Chapter 8.1 – Structures of the Circulatory System - PowerPoint PPT Presentation

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Chapter 8.1 – Structures of the Circulatory System

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Chapter 8.1 – Structures of the Circulatory System
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Chapter 8.1 – Structures of the Circulatory System

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  1. Chapter 8.1 – Structures of the Circulatory System Pages 268 - 281

  2. Introduction: Launch Lab – Watching Blood Flow(Page 267) • Procedure: • Watch the video clip showing blood circulation in the tail of a gold fish. • Answer the analysis questions. Circulation in a Goldfish Tail

  3. Structures of the Circulatory System • The circulatory system is the transportation system of the body. • 3 Main Functions • Transports gases • Regulates internal temperature • Protect against blood lose and infection

  4. Major Components • 3 Major Components: • The heart – an organ that pushes blood through the body with its pumping action. • The blood vessels – serve as the “roadways” through which the blood moves. • The blood – carries nutrients, oxygen, carbon dioxide, water, wastes and many other materials throughout the body.

  5. The Cardiovascular System • Together the heart and the blood vessels are known as the cardiovascular system.

  6. The Structure of the Heart • Located on the left side of the chest • The heart: • Pumps blood • Separates oxygen rich and poor blood • Keeps blood flow in one direction

  7. The walls of the heart are made up of cardiac muscle tissue • The contractions of the cardiac muscle tissues are rhythmical and involuntary

  8. The human heart has 4 chambers: • Left and right atria – fill with blood from body or lungs • Left and right ventricles – pump blood to the body or lungs • The left and right side is separated by a thick wall called the septum

  9. Blood Flow through the Heart • Oxygen-poor blood enters the heart from the vena cava • Superior vena cava collects blood from upper body • Inferior vena cava collects blood from below the chest

  10. vena cava  R atrium  R ventricle  pulmonary arteries  lungs  L atrium  L ventricle  aorta  body

  11. Valves of the Heart • 4 valves control direction of flow: • Right atrioventricular valve: • Separates right atrium and ventricle • Tricuspid; made of 3 flaps • Left atrioventricular valve: • Separatesleft atrium and ventricle • Bicuspid; made of 2 flaps

  12. Chordae tendinae: • hold atrioventricular valves in place • prevent valves from being pushed back into atria • Semilunar valves control the flow of blood into the aorta and pulmonary artery

  13. Using blue and red pencils or pens, diagram the pathway of blood through the heart using arrows. Use blue to represent deoxygenated blood and red for oxygenated blood.

  14. Blood enters the right atrium through the ________________. • Blood flows from the right atrium into the right ventricle through the _________________. • Blood is pumped from the right ventricle into the pulmonary trunk that splits into the right and left _____________________. • Blood returns from the lungs by way of the right and left ____________________. • Blood enters the ____________________ when it returns from the lungs. • Blood flows past the ________________________ as it enters the left ventricle. • The left ventricle pumps out past the ______________________ into the aorta.

  15. The Structure of Blood Vessels • Three types of blood vessels: • Arteries: • carry oxygen-rich blood away from the heart • thick and highly elastic walls • Veins: • carry oxygen-poor blood towards the heart • thinner walls and large inner circumference • have one-way valves to prevent back flow

  16. Capillaries: • network of fine vessels where gas and nutrient transfer to tissues occurs. Capillaries join arteries to veins • Capillary walls are a single cell thick

  17. Label the diagram • Use blue and red to indicate whether the vessel carries oxygenated blood (red), deoxygenated blood (blue) or both.

  18. Compare the structure and function of the three types of blood vessels.

  19. The Beating Heart • The stimulus that triggers a heartbeat is an electrical signal that originates from within the heart. • The sinoatrial (SA) node is a bundle of specialized muscle tissue that stimulates the muscle cells to contract and relax rhythmically • Located in the wall of the right atrium • SA node is also called the “pacemaker” because it sets the pace for cardiac activity

  20. The SA node generates an electrical signal that spreads over the two atria simultaneously. • As the atria contract, the signal reaches the atrioventricular (AV) node. • The AV node transmits the electrical signal through the bundle of specialized fibres called the bundle of His. • The bundle of His relays the signal through two bundle branches that divide into fast-conducting Purkinje fibres • Purkinje fibres initiate the simultaneous contraction of all cells of the right and left ventricles Heartbeat signal

  21. ECG • Changes in voltage of the heart can be measured using an electrocardiogram (ECG) • An ECG measures the electrical activity of the heart as it contracts and relaxes • Irregular spikes or changes in the spacing of waves can be used to diagnose different heart conditions

  22. Blood Pressure • Blood passing through vessels exerts pressure against vessel walls, called blood pressure • Changes in blood pressure corresponds to phases of the heartbeat • Maximum pressure is called systolic pressure, during ventricle contraction • Lowest pressure is called diastolic pressure, occurs just before the ventricles contract • Sphygmomanometer (blood pressure cuff) measures blood pressure

  23. Cardiac Output and Stroke Volume • Cardiac output is the amount of blood pumped by the heart, measured in mL/min • Cardiac output is an indicator of the level of oxygen delivered to the body and the amount of work the body’s muscles can perform • Heart rate is the number of heartbeats per minute • Stroke volume is the amount of blood forced out of the heart with each heartbeat. • cardiac output = heart rate x stroke volume

  24. Stroke volume depends on: • How easily the heart fills with blood, related to “stretchiness” of ventricular walls and volume returning to heart from veins • How readily the heart empties, related to the strengthof the ventricular contraction • Average person has a stroke volume of 7o mL and a resting heart rate of 70 beats/min • Cardiac output = 70 mL x 70 beats/min = 4900 mL/min • Average person has 5 L of blood in their body; the total volume of blood circulates through the heart about once every minute.

  25. Pathways of the Circulatory System • The circulatory system has 3 pathways: • Pulmonary pathway – transports blood between the heart and the lungs • Systemic pathway – moves blood from the left ventricle to the tissues and back to the right atrium • Coronary pathway– provides blood to the heart itself

  26. Tracing the Pathways… • Tracing the pathway of blood beginning in right atrium… pulmonarypulmonary  systemic  systemic (to lungs) (to heart) (to tissues) (to heart)

  27. Tracing the pathway of blood through coronary… • Heart does not use blood inside chambers to get nutrients/ remove wastes; walls are too thick fordiffusion • The heart is covered in a network of vessels • Oxygenated blood is supplied from the coronary artery coming off of the aorta • Deoxygenated blood enters the right ventriclebefore heading to the lungs.

  28. Cardiovascular Disorders and Treatments • Cardiovascular disease is the leading cause of death for Canadians • Can be reduced with lifestyle changes: • not smoking • Eating healthy diet • Exercising • Atherosclerosis: • thickening of artery walls • Elasticproperties diminished

  29. Atherosclerosis: • Build-up of fatty deposits on wall of artery • Blood flow is decreased, blood pressure is increased • Especially dangerous in arteries of heart, neck, brain, legs, kidneys • Treated withaspirinto prevent platelets from sticking together (clots) • Treated with medication tobreakdown existing clots Artherosclerosis

  30. Surgical treatments such as angioplasty; permanent stent is inserted into artery to “re-open” passage way Angioplasty

  31. Coronary bypass operation – healthy vessels are taken from elsewhere in the body and used to create a new pathway around a blocked vessel. Coronary Bypass Surgery

  32. Congenital Heart Defects • Some heart defects are congenital, they are present since birth • Common congenital defects: • wallsdividing chambers • valvesof the heart • structure of the blood vesselsnear the heart

  33. Heart murmur – describes any misflow of blood through the heart • Ie. One or more of the valves not opening properly • Valve defects can beheard with a stethoscope as a whooshing or rasping sound (caused by blood “leaking” through the valve • Can be also be diagnosed with CT scan, CAT scan, MRI scan by creating a 3D image of the organ Bicuspid/ Mitral valve Regurgitation Heart Transplant

  34. 8.2 – Blood and Circulation Pages 282 - 291

  35. The Components of Blood • Blood is considered to be a tissue because it has a solidand fluid portion • Plasma: • fluid component • 55%of volume • contains: dissolved gases, proteins, sugars, vitamins, minerals, hormones, waste products

  36. Formed portion: • solid component • 45%of volume • Red blood cells • White blood cells • Platelets • produced in the bone marrow The Components of Blood

  37. Red blood cells (erythrocytes): • 44%of blood volume • O2 transport • disc shaped, lack a nucleus • contain hemoglobin: • iron rich protein • readily picks up O2 • carries CO2away from cells • transfers gases via diffusion

  38. Anemia: • Due to shortage of RBCs or hemoglobin • Can be due to lack of iron • Reduced O2 transport • Sufferers experience fatigue Normal number of red blood cells VS anemic number of red blood cells. Role of Red Blood Cells in Anemia

  39. White blood cells (leucoytes): • Respond to infection • 1% of blood volume • volume may double during infection • Contain nuclei • Colourless

  40. Types of White Blood Cells: • Granulocytes – can leave the blood stream to destroy bacteria • Monocytes and lymphocytes– found in blood stream, engulf and destroy foreign bodies

  41. Platelets: • Fragments of cells, have no nucleus • Key role in clotting • Formed in marrow when large cells break apart

  42. How a clot is formed: • Vessel is injured • Platelets attracted to site by chemical signal • Buildup of platelets stops the bleeding • Fibrin, strand-like material, reinforces the clot from the inside of the vessel

  43. Plasma: • Suspends blood cells • Key role in CO2 transport • 92% water • 7% proteins • 1% ions • Trace amount organic substances

  44. The Components and Functions of Blood • Transporting nutrients and wastes • Regulating internal temperature • Protecting the body from pathogens

  45. Blood Transport: • Materials and energy distributed • Absorbs nutrients from small intestineand other areas of the body • Transports nutrients to liver for storage or further transport. • Circulates through the lungs for gas exchange. • Delivers waste products (urea, ions, other) to kidneys for excretion.

  46. Relays messages by transporting hormones between glands and organs • Hormones play key role in regulating and coordinating internal body systems.