The Heart and the Circulatory System
Glossary
Aorta: the main systemic artery of the body, emerging directly from the left ventricle.
Arteriole: a small arterial branch that delivers blood directly to a capillary bed.
Artery: a muscular blood vessel that carries blood away from the heart.
Atrium: one of the chambers of the heart that receives blood directly from a vein.
Circulatory system: the system of the body responsible for internal transport. Composed of the
heart, blood vessels, lymphatic vessels, lymph, and the blood.
Coronary artery: one of the arteries that supply blood to the heart.
Coronary vein: one of the veins that receive blood from the heart muscle and empty directly
into the right atrium.
Heart: the muscular organ composed of cardiac muscle that is responsible for pumping blood
throughout the body.
Pulmonary artery: one of the arteries carrying deoxygenated blood from the heart to the lungs.
Septum: the wall dividing the two ventricles.
Sinus: a cavity into which blood flows and baths the internal organs in organisms with an open
circulatory system.
Vein: one of the blood vessels that carries blood to the heart.
Ventricle: one of the muscular chambers of the heart that is responsible for pumping blood from
the heart into the arteries.
Venule : a small venous branch that carries blood from a capillary bed to a vein.
= without oxygen
= with oxygen
Same Structures:
1 & 15
3&9
4 & 10
Answer Key:
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Aorta
Superior Vena Cava
Pulmonary Artery
Pulmonary Veins
Right Atrium
Tricuspid Valve
Right Ventricle
Inferior Vena Cava
Pulmonary Artery
Pulmonary Vein
Left Atrium
Mitral Valve
Aortic Valve
Left Ventricle
Aorta
Extra Credit  Compare and Contrast
characteristics of arteries and veins
The Blood Vessels
We need to briefly discuss the anatomy of the vessels. There are three
types of vessels - arteries, veins, and capillaries. Arteries, veins, and
capillaries are not anatomically the same. They are not just tubes
through which the blood flows. Both arteries and veins have layers of
smooth muscle surrounding them. Arteries have a much thicker layer,
and many more elastic fibers as well. The largest artery, the aorta
leaving the heart, also has cardiac muscle fibers in its walls for the first
few inches of its length immediately leaving the heart. Arteries have to
expand to accept the blood being forced into them from the heart, and
Blood vessel anatomy
then squeeze this blood on to the veins when the heart relaxes. Arteries
have the property of elasticity, meaning that they can expand to accept a
volume of blood, then contract and squeeze back to their original size after the pressure is
released. A good way to think of them is like a balloon. When you blow into the balloon, it
inflates to hold the air. When you release the opening, the balloon squeezes the air back out. It is
the elasticity of the arteries that maintains the pressure on the blood when the heart relaxes, and
keeps it flowing forward. if the arteries did not have this property, your blood pressure would be
more like 120/0, instead of the 120/80 that is more normal. Arteries branch into arterioles as they
get smaller. Arterioles eventually become capillaries, which are
very thin and branching.
Capillaries are really more like a web than a branched tube. It is
in the capillaries that the exchange between the blood and the
cells of the body takes place. Here the blood releases its oxygen
and takes on carbon dioxide, except in the lungs, where the
blood picks up oxygen and releases carbon dioxide. In the
special capillaries of the kidneys, the blood gives up many waste
Capillary Bed
products in the formation of urine. Capillary beds are also the
sites where white blood cells are able to leave the blood and
defend the body against harmful invaders. Capillaries are so small that when you look at blood
flowing through them under a microscope, the cells have to pass through in single file. As the
capillaries begin to thicken and merge, they become venules. Venules eventually become veins
and head back to the heart. Veins do not have as many elastic fibers as arteries. Veins do have
valves, which keep the blood from pooling and flowing back to the legs under the influence of
gravity. When these valves break down, as often happens in older or inactive people, the blood
does flow back and pool in the legs. The result is varicose veins, which often appear as large
purplish tubes in the lower legs.
Circulatory System
A system made up of three parts:
Transport nutrients and gases to different parts of the body where they can be used by the cells
Transport waste for removal along with __________________________________________
Types of Blood Vessels
_______________________: a muscular blood vessel that carries blood away from the heart.
____________________________________: a small arterial branch that delivers blood directly
to a capillary bed.
_______________________: one of the blood vessels that carries blood to the heart.
____________________________________: a small venous branch that carries blood from a
capillary bed to a vein.
________________________: the smallest blood vessel that allows oxygen to be exchanged.
Components of Blood
________%
___________________________- fluid part of blood
________%
___________________________- destroy bacteria and viruses
________%
of your body
___________________________- made from bone marrow and repair damaged areas
________%
___________________________- oxygen carries
Structures of the heart
The Heart
Two sides separated by a thick wall
Each side has an atrium and a ventricle
_____________________________: receives blood entering the heart
_____________________________: pumps blood from the heart to the rest of the
body
One way valves (their closing makes your heartbeat)
A double pump
_____________________________ = pumps blood to the lungs
_____________________________ = pumps blood to the rest of the body
Regulation of Heart Beat
Heart beat varies from person to person…why?
_______________________________- located in the right atrium, this group of cells regulate the rate
at which the cardiac muscles contract (____________________________)
__________________________________ regulates heart rate, but pacemaker works independently
The cardiac cycle
The contraction of the heart cause the distinctive sounds heard when listening to the heart with a
stethoscope. The "_____________________" sound is the sound of the valves in the heart closing.
When the atria end their contraction and the ventricles begin to contract, the blood is forced back
against the valves between the atria and the ventricles, causing the valves to close. This is the
"___________________" sound, and signals the beginning of ventricular contraction, known as
__________________ The "_________________" is the sound of the valves closing between the
ventricles and their arteries, and signals the beginning of ventricular relaxation, known as
________________________.
Pulmonary and Systemic Circulations
__________________________________Circulation: the pathway that blood follows from the heart to
the lungs (right side of the heart)
__________________________________Circulation: the route that blood travels from the heart to
most of the body and then back to the heart (left side of the heart)
The Pulmonary and Systemic Circuits and the Blood Supply to the Heart.
Systemic Circuit
_________________ side of the heart
__________________ in size (must pump blood to the rest of the body)
blood leaves through the _____________________, goes to ___________________________________
of the body through the systemic arteries, and then __________________________________________
through the systemic veins
Pulmonary Circuit
______________side of the heart
_____________________ in size (only pumps blood to the lungs)
blood leaves the heart through the ____________________________________________, goes to the
______________________, and returns to the heart through the
_________________________________________________.
How does the heart get blood?
__________________________________________________
arise from the aorta right after it leaves the heart.
branch into capillary beds that course throughout the heart walls and supply the heart muscle
with oxygenated blood.
_____________________________________________________
return blood from the heart muscle,
empty directly into the right atrium.
Flow of blood through the body
Right ventricle  pulmonary arteries  Lungs  pulmonary veins  left atrium  left ventricle 
aorta  arteries  capillaries  veins  vena cavas  right atrium  right ventricle
Blood Types
_____________________________________- classification based on whether certain proteins are
present on the surface of the red blood cells.
Types A, B, O, or AB
If different blood types are mixed, RBC’s will clump together
_____________________________- determines a blood type is in a blood group (positive or negative)
How is your blood type determined?
Each biological parent donates one of their two ABO alleles to their child.
A mother who is blood type O can only pass an O allele
A father who is blood type AB could pass either an A or a B allele
This couple could have children of either blood type A (O from mother and A from
father) or blood type B (O from mother and B from father).
Remember the _______________________________has a greater genetic influence than the
____________________________!
Rh+ = ______________________ or___________________
Rh-= ______________________
Just like the ABO alleles, each biological parent donates one of their two Rh alleles to their child.
A mother who is Rh- can only pass an Rh- allele
A father who is Rh+ could pass either an Rh+ or Rh- allele
This couple could have Rh+ children (Rh- from mother and Rh+ from father) or Rhchildren (Rh- from mother and Rh- from father).