2. Contents  Functions of the Cardiovascular System  The Heart  Blood Vessels  Blood

3. Functions of the Cardiovascular System OBJECTIVE: Describe the main functions of the cardiovascular system  The main functions of the cardiovascular system include delivering materials to cells and carrying wastes away. Also, blood contains cells that fight disease.

4. Functions of the Cardiovascular System Delivering Materials  The heart continuously pumps blood in the blood vessels throughout the whole body.  Many of the substances your body needs dissolve into the blood Removing Wastes  The Cardiovascular System also transports waste form cells.

5. Functions of the Cardiovascular System Fighting Disease  Blood contains cells that attack micro- organisms that cause disease.  It contains substances that seal cuts, preventing blood loss and the entry of microorganism.

6. The Heart  The cardiovascular system contains a network of blood vessels with two major loops.  The first loop from the heart to the lungs releases carbon dioxide and picks up oxygen by the blood, and then returns to the heart.  The second loop delivers oxygen nutrients and picks up wastes throughout the body.  The loops cross paths at your heart.

7. The Heart Structure of the Heart  The heart has a right side and a left side, separated by a thick wall.  Each side has two chambers: the Atrium (upper chamber) and the Ventricle (lower chamber).

8. The Heart OBJECTIVE: Trace the pathway of blood through the heart.  The atria receive blood entering the heart. Blood flows from the atria to the ventricles, which pump blood out of the heart.

9. The Heart Your Heartbeat  The heart has 2 main phases. Diastole and Systole  In Diastole, the heart relaxes and the atria fills with blood.  In Systole, the heart contracts and pumps blood.

10. The Heart  The rate at which your heart muscles contract is regulated by the pacemaker, a small group of cells in the wall of the right atrium.  Your heart beats at approximately 70 to 80 times per minute. When you are active, your heart speeds up depending on the body’s need for more oxygen and nutrients and to remove excess carbon dioxide.

11. Blood Vessels  Your heart pumps blood through an extensive network of blood vessels OBJECTIVE: Identify three types of blood vessels  The three main types of blood vessels in your body are arteries, capillaries, and veins.

12. Blood Vessels Arteries  Arteries are blood vessels that carry blood away from the heart.  Most arteries carry oxygen-rich blood.  The largest artery in the body is the aorta. Blood leaves the left ventricle through the aorta, which branches into many smaller arteries.

13. Blood Vessels Veins  Veins are large, thin-walled blood vessels that carry blood to the heart.  From the capillaries, blood flows into small vessels that join together to form veins.  Skeletal muscle contractions help to squeeze blood back toward the heart. By then, the pumping force of the heart has little effect.  Valves inside the veins prevent blood from flowing backward.

14. Blood Vessels Capillaries  Capillaries branch out from the smallest arteries. They are the smallest blood vessels in your body.  Oxygen and dissolved nutrients diffuse as blood flows through the capillary walls and into your body’s cells. At the same time, wastes from body cells (carbon dioxide), diffuse into the blood.  They are involved in regulating body temperature.

15. Blood Vessels Measuring Blood Pressure  Blood Pressure is the force with which blood pushes against the walls of your blood vessels.  a sphygmomanometer is an instrument to measure blood pressure.  The first reading represents the systolic pressure – the pressure caused when the heart’s ventricles contract. When the sound stops, the provider records the second reading – diastolic pressure – the pressure when the ventricles are relaxed.

16. Blood Vessels  Normal Blood Pressure: Blood pressure is considered normal if it falls within the range of 90/60 to 119/79.  Low Blood Pressure: Blood pressure lower than 90/60. Causes of Blood pressure include medications, dehydrations, and allergic reactions.  High Blood Pressure: A person whose blood pressure is consistently 140/90 or greater. People with high blood pressure are likely to develop hypertension.

17. Blood OBJECTIVE: Identify the four components of blood.  The four components of blood are plasma, red blood cells, white blood cells, and platelets. Plasma  Plasma is the liquid component of the blood.  It makes up about 55% of the blood.  It is mostly water, with nutrients, hormones, and salts dissolved in it.  Plasma also carries waste products such as urea to the kidneys for removal from the body.

18. Blood White Blood Cells  White blood cells help protect you against disease and foreign substances.  They are larger than red blood cells but are less numerous.  Some white blood cells make chemicals that help your body resist diseases such as cancer.  Others destroy invading microorganisms by surrounding and consuming them.

19. Blood Red Blood Cells  Red blood cells are cells that carry oxygen from the lungs to all the parts of your body.  Contains hemoglobin which is an iron-containing substance to which oxygen binds.  The reaction between oxygen and the iron in hemoglobin gives blood its bright red color.  Once the oxygen is diffused to tissues, blood becomes a dull red.

20. Blood Platelets  Are cell fragments that play an important role in the blood clotting process.  Platelets stick to the edges of the cut and release proteins called clotting factors.  Clotting factors and other plasma proteins form a net of fibers across the cut trapping platelets and blood cells until a plug forms to seal the cut.  When the plug dries, it forms a scab.

21. Blood Blood Types  A person’s blood type is determined by the proteins present on the surface of the red blood cells (It can be A, B, AB, or O– depending on which proteins are present.)  A second blood type is determined by the presence or absence or the Rh factor protein.  If red blood cells have the Rh factor, it is said to be Rh positive. If red blood cells lack the Rh factor, your blood is Rh negative.  About 85% of people are Rh positive

22. Blood Transfusions  After an injury, surgery or some illness, a person may require blood transfusion.  During a transfusion, blood form a donor is transferred to the patient’s bloodstream.  Donated blood is tested to identify the blood type. It is also screened for the presence of some microorganisms such as those that cause hepatitis or AIDS  If a patient is given the wrong blood type during a transfusion, the blood will clump together in the patients blood vessels. This is a life threatening reaction.

24. Questions What are the main functions of the cardiovascular system? What are the 2 main phases of the heart? Name the blood types

25. Answer Delivering materials to cells, carrying wastes away, and fighting diseases. Diastole and Systole A, B, AB, and O