Download The Circulatory System



Provides cells with oxygen and nutrients and
removes wastes
Includes the heart, several kilometers of blood
vessels, and blood


Diffusion: material moves to area where there
is less of it (no energy needed)
Active transport: uses energy to move material
to an area even though there might already be
a lot of that material there



Carry blood to and from the heart
Blood moving away from the heart: full of
oxygen and nutrients
Blood moving back to the heart: full of carbon
dioxide and wastes


Like a one-way street: blood only moves in one
direction
3 types of blood vessels: can you name them?

Hint: one carries blood to heart, one carries blood
away from heart, and one connects them

Arteries: carry blood away from the heart



Thick, elastic walls
Veins: carry blood back to the heart
Capillaries: microscopic blood vessels that
connect arteries and veins


Walls are only one cell thick (allows for nutrients
and oxygen to diffuse out of capillaries and carbon
dioxide and waste to diffuse back into capillaries)
Every cell is within 0.15mm of a capillary




Made of four compartments (chambers)
Upper chambers: atriums
Lower chambers: ventricles
Blood flows from left atrium to left ventricle,
and right atrium to right ventricle, but not
between right and left chambers

One side has oxygen-rich blood and one side has
blood with very little oxygen

Coronary circulation

Pulmonary circulation

Systemic circulation

All are controlled by the beating of your heart


One heartbeat: both atriums contract at same time,
then both ventricles contract at same time
Blood flow: one atrium to one ventricle to an
artery


Flow of blood to and from tissues of the heart
The heart, like any other muscle, needs blood
vessels



Supply it with nutrients and oxygen
Remove wastes and carbon dioxide
If coronary arteries become damaged, it can
lead to heart attacks


Flow of blood through the heart, to the lungs,
and back to the heart
Blood returning to the heart enters the right
atrium (think Right = Return)

Enters through 2 main veins: superior and interior
vena cava
 Superior vena cava: returns blood from head and neck
 Inferior vena cava: returns blood from lower body


Blood is high in carbon dioxide and low in oxygen
Right atrium contracts and forces blood down
into right ventricle





Right ventricle contracts, forcing blood out of
heart and into pulmonary artery
Pulmonary artery carries blood to lungs, where
is exchanges carbon dioxide for oxygen
Pulmonary vein carries oxygen-rich blood from
lungs back to heart, where is enters through left
atrium
Left atrium contracts and forces blood down
into left ventricle
Left ventricle contracts and forces blood out of
heart and into aorta (main artery)




Oxygen-rich blood flows to organs and body
tissues, and oxygen-poor blood returns to the
heart
Largest of the three parts of the circulatory
system
Oxygen-rich blood exits left ventricle, enters
aorta, and is taken throughout body by arteries
and capillaries
Oxygen-poor blood is taken back to heart by
veins, then superior and inferior vena cava take
this blood to heart’s right atrium


Your blood puts pressure on the walls of the
blood vessels too
Blood pressure: the force of the blood on the
walls of the blood vessels


Measured in large arteries by 2 numbers



Highest in arteries, lowest in veins
Systolic: top number, when ventricles contract and
blood is pushed out of heart
Diastolic: bottom number, occurs as ventricles fill
with blood just before they contract
Sample blood pressure: 120 over 80


Your body wants to keep it normal to keep
blood reaching all organs
When blood pressure changes and falls out of a
normal range, nerves send messages to the
brain to adjust this by speeding up or slowing
down the heart rate


Also called cardiovascular disease
Common types of heart disease:
Hypertension
 Heart failure
 Stroke
 Athersclerosis
 Heart attack




With a partner, you will research one of the
common heart diseases on the previous slide
Be prepared to explain to the class what exactly
happens to the heart, what may cause it, what
risks are associated, and what can be done to
avoid it
Other factors to consider: is it related to another
disease? Does it cause death or another illness?
How many people does it kill annually?



Atherosclerosis: fatty
deposits build up on
walls of arteries, and
blood can’t get through
Comes from eating foods
high in cholesterol and
saturated fats
See p. 236



Hypertension: high blood pressure for an
extended period of time
Puts extra strain on your heart to get nutrients
and oxygen to all the body’s cells
Can be caused by atherosclerosis