MacKenzie Smart, Leah Harris, Emma Dumford, and Anna Sivey
The Circulatory System
The
Heart
Blood Vessels
Blood Pressure
Blood Plasma
Blood Cells
The Heart <3
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composed mostly of muscle
hollow organ—size of clenched fist
enclosed in a protective sac of tissue called
Pericardium
two thin layers of epithelial and connective tissue that
surround a thick layer of muscle called Myocardium
contractions of the Myocardium (heartbeat) pump
blood through the circulatory system
heart muscle contracts an average of 72 times a
minute—pumps 70 mL of blood
the Septum divides the right side of the heart from the
left and prevents Oxygen-poor blood from mixing with
Oxygen-rich blood
Heart—valves
 four
chambers-two upper chambers
(left and right atria) and two lower
chambers (left and right ventricles)
 right atrium has thinner walls and is
larger than the left
 the left ventricle is the strongest
and largest chamber in the heart
Heart—valves
 four types of valves:
 Tricuspid valve- separates the right atrium
from the right ventricle and regulates blood
flow between them
 Pulmonary valve- separates the right ventricle
from the left pulmonary artery and controls
blood flow from each other
 Mitral valve- separates the left ventricle from
the left atrium
 Aortic valve- separates the left ventricle from
the Aorta and controls the blood flow from the
ventricle into the rest of the body
Heart—arteries
 arteries
push blood through the blood
vessels when the heart relaxes from
its contractions
 arteries transport Oxygen-rich blood to
the capillaries where exchange of CO2
and Oxygen takes place
Heart—arteries
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arteries of the heart:
 Pulmonary artery- carries deoxygenated blood
from the right side of the heart to the lungs for
purification, it also divides into right and left
branch
 Aorta-main artery of the heart which carries
oxygenated blood to the rest of the body;
branches off to smaller arteries that supply blood
for the body
 Coronary arteries- attached to the heart and
supply blood to heart muscles
Heart—veins
 veins
are like arteries but do not
transport blood at high pressure
 after the exchange of CO2 and O, the
blood containing waste products is
received by the veins
 Pulmonary vein- carries oxygenated
blood from the lungs to the left side of
the heart
Heart—veins
 all
four pulmonary veins pour oxygenated
blood into the left atrium (two left and two
right)
 Venae Cavae- two large veins carry
deoxygenated blood from the body to the
heart
 Superior Venae Cavae- brings deoxygenated
blood from parts above heart into the right
atrium
 Inferior Venae Cavae- brings blood from the
parts below the heart to the right atrium
Blood Vessels
Three types of blood vessels:
 Arteries
 Capillaries
 Vein
 Arteries: the largest vessels that carry blood
from the heart to the tissues.
 Except for the pulmonary and umbilical
arteries, all arteries carry oxygen loaded
blood.
 Arteries have thick walls to withstand the
pressure from the heart when it contracts and
pushes blood into them.
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Blood Vessels
 Arteries
have three layers….
 Adventitia: outside layer; elastic
to allow the arteries to expand
under pressure.
 Media: middle layer; contracts
to regulate the diameter
 Endothelium: inside layer;
smooth lining to allow blood to
flow
Blood Vessels
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Aorta: Largest vessel leaving the left ventricle and leads
down to the rest of the arteries.
Arterioles: small vessels that branch off from the arteries
and lead to the capillaries
Capillaries: Smallest, “side-streets”. The walls are only
one cell thick. These are the main vessels that nutrients
and oxygen is brought to tissues.
Veins: After passing through the capillary system, blood
returns to the heart for oxygen
Blood flows against gravity through the veins.
Large veins, like in the leg, have valves that push the
blood towards the heart.
Exercising helps keep the blood from accumulating in
one spot, which produces a blood clot.
Blood Pressure
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Blood Pressure ~ the force of blood
against the walls of the arteries.
Systolic pressure: the pressure as the
heart beats
Diastolic pressure: the pressure as the
heart relaxes between beats
Equation: systolic/diastolic mmHg
(millimeters of mercury)
the normal or “desired” number is 120/80
mmHg
Blood Plasma
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Blood Plasma 55% of blood is plasma. Plasma is 90% water and
10% dissolved gasses, salts, nutrients, enzymes,
hormones, waste products, and proteins.
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Plasma proteins:
 Albumins- helps regulate osmotic pressure and
blood volume, and transports substances
 Globulins- transports substances, and fights viral
and bacterial infections
 Fibrinogen- gives blood the ability to clot
Blood Cells
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Red Blood Cells
 1 milliliter of blood has about 5 million red blood
cells
 Red blood cells transport oxygen
 They get their red color from hemoglobin (ironcontaining protein that binds to oxygen in the
lungs and transports it to tissue throughout the
body)
 They are disk-shaped cells without a nucleus
made from cells in red bone marrow
 Red blood cells last for about 120 days before
they are destroyed in the spleen
Blood Cells
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White Blood Cells
 less common, out numbered almost 1000 to 1
 guard against infections, fight parasites, attack
bacteria
 they can slip out of capillaries and fight
infections throughout the body
 the body can increase the number of white
blood cells when fighting
 have nuclei and are made in bone marrow
 live for days, months, even years
Blood Cells
 Platelets
 there are about 150,000 to 350,000
platelets per micro liter
 blood clotting is made possible by
plasma proteins and platelets
 they aren't actually cells, but cell
fragments produced in bone
marrow
Diseases
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2 Types
 Present at Birth
 Acquired
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Aortic Aneurysm
 Bulging in the wall of the aorta (largest artery)
 Caused by a tear or defect in the aortic wall
 Can be a complication of other diseases such as high
blood pressure
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Angina
 Pain or discomfort in the chest area caused by
leakage in the blood vessels leading to the heart
 Pain lasts usually about 10 minutes
Diseases
 Arrhythmia
 Irregularity in the heart rhythm, varies from
very slow to very fast
 Can occur at any point in life
 Atherosclerosis
 The hardening of the arterial wall because
of plaque or artheroma
 Plaque is composed of cholesterol, calcium,
and fatty deposits
 Can slow or stop blood circulation
 There is a sharp pain in the affected area
Diseases
High Blood Pressure
 When the systolic pressure Is over 140 mmHg
and disastolic pressure is over 90 mmHg
 Caused by heredity or unhealthy lifestyle
habits such as heavy drinking and smoking
 Peripheral Vascular Disease
 a disorder in the blood vessels
 caused by fatty acid deposits in the arteries of
the leg portion
 can be hereditary or acquired by unhealthy
living
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Diseases
 Ways
to Prevent Circulatory
Diseases:
 Do not Smoke or use any other
nicotine source
 Exercise consistently
 Eat Healthy
 Get enough sleep each 24-hours
 Avoid high amounts of stress
Overview
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Three Major Parts
 The Heart
 The Blood
 The Blood Vessels
The Heart removes waste materials and pumps and circulates blood
The Blood has the oxygen and nutrients necessary for cell survival
The Blood Vessels transport blood to and from the heart
The Circulatory System is the main transportation and cooling
system of the body
It is basically like the roads in cities used to transports goods and
other important materials.
When your heart beats, it forces the oxygen-rich blood through the
circulatory system