Download hba semester 1, unit 2 exam notes 2013

HBA SEMESTER 1, UNIT 2 EXAM NOTES 2013 THE HEART (Lecture 10+11) Qu. Is the heart a single or double pump? Double pump, right and left Qu. What are the 3 components that make up the cardiovascular system? 1. Blood 2. Vessels 3. Heart The blood is found within a set of tubes which are connected to a pump Qu. What are the 2 circuits in the cardiovascular system? Which side of the heart is responsible for which? 1. Pulmonary circuità Right side of heartà Receives deoxygenated blood from the body tissues then pumps this blood to the lungs to pick up O2 and dispel CO2. (Blood vessels carry blood to and from the lungs) 2. Systemic circuità Left side of heartà Receives oxygenated blood returning from the lungs and pumps this blood throughout the body to supply O2 and nutrients to body tissues. (Blood vessels carry blood to and from all body tissues) Qu. What are the 4 types of vessels found in the circulatory system? -­‐ Veinsà blood vessels that carry blood back TOWARD your heart -­‐ Arteriesàblood vessels that carry oxygen rich blood AWAY from the heart. (arteries-­‐ away) -­‐ Capillariesàconnect arteries to veins. Nutrients, oxygen and wastes are exchanged in and out of your blood through the capillary walls. -­‐ Lymphatic vesselsà Collect ‘leaked’ interstitial fluid from tissue Qu. Relate their structural features to their function VEINS -­‐ Use skeletal muscle pump to return blood to heart -­‐ Layers of smooth muscle -­‐ Thin walls (more compliant) -­‐ Not as elastic as arteries -­‐ Have valves to prevent back-­‐flow of blood ARTERIES -­‐ Layers of smooth muscle -­‐ Thick elastic wallsà needs to be able to expand to accommodate blood coming in, and contract to squeeze it out -­‐ Arteries branch into arterioles as they get smaller -­‐
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Arterioles eventually become capillaries, which are very thin and branching. More like a web, than a branched tube Walls need to be thin to allow for rapid diffusion of gases, nutrients and wastes So small that blood cells have to pass through 1 by 1 A part of the systemic circuit Qu. What is the function of heart valves? -­‐ Allows blood to flow through the heart in 1 direction Qu. What causes heart valves to open and close? -­‐ Pressure -­‐ Forwards pressure gradient forces it to open -­‐ When pressure is greater in front of the valve, it closes Structures of the heart (Lecture 10+11) Qu. Define the structures of the heart and describe their functions Superior vena cava Returns blood from body above the diaphragm Inferior vena cava Returns blood from body below the diaphragm Atria Receiving chambers for blood returning to the heart from circulation Ventricle Discharging chambersà the actual pumps of the heart Pulmonary trunk Carries deoxygenated blood to lungs so they can get oxygen Pulmonary artery The artery that carries venous blood from the right ventricle and divides into the right and left pulmonary arteries Pulmonary veins Where the left atrium receives oxygenated blood from; it has thicker walls than those of the right atrium. Aorta VALVES Tricuspid valve Right AV valve with 3 cusps Biscuspid valve Left AV valve with 2 cusps (mitral valve) chordae tendinae fibres attached to the tricuspid valve which pull it closed when papillary muscles contract, preventing backflow of blood Pulmonary valve A SL valve between the right ventricle and the pulmonary artery Aortic valve A SL valve between the left ventricle and the aorta CORONARY CIRCULATION Coronary sinus A short sinus receiving most of the veins of the heart Right coronary artery Supplies blood to right atrium, portions of both ventricles and cells of AV nodes and SA node. (divides into the right marginal artery + posterior interventricular artery) Left coronary artery One of two arteries from the aorta that nourish the heart (divides into the circumflex and anterior descending branches) LAYERS OF THE HEART Pericardium Double layered serous membrane that surrounds the heart Epidcardium The innermost of the two layers of the pericardium Myocardium The middle muscular layer of the heart wall Endocardium The membrane that lines the cavities of the heart and forms part of the heart valves Qu. Why is the left ventricle 3x thicker than the right ventricle? -­‐ Left ventricle is apart of the systemic circuit. It needs to expand and generate enough pressure to push blood around the entire body