The Blood System

The Blood System Blood State the four main components of blood Plasma 1. …………………………………………………………………………………………………………………………………………………... Red blood cells (erythrocytes) 2. …………………………………………………………………………………………………………………………………………………... White blood cells (leukocytes) 3. …………………………………………………………………………………………………………………………………………………... Platelets (thrombocytes) 4. …………………………………………………………………………………………………………………………………………………... List the things that are transported by the blood plasma Nutrients, Antibodies, Carbon dioxide, Hormones, Oxygen ………………………………………………………………………………………………………………………… Urea, Heat ………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………… Blood Vessels Discuss William Harvey’s findings on the circulation of blood William Harvey disproved the prior theories of Galen by suggesting that: ………………………………………………………………………………………………………………………………………………….......... The major blood vessels (arteries and veins) are part of a single connected blood network ………………………………………………………………………………………………………………………………………………….......... Blood flow is unidirectional (due to valves) and continuously flows (it is not consumed by the body) ………………………………………………………………………………………………………………………………………………….......... The heart is a central pump (blood carried from the heart by arteries and to the heart by veins) ………………………………………………………………………………………………………………………………………………….......... Describe the circulation of blood according to both pulmonary and systemic circulation Pulmonary: Deoxygenated blood returns from the body (via vena cava) to the RIGHT side of the heart ………………………………………………………………………………………………………………………………………………….......... It is pumped (by right atrium / right ventricle) to the lungs via the pulmonary artery ………………………………………………………………………………………………………………………………………………….......... Systemic: Oxygenated blood returns from the lungs (via pulmonary vein) to the LEFT side of the heart ………………………………………………………………………………………………………………………………………………….......... It is pumped (by left atrium / left ventricle) to the body via the aorta ………………………………………………………………………………………………………………………………………………….......... Compare arteries, capillaries and veins Arteries Capillaries Veins Fast Slow Slow High (80 - 120 mmHg) Low (~20 mmHg) Low (<15 mmHg) Extremely narrow Wide Structure Blood Speed Blood Pressure Size of Lumen Valves Wall Composition Function Narrow No No Yes Thick wall with large Extremely thin wall Thin wall with small amounts of muscle and composed of single amounts of muscle and elastic fibres layer epithelium elastic fibres Carry blood from heart Gas / material exchange Carry blood to heart Explain how the structure of the blood vessels relates to their respective functions Arteries have thick walls and narrow lumens because they transport blood at high pressure ………………………………………………………………………………………………………………………………………………….......... Capillaries have walls that are a single cell thick because they exchange materials between blood and tissue ………………………………………………………………………………………………………………………………………………….......... Veins have thin walls with wide lumens and valves because they transport blood at low pressure ………………………………………………………………………………………………………………………………………………….......... Arteries have muscular/elastic walls to stretch with pulse flow ; veins have valves to prevent backflow ………………………………………………………………………………………………………………………………………………….......... Outline the role and location of valves in the circulation of blood Valves in veins and the heart ensure the circulation of blood is unidirectional by preventing back flow ………………………………………………………………………………………………………………………………………………….......... Heart valves include AV valves (tricuspid and bicuspid) and semilunar valves (pulmonary and aortic valves) ………………………………………………………………………………………………………………………………………………….......... State which blood vessels supply the heart tissue with oxygen and nutrients Coronary arteries ………………………………………………………………………………………………………………………………………………….......... Heart Label the following diagram of the human heart Myocardium (thicker on left side of heart) 0. ………………………………………………………......... Right atrium 1. ………………………………………………………......... Right ventricle 2. ………………………………………………………......... Left atrium 3. ………………………………………………………......... Left ventricle 4. ………………………………………………………......... Superior vena cava 5. ………………………………………………………......... Inferior vena cava 6. ………………………………………………………......... Pulmonary artery 7. ………………………………………………………......... Pulmonary vein 8. ………………………………………………………......... Aorta 9. ………………………………………………………......... Pulmonary valve (semilunar valve) Tricuspid valve (AV valve) a. ………………………………………………………......... b. ………………………………………………………......... Bicuspid / mitral valve (AV valve) c. ………………………………………………………......... d. ………………………………………………………......... Aortic valve (semilunar valve) Describe the electrical events that trigger the contraction of the heart muscle fibres The heart beat is myogenic - meaning cardiac contraction is initiated by the heart ………………………………………………………………………………………………………………………………………………….......... Electrical signals are initiated by the sinoatrial (SA) node (the pacemaker) ………………………………………………………………………………………………………………………………………………….......... It stimulates the atria to contract and also relays signals to an atrioventricular node ………………………………………………………………………………………………………………………………………………….......... The atrioventricular node sends signals via the Bundle of His to Purkinje fibres ………………………………………………………………………………………………………………………………………………….......... These fibres innervate the ventricles and cause them to contract ………………………………………………………………………………………………………………………………………………….......... ………………………………………………………………………………………………………………………………………………….......... Describe the role of the medulla and epinephrine (adrenaline) in regulating heart rate The SA node (pacemaker) maintains the heart’s normal sinus rhythm (60 – 100 bpm) ………………………………………………………………………………………………………………………………………………….......... The pacemaker may be regulated by the medulla (brainstem), with sympathetic nerves increasing heart rate ………………………………………………………………………………………………………………………………………………….......... by releasing noradrenaline and parasympathetic nerves decreasing the heart rate by releasing acetylcholine ………………………………………………………………………………………………………………………………………………….......... Heart rate may also be increased by the release of epinephrine (a.k.a. adrenaline) into the bloodstream ………………………………………………………………………………………………………………………………………………….......... Differentiate between systole and diastole Systole describes the period of heart contraction, whereas diastole describes the period of heart relaxation ………………………………………………………………………………………………………………………………………………….......... ………………………………………………………………………………………………………………………………………………….......... With the aid of the following diagram, outline the pressure changes in the heart during the cardiac cycle Atrial Ventricular Systole Systole Diastole Contraction (C) / relaxation (R) Atrium C R R Ventricles R C R Open (O) / closed (C) AV valve O C O Aortic valve C O C Blood returning to the heart will flow into the atria and ventricles as the pressure in them is lower ………………………………………………………………………………………………………………………………………………….......... As ventricles fill, atria contract (atrial systole), increasing pressure in atria and forcing blood into ventricles ………………………………………………………………………………………………………………………………………………….......... As ventricles contract, ventricular pressure exceeds atrial pressure and AV valves close to prevent back flow ………………………………………………………………………………………………………………………………………………….......... When ventricular pressure exceeds pressure in aorta, the aortic valve opens to release blood into the aorta ………………………………………………………………………………………………………………………………………………….......... As blood exits the ventricle, ventricular pressure falls below aortic pressure, so the aortic valve closes ………………………………………………………………………………………………………………………………………………….......... When ventricular pressure drops below atrial pressure, the AV valve opens and cycle begins again ………………………………………………………………………………………………………………………………………………….......... Describe the causes and consequences of occlusions to the coronary arteries Causes: Atherosclerosis can be caused by age, hypertension, obesity, diseases (e.g. diabetes), smoking, genetics, ………………………………………………………………………………………………………………………………………………….......... diet (high levels of trans fats) and lack of exercise ………………………………………………………………………………………………………………………………………………….......... Consequences: Coronary heart disease (CHD) occurs when coronary arteries become narrower ………………………………………………………………………………………………………………………………………………….......... Coronary arteries oxygenate heart tissue so their occlusion results in myocardial infarctions (heart attacks) …………………………………………………………………………………………………………………………………………………..........