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Punctuality No one is to be later than me. Homework to be returned punctually. Cleanliness

Class Rules. Punctuality No one is to be later than me. Homework to be returned punctually. Cleanliness Courtesy If you need to speak, raise your hands. If someone is speaking, open your ears, and not your mouth. Consistency You must always have your notes with you. Commitment

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Punctuality No one is to be later than me. Homework to be returned punctually. Cleanliness

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  1. Class Rules • Punctuality • No one is to be later than me. • Homework to be returned punctually. • Cleanliness • Courtesy • If you need to speak, raise your hands. • If someone is speaking, open your ears, and not your mouth. • Consistency • You must always have your notes with you. • Commitment • If you are tasked to do something, I expect it to be done with all your effort.

  2. Chapter Overview Transport in Mammals • 9.2 The Tissue Fluid • 9.1 The Circulatory System - Introduction & Anatomy • 9.3 The Cardiac Cycle • 9.4 Heart Diseases • 9.1.1 The need for transport • 9.1.2 Double Circulation • 9.1.3 Veins and Arteries • 9.1.4 The Heart • 9.3.1 Blood Pressure • 9.3.2 Heart valves, Systole and Diastole • 9.2.1 Components of the Tissue Fluid • a) Blood Plasma • b) Red Blood Cells • c) White Blood Cells • d) Platelets • 9.2.2 Exchange of Substances and The Lymphatic System • 9.2.3 Haemoglobin • 9.2.4 Rejection and ABO Blood Group • 9.4.1 Myocardial infarction • 9.4.2 Causes of Heart Diseases

  3. Learning Objectives • By the end of the lesson, you should be able to: • *Describe the circulatory system as a system of tubes with a pump and valves to ensure one-way flow of blood. • *Describe the double circulation in terms of a low pressure circulation to the lungs and a high pressure circulation to the body tissues and relate these differences to the different functions of the two circuits. • Describe the structure and function of the heart in terms of muscular contraction and the working of valves. • Identify the main blood vessels to and from the heart, lungs, liver and kidney. • Describe the structure of arteries, veins and capillaries in relation to their functions and be able to recognize these vessels from photomicrographs.

  4. Introduction As an organism grows….

  5. Introduction It requires food and oxygen… … It also needs to remove waste and carbon dioxide…. For unicellular or simple organisms, getting food and removing waste is a rather simple task…

  6. The Need for Transport Unicellular and Simple organisms All they rely on is…. SIMPLE DIFFUSION

  7. The Need for Transport What makes simple diffusion a reliable mechanism in unicellular organisms? Here are two important factors: Surface Area to Volume Ratio Maintaining a Steep Diffusion gradient

  8. The Need for Transport Unicellular and Simple organisms Multicellular organisms Simple diffusion cannot service the cells deep in tissue layers. Simple diffusion is sufficient for exchange of materials

  9. The Need for Transport Multicellular organisms thus cannot depend on simple diffusion because they have: LARGE Surface Area to Volume Ratio DIFFICULTY in maintaining a STEEP Diffusion gradient How could they solve these problems?

  10. The Need for Transport This system of channels increases the Surface Area to Volume Ratio, thus allowing substances to be transported quickly. They develop a system of channels that service cells that are deep in the body of the organism. Thus, multicellular organisms found a strategy to solve the problem of access to dissolved gases and removal of waste.

  11. The Need for Transport Sponges are simple organisms with channels and sinuses. Water from the environment enters from tiny pores and exits from a big opening at the top of each column of a sponge.

  12. The Need for Transport Gastrovascular Cavity Bell Mouth/Anus Oral Arms Jellyfishes has a highly branched gastrovascular cavity which services cells in the deeper regions of the bell.

  13. The Need for Transport • The simple transport system of the jellyfish and sponge may suffice for small organisms. • However, in bigger organisms this would be inefficient. Why is that so?

  14. Common Features of Circulatory Systems • Before we examine the mammalian circulatory system, what are the common features in the circulatory system of the jellyfish and sponge? • Big terrestrial organisms such as mammals also possess the following features. However, they need a more efficient pump… A fluid to transport metabolites A network of chambers and sinuses A means of generating current Blood Vessels Heart

  15. Human Circulatory System Heart Vessels

  16. Single and Double Circulation

  17. Single and Double Circulation

  18. Single and Double Circulation • Advantages of Double Circulation System • Blood entering pulmonary circulation at low pressure •  gives time for uptake of oxygen and removal of carbon dioxide. • Blood leaving the left ventricle at high pressure •  Quickly delivers oxygenated blood to rest of the body.

  19. Structure of the Mammalian Heart The Heart Chambers The left ventricle has a more muscular wall than the right ventricle. This allows the heart to pump blood at great pressures so as to bring blood to the extremities of the body. The right ventricle also has muscular walls, but are relatively thinner than the left ventricle as it only needs to pump blood to the pulmonary circulation. The left atrium receives oxygenated blood directly from the pulmonary veins. The bicuspid valve separates the left atrium from the left ventricle. The right atrium receives deoxygenated blood directly from both the superior and the inferior vena cava.

  20. Structure of the Mammalian Heart The Heart Valves The bicuspid valve or mitral valve consists of two flaps that point into the left ventricle. It opens to allow blood to flow from the left atrium to the left ventricle. The tricuspid valve separate the right atrium from the right ventricle. It consists of three flaps which point into the right ventricle. Tendons connect these flaps to the walls of the right ventricle. Semi-lunar valves are found at the base of the pulmonary artery and the aorta to prevent backflow of blood.

  21. Structure of the Mammalian Heart The Main Vessels The aorta is a large artery, through which blood from the left ventricle leaves the heart. It is thick and muscular in order to withstand the high blood pressure which results from the contraction of the left ventricle. The superior and inferior vena cava are two large veins that collect and return deoxygenated blood to the right atrium.

  22. Structure of the Mammalian Heart The Median Septum The Main Vessels The pulmonary artery brings deoxygenated blood from the right ventricle to the lungs. It branches off to the left and the right lungs upon leaving the heart. The median septum is a muscular wall that separates the left side of the heart from the right side of the heart. The left and right pulmonary vein brings oxygenated blood from both lungs back into the heart via the left atrium.

  23. Structure of the Mammalian Heart

  24. The Blood Vessels • There are 5 types of vessels in the mammalian circulatory system. • Arteries • Arterioles • Veins • Venules • Capillaries

  25. The Blood Vessels • Arteries Structure • 3 layers of tissues • Thick elastic, muscular walls •  withstand high blood pressure •  recoil and stretch to push blood along • Smooth muscles contract or dilates •  lumen constrict or dilate thus controlling blood flow

  26. The Blood Vessels • Veins Structure • 3 layers of tissues • Less elastic, muscular walls • Presence of valves •  prevent backflow of blood

  27. The Blood Vessels • Capillaries Structure • Walls are only one-cell thick •  facilitate rapid diffusion • Highly branched •  increase SA/V ratio compared to arteriole from which the branches originate.

  28. Comparing the Blood Vessels

  29. Components of Blood Plasma – 55% total volume of blood  mostly liquid water (91%)  soluble blood proteins (7%)  hormones  electrolytes  nutrients Cellular Component – 45% total volume of blood  White blood cells  Platelets  Red blood cells (2%)

  30. Components of Blood Red Blood Cells (Erythrocytes) Biconcave, circular, flattened discs  Increase surface area to volume ratio Lack nucleus  To carry more haemoglobin Elastic  To move through capillaries Possess haemoglobin  To transport oxygen

  31. Components of Blood White Blood Cells (Leucocytes) Two groups of leucocytes: Lymphocytes  Formed in bone marrows and mature in lymph node  Typically round with rounded nucleus  Produces antibodies that fight against pathogens Phagocytes  Many types, shapes and sizes  Granular with lobed nucleus  Ingests foreign bodies by phagocytosis

  32. Components of Blood Platelets (Thrombocytes) Not true cells; cytoplasmic fragments Critical role in the clotting of blood (to be discussed later)

  33. Functions of Blood We shall first look at the details of blood as an agent for the transport of materials. • Transport • Oxygen • Carbon Dioxide • Food • Hormones • Waste • Protection • Production of antibodies • Phagocytosis of foreign bodies • Clotting of blood (prevent loss of blood) • Distribute body heat

  34. Functions of Blood – The Role of Haemoglobin • Transport • Oxygen Fe • Haemoglobin • A protein complex that contains 4 iron atoms • Gives blood its red colour • Able to bind to oxygen molecules • In the unbound state, haemoglobin is a deep purplish red. • When oxygen is bonded, haemoglobin turns into a bright red oxyhaemoglobin. O2 Fe Fe Fe O2 O2 O2

  35. Functions of Blood – The Role of Haemoglobin • Transport • Oxygen • Haemoglobin • Unbound state  haemoglobin has • HIGH AFFINITY for oxygen. • Binds to oxygen easily. • Reversible process. How is it reversible? Fe Fe Fe Fe Fe Fe Fe Fe

  36. Functions of Blood – The Role of Haemoglobin • Transport • Oxygen

  37. Functions of Blood – The Role of Haemoglobin • Transport • Oxygen Red Blood Cell Body Tissues Fe O2 Fe O2 Fe O2 Fe O2 • Dissociation of O2 occurs when RBCs with HbO enters oxygen poor tissues

  38. Functions of Blood • Transport • Carbon dioxide HCO3- CO2 • Converted to HCO3- ions • CO2 diffuse into blood plasma • Transported to lungs • HCO3- ions converted back to CO2 • Conc. of CO2 higher in plasma than lungs • Diffusion from plasma to lungs CO2

  39. Functions of Blood • Examples • Glucose • Amino Acids • Vitamins • Transport • Food • Hormones • Waste • Excretory products delivered to the kidneys for removal. • Examples • Urea • Uric Acid • Creatinine • Chemical messengers that control many metabolic processes. • Examples • Insulin • Glucagon • Adrenalin

  40. Functions of Blood So we have seen how blood transports metabolic substances and the important role played by haemoglobin…. Next, we shall look at the protective functions of blood. • Transport • Oxygen • Carbon Dioxide • Food • Hormones • Waste • Protection • Production of antibodies • Phagocytosis of foreign bodies • Clotting of blood (reduce loss of blood) • Distribute body heat • Protection • Production of antibodies

  41. Functions of Blood • Protection • Production of antibodies • Antibodies are soluble proteins… • Mostly produced by lymphocytes. • Capable of recognizing foreign objects… • Then binds to them… • Foreign objects with antibodies bounded to them are destined for destruction by immune system.

  42. Functions of Blood • Protection • Phagocytosis of foreign bodies • Phagocytes are able to ingest foreign particles. • Forms pus at wounded sites.

  43. Functions of Blood • Protection • Clotting of blood (reduce loss of blood) • Serves to prevent excessive blood loss • Serves to reduce infection by pathogens • 3 steps involved: • Damaged tissues and platelets release thrombokinase. • Prothrombin Thrombin • Fibrinogen Fibrin

  44. ABO Blood Groupings

  45. Lymphatic System • Movement of Blood Plasma into Body Tissues • Blood in arterioles  Higher pressure than capillaries • Blood plasma hence forced to leave capillaries • And enter body tissues • Soluble proteins cannot pass through capillaries. • Hence the fluid that enters the body tissues does not contain these proteins. • This fluid is known as interstitial fluid or tissue fluid.

  46. Lymphatic System • Where does interstitial fluid goes? • Collected in lymph vessels. • Part of the lymphatic system.

  47. Lymphatic System • Where does interstitial fluid goes? • Returned back to bloodstream via left subclavian vein

  48. Cardiac Cycle • Cardiac Cycle • Is the sequence of contraction and relaxation of the atria and ventricles. • Systole = contraction • Diastole = relaxation • May be divided into • 3 phases.

  49. Cardiac Cycle

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