Download Functions of The Human Circulatory System

Functions of
The Human Circulatory System
• The human circulatory system, or cardiovascular system, has the
great job of transporting oxygen and nutrients to the organs
and tissues of the body, and to carry away waste products.
• It regulates the body’s temperature and increases blood flow to
meet demands during exercise.
• This system also sends parts of the immune system (white blood
cells and antibodies) to fight off foreign substances upon their
invasion.
• Should injury or bleeding occur, it sends clotting cells and
proteins to help stop bleeding and promote healing.
Follow me!
Bluish, deoxygenated blood enters the heart at the right
atrium, through the vena cava. It then drops down to the
right ventricle through a valve that opens only in one
A single
drop
of blood
goes
longnext
direction.
Entering
the pulmonary
artery,
theablood
goes to
the through
lungs, wherethe
it is “reimbursed”
with oxygen,
way
human
body.
In
becoming bright red again. It goes back to the heart
fact,
all theveins
arteries,
veins,
and
through
the if
pulmonary
to the left
atrium.
This
voyage
through thein
lungs
is
pulmonary
circulation.
Its
capillaries
an
adult
human’s
body
function is to fill the blood with oxygen from the lungs.
placed
to end,thethe
Next,were
it’s down
to the end
left ventricle,
mosttotal
powerful
chamber
of the
heart. stretch
From here nearly
it enters the
aorta,
to
length
would
two
and
the body’s arteries, then arterioles, to veinioles, to
times
around
veins, a
andhalf
finally
back to
the venathe
cava.earth’s
This journey
throughout
the body
is called
systemic
circulation.
Its
equator.
This
is
over
100,000
km
mission is to bring oxygen to the organs and tissues of
(60,000
miles).
the body, and to carry
away waste
materials back to the
lungs, where they are exhaled. When blood is being
transmitted through the heart, that is coronary
Blood on the right side of the
heart is bluish and the oxygen
has all been used up. Blood on
the left side, however, is bright
red and full of oxygen to take to
the body.
BLOOD
• Blood is made up of red and white blood cells, and
platelets, all carried in plasma:
– Red blood cells: bear oxygen
• Hemoglobin: bears iron (inside the red b.c.’s)
– White blood cells: fight disease (a part of the
immune system)
– Platelets: clot blood--this slows, stops bleeding
– Plasma: yellowish, it consists of water, salts,
proteins, vitamins, minerals, hormones, dissolved
gases, and fats.
BLOOD PRESSURE
• Blood pressure is the pressure generated when the pumping action of the
heart propels blood to the arteries.
• It’s measured using a sphygmomanometer, wrapped around the upper arm.
This is displayed as a ratio--average is 120/80.
• Blood pressure is measured during systole and diastole.
– Systole: active pumping phase of the heart.
– Diastole: resting phase between heartbeats.
Heartbeats are triggered by myocardium, the muscle forming the walls of the heart’s four
chambers. This muscle rhythmically and continuously contracts to pump blood. The pumping
phase of the heartbeat consists of two cycles: systole, the pumping of the heart; and diastole, the
resting in between pumps.
DISEASES OF THE HEART
• Hypertension
- High blood pressure: blood vessels narrow, making heart pump harder.
- Eventually the heart will need more oxygen. This can lead to heart failure
or brain stroke.
• Atherosclerosis
- High concentrations of cholesterol lead to plaque, which deposits on the
sides of arteries, reducing blood flow.
- Blood clots can form where plaque roughens artery walls.
- This causes damage to organs.
* When a brain artery is blocked--stroke.
* When a coronary artery is blocked--heart attack, and
heart muscle is destroyed.