The Cardiovascular System

The Cardiovascular System
Amazing Heart Facts
Your heart is about the same size as your fist.
An average adult body contains about five
quarts of blood.
All the blood vessels in the body joined end to
end would stretch 62,000 miles or two and a half
times around the earth.
The heart circulates the body's blood supply
about 1,000 times each day.
The heart pumps the equivalent of 5,000 to
6,000 quarts of blood each day.
A. Fully formed by the 4th week of
embryonic development
B. Hollow Muscular Organ That Acts as a
2 sided, Double Pump – Pump #1 – rt.
side - O2 deficient - to the lungs; Pump
#2 – left side – O2 rich – to the body
C. Continuous pump - once pulsations
begin, heart pumps endlessly until death
Heart Anatomy
• General
• 1.
Size: approximately the size of a person’s fist
• 2.
Location: in the mediastinum; between the
lungs in the thoracic cavity
• Positioned partially to the left of the sternum
Coverings: Pericardium
1. Double layered sac – parietal and visceral
2. Contains 10 - 20 cc. Of pericardial fluid to
reduce the friction of the beating heart
3. Parietal layer: fibrous membrane; outer
4. Visceral layer: serous membrane; also
called the epicardium; attached to
Heart Wall
Myocardium: heart muscle;
thickest layer
2. Endocardium: smooth layer of
cells lining the inside of the heart
chambers; and forms the valves
Chambers: Atria
a. 2 upper chambers of heart
b.Thin walls, smooth inner surface
c.Foramen ovale: passageway between the
2 atria so that the lungs are bypassed in
the developing fetus
d.Fossa ovale: scar tissue where the
foramen ovale existed until it closed up
shortly after birth
Atria Continued
e.Responsible for receiving blood
f. Right atrium receives deoxygenated
(oxygen poor) blood from the body through
the superior and inferior vena cava
g. Left atrium receives oxygenated
(oxygen rich) blood from the lungs
through the pulmonary veins
Chambers: Ventricles
a. 2 lower chambers of the heart
b. Thicker walls, irregular inner surface
c. Contain papillary muscles and
chordae tendineae (prevent heart
valves from turning inside out when
ventricles contract)
d. Left wall 3 times as thick as right wall;
forms apex of heart
Ventricles Continued
e.Responsible for pumping blood away
from the heart
f. Right ventricle sends deoxygenated
blood to the lungs via the pulmonary
g. Left ventricle sends oxygenated
blood to all parts of the body via the
Accessory Structure
Septum: muscular wall dividing
the heart into right and left halves
Heart valves - prevents the
backflow of blood
Papillary muscles
Chordae tendineae
Great Vessels
1. Superior and inferior vena cava: receive
deoxygenated blood from all parts of the
2. Coronary sinus: carry O2 to the heart
muscle itself
3. Pulmonary arteries: carry deoxygenated
blood to the lungs from the right ventricle
4. Pulmonary veins: carry oxygenated blood to
the left atrium from the lungs
5. Aorta: carries oxygenated blood to
distribute to all parts of the body
Pathway of Blood through Heart
• Inferior/Superior Vena
• Right Atrium
• Tricuspid Valve
• Right Ventricle
• Pulmonary Valve
• Pulmonary Artery
• Lungs
• Pulmonary Veins
• Left Atrium
• Bicuspid (mitral)
• Left Ventricle
• Aortic Valve
• Aorta
• Body
Pathway of Blood through Body
Superior/ inferior vena
1.Tough fibrous tissue between the heart
chambers and major blood vessels of
the heart
2.Gate-like structures to keep the blood
flowing in one direction and to prevent
regurgitation or backflow of blood
Atrio-ventricular valves
ventricles contract, blood is forced
upward and the valves close; attached
by papillary muscles and chordae
a. Tricuspid valve: between the right
atrium and the right ventricle
b. Bicuspid/mitral valve: between the
left atrium and the left ventricle
Semilunar Valves:
3 half moon pockets that catch blood and
balloon out to close the opening
a. Pulmonary semilunar valve: between
the right ventricle and the pulmonary
b. Aortic semilunar valve: between the left
ventricle and the aortic arch/aorta
Heart Sounds
a. When the AV (atrioventricular) and semilunar
valves close, they make the sound heard as “lubdub” (auscultated with stethoscope)
b. First sound = S1 - ventricles are contracting and
forcing blood to the lungs and entire body (AV
valves closing)
c. Second sound = S2 - atria are contracting and
the semilunar valves are closing
d.Abnormal heart sounds = murmur; valve
pathology (M1, M2)
A. Nerve Supply to Heart
1. Alters rate and force of cardiac contraction
2. Vagus nerve (parasympathetic nervous
system): slows heart rate
3. Sympathetic nerves: increase heart rate
4. Epinephrine/norepinephrine: increase heart
5. Sensory (afferent) nerves: detect atria
being stretched and lack of oxygen
(changes rate of contractions)
Angina: chest pain due to lack of oxygen in
coronary circulation
• Carry Blood away
from heart
• All BUT pulmonary
artery carries
oxygenated blood
• Aorta:largest artery
• Arterioles: smallest
• Coronary arteries:
nourish heart
• Carry blood TOWARD
• All BUT Pulmonary vein
carries unoxygenated
• Layers much thinner;
• Series of internal valves
that work against the flow
of gravity to prevent
• Inferior/superior vena
• Venules:smallest
Tiny, microscopic vessels
Walls one cell layer thick
3. Function: to transport and diffuse
essential materials to and from the
body’s cells and the blood
Function of Circulatory System
• An efficient pumping system to supply all body
systems with oxygen and nutrients
• Transport cellular waste products from the cells to
the kidneys for excretion
• An important role in the immune system –
distributes hormones and antibodies throughout
the body
• Helps control body temperature and maintain
electrolyte balance

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