Cardiovascular System
Cardiovascular System
• Function: Uses blood to transport oxygen,
nutrients, cell wastes, hormones, etc.
• Force to move blood around body is provided
by heart and blood pressure
Structure of the Heart
•Heart Size – about 14 cm
x 9 cm (the size of a fist).
•Weighs less than a
pound
•Located in the
mediastinum (space
between lungs, backbone,
sternum), between the
2nd rib and the 5th
intercostal space.
•The distal end of the
heart is called the apex.
•Fibrous Pericardium encloses the heart (like a
bag) and has 2 layers
•visceral pericardium (inner)
•parietal pericardium (outer, attached to
diaphragm, sternum and vertebrae)
•Pericardial cavity – contains fluid for the heart
to float in, reducing friction
•Wall of the Heart
•Epicardium – outer layer, reduces friction
•Myocardium – middle layer, mostly cardiac muscle
•Endocardium – thin inner lining, within chambers of
the heart
Heart Chambers & Valves
• Heart has 4 chambers:
o 2 Atria – thin upper
chambers that receive blood
returning to the heart
through veins.. Right and
Left Atrium
o 2 Ventricles – thick,
muscular lower chambers.
Receive blood from the atria
above them. Force (pump)
blood out of the heart
through arteries. Right and
left ventricle.
o Septum – separates the right
and left sides of the heart
• Valves of the Heart – allow one-way flow of
blood.
• 4 total
• 2 Atrioventricular Valves (AV) & 2 Semilunar
valves
Left Atrioventricular valve – also called the bicuspid
valve or mitral valve. Between left atrium and ventricle
o Right Atrioventricular valve – also called the tricuspid
valve. Between right atrium and ventricle
o
• Aortic Semilunar – or just aortic valve. Between
the left ventricle and the aorta
• Pulmonary Semilunar, or just pulmonary valve.
Between the right ventricle and the pulmonary
artery
•Mitral = bicuspid (left side)
•Tricuspid (right side)
•Aortic and Pulmonary are
both semilunar valves
Path of Blood Flow
Tainted Love…?
•Systemic Circulation
– delivers blood to all
body cells and carries
away waste
•Pulmonary
Circulation –
eliminates carbon
dioxide and
oxygenates blood
(lung pathway)
Pulmonary Circulation
• Your heart is a double pump. Circulation is a double circuit:
Pulmonary (lungs only) and systemic (rest of the body)
• The right side works as the pulmonary circuit pump. It
receives oxygen-poor blood from the veins through the
superior and inferior vena cava and pumps it through the
pulmonary trunk.
• The pulmonary trunk splits into the right and left pulmonary
arteries (only arteries without oxygenated blood), which carry
blood to the lungs.
• Oxygen is picked up in longs and carbon dioxide is unloaded.
• Oxygen-rich blood drains from the lungs and is returned to
the left side of the heart through the four pulmonary veins
(only veins with oxygenated blood).
Systemic Circulation
• Blood returned to the left side of the heart is
pumped out of the heart into the aorta
• Systemic arteries branch to supply all essential
body tissues.
• Oxygen-poor blood circulates from the tissues
back to the right atrium via the systemic veins
into the superior or inferior vena cava.
• This systemic circulation supplies the body with
oxygen and nutrient rich blood.
• Left ventricle pumps blood all over body and is
thicker and more powerful pump than right.
Check your labels!
Name the
valves
(#5 is not a
valve)
1 Pulmonary Valve
2 Tricuspid Valve
3 Mitral (Bicuspid)
Valve
4 Aortic Valve
5 Heart Apex
Heart Actions
• Cardiac Cycle: One complete heartbeat.
• The contraction of a heart chamber is called
systole
• The relaxation of a chamber is called diastole.
•The cusps (flaps) of the bicuspid and tricuspid valves are
anchored to the ventricle walls by fibrous “cords” called
chordae tendineae.
•These attach to the wall by papillary muscles.
•This prevents the valves from being pushed up into the
atria during ventricular systole.
Can you identify
these parts?
• Right Atrium
• Right Atrioventricular Valve
(Tricuspid Valve)
• Right Ventricle
• Left Atrium
• Left Atrioventricular Valve (Mitral
Valve)
• Left Ventricle
• Papillary Muscle
• Chordae Tendinae
• Mitral Valve cusps