The Circulatory System is responsible for transporting
materials throughout the entire body. It transports nutrients,
water, and oxygen to your billions of body cells and carries away
wastes such as carbon dioxide that body cells produce. It is an
amazing highway that travels through your entire body connecting
all your body cells.
Which gases are transported to and from the bodys cells by the
blood flowing in the circulatory system? carbon dioxide oxygen
Oxygen is the gas needed for respiration and is transported to the
The circulatory system carries two types of blood Arrangement
of the circulatory system means that these two types of blood do
not mix. Oxygen-rich blood c De-Oxygen rich blood Blood travelling
to the body cells High oxygen content Low carbon dioxide content
Blood travelling away from the body cells Low oxygen content High
carbon dioxide content
The heart is the organ at the centre of the circulatory system.
It pumps blood around the body.
The inside of the heart is divided into two sections so that
the two types of blood (oxygen-rich and oxygen- poor) are kept
apart Oxygen-poor blood Right side of the heart Oxygen-rich blood
Left side of the heart
The right and left sides of the heart are separated by a
septum, or wall. The septum prevents the mixing of oxygen rich and
oxygen poor blood. On each side of the septum are two chambers. The
upper chamber (receives blood) is the atrium. The lower chamber
(pumps blood out of heart) is the ventricle.
Four chambers Two Atria Upper chambers Left and right Separated
by interatrial septum Two Ventricles Lower chambers Left and right
Separated by interventricular septum Right Ventricle Right Atrium
Left Ventricle Left Atrium
The chambers of the heart have different functions: blood to
the body blood from the body blood to the lungs blood from the
lungs The Atria collect blood that enters the heart. The ventricles
pump blood out of the heart.
The valves between the atria and ventricles are connected to
the inner walls of the heart by tough tendons. valve open
The tendons allow the valves to close and hold the valve flaps
in place. They prevent the valves from flipping up and turning
inside out valve open valve closed
A valve acts like a door that only opens in one direction. In
the heart, the tendons holding the valve are like the arm holding
the door. One end of each tendon is fixed to the wall of the heart
and so the valve can only open in one direction.
The heart can pump blood because it is made of muscle. Muscle
tissue works by contracting (squeezing) and relaxing.
All the parts of the heart on either side, work together in a
repeated sequence. The two atria contract and relax; then the two
ventricles contract and relax. This is how blood moves through the
heart and is pumped to the lungs and the body. One complete
sequence of contraction and relaxation is called a heartbeat.
As blood moves through the circulatory system it moves through
3 types of blood vessels: Arteries: Carry blood away from the heart
. Capillaries: Link arterioles to veins. Veins: Carry blood towards
Arteries Large vessels Carry blood from heart to tissues of
body. Carry oxygen rich blood, with the exception of pulmonary
arteries. Thick walls-need to withstand pressure produced when
heart pushes blood into them. Smallest blood vessels Walls are only
one cell thick and very narrow. Important for bringing nutrients
and oxygen to tissues and absorbing CO2 and other waste products.
Once blood has passed through the capillary systems it must be
returned to the heart. Done by veins Walls contains connective
tissue and smooth muscle. Largest veins contain one way valves that
keep blood flowing toward heart. Many found near skeletal muscles.
When muscles contract, blood is forced through veins.
The heart produces pressure The force of blood on the wall of
the arteries is known as blood pressure. Blood pressure decreases
as the heart relaxes, but the rest of the circulatory system is
still under pressure.
When blood pressure is taken, the cuff is wrapped around the
upper portion of the arm and pumped with air until blood flow in
the artery is blocked. As the pressure in the cuff is relaxed, 2
numbers are recorded. Systolic pressure- the first number taken, is
the force felt in the arteries when the ventricles contract.
Diastolic pressure- the second number taken, is the force of the
blood on the arteries when the ventricles relax.
Blood What percent of your body is blood? How much blood do we
contain? On average 4-6 liters We contain about a pint of blood for
every 15 pounds of body weight Composition of Blood: What percent
of your blood is cellular? What percent of your blood is plasma? 8%
Composed of plasma and blood cells Types of Cells are: Red
Blood Cells White Blood Cells Platelets Plasma Straw colored 90%
water 10% dissolved gases, salts, nutrients, enzymes, hormones,
wastes, and proteins.
Plasma proteins 3 Types: Albumins, globulins and fibrinogen.
Albumins and Globulins- transport substances such as fatty acids,
hormones and vitamins. Fibrinogen- Responsible for bloods ability
to clot Most numerous type Transport oxygen Get color from
hemoglobin Disk shaped Made in red bone marrow Circulate for 120
Guard against infection, fight parasites, and attack bacteria
Number of WBCs increases when body is fighting Lymphocytes produce
antibodies which fight pathogens and remember them Platelets Aid
the body in clotting Small fragments Stick to edges of broken blood
cell and secrete clotting factor to help form clot.
Blood has 3 main Functions Transport Protection Temperature
Regulation Plasma Red Blood Cells Platelets White Blood Cells