein in red blood cells that allows the
bonding and release of oxygen. These cells lack a nucleus and are relatively
small, but greater in number than white blood cells.
White blood cells (leukocytes) are part of the body’s immune system
and fight infections in the blood. They are larger and lower in abundance
than red blood cells. They do have a nucleus. There are five different kinds
of white blood cells – Neutrophils, Eosinophils, Basophils, Monocytes and
Lymphocytes.
For more information, refer to pages 84 and 85 in your lab manual.
Electrical Activity of the Heart
The pumping of the heart is controlled by electrical signals sent from
the pacemaker, or SA node. After the SA node sends an excitation signal,
the atria contract. Once the impulse reaches the AV node, the electrical
signal diffuses into smaller Purkinje fibers that signal the ventricles to
contract.
An electrocardiogram (ECG) illustrates the electrical signals in
graphical form, and is what many people are familiar with in hospitals for
tracking vital signs. The first wave, the p wave, is small and signals the
stimulus of the SA node. Next, the QRS wave is a steep spike indicating the
signal has reached the AV node and the ventricles are about to contract.
Finally, a smaller T wave shows the ventricles recovering from contraction.
For more information, refer to page 81 of your lab manual.
Heartbeat
Systole - chamber contracts
Diastole - Chamber relaxes
For more information, refer to page 82 of your lab manual.