Name ____________________________________________________
The Heart
The Path of Blood
After reading, color the bolded terms on the diagram above. Make a key.
The right atrium (A), which is the upper chamber of the right side of the heart,
receives blood from the upper body through the superior vena cava (B), and from the lower
body the inferior vena cava (C). The blood is a darker color because it is returning from the
body carrying carbon dioxide (cellular waste) that was release by cells as the blood deposited
oxygen.
Blood then flows through the tricuspid valve (D) into the right ventricle (E), which
is the lower chamber on the right side of the heart. Through contraction of the right
ventricle, the darker-colored blood is forced through the pulmonary valve (F) into the
pulmonary artery (G). The pulmonary artery transports blood to the right and left lung to
pick up oxygen and release carbon dioxide waste. While in the lungs, the blood changes
color to a bright red because it is now full of fresh oxygen needed by the body. It returns
from both lungs through the pulmonary veins (H).
The red blood carrying oxygen for all the body cells will now re-enter the left upper
chamber of the heart, the left atrium (I). It then flows through the mitral valve (L) and into
the lower left chamber, the left ventricle (K). Finally the oxygenated blood passes through
the aortic valve (L) into the aorta (M), the largest artery, where it is sent to all parts of the
body
The Heart Cycle
Use the diagrams and reading you just completed to answer the questions below.
1. Starting from and ending with the heart, trace the blood flow through the
human circulatory system by numbering the following in the correct order.
2.
________ heart
_______ capillaries
________ veins
_______ arteries
________ arterioles
_______ venules
Starting from and ending with the right atrium, trace the flow of blood
through the heart and body by numbering the following in correct order
________ right atrium
________ lungs
________ left atrium
________ right ventricle
________ pulmonary artery
________ left ventricle
________ vena cava
________ body cells
________ aorta
________ pulmonary veins
3.
The ____________________ (left or right) side of the heart contains blood with a
low level of oxygen.
4.
The ____________________ side of the heart contains blood with a high level of
oxygen.
Stage 1: Deoxygenated blood enters the right atrium through the superior and inferior vena
cava. Color the area BLUE around the numbers 1 ,2, and 3.
5.
The ____________________ side of the heart pumps blood to all the organs of the
body.
Stage 2: When the right atrium is full, it contracts and forces blood through the bicuspid
valve and into the right ventricle. Color the area Draw BLUE around number 4.
6.
Through which veins does the deoxygenated blood enter the right atrium?
7.
What structure must the blood pass through before it enters the right ventricle?
8.
Where is the blood pumped after it leaves the right ventricle?
Stage 4: The blood returns from the lungs to the left atrium through the pulmonary veins.
While in the lungs, the red blood cells become saturated with oxygen and change from a
bluish color to a bright red. Color the area RED on numbers 6 and 7.
9.
What is the job of the pulmonary veins?
Stage 5: When the left atrium is full, in contracts and forces blood through the bicuspid valve
and into the left ventricle. Color the area RED on number 8.
10. What happens when the left atrium is full?
Stage 6: The last stage of the heart cycle occurs when the bicuspid valve slams shut and the
oxygen enriched blood in pumped out of the left ventricle through the aorta. From the aorta,
the blood is directed to the body’s cells. Color the area RED on 9 and 10.
11. Why are the lower chambers of the heart more muscular than the upper
chambers?
Stage 3: After the blood passes into the right ventricle, the tricuspid valve slams shut. The
muscular wall of the right atrium contracts, forcing blood through the pulmonary artery and
into the lungs. Color the area BLUE around number 5.
12. Why is the left ventricle so much more muscular than the right?