1. The Circulatory System

2. Like a house, the circulatory system doesn’t just deliver blood to the body, but also carries away wastes like carbon dioxide

3. Blood vessels Arteries carry blood away from the heart
Veins carry blood to the heart
Capillaries exchange oxygen, nutrients, waste. They are very tiny.
Arteries also have adaptation to help them withstand pressure; they are stretchy and muscular. Bad diets or diseases can cause build up of unwanted materials in the blood vessels. Fat plaques are an example of this.

4. Veins have valves to prevent backwards flow of blood

5. Capillaries are so small, sometimes red blood cells have to move through them single file. Some capillaries have cell walls only a single cell thick! This is to help gasses such as oxygen and carbon dioxide pass from the blood to cells, or vice versa.

6. Red blood cells contain hemoglobin; a compound that carries oxygen.

7. Alveoli
Tiny air sacks in the lungs are surrounded by capillaries which help exchange oxygen

10. You do not need to remember the specific names of the valves

11. A heartbeat has two parts; the systole and diastole
A heartbeat has two parts; the systole and diastole. The diastole pumps blood from the top of the heart into the bottom, the systole pumps blood from the bottom of the heart to the lung and the rest of the body.

12. The tricuspid valve; an example of what a heart valve looks like

13. Blood components
Red Blood Cells
Contain no nucleus

14. Blood components White Blood Cells
You don’t need to know what each of the types does, but do know that white blood cells are heavily involved with the immune system and use phagocytosis to destroy invaders to the body (invaders are things like bacteria, viruses, etc.)

15. Blood components Platelets
Platelets help blood clot. They form a net of fibrin which catches red blood cells and forms a clot.

16. The blood is not just made of cells; plasma is a fluid that keeps blood runny, and cells are suspended in this plasma.