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level: cardiovascular system

Questions and Answers List

level questions: cardiovascular system

Question	Answer
- main system of internal transport	cardiovascular system
- made up of 55% plasma and 45% formed elements	blood
- transport of oxygen and nutrients to cells - transports carbon dioxide and other wastes away from cells - transports hormones to cells - distributes hear and maintain body temperatures - maintains water content and ion concentration in the body fluids - protects against foreign micro-organisms - clotting when vessels are damaged, preventing blood loss	functions of blood
- 91% water - 9% dissolved substances: nutrients, ions, gases, hormones, antibodies, plasma proteins and wastes	plasma
- transports oxygen and some carbon dioxide - no nucleus: more room for haemoglobin - contains a haemoglobin protein: able to combine with oxygen - circular biconcave disc: increases surface are for oxygen exchange, thicker edges give large volume allowing more room for haemoglobin - number per mm3: 4.8-5.4 million - site of production: red bone marrow - lifespan: 120 days	red blood cells (erythrocytes)
- protects against foreign micro-organisms (phagocytosis) - removes dead cells and cell debris - granular: have granules and loved nucleus - agranular: no granules and spherical nucleus - number per mm3: 5000-10000, increased count when infected - site of production: red bone marrow - lifespan: a few days	white blood cells (leucocytes)
- blood clotting - very small and no nucleus - number per mm3: 250000-400000 - site of production: red bone marrow - lifespan: around a week	platelets (thrombocytes)
- nutrients and wastes are transported dissolved in plasma - nutrients: essential elements we obtain from the food we eat - inorganic nutrients transport as ions: Na, Ca, K, Cl, I - organic nutrients dissolved in the blood plasma: glucose, vitamins, amino acids, fatty acids, glycerol - metabolic wastes: urea, creatinine and uric acid	transports of other substances
- located in the middle of chest cavity between the lungs (mediastinum space) - approximately the size of a human fist - pericardium: membrane enclosing heart, hold hear in place but also allows it to beat, prevents overstretching - made up of cardiac muscular tissue - heart is a double pump: left pumps from lungs to body, right pumps from body to lungs	heart structure
- the heart consts of 4 muscular chambers - the left 2 are separated from the right by the septum - atria: upper chambers, receive blood, thin walls as it only pumps blood to ventricles - ventricles: lower/pumping chambers, thicker walls as it pumps to lungs and body, left ventricle is thicker than right	heart chambers
- direction of the blood flow is controlled by four valves, small flaps of tissue that function to prevent the backflow of blood - atrioventricular valves: between atria and ventricle, held in position by strong tendons, the chordae tendinae - semi-lunar valves: prevent backflow of blood from arteries to ventricles - the heart sounds "lubb-dubb" result from the valves snapping shut	heart valves
- aorta - pulmonary trunk which branches into pulmonary arteries - pulmonary veins - inferior and superior vena cava	blood vessels of the heart
- vena cava carries deoxygentaed blood from body to right atrium - pulmonary arteries carry deoxygenated blood from right ventricle to lungs - pulmonary veins carry oxygenated blood from the lungs to the left atrium - aorta carries oxygenated blood from the left ventricle to the body	major blood vessels
- LORD: left-oxygenated, right-deoxygenated - left: pulmonary vein -> left atrium -> left atrioventricular valve -> left ventricle -> aortic semi lunar valve -> aorta -> body - right: pulmonary artery -> right atrium -> right atrioventricular valve -> right ventricle -> pulmonary semi lunar valve -> pulmonary trunk/arteries -> lungs	circulation of blood
- arteries - arterioles - capillaries - veins - venules	blood vessels
- carry blood away from the hear - walls contain thick smooth muscle and thick elastic fibres - walls of arteries can stretch to accommodate extra blood from ventricles - elastic recoil keeps blood moving and maintaining high pressure - form arterioles - vasoconstriction: muscle of walls contracts to reduce diameter of vessel and therefore reduce blood flow through artery - vasodilation: muscle of wall relaxes to increase diameter of vessel and therefore increase blood flow	arteries