OCR TRANSPORT IN ANIMALS.

OCR TRANSPORT IN ANIMALS



*Single Circulatory System - ANSWER-Circulatory system where the blood only
passes through the heart once for each circuit of the body e.g. in fish: heart ->
gills -> body -> heart

Double Circulatory System - ANSWER-Circulatory system where the blood
passes through the heart twice for each circuit of the body. E.g. in mammals and
birds: heart -> body -> heart -> lungs -> heart

Open Circulatory System - ANSWER-Circulatory system where the blood is
pumped into an open space surrounding cells/tissues where exchange takes
place by diffusion then the blood drains back to the heart. e.g. in insects

*Closed Circulatory System - ANSWER-Circulatory system where the blood is
contained within blood vessels at all times. Exchange takes place at the
capillaries by diffusion.

Arteries - ANSWER-Blood vessels that carry blood away from the heart at high
pressure. It has a narrower lumen than a vein, a thick muscular wall, elastic
tissue and a folded endothelium.

Veins - ANSWER-Blood vessel that carries blood back to the heart at lower
pressure. It has a wide lumen, a thin muscular wall, smooth endothelium and
pocket valves that prevent the backflow of blood

Capillaries - ANSWER-Thin blood vessels that surround all cells for the
exchange of substances. The endothelium is one cell thick and they collectively
have a large surface area.

Tissue Fluid - ANSWER-Fluid (water and small molecules such as oxygen,
glucose and sodium ions) that is forced out of capillaries at high hydrostatic
pressure and surrounds respiring cells so that exchange of substances can take