transport in humans

• what is the SF of arteries: S1— thick, muscular & elastic. F1— withstand high pressure of blood from ❤️, arteries can stretch & recoil to allow blood to flow in spurts. S2— contractio & relaxation of muscles in arterial walls. F2— arteries consrict & dilate, blood flow changes.
• what is the SF of veins: S1— walls are not as thick as arteries, elastic walls reduced. F1—lower blood pressure of blood. S2— valves present. F2— prevent backflow of blood
• what is the SF of capillaries: S1— single layer of flattened partially permeable cells makes up wall. F1— allows dissolves substances to diffuse rapidly. S2— repeated branching. F2— increases SA:vol for rapid exchange of substances btw blood & tissue cells, branching from arterioles to increases total-cross sectional area to reduce rate of flow of blood for increased time for diffusion of dissolved substances. S3— one cell thick walls with no muscular layer. F3— low blood pressure to reduce rate of flow of blood to increase time for exchange of gases
• what is transported from cells to blood: excretory waste (urea, uric acid), CO2 (to plasma in blood)
• what is transported from blood to cells: dissolved food substances (amino acids, glucose, fats) O2 gas (rbs in blood to cells)
• describe the process of blood clotting: damaged tissues & platelets produces thrombokinase. thrombokinase converts prothrombin in plasma to thrombin in the presence of calcium ions (Ca2+) thrombin catalyses conversion of soluble fibrinogen to insoluble fibrin thread which forms a mesh to trap cells
• label the structure of the heart: 1 & 4) vena cava 2) pulmonary artery 3) right atrium 5) tricuspid valve 6) right ventricle 7) median septum 8) cardiac muscle 9) left ventricle 10) chordae tendineae 11) bicuspid valve 12) semi-lumar valve q

  
• describe atrial systole: muscle of the atria contracts (squeeze blood), pressure within atria increases, atrium p. > ventricular p. , bicuspid & tricuspid valve are forced open, blood is forced from atria into ventricles
• describe ventricular diastole: muscles of ventricle relaxes, pressure within ventricle decreases, aortic & P.A p. > ventricular p. , semi-lunar valves are forced close to prevent backflow of blood, produces a ‘dub’ sound
• describe atria, diastole: muscles of atria relaxes, blood fills the atria of ❤️, left side receives oxygenated blood, right side receives deoxygenated blood from rest of the body via P.V & vena cava
• describe ventricular systole: muscles of ventricle contracts & muscles of atria relaxes, pressure within ventricle increases, ventricular p. > aortic, P.A p. , tricuspid & bicuspid valve forced close to prevent backflow of blood, produces a ‘lub’ sound, semi-lunar valves forced open, blood is forced from ventricles to aorta/P.A to rest of the body/lungs
• what is coronary heart disease: process whereby fatty substances such as cholesterol and polysaturated fats get deposited on the inner surface of coronary arteries, narrowing the lumen of arteries, increasing blood pressure