• The Circulatory System
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The cardiovascular system is made up of six main parts: The Heart, Arteries,
Arterioles, Capillaries, Venules, and Veins
The Heart
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The heart is a double pump.
The right side is responsible for getting oxygen-poor blood to the lungs.
This is Pulmonary Circulation
The left side is responsible for getting oxygen-rich blood around the body.
This is Systemic Circulation
The atria are responsible for receiving blood from the veins and passing it to the
ventricles.
- The ventricles are responsible for pushing the blood out of the heart and into the
arteries.
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Heart Beat
- Blood enters both atria when heart muscles are at rest, this is called diastole.
- The heart contracts once to push the blood into the ventricles, then once more a few
seconds later to push blood into the arteries. This is called systole.
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The Heart
- The average human heart, beating at 72 beats per minute, will beat approximately
2.5 billion times during an average 66 year lifespan
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Arteries
- An Artery is a blood vessel that carries blood from the heart to other parts of the
body.
- They are the largest and thickest blood vessels in the body
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Capillaries
- Capillaries are blood vessels with thin walls where gases, liquids and white blood cells
are exchanged between the circulatory system and the rest of the body by diffusion
- Arteries branch and narrow into smaller arteries called arterioles which narrow into
even smaller capillaries
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Veins
- Veins are blood vessels that carry blood back to the heart
- Once capillaries have irrigated the organs, they reunite to form larger venuoles and
even larger veins.
- There is very little pressure in veins, blood moves forward due to muscle
contractions.
- There are also valves which prevent blood from flowing the opposite direction.
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Blood is composed of:
- RED BLOOD CELLS (Erythrocytes) – The most abundant cells in our blood; they are
produced in the bone marrow and contain a protein called hemoglobin that carries
oxygen to our cells.
- WHITE BLOOD CELLS (Leukocytes) – They are part of the immune system and destroy
infectious agents called pathogens.
- PLASMA – This is the yellowish liquid portion of blood that contains electrolytes,
nutrients and vitamins, hormones, clotting factors, and proteins such as antibodies to
fight infection.
- PLATELETS(Thrombocytes) – The clotting factors that are carried in the plasma; they
clot together in a process called coagulation to seal a wound and prevent a loss of
blood.
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Blood Facts
- The average adult has about FIVE liters of blood inside of their body, which makes up
7-8% of their body weight.
- Blood is a living tissue that
Carries oxygen nutrients to all parts of the body
Carries nutrients to all parts of the body
Carries carbon dioxide and other waste products for disposal.
Fights against infection and helps heal wounds, so we can stay healthy.
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Red Blood Cells
- There are 4 to 6 BILLION in one mL of blood
- The have a biconcave disk shape (concave on both sides), have NO nucleus and few
organelles.
- They contain HEMOGLOBIN to help transport oxygen
- They also transport Carbon Dioxide
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White Blood Cells
- There are 4-11 MILLION in one mL of blood
- Very important for immunity and defense against disease
• Genetics of Blood Types
- Your blood type is established before you are BORN, by specific GENES inherited
from your parents.
- You inherit one gene from your mother and one from your father.
- These genes determine your blood type by causing proteins surface of all of your red
blood cells. These proteins are named substance A and substance B.
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What are blood types?
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Rh Factors
- While studying Rhesus monkeys, a certain blood protein was discovered. This protein
is also present in the blood of some people. Other people, however, do not have the
protein.
- The presence of the protein, or lack of it, is referred to as the Rh (for Rhesus) factor.
- If your blood does contain the protein, your blood is said to be Rh positive (Rh+). If
your blood does not contain the protein, your blood is said to be Rh negative (Rh-).
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Blood Evidence
- Blood samples – Can be analyzed to determine blood type and DNA, which can be
matched to possible suspects.
- Blood droplets – Can be analyzed to give clues to the location of a crime, movement
of a victim, and type of weapon.
- Blood spatter – Can be analyzed to determine patterns that give investigators clues
to how a crime might have happened.