Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Upcoming SlideShare
What to Upload to SlideShare
What to Upload to SlideShare
Loading in …3
×
1 of 69

Cardiovascular system

2

Share

Download to read offline

BLOOD CIRCULATION
BLOOD COMPONENT

Related Books

Free with a 30 day trial from Scribd

See all

Related Audiobooks

Free with a 30 day trial from Scribd

See all

Cardiovascular system

  1. 1. Cardiovascular System Biology (Case 1) Block 3 PBL G5
  2. 2. The Objectives : Define the cardiovascular system and explain its general function 2- Identify the three components of the cardiovascular system . 3- Describe the Anatomy of the heart 4- Describe the histology of the heart 5- Identify the component of the blood and distinguish its different function . 6- Describe the function and the histology of the three types of blood vessels . 7- Explain the Physiology of Circulation . 8- Describe the circulation pathway . 9- Describe the cardiovascular diseases and explain the causes and the treatments.
  3. 3. Introduction to Cardiovascular System The cardiovascular system is sometimes called the blood-vascular, or simply the circulatory system. It consists of the heart, which is a muscular pumping device, and a closed system of vessels called arteries, veins, and capillaries. As the name implies, blood contained in the circulatory system is pumped by the heart around a closed circle or circuit of vessels as it passes again and again through the various "circulations" of the body.
  4. 4. Introduction to Cardiovascular System As in the adult, survival of the developing embryo depends on the circulation of blood to maintain homeostasis and a favorable cellular environment. In response to this need, the cardiovascular system makes its appearance early in development and reaches a functional state long before any other major organ system. Incredible as it seems, the primitive heart begins to beat regularly early in the fourth week following fertilization.
  5. 5. The vital role of the cardiovascular system in maintaining homeostasis depends on the continuous and controlled movement of blood through the thousands of miles of capillaries that permeate every tissue and reach every cell in the body. It is in the microscopic capillaries that blood performs its ultimate transport function. Nutrients and other essential materials pass from capillary blood into fluids surrounding the cells as waste products are removed.
  6. 6. Numerous control mechanisms help to regulate and integrate the diverse functions and component parts of the cardiovascular system in order to supply blood to specific body areas according to need. These mechanisms ensure a constant internal environment surrounding each body cell regardless of differing demands for nutrients or production of waste products.
  7. 7. THE HEART ANATOMY The heart weighs between 7 and 15 ounces (200 to 425 grams) and is a little larger than the size of your fist. By the end of a long life, a person's heart may have beat (expanded and contracted) more than 3.5 billion times. In fact, each day, the average heart beats 100,000 times, pumping about 2,000 gallons (7,571 liters) of blood.
  8. 8. Your heart is located between your lungs in the middle of your chest, behind and slightly to the left of your breastbone (sternum). A double-layered membrane called the pericardium surrounds your heart like a sac. The outer layer of the pericardium surrounds the roots of your heart's major blood vessels and is attached by ligaments to your spinal column, diaphragm, and other parts of your body. The inner layer of the pericardium is attached to the heart muscle. A coating of fluid separates the two layers of membrane, letting the heart move as it beats.
  9. 9. Your heart has 4 chambers. The upper chambers are called the left and right atria, and the lower chambers are called the left and right ventricles. A wall of muscle called the septum separates the left and right atria and the left and right ventricles. The left ventricle is the largest and strongest chamber in your heart. The left ventricle's chamber walls are only about a half-inch thick, but they have enough force to push blood through the aortic valve and into your body.
  10. 10. Histology of the heart The Heart Wall: Consist of three-layered structure. Inner layer = endocardium Middle Layer = myocardium Outer layer = epicardium (also called the pericardium) A fundamental characteristic of the heart wall is that its thickness varies from location to location
  11. 11. Epicardium ( Pericardium) The outer layer of the heart and consists of a connective tissue region covered by a mesothelium( simple squamous epithelium)on its outer surface. Composed of connective tissue with nerves, vessels, adipocytes Supports the blood vessels and nerves that supply the heart. It Covers and protects the heart The space between the linings is called the pericardial cavity
  12. 12. Myocardium The largest of the three layers, and contains cardiac muscles is thickest in the left ventricle, since the left ventricle is responsible for pumping blood throughout the systemic circulation. Consist of cardiac muscle cells (myocytes) :Different from smooth or skeletal muscle cells due to placement of nuclei, cross striations, and intercalated disks
  13. 13. Intercalated disks –Junctional complexes that contain fascia adherens, desmosomes, and gap junction to provide connection and communication. –Bind myocytes and allow ion exchange to facilitate electrical impulses to pass
  14. 14. Endocardium The inner layer of the heart. blood vessels. and itself is layered. By inner layer Simple squamous epithelium (Endothelium) The middle layer is (Connective Tissue and Smooth Muscle) The outer layer (Subendocardial Layer)
  15. 15. Cardiac Valves Composed of connective tissue layers covered by endothelium on each side; 3 layers –Spongiosum: loose collagen –Fibrosa: dense core of connective tissue –Ventricularis: dense connective tissue with many elastic and collagen fibers
  16. 16. Blood ● Blood is a fluid that circulates within the cardiovascular system ● It provide a vehicle for the distribution of respiratory gases , nutrients, water, electrolytes,hormones and heat throughout the body. ● It is composed of cellular elements which are suspended in blood plasma. ● The cellular elements are : 1. Red blood cells. 2. White blood cells 3. Platelets
  17. 17. Red blood cells. ● Red blood cells are disked shaped anucleate cells,and are 7-8 micrometer in diameter . ● The mature red cells lack nuclei and organelles. ● The cytoskeleton of red cells cause them to extremely pliable and allow them to pass through circulation.
  18. 18. ● Red blood cells have hemoglobin which is essential for transport of respiratory gases. ● In blood vessels the red blood cells pick up oxygen from inhaled air and carry it through the bloodstream to all parts of the body. ● The cells need oxygen for metabolism ,which also creates carbon dioxide as a waste product.Red blood cells pick up carbon dioxide and send it back to the lungs. Function
  19. 19. White blood cells. ● White blood cells play an important role in immune system , they defend the body from invaders. ● They have a cell nucleus and do not contain hemoglobin. ● White blood cells are made inside the bone marrow and stored in blood and lymphatic tissues. ● They flow through bloodstream to destroy viruses, bacteria, and other foreign invaders that threaten health.
  20. 20. ● They form two main groups both with defensive functions: 1. phagocytosis : which engulf and destroy bacteria and other foreign matter 2. lymphocytes : the effector cell of the imune system . ● White blood cells have 5 types which develop in bone marrow : 1. Neutrophills. (digest bacteria,fungi) 2. Monocytes (bacteria) 3. Eosinophills (bacteria,parasite,cancer cells) 4. Basophills (infection) 5. lymphocytes (antibodies)
  21. 21. Platlets Platelets are needed to prevent and/or stop bleeding. Not uncommonly, trauma victims, whose platelets are lost due to bleeding and related processes, require platelet transfusions.
  22. 22. Platelets transfusions are often critically needed by: Heart surgery patients also are frequently transfused with this product owing to treatment-related loss, damage, and/or destruction of their platelets. Also patients battling leukemia and other cancers – especially if they undergo transplantation with bone marrow (or related stem cell sources) – will require transfusions to make up for their platelets that are destroyed by chemotherapy and/or radiation. Because platelets last for only 5 days after they are donated, a constant supply is vitally needed.
  23. 23. Blood plasma Plasma is the liquid portion of blood. It's what suspends red blood cells, platelets, and other cells within our bloodstream. It also contains thousands of different proteins and other substances (electrolytes for example) that are needed for our bodies to function normally.
  24. 24. Plasma transfusions are often critically needed by: ● Burn and trauma victims ● Some organ transplant recipients ● People with certain rare blood disorders Plasma donations can be frozen for up to one year prior to their transfusion into recipients. They also may be used to create a variety of medicines – such as albumin, clotting factors, and immune globulins – needed to treat patients with medical conditions including massive blood loss, blood clotting abnormalities (such as hemophilia), and immunodeficiency disorders.
  25. 25. Summary of blood
  26. 26. Blood Vessels Blood vessels form a closed circuit of tubes that carry blood throughout the body. The five main types of blood vessels are arteries, arterioles, capillaries, venules, and veins. Except for capillaries, the walls of blood vessels have three layers or tunics. The three structural layers of a generalized blood vessel from innermost to outermost are; ● The tunica interna (intima), ● Tunica media, ● Tunica externa (adventitia) Aorta-Arteries-Arterioles-Capillaries-Venules-Veins-Vena Cava
  27. 27. Arteries Arteries are muscular blood vessels that carry oxygenated blood away from the heart to the body. Arteries have a thick wall that consists of three layers. The artery walls are thick so that when blood enters under pressure the walls can expand. Aorta is the largest artery Pulmonary artery is the only artery carrying deoxygenated blood
  28. 28. Arterioles An arteriole is a small artery that extends and leads to capillaries. Arterioles have thick smooth muscular walls. These smooth muscles are able to contract (causing vessel constriction) and relax (causing vessel dilation). This contracting and relaxing affects blood pressure; the higher number of vessels dilated, the lower blood pressure will be. Arterioles are just visible to the naked eye.
  29. 29. Tunica Intima: ● Forms the innermost lining, surrounding the lumen ● It is made of a layer of endothelium resting on basement membrane. ● The Endothelium is made of squamous epithelial cells and the basement membrane of collagen. ● The basement membrane provides great tensile strength as well as the ability to stretch and recoil ● Between tunica intima and tunica media is the Internal Elastic Lamina made of elastic fibres. Histological structure of Arteries.
  30. 30. Tunica Media: ● It is the middle layer made of muscle (smooth muscle cells) and connective tissue layer(elastic fibres). ● It shows the greatest variation among different types of blood vessels ● Arteries have have a thick tunica media. Hence, due to plentiful elastic fibres they can easily stretch in response to small increase in pressure. ● The smooth muscle cells regulate the diameter of the lumen
  31. 31. ● When the sympathetic stimulation increases, it causes arteries to contract; a term called vasoconstriction ● When the sympathetic stimulation decreases, the smooth muscles relax causing the arteries to dilate; a term known as vasodilation. ● Between the tunica media and tunica externa is a network of elastic fibres called External Elastic Lamina.
  32. 32. Tunica Externa ● It is the outermost covering consisting of elastic and collagen fibres. ● It consist of numerous nerves ● It’s thickness is different in different blood vessels.
  33. 33. Structure of Arterioles ● They have a thin tunica intima. ● The tunica media consist of 1 or 2 layers of smooth muscle cells ● The terminal of arterioles is called metarteriole which tapers towards capillary junction. ● At the metarteriole-capillary junction, muscle cells form precapillary sphincter which monitors blood flow into capillary. ● The tunica externa consist of connective tissue and many unmyelinated sympathetic nerves.
  34. 34. Capillaries ● Capillaries connect arterioles to venules. They allow the exchange of nutrients and wastes between the blood and the tissue cells. ● Despite their small size and easy permeability, capillaries are quite strong. ● composed only of the tunica intima.
  35. 35. ● The thinness of the capillaries helps efficient exchange between the lumen of the capillary and the surrounding tissue. ● Capillaries deliver nutrients and oxygen to tissues and remove the byproducts of cellular reactions, such as carbon dioxide and water. ● Capillaries are much thinner than arteries and veins, because their walls are made up of only a single layer of endothelial cells, the flat cells that line all blood vessels.
  36. 36. There are three types of capillary:- ❖ continuous ❖ fenestrated ❖ discontinuous
  37. 37. Continuous capillary Tight junctions of the endothelium to make them highly impermeable to anything but the smallest molecules. Their pores are so tiny that only water and small ions can pass through.
  38. 38. This type is found in areas of the body such as the central nervous system, skeletal muscles, and skin. Brain capillaries are continuous capillaries. The nucleus of one cell bulges into the lumen of the capillary. The nucleus of the other cell cannot be seen.
  39. 39. Fenestrated capillaries ● These are found in some tissues where there is extensive molecular exchange with the blood such as the small intestine, endocrine glands and the kidney. The 'fenestrations' are pores that will allow larger molecules though. ● have numerous pores of various sizes. Small intestine walls have fenestrated capillaries to allow digested food molecules to be carried into the blood.
  40. 40. Discontinuous Capillaries Wide pores in their cell walls and large spaces between cell layers to allow large molecules to pass through. Discontinuous capillaries are found primarily in the liver, which produces a number of different proteins that need the larger space to pass through into the body. so only found in the liver.
  41. 41. Sinusoids are a special type of capillary that have a wide diameter. These are found in the liver, spleen, lymph nodes, bone marrow and some endocrine glands. They can be continuous, fenestrated, or discontinuous.
  42. 42. A vein is a vessel that carries blood toward the heart. All of the veins except the pulmonary veins contain deoxygenated blood. Small veins are called venules. Both arteries and veins are macroscopic structures; that is, they can be seen without the aid of a microscope The average blood pressure in veins is considerably lower than in arteries. VEINS
  43. 43. ● Veins function both as collectors and as reservoir vessels. ● They accommodate varying amounts of blood. The structural feature that allows them to accommodate varying amounts of blood, with almost no change in blood pressure,is their great ability to stretch. ● Transport blood away from capillaries ● Carry blood toward heart ● Have larger diameters ● Usually carry deoxygenated blood Functions of Veins
  44. 44. Histological structure of veins The walls of the larger blood vessels, the veins, have three layers The innermost layer of a blood vessel is called the tunica intima.The tunica intima is made up of endothelium that is continuous with the endothelium that lines the heart.The tunica interna of veins is thinner than that of arteries Smooth lining with semilunar valves to ensure one-way flow The middle layer,the tunica media of veins is much thinner than in arteries, with relatively little smooth muscle and elastic fibers.Allows constriction and dilation of vessels The outermost layer is called the tunica adventitia.The tunica externa of veins is the thickest layer and consists of collagen and elastic fibers. Provides flexible support that resists collapse or injur
  45. 45. Type of Vessel Tunica Intima (Endothelium) Tunica Media (Smooth Muscle; Elastic Connective Tissue) Tunica Adventitia (Fibrous Type of Vessel Connective Tissue) Arteries Smooth lining Allows constriction and dilation of vessels; thicker than in veins; muscle innervated by autonomic fibers Provides flexible support that resists collapse or injury; thicker than in veins; thinner than tunica media Veins Smooth lining with semilunar valves to ensure one-way flow Allows constriction and dilation of vessels; thinner than in arteries; muscle innervated by autonomic fibers Provides flexible support that resists collapse or injury; thinner than in arteries; thicker than tunica media Capillaries Makes up entire wall of capillary; thinness permits ease of transport across vessel wall (Absent) (Absent)
  46. 46. Circulatory system : How it work? The circulatory system consists of three independent systems that work together: 1 - The heart (cardiovascular). 2 - lungs (plumonary). 3 - arteries, veins, coronary and portal vessels (systemic). *The system is responsible for the flow of blood, nutrients, oxygen and other gases, and as well as hormones to and from cells.
  47. 47. Circulatory system : How it work? 1 - The heart : The heart is a muscular organ with four chambers, it pumps blood through the network of arteries and veins. 2 - Lungs (Pulmonary) circulation: The circuit through the lungs where blood is oxygenated. 3 - The systemic circulation: The network of veins, arteries and blood vessels, transports oxygenated blood and nutrients from the heart,to the body's cells and then returns deoxygenated blood back to the heart.
  48. 48. Circulatory system : How it work? ● Arteries: A- carry blood away from the heart. B- carry oxygenated blood (pure blood). ● Veins: A- carry blood back to the heart. B- carry deoxygenated blood (impure blood).
  49. 49. The Cardiovascular Pathways ➢ The blood flows in two circuits: ● The pulmonary circuit: takes blood from the heart to the lungs and back to the heart. ● The systemic circuit: carries blood from the heart to all other organs, and then returns blood to the heart.
  50. 50. FIRST: The Pulmonary Circuit The steps: 1) Blood from all regions of the body collects in the right atrium and then passes into the right ventricle (pumps the blood into the pulmonary trunk) i) “The Pulmonary trunk is divided into the right and left pulmonary arteries”. 2) The arterioles take blood to the pulmonary capillaries (where CO2 is given off and O2 is picked up) 3) Blood passes through the pulmonary venules which lead to the four pulmonary veins that enter the left atrium in the heart. ★ Blood in the pulmonary arteries is O2 - poor. ★ Blood in the pulmonary veins is O2 - rich.
  51. 51. SECOND: The Systemic Circuit
  52. 52. SECOND: The Systemic Circuit The steps: Left ventricle aorta common iliac artery femoral artery lower leg capillaries lower leg veins femoral vein common iliac vein inferior vena cavae right atrium. ★ The Superior and Inferior Venae Cavae both enter the right atrium. ★ The Superior and Inferior Venae Cavae return blood to the heart.
  53. 53. Disorders: Varicose Veins Varicose veins are common in people who stand for long periods of time (for example, dentists and hairdressers) and in obese (or pregnant) individuals , The common factors are the pooling of blood in the feet and legs and inefficient venous return resulting from inactivity or pressure on the veins. What Causes Varicose Veins? Varicose veins occur when your vein isn’t functioning properly. Veins have one-way valves that prevent blood from flowing backwards. When these valves fail, blood begins to collect in the vein rather than continuing toward your heart. Varicose veins often affect the legs because they are the farthest from the heart and gravity makes it harder for the blood to flow upward.
  54. 54. Disorders: Varicose Veins ● Most varicose veins are only a cosmetic problem. Occasionally they will cause pain, muscle cramps, or itching and become a medical problem. There are safe and effective ways to get rid of them, so see your doctor but sometimes there is A serious complication of varicose veins : ● Thrombophlebitis : inflammation of a vein that results when a clot forms in a vessel with poor circulation.
  55. 55. Hypertension Hypertension, also known as high blood pressure, is when the pressure of the blood being pumped through your arteries is higher than it should be. it often has no warning signs or symptoms, and many people do not even know they have it. Blood pressure is usually measured using a pressure cuff or an electronic device placed on your upper arm Types of Hypertension •Primary/essential Causes are indirect ❖ Smoking,obesity,hyperlipidemia and diabetes •Secondary Causes are direct ❖ Kidney disease and Aortic coarctation
  56. 56. What set hypertension •Genetics - having family members with hypertension increases the likelihood that you will too. •Race - high blood pressure is more common in people with dark skin than in people with pale skin. •Age - your blood vessels become more rigid as you age, preventing them from opening as effectively as when you were younger, which increases peripheral resistance. • The most common risk factors include being overweight and inactive, eating a high salt diet, and smoking.
  57. 57. How likely are you to become hypertensive? •High blood pressure is more common in men during middle-age, around 45 years, with women catching up after age 65. •Worryingly, children can also become hypertensive for many of the same reasons as adults - inactivity, unhealthy diet, and obesity Effect on heart Development of more muscles on the left ventricle[that pumps blood] which may result to cardiac arrest and also left heart failure Effect on vessels 1. Vessels become firm[not elastic any more] 2. Part of the artery wall starts to become weak leading to hemorrhage
  58. 58. Treatments •Lifestyle changes 1. Eating a healthy diet 2.Exercise 3.Reducing or better still quitting smoking •Medication 1.Diuretics 2.Beta-blockers 3.Angiotensin-converting enzyme inhibitors, (ACE inhibitors) 4.Calcium channel blockers 5.Angiotensin II receptor blockers
  59. 59. Factors Affect Blood Pressure A. Central factors, which are pertaining to the heart: 1. Cardiac output 2. Heart rate B. Peripheral factors, which are pertaining to blood and blood vessels: 3. Peripheral resistance
  60. 60. CENTRAL FACTOR 1.Cardiac Output Blood pressure is directly proportional to cardiac output. Whenever the cardiac output increases, the Blood pressure is increased and when cardiac output is less, the systolic pressure is reduced.
  61. 61. 2.Heart Rate Moderate changes in heart rate do not affect arterial blood pressure much. However, marked alteration in the heart rate affects the blood pressure by altering cardiac output.
  62. 62. PERIPHERAL FACTORS 3.Peripheral Resistance Peripheral resistance is the important factor, which maintains diastolic pressure. Peripheral resistance is the resistance offered to the blood flow at the periphery. Resistance is offered at arterioles, which are called the resistant vessels. When peripheral resistance increases, diastolic pressure is increased and when peripheral resistance decreases, the diastolic pressure is decreased.
  63. 63. 4- Blood Volume Blood pressure is directly proportional to blood volume. Blood volume maintains the blood pressure through the venous return and cardiac output. If the blood volume increases, there is an increase in venous return and cardiac output, resulting in elevation of blood pressure
  64. 64. References ➢ Books: ● Human Biology Book. Sylvia S. Mader & Michael Windelspecht. 12th edition. chapter 5.pages 91, 102 and 103. ● Essentials of human anatomy & physiology, Elaine N. Marieb, Eleventh Edition, chapter 11 :The cardiovascular System, pages 361 and 373. ● Essential of medical physiology sixth edition Pages:604-605
  65. 65. ➢ Websites: ● http://www.bloodsource.org/Donate/What-is-Blood ● http://www.redcrossblood.org/learn-about-blood/blood-components/plasma ● http://www.healthline.com/health/varicose-veins ● http://www.livescience.com/27585-human-body-system-circulation-infographic.htm l ● http://www.majordifferences.com/2013/02/difference-between-artery-and-vein.html #.WNpieG_yuUk References

×