Circulatory System Notes
[Part 1]
Functions of the Circulatory System
1. Carry needed substances to cells
a. Examples:
2. Carry waste products away from cells
a. Example:
3.
What are the 2 Major structures of the Circulatory System?
The Heart
 The human heart has 4 chambers
o The two top chambers are called _________ (singular = atrium)
o The bottom two chambers are called _______________
Blood Flow through the Heart
Inferior Vena Cava & Superior Vena Cava  ____________________  Tricuspid Valve  Right
Ventricle  Pulmonary Arteries  Lungs  Pulmonary Veins  Left Atrium  _________________ 
Left Ventricle  __________  Body  Inferior Vena Cava & Superior Vena Cava
[Part 2]
Blood Vessels



These are elastic! They get bigger and smaller…
o Vessels getting ______________ = dilating
o Vessels getting smaller = _________________
Your blood vessels help you out when you are hot and when you are cold!
o If you are hot…Your blood vessels get bigger (__________________). They move closer
to the epidermis and _____________ heat. This cools you off!
o If you are cold…Your blood vessels get smaller (_________________). They move
_____________________ from the epidermis and keep heat in. This warms you up!
Draw a picture below of vasodilation and vasoconstriction:
2 Types of Blood Vessels
1. Arteries - blood vessel that leads blood __________ from the heart
o ___________________ – arteries start branching into smaller vessels called arterioles
2. Veins - Blood vessel that leads blood ______________ the heart
a. Venules – veins start ________________ into smaller vessels called venules arterioles
In between…Capillaries
o Where arterioles turn into venules
o Smallest blood vessels
o Only big enough for _______________________ to get through at a time
o _________________ of oxygen and carbon dioxide occur here
2 Loops
Your circulatory system is basically 2 loops:
 Pulmonary Loop:

Systemic Loop:
[Part 3]
What are some facts about blood?
Erythrocytes
 AKA: ____________________________________
 Donut shaped! (But there’s not a hole in the middle, it’s just flattened out)
 Makes up ______ of all blood
 Main job:
 Only last for __________________, then they are removed from the body by the liver
 Contains hemoglobin
Hemoglobin
 Protein on the erythrocyte that holds the ______________ molecule
Leukocytes
 AKA: ______________________________
 Makes up _____ of all blood
 Protects body, fights infection
 Can leave the blood vessels to hunt down and ___________________________!
 Leukocyte levels can be measured to determine if person is sick
 If you are sick (fighting infection), your body makes a lot of leukocytes to win the fight… so more
leukocytes = ______________________________
Platelets
 Makes up _____ of all blood
 Pieces of cells
 _______________________
Plasma
 Makes up 53% of all blood
 Fluid part of blood
o Mostly water
Hematopoiesis
 Blood cell formation (making blood cells)
 Happens in:
o the ends of long bones in red bone marrow
o flat bones like skull and pelvis
o ribs & sternum
Blood Transfusions
 Blood Transfusion – the transfer of blood from one person to another
 Why would someone need to receive blood from another person?
o Certain diseases like Sickle Cell Anemia
o Cancer, for example Leukemia
o Surgeries like organ transplant or Open-Heart Surgery
 Open-Heart surgeries can require up to 10 pints of blood
Blood Types
What are the 4 blood types in humans?
A, B, AB, & O
Remember... The Key to Blood Donation is Blood Types!
1. Antigens are little proteins on the outside of red blood cells
2. Antibodies are made for any antigens you don’t have on your red blood cells
3. If you put blood in your body, and you have already made antibodies for those antigens, your
body will start attacking
4. This attacking can lead to blood clots, which can cause heart attacks and strokes
[Part 4]
Blood Disorders
Anemia – Decrease in the erythrocyte’s ability to carry oxygen
Causes:
1. Low erythrocyte count
2. Low hemoglobin count
3. Abnormal hemoglobin: Sickle Cell Anemia
Symptoms:
1. Fatigue – tiredness
2. Tachycardia – fast heart rate
3. Feeling cold
4. Dizziness/Fainting
Sickle Cell Anemia
Sickle-shaped cells are sticky and can start blocking blood vessels. No blood flow = very bad!
Symptoms:
1. Pain
2. All other anemia symptoms
Hemophilia
Symptoms:
1. “Free Bleeder”
2. Cannot clot blood
3. Bruise easily
4. Can cause death
Leukemia
Cause:
•
Too many white blood cells are made
•
Those cells don’t work well (they aren’t doing their job!)
•
Crowd out normal, healthy cells and keep them from doing their job too
Symptoms:
• Frequent/severe infections
• Fever
• Fatigue/weakness
• Unexplained weight loss