1. Notes 3 The Circulatory System Part 2
Bio Unit 3
Notes 3
The Circulatory System Part 2

2. Pulmonary (to and from heart and lungs) Systemic (to the body systems)
Now that we have looked at the structure of the heart and blood vessels we can look at blood composition and blood flow. There are three main pathways that blood has to follow in the human heart:
Cardiac (in the heart)
Pulmonary (to and from heart and lungs)
Systemic (to the body systems)
The only one we need to know in detail is the cardiac pathway!

3. A few things to know: Blood enters the heart through the atria, and leaves through the ventricles.
The two atria contract simultaneously and then two ventricles contract simultaneously shortly after. This is the “double pump” feeling you get when you check your pulse. Try it!\

5. Path of the Blood in the Heart
Flows into the right atrium from the superior vena cava
Pumped into the right ventricle from the right atrium
Pumped into the lungs from right ventricle by pulmonary artery
Enters left atrium from pulmonary vein
Pumped into left ventricle from left atrium
Pumped into aorta from left ventricle and into systemic circulation

8. Notes 4 - Components of Blood
Blood has 3 main components:
Plasma
Red blood cells
White Blood Cells

9. See fig. 9.10 on page 309 and add to the following diagram

10. Plasma
55% of blood
Refers to the fluid portion of your blood (everything else is cells) Made up of:
Water, dissolved gases, proteins, sugars, vitamins, minerals, waste, etc.

11. Red Blood Cells (RBC) 44% of your blood
Also called erythrocytes Transport of Oxygen (O2) and Carbon Dioxide (CO2) to and from body tissue
See fig 9.11 on page 309 for images
Contains hemoglobin ( a molecule that binds with oxygen to transport oxygen in the blood)
Has no nucleus

12. RBC = Red Blood Cells

13. White Blood Cells (WBC)
Remaining 1% of your blood Also called leukocytes Double in numbers when your body is fighting off infection. Contains a nucleus and cytoplasm Two main types: Macrophages & Lymphocytes Macrophages are phagocytic meaning that they “eat and digest pathogens aka infectious cells” Macrophages are a part of the body’s natural innate immune response Lymphocytes are nonphagocytic and they help with our acquired immune response, which means they simply recognize and defend specific pathogens only.