Flashcards · 0610 · Topic 9

Transport in animals flashcards

20 cards on Topic 9, subtopics 9.1 to 9.4. Pick a subtopic or study them all.

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Circulatory system: A system of blood vessels with a pump and valves to ensure one-way flow of blood.
Single vs double circulationExtended: Single (fish): blood passes through the heart once per circuit: heart → gills → body → heart. Double (mammal): twice per circuit: heart → lungs → heart → body → heart.
Advantages of a double circulationExtended: Blood is pumped again after the lungs, so it reaches the body at high pressure and flows faster. Blood goes to the lungs at lower pressure. Oxygenated and deoxygenated blood are kept separate.

Route of blood through the heart: Vena cava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta → body.
Three ways to monitor the activity of the heart: ECG, pulse rate, and listening to the sounds of the valves closing.
Coronary heart disease: Blockage of the coronary arteries, so heart muscle gets less oxygen and glucose, cannot respire, and may die (heart attack).
Risk factors for coronary heart disease: Diet, lack of exercise, stress, smoking, genetic predisposition, age and sex.
Why is the left ventricle wall thicker than the right?Extended: It pumps blood round the whole body at higher pressure; the right ventricle pumps only to the lungs. (Higher pressure, not a bigger volume.)
Atrioventricular and semilunar valves during a heartbeatExtended: Ventricles contract: atrioventricular valves close (no backflow into the atria) and semilunar valves open. Ventricles relax: semilunar valves close (no backflow into the ventricles).
Explain why heart rate rises during exerciseExtended: Muscles respire faster, so need more oxygen and glucose and must lose more carbon dioxide. A faster heart rate delivers blood faster.

Artery and vein (definitions): Artery: carries blood away from the heart. Vein: carries blood back to the heart. (Defined by direction, not oxygen: the pulmonary artery carries deoxygenated blood.)
Artery vs vein vs capillary: wall, lumen, valves: Artery: thick muscular elastic wall, narrow lumen, no valves. Vein: thin wall, wide lumen, valves. Capillary: wall one cell thick, very narrow lumen, no valves.
Blood vessels into and out of the lungs and the kidneys: Lungs: in by the pulmonary artery, out by the pulmonary vein. Kidney: in by the renal artery, out by the renal vein.
Link the structure of each vessel to its functionExtended: Artery: thick wall withstands high pressure; elastic tissue stretches and recoils. Vein: low pressure, wide lumen, valves stop backflow. Capillary: one-cell-thick wall gives a short diffusion distance.
Hepatic portal veinExtended: Carries blood with absorbed nutrients from the gut to the liver. (The liver also receives the hepatic artery and drains into the hepatic vein.)

Functions of red blood cells, white blood cells and platelets: Red cells: transport oxygen (haemoglobin combines with oxygen). White cells: phagocytosis and antibody production. Platelets: clotting.
What does plasma transport?: Blood cells, ions, nutrients, urea, hormones and carbon dioxide. (Not oxygen: red blood cells carry that.)
Why is blood clotting important?: It prevents blood loss and the entry of pathogens.
Lymphocyte vs phagocyteExtended: Lymphocyte: large round nucleus, little cytoplasm; produces antibodies. Phagocyte: lobed nucleus, more cytoplasm; engulfs pathogens by phagocytosis.
Process of blood clottingExtended: Soluble fibrinogen is converted to insoluble fibrin, which forms a mesh that traps blood cells to form a clot.