1. The Circulatory System
Sections 11.1, 11.2, 11.3

2. The Circulatory System
Learning Goal: To explore the circulatory system.
Success Criteria:
I know I am succeeding when I can…
discuss the functions of the circulatory system
list the main parts of the circulatory system
describe the components of blood and the function of each
discuss the different types of blood vessels, including their structures and functions
explain the value of pulse and blood pressure measurements

3. The Circulatory System
Circulatory System: the organ system that transports oxygen, nutrients and other materials throughout the body and carries away waste
also maintains body temperature and transports white blood cells to fight disease

4. The Circulatory System Cont’d…
the circulatory system is made up of the heart, blood, and blood vessels

5. Blood
blood is connective tissue
there are four components of blood

6. 1. Plasma liquid in which blood cells and platelets are suspended
90% of plasma is water
plasma contains a variety of substances: oxygen, proteins, and nutrient molecules such as glucose, minerals, and vitamins, along with carbon dioxide
plays an important role in balancing the amount of water within the body and maintains volume of blood

7. 2. Red Blood Cells (Erythrocytes)
carry oxygen from the lungs to the body cells, and to carry carbon dioxide from the body cells back to the lungs to be expelled
oxygen binds to hemoglobin molecules on the RBC
Red blood cells lose their nucleus’ to make more room for hemoglobin to increase their capacity to transport oxygen
a.k.a erythrocytes
biconcave disks (increases surface area)
carry oxygen from the lungs to the body cells, and to carry carbon dioxide from the body cells back to the lungs to be expelled
oxygen binds to hemoglobin molecules on the RBC
Oxygen lose their nucleus’ to make more room for hemoglobin to increase their capacity to transport oxygen
made in the bone marrow and once they die (approx. 120 days) they are removed by the liver and spleen
if the RBC are too low, the kidney will release the EPO hormone which will stimulate the marrow to make more

8. 2. Red Blood Cells (Erythrocytes)
RBC are made in the bone marrow and once they die (approx. 120 days) they are removed by the liver and spleen
if the RBC are too low, the kidney will release the EPO hormone which will stimulate the bone marrow to make more
a.k.a erythrocytes
biconcave disks (increases surface area)
carry oxygen from the lungs to the body cells, and to carry carbon dioxide from the body cells back to the lungs to be expelled
oxygen binds to hemoglobin molecules on the RBC
Oxygen lose their nucleus’ to make more room for hemoglobin to increase their capacity to transport oxygen
made in the bone marrow and once they die (approx. 120 days) they are removed by the liver and spleen
if the RBC are too low, the kidney will release the EPO hormone which will stimulate the marrow to make more

9. 3. White Blood Cells (Leukocytes)
fight against harmful bacteria, viruses, and other organisms that can cause diseases
several different types of leukocytes (all have nuclei)
formed in bone marrow

10. 3. White Blood Cells (Leukocytes) Cont’d…
many leukocytes use phagocytosis (engulfing) to destroy bacteria or harmful substances within cells
once the cell has engulfed its target, enzymes are released and destroy the target and the leukocyte itself
the remnants of the leukocyte and whatever it engulfed are left behind as a whitish substance known as pus
formed in bone marrow

11. 4. Platelets
platelets are small cell fragments that are essential in blood clotting, or coagulation
Produced by stem cells in bone marrow

12. 4. Platelets Cont’d…
when a blood vessel is broken, platelets stick to the blood vessel wall to seal the hole in the blood vessel
a blood clot (made of fibrin from the plasma, platelets, and blood cells) is then formed underneath that stops the leakage of blood and allows time for the injury to heal
Produced by stem cells in bone marrow

13. Blood Vessels
blood vessels form a network of tubes that transport blood throughout the body
there are three main types of blood vessels
Produced by stem cells in bone marrow

14. i. Arteries and Arterioles
carries blood away from the heart toward the body tissues
have thick , elastic walls to withstand pressure of the blood being pump from the heart

15. i. Arteries and Arterioles Cont’d…
when blood is forced through the artery by the contraction of the heart, the artery expands
felt as the pulse of the artery is fairly large, close to the skin, and in front of a bone or other firm structure
there are different pulse points on the body

16. i. Arteries and Arterioles Cont’d…
arteriole: the smallest artery
since they have smooth muscle in their walls, signals from the nerves can regulate the diameter of the arterioles and control the blood flow to certain parts of the body
vasodilation increases the blood flow to tissues
vasoconstriction decreases the blood flow to tissues

17. ii. Capillaries
networks of blood vessels that supply oxygen and nutrients to EVERY cell throughout the body tissues (no body cell is farther than two cells away from a capillary)
have VERY thin walls (one cell thick) to allow for diffusion of O2, CO2, nutrients and wastes

18. ii. Capillaries Cont’d…
there are pre-capillary sphincter muscles where the arteriole branches into a capillary
if blood is not needed in a particular capillary network, the pre-capillary sphincters contract and reduce blood flow
during exercise, for example, the arterioles and sphincters are fully relaxed, and the blood flow to the muscles is increased

19. iii. Veins and Venules
veins and venules (smallest veins) carry deoxygenated blood containing carbon dioxide and other waste products from the body tissues to the heart
veins are thinner and less elastic than arteries, since blood flowing through veins is low pressure after moving through the capillaries

20. iii. Veins and Venules Cont’d…
some veins have internal valves to make sure blood moves in the right direction
also when our muscles contract, they squeeze the veins which increases the pressure in the veins and helps push the blood back toward the heart

21. The Circulatory System
Learning Goal: To explore the circulatory system.
Success Criteria:
I know I am succeeding when I can…
discuss the functions of the circulatory system
list the main parts of the circulatory system
describe the components of blood and the function of each
discuss the different types of blood vessels, including their structures and functions
explain the value of pulse and blood pressure measurements

22. Homework
11.1 questions #1-5
11.2 questions #1-2
11.3 Questions #1-6