Cardiovascular System
heart and blood vessels
Systemic
Circulation –
delivers blood to
all body cells
and carries
away waste
Pulmonary
Circulation –
eliminates
carbon dioxide
and oxygenates
blood (lung
Structure of the Heart
Heart Size – about 14
cm x 9 cm (the size of
a fist).
Located in the
mediastinum (space
between lungs,
backbone, sternum),
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)
•and 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
•Your heart is a double pump. Circulation
•
is a double circuit: Pulmonary (lungs
only) and systemic (rest of the body)
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.
•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)
o 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
•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
Check your labels!
Heart Actions
•Cardiac Cycle: One complete heartbeat. The
•
•
•
contraction of a heart chamber is called
systole and the relaxation of a chamber is
called diastole.
The beginning of ventricular systole- lub
The end of ventricular systole- dub
http://www.youtube.com/watch?v=riDPxasIz_
I
Blood pressure is the
force of blood against
the walls of arteries.
Blood pressure is
recorded as two
numbers—the
systolic pressure (as
the heart beats) over
the diastolic pressure
(as the heart relaxes
between beats).
The average (normal) blood pressure for an adult is
120/80. This number varies by person and it is best
if you know what is *normal* for you, so that you (or
your doctor) recognize when something is not
normal.
SPHYGMOMANOMETER
The cusps (flaps) of the bicuspid and tricuspid
valves are anchored to the ventricle walls by fibrous
“cords” called chordae tendineae, which 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?
Animation of Heart Contraction
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter22/animation
__the_cardiac_cycle__quiz_1_.html
13.4 BLOOD VESSELS
Blood Vessels: arteries, veins, capillaries
ARTERIES : strong elastic vessels which carry blood
moving away from the heart. Smallest ones are
arterioles which connect to capillaries.
VEINS - Thinner, less muscular vessels carrying blood
toward the heart.
Smallest ones are called venules which connect to
capillaries. Contain valves.
Capillaries: Penetrate nearly all tissues. Walls are composed
of a single layer of squamous cells – very thin. Critical function:
allows exchange of materials (oxygen, nutrients) between blood
and tissues.
Blood Clots can occur if blood does not flow properly through
the veins - can occur if a person does not move enough
Major Blood Vessels
Aorta - Ascending Aorta, Aortic Arch, Descending Aorta,
Abdominal Aorta. The aorta is the largest artery. (leaves left
ventricle)
Pulmonary Trunk – splits into left and right, both lead to the
lungs (leaves left ventricle)
Pulmonary Veins – return blood from the lungs to the heart
(connects to left atrium)
Superior and Inferior Vena Cava – return blood from the head
and body to the heart (connects to right atrium)