1. The Circulatory System

2. The Circulatory System
Transportation system of a living organism (move things around body like streets and highways of a city)
Humans have closed circulatory system (blood flows through vessels)
In pictures, the heart will be pictured “backwards”

3. The Heart Composed mostly of muscle and is the size of a fist
Contractions of heart pump blood through circulatory system
Right side of heart divided from left side by septum (a wall of muscle). This wall prevents mixing of O2 poor blood and O2 rich blood
Heart has four chambers
2 atria – upper chambers, left and right atrium, receive blood into heart
2 ventricles – lower chambers, left and right ventricles, pump blood out of heart

4. The Heart CO2 Rich, O2 Poor Blood from body To Body To Lungs
Inferior Vena Cava
Vein that brings oxygen-poor blood from the lower part of the body to the right atrium
Tricuspid Valve
Prevents blood from flowing back into the right atrium after it has entered the right ventricle
Pulmonary Valve
Prevents blood from flowing back into the right ventricle after it has entered the pulmonary artery
Pulmonary Veins
Bring oxygen-rich blood from each of the lungs to the left atrium
Superior Vena Cava
Large vein that brings oxygen-poor blood from the upper part of the body to the right atrium
Aorta
Brings oxygen-rich blood from the left ventricle to the rest of the body
Pulmonary Arteries
Bring oxygen-poor blood to the lungs
Aortic Valve
Prevents blood from flowing back into the left ventricle after it has entered the aorta
Mitral Valve
Prevents blood from flowing back into the left atrium after it has entered the left ventricle
To Body
Left Atrium
To Lungs
O2 Rich, CO2 Poor Blood from lungs
Right Atrium
Left Ventricle
Septum
Right Ventricle

5. Circulation Through the Body
Heart is two separate pumps
Right side pumps O2 poor blood from heart to lungs = pulmonary circulation (in lungs, CO2 leaves blood and O2 enters blood)
Left side pumps O2 rich blood to body = systemic circulation

6. Just so You Know……..
ALL BLOOD IS RED!!!!!!!!!! O2 rich and O2 poor blood is RED!!!!!!!!! In PICTURES, O2 poor blood is often colored blue so that you can see the path of the O2 poor blood. ALL BLOOD IS RED!!!!!!!!!!

7. Blood Flow Through Heart
Blood enters heart through the atria and flows into the ventricles and then out from the ventricles
Valves in the heart between the atria and ventricles prevent blood from moving backwards within the heart
Valves at the exits of the ventricles prevent blood from flowing back into the heart
These valves keep blood moving in ONE direction

8. Circulation Through the Body
Capillaries of head and arms
Capillaries of abdominal organs and legs
Inferior vena cava
Pulmonary vein
Capillaries of right lung
Superior vena cava
Aorta
Pulmonary artery
Capillaries of left lung

9. The Circulatory System

10. Heartbeat
Muscle fibers (one in the atria and one in the ventricles) are stimulated by the nervous system = contraction of the heart
Heart beats faster or slower depending on how much O2 the body needs

11. Heartbeat

12. Blood Vessels
Three types of blood vessels in circulatory system – arteries, capillaries, and veins

13. Arteries
Arteries – large vessels that carry blood from the heart to the body
Almost all arteries carry O2 rich blood
Thick walls made of smooth muscle that withstand the pressure of the blood coming out of the heart
When you feel your pulse, you are feeling the walls of an artery moving

14. Capillaries Capillaries – smallest blood vessels
Very thin walls (one cell thick) and VERY small
Bring nutrients and O2 to cells and remove CO2 from cells

15. Veins Veins – blood returns to heart in veins Made of smooth muscle
Have valves to prevent backflow

16. The Three Types of Blood Vessels
Artery
Vein
Connective tissue
Smooth muscle
Endothelium
Valve
Venule
Arteriole
Capillary

17. Blood Pressure Force of blood on arteries’ walls = blood pressure
Two numbers – systolic and diastolic pressures
Systolic pressure = force felt in arteries when ventricles contract (top number)
Diastolic pressure = force felt in arteries when ventricles relax (bottom number)
Average for adults is 120/80

18. Blood
Blood collects O2 from lungs, nutrients from digestive tract, and waste products from cells
Helps regulate body temperature
Helps fight infections
Helps to form clots to repair vessels
4 to 6 Liters of blood in body

19. Blood Plasma Platelets White blood cells Red blood cells
Whole Blood Sample
Sample Placed in Centrifuge
Blood Sample That Has Been Centrifuged

20. Blood Plasma Platelets White blood cells Red blood cells
Whole Blood Sample
Sample Placed in Centrifuge
Blood Sample That Has Been Centrifuged

21. Blood Plasma 45% of blood is cells
55% is plasma, which is mostly water
Plasma helps to transport substances, clot blood, and fight infections

22. Blood Cells Two types of blood cells – Red and White Blood Cells
Red Blood Cells (RBC) – transport O2
Most numerous
Get color from hemoglobin
Shaped like discs
Made from red bone marrow
Live for 120 days
White Blood Cells (WBC) – attack foreign substances or organisms
Less numerous
No hemoglobin
Most live for a few days

23. Blood Clotting
Made possible by plasma proteins and cell fragments called platelets
When platelets come into contact with broken blood vessels, they become sticky and cluster around would. They release proteins that start a series of chemical reactions, eventually forming tiny filaments which stop the bleeding

24. Blood Clotting Break in Capillary Wall Blood vessels injured.
Clumping of Platelets
Platelets clump at the site and release thromboplastin. Thromboplastin converts prothrombin into thrombin..
Clot Forms
Thrombin converts fibrinogen into fibrin, which causes a clot. The clot prevents further loss of blood..

25. Inflammation

26. The Lymphatic System As blood circulates, some leaks into tissues
Network of vessels (lymphatic system) collects this fluid lost by the blood and returns it to the circulatory system
Helps with nutrient absorption
Helps fight off infection – “swollen glands” when you’re sick