Cardiovascular System Part 2

1. Cardiovascular SystemPart 2 Sport Books Publisher

2. Properties of Vascular System Vascular System = a network of vessels that transports blood throughout the body 4 Main Categories: • Arteries thick, strong, elastic vessels • Carry blood away from the heart to different organs • Assists with movement of blood because of its ability to stretch and recoil (like an elastic band) • Arteriolessmaller in size than arteries • Have rings of smooth muscle which can contract (vasoconstriciton) and relax (vasodilation) • Regulate blood distribution to various tissues of the body • Controlled by nervous system and local chemical factors • Effect of locally produced chemical compounds on blood flow called autoregulation Sport Books Publisher

3. Properties of Vascular System 4 Main Categories cont: • Capillaries smallest vessels in the body • Where gas and nutrient exchange takes place, therefore capillaries are only 1 cell thick • Nutrients and gas exchange occurs via diffusion • Connect the smallest arterioles and smallest venules • Veins (venules)softer, thinner vessels, with less smooth muscle • Carry deoxygenated* blood to the heart under low pressure • Walls contain semilunar valves to prevent backward flow of blood • Smallest veins are called venules Sport Books Publisher

4. If blood pressure is low in veins, how does blood get back to the heart? • Think/Pair/Share – brainstorm ways you think the body could deal with getting blood back to the heart – against gravity?

5. If blood pressure is low in veins, how does blood get back to the heart? • The skeletal muscle pump: • Upon contraction of skeletal muscle, blood is pushed/massaged back to the heart The skeletal muscle pump

6. If blood pressure is low in veins, how does blood get back to the heart? • The thoracic pump: • Pressure in veins (in the chest) decrease while pressure in veins (in the abdominal cavity) increase upon intake of breath • Difference in pressure pushes blood from veins in the abdominal cavity into veins in the thoracic cavity • The nervous system: • Sends a signal to veins • Veins constrict allowing more blood back to the heart this is called venoconstriction

7. Break!!!!! It’s now your turn. Look at questions 1-4 pg. 253, can you answer them? Sport Books Publisher

8. The Heart Structure • Hollow organ, comprised of cardiac muscle or myocardium • Surrounded by fluid-filled membrane called the pericardium = touch protective sac • Allows heart to expand and contract • Considered a ‘double-pump’ and is divided into the right and left heart • Divided into left and right sides by the interventricular septum Sport Books Publisher

9. The Heart • Heart is made up of four separate chambers • Atria = upper chambers; receive blood from peripheral organs and pump blood into the ventricles • Ventricles = lower chambers; pump blood through the body • Atria are separated from ventricles by specialized valves called Atrioventricular (AV) valves • Valves prevent blood from traveling in the wrong direction • There are also valves where blood leaves the heart • These are a type of semilunar valve Sport Books Publisher

10. Internal Anatomy of the Heart • With what you know – see if you can label the diagram. • Use your text as a guide (after you’ve given it some thought!).

11. The Internal Anatomy of the Heart Aorta Superior vena cava Left pulmonary artery Right pulmonary artery Left pulmonary veins Aortic semilunar valve Right pulmonary veins Left atrium Pulmonary semilunar valve Bicuspid (mitral) valve Left ventricle Right atrium Interventricular septum Chordae tendinae Papillary muscles Tricuspid valve Chordae tendinae Right ventricle Papillary muscles Inferior vena cava Thoracic aorta (descending)

12. Where does the blood go? • Left ventricle or left heart pumps blood through the entire body (it is larger and with stronger muscle walls than the right ventricles) • Called systemic circulation • Right ventricle or right heart pumps blood a short distance to the lungs • Called pulmonary circulation Sport Books Publisher

13. The Pathway of Blood Flow In general : • The right atrium receives deoxygenated blood from the superior and inferior vena cava • The blood moves from the right atrium to the right ventricle and pumps it to the lungs • The left atrium receives the oxygenated blood from the lungs and pumps it to the left ventricle • The blood is now oxygen-rich and is transported to the entire body via the aorta Sport Books Publisher

14. Where does the blood go? See if you can trace the path of blood through the heart and body (Systemic and pulmonary circulation). When is the blood oxygenated and when is it deoxygenated? Sport Books Publisher

15. Deoxygenated Oxygenated Pathway of Blood Flow Inferior vena cava Superior vena cava RIGHT ATRIUM Tricuspid valve RIGHT VENTRICLE Veins Pulmonary semilunar valve Pulmonary arteries Capillaries Lungs Pulmonary veins Arteries LEFT ATRIUM Bicuspid valve LEFT VENTRICLE Aortic semilunar valve Aorta Sport Books Publisher

16. Coronary Circulation Aorta Superior vena cava Left pulmonary artery Branches of left pulmonary artery Branches of right pulmonary veins Pulmonary trunk Left pulmonary veins Right pulmonary veins Left atrium Anterior interventricular branch of left coronary artery Right atrium Right coronary artery Great cardiac vein Small cardiac vein Right ventricle Left ventricle Inferior vena cava Thoracic aorta (descending)

17. Break!!!!! It’s now your turn. Look at questions 1-4 pg. 258, can you answer them? Sport Books Publisher

18. Excitation of the Heart • The heart contracts in a constant rhythm that may speed up or slow down depending on the need for blood (and oxygen) in the body. • It can do this because cardiac muscle cells are all interconnected  this means when a single cardiac muscle cell is stimulated to contract, all the muscle cells in the heart will contract – and at the same time! (This is called syncytium) • The rhythm of the heart is governed by an automatic electrical impulse generated by the sinus node = pacemaker • i.e. the SA node, without any input from the nervous system, will cause the heart to contract at approximately 70-80 beats/min • The sinus node is a small bundle of nerve fibers that are found in the wall of the right atrium - Autonomic nervous system can change/regulate the basic rate of contraction Sport Books Publisher

19. Excitation of the Heart What happens? • The sinus node generates an electrical charge called an action potential. • The action potential causes the muscle walls of the heart to contract. This action potential travels through the two atria and the two ventricles via specialized tissue called the Atrioventricular node or a-v node and the Purkinje fibres. • The arrangement of tissue allows the contraction of the heart to be initiated in the atria from the top downward • Because the contraction moves from top to bottom, blood gets pushed from the atria into the ventricles before the ventricles contract. • Once filled, the ventricles then contract • The ventricles contract from the bottom up  forces blood into the aorta and pulmonary arteries Sport Books Publisher

20. The Heart – Electrical Conduction System Sinoatrial (SA) node Atrioventricular (AV) node Internodal pathways Bundle of His (AV bundle) Right and left bundle branches Purkinje fibres

21. How do we measure the electrical activity of the heart? We measure the activity of the heart using an Electrocardiogram or ECG An ECG = graphical representation of electrical sequence of events occurring with each contraction of the heart

22. How do we measure the electrical activity of the heart? Each part of the contraction is named. - P wave = depolarization through the atria - QRS complex = depolarization of the ventricles - T wave = repolarization of the ventricle

23. Cardiac Cycle • Cardiac cycle: series of events occurring through one heartbeat • Involves two phases: • Diastole phase (relaxation) • Heart fills with blood • Systole phase (contraction) • Heart contracts and ejects blood

24. (b) The mitral and tricuspid valves open, and the atria, squeezing into systole, force blood into the ventricles. (c) As the ventricle compartments fill with blood, they contract, thereby ejecting blood to the lungs and body. (d) The atria again relax and refill with blood. The Finely Tuned Cardiac Cycle (a) As the heart relaxes in diastole, both atria simultaneously fill with blood. Sport Books Publisher

25. Cardiac Cycle & Blood Pressure During the cardiac cycle there are dramatic changes in pressure in the heart. It is this pressure, which propels the blood through the body • Changes in pressure can be measured in our arteries as our blood pressure • Systolic blood pressure = pressure observed in the arteries during the contraction phase • Diastolic blood pressure = pressure observed in the arteries during the relaxation phase of the heart. • At the doctors – they report blood pressure as systolic pressure/diastolic pressure • The normal range of pressure in the atria during diastole is about 80 mmHg, and during systole is about 120 mmHg. Sport Books Publisher

26. Measuring Blood Pressure • Doctor taking patient’s blood pressure Sport Books Publisher

27. Break!!!!! Sport Books Publisher

28. Properties of Blood • Two main components: • Plasma • Fluid component of blood (mostly water) • Blood cells • Red blood cells (erythrocytes) • Made in bone marrow • Transport O2 and CO2 in the blood • Transport nutrients and waste • Contain hemoglobin • White blood cells (leukocytes) • Destroy foreign elements • Critical in the function of the immune system • Platelets • Regulate blood clotting Plasma 55%90% water7% plasma proteins3% other (acids, salts) Formed elements 45% >99% red blood cells <1% white blood cells and platelets

29. The Red Blood Cell • Single red blood cell or erythrocyte Sport Books Publisher

30. The Heart Hemoglobin • A molecule made up of proteins and iron • Each molecule can bond to and transport four oxygen molecules. • The amount of oxygen that is carried by the blood is dependent upon the partial pressure of oxygen (PO2). • The difference in the amount of oxygen that is present in the blood as it leaves the lungs and the amount of oxygen that is present in the blood when it returns to the lungs is called the arterial-venous oxygen difference (a-v O2 difference), measured in ml of oxygen per litre of blood (ml O2 / l ) • If the a-v O2 difference increases, it means that the body is using more oxygen. • The typical a-v O2 difference at rest is about 4 to 5 ml O2 / l, while during exercise the a-v O2 difference can increase to 15 ml O2 / l. Sport Books Publisher

31. The Heart Hemoglobin • New red blood cells or reticulocytes are produced in the bone marrow • Erythropoietin (EPO),a circulating hormone, is the principal factor that stimulates red blood cell formation • EPO is secreted in response to low oxygen levels (when one goes to altitude) and also in response to exercise, thusincreasing the percentage of new red blood cells in the body • New red blood cells contain more hemoglobin than older red blood cells and thus can carry greater amounts of oxygen Sport Books Publisher

32. EPO Production • High altitude (low oxygen level) has an effect on EPO production which in turn generates a high production of red blood cells. Sport Books Publisher

33. CO2 + H2O H2CO3 Transport of Carbon Dioxide • CO2 is produced in the body as a by-product of metabolism • CO2 diffuses from the cells to the blood where it is transported to the lungs via one of three mechanisms: 1. A small percentage of the produced CO2 is dissolved in the blood plasma 2. CO2 bonds to the hemoglobin molecule 3. The primary mechanism whereby CO2 is transported through the body is via combining with water to form bicarbonate molecules that are then transported through the body. This happens according to the following reversible reaction Sport Books Publisher

34. Break!!!!! Sport Books Publisher

35. The Heart Stroke Volume: • The amount of blood pumped out of the left ventricle each time the heart beats. • Measured in milliliters. • A typical stroke volume for a normal heart is about 70 milliliters of blood per beat. Cardiac Output: • The amount of blood that is pumped into the aorta each minute by the heart. • Cardiac output (ml/bpm) = stroke volume (ml) x heart rate (bpm) Sport Books Publisher

36. Measuring Heart Rate • Taking heart rate with fingers on wrist and neck (a) Feeling the carotid pulse (b) Feeling the radial pulse Sport Books Publisher

37. Maximum heart rate = 220 – age (years) The Heart Heart Rate • The number of times the heart beats in one minute, measured in beats per minute (bpm). • The contraction of the walls of the heart is commonly known as a heart beat. • The resting heart rate of an adult can range from 40 bpm in a highly trained athlete to 70 bpm in a normal person. • During intense exercise, the heart rate may increase to up to 200 bpm Sport Books Publisher

38. Oxygen uptake • is the amount of oxygen that is consumed by the body due to aerobic metabolism • It is measured as the volume of oxygen that is consumed (VO2) in a given amount of time, usually a minute • Oxygen uptake increases in relation to the amount of energy that is required to perform an activity • (VO2max): a measure used to evaluate the maximal volume of oxygen that can be supplied to and consumed by the body Sport Books Publisher

39. Testing for Maximal Oxygen Uptake • Testing maximal aerobic power (VO2max) Sport Books Publisher

40. Oxygen Uptake • Changes in hematocrit (concentration of red blood cells in the blood) can also alter the oxygen uptake by increasing or decreasing the amount of oxygen that is supplied to working tissues. • The ability of the tissues to extract oxygen (a-vO2 difference) directly affects the oxygen uptake. • Increases in a-vO2 difference may arise due to an increased number of mitochondria in the muscles, or increased enzyme efficiency in working tissues Sport Books Publisher

41. Oxygen Uptake • Increased capillarization (number of capillaries in tissue) can affect the ability of the circulatory system to place red blood cells close to the tissues that are using the oxygen. • As a result, this increases the ability of those tissues to extract the required oxygen due to a shorter diffusion distance. Sport Books Publisher

42. VO2max = Cardiac Output x (a-vO2) difference Cardiovascular Anatomy Summary • The central component primarily concerns the effectiveness of the heart and the peripheral factors include; 1. the ability of the lungs to oxygenate the blood 2. the ability of the body to extract that oxygen. • Training can increase the maximal oxygen consumption of the human body. How this is accomplished will be presented in the next section. Sport Books Publisher

43. RESPIRATORY ANATOMY Sport Books Publisher

44. The primary role of the respiratory system is to: 1. deliver oxygenated air to blood 2. remove carbon dioxide from blood, a by-product of metabolism. The respiratory system includes: 1. the lungs 2. several passageways leading from outside to the lungs 3. muscles that move into and out of the lungs. Sport Books Publisher

45. The term respiration has several meanings: 1. ventilation (breathing) 2. gas exchange (occurs between the air and blood in the lungs and between the blood and other tissues of the body) 3. oxygen utilization by the tissues for cellular respiration. Sport Books Publisher

46. The Lungs • located within the thoracic cavity/chest. • the lungs are asymmetrical. The right lung is larger than the left lung because the heart takes up more space on the left side. • The air passages of the respiratory system are divided into two functional zones: 1. The conduction zone 2. The respiratory zone Sport Books Publisher

47. The Conduction Zone • the set of anatomical structures in which air passes before reaching the respiratory zone. • Air enters through the nose and or mouth, where it is filtered, humidified, and adjusted to body temperature in the trachea (windpipe). Sport Books Publisher

48. The Conduction Zone • The trachea branches into the right and left bronchithat enter the lung and continue to branch into smaller and smaller tubes called bronchiolesand finally the terminal bronchioles. • The whole system inside the lung looks similar to an upside-down tree that it is commonly called the “respiration tree”. Sport Books Publisher

49. The Respiration Zone • The region where gas exchange occurs. • The functional units of the lungs are the tiny air sacs, known as alveoli. • Alveoli are clustered in bunches like grapes, with a common opening into an alveolar duct called an alveolar sac. Sport Books Publisher

50. Nose Mouth Trachea Bronchus Bronchiole Terminal Bronchiole Alveolus The Structure of the Respiratory System Sport Books Publisher