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The Circulatory System
Consists of the heart, the
blood vessels, and the
lungs
Functions of the Circulatory System
1.Transports O2 & nutrients
(sugars, amino acids) to
body cells
2.Transports hormones
throughout body
3.Carries wastes away from
cells
4.Works with the immune
system to protect body
against disease causing
pathogens
Parts of the Blood
1. Plasma – fluid portion
– transports all of the material
2. Red Blood Cells: (RBC’s)
a.Transports oxygen to body cells
b.Removes waste from body cells
3. White blood cells: (WBC’s)
a.Protect against infection; fight
parasites & attack bacteria
4. Platelets: cell fragments
a.Release proteins that help clot
blood
Plasma
Platelets
WBC’s
RBC’s
Blood Vessels
1. Arteries: large vessels; carry blood away from
heart
a.Most arteries carry O2 rich blood
2. Veins: large blood vessels; return blood to heart
a.Have valves to keep blood from flowing
backwards
3. Capillaries – smallest blood
vessels
a.Bring nutrients & O2 to cells
b.Absorb CO2 & wastes from body cells
The Heart
1. Heart – muscular organ
a. 4 chambers
b. Pumps blood from heart to lungs
& back to heart, to tissues
throughout body
2. Septum: muscular wall in heart
a. Separates right side from left side
b. Keeps O2 poor & O2 rich blood from mixing
The Heart
3. Atria – 2 upper chambers
a. Receive blood from body (right) or lungs (left) &
pump blood into ventricles
4. Ventricles – 2 lower chambers
a. Pump blood out of heart to lungs (right) or aorta
(left)
How the Heart Works: Pulmonary Circulation
a.Transports O2 poor blood
to lungs and O2 rich blood
back to the heart
b. Blood travels from right
side of heart to lungs
c. Blood picks up O2 &
releases CO2 in lungs
d. O2 rich blood returned to
left side of heart
Pathway: Pulmonary Circulation
Blood pumped from the right side of the heart to
lungs and to left side of the heart
How the Heart Works: Systemic Circulation
a. O2 rich blood exits left ventricle
& enters aorta
b. O2 rich blood travels through
arteries then capillaries
c. O2 diffuses out of capillaries &
into cells; blood picks up CO2 &
other wastes
d. Veins return O2 poor blood to
right side of heart (right atria)
Pathway: Systemic Circulation
Blood pumped from left side of heart to the body
and back to the right side of the heart.
Circulatory System Diseases
1.Leukemia: bone marrow produces
abnormal WBCs which crowd out normal
WBCs, RBCs & platelets.
2. Hemophilia: inherited disorder; person
cannot produce clotting factors and bleeds
longer than normal. Also has internal
bleeding, mainly into muscles & joints.
Circulatory System Diseases
3. Arteriosclerosis: arteries become hard &
brittle because calcium is deposited in their
walls. Vessels become thickened & lose
elasticity. Blood pressure increases & blood
clots may form
4. Stroke: blood clot blocks artery or a blood
vessel breaks, interrupting blood flow to an
area of the brain. Brain cells begin to die &
abilities controlled by that area of the brain
are lost.
Circulatory System Diseases
5. High Blood Pressure: hypertension; BP 140 / 90
or higher for an extended period of time. Damage to
heart & blood vessels; makes it harder to pump
the heart. Can lead to stroke or heart attack