69959
| Question | Answer |
| 6 things that need to be controlled by homestasis | . temperature . water content . ion content . blood sugar level . carbon dioxide . urea |
| Stents | keep arteries open lower risk of heart attack but artery can narrow and stents can irritate the atery |
| homestasis | is the maintenence of a contstant environment see page 83 |
| white blood cells | defend against disease change shape to engulf microorganisms produce antibodies and antitoxins |
| platelets | help blood clot |
| plasma | the liquid that carries everything in the blood |
| red blood cells | .carry oxygen from lungs to all cells of body .donought shapelarge surface area, no nucleus for abdorbing more oxygen . contain haemoglobin |
| haemoglobin | in lungs - combine with oxygen (oxyhaemaglobin) in body tissues - reverse, oxyhaemoglobing splits and releases oxygen into cells |
| double circulatory system: two circuits joined together 1. pumps deoxygenated blood to the lungs to take in oxygen, blood then returns to heart 2. pumps oxygenated blood around all other organs, blood gives up oxygen at body cells and deoxygenated returns to heart. | |
| the heart | page 79 text book |
| arteries | carry blood away from heart at a high pressure walls are thick compared to lumen |
| capillaries | . involved in the exchange of materials at the tissues . carry blood close to every cell to exchange substances . permeable walls, 1 cells thick for diffusion . supply food and oxygen and take away waste e.g CO2 |
| veins | carry blood to heart low pressure thin walls, thick lumen valves to keep blood flowing in correct direction |
| circulatory system | carries food and oxygen to every cell in the body carries waste products e.g carbon dioxide and urea to where they can be removed. |
| root hair cells | . for absorbing water and minerals . long 'hairs' give large surface area |
| active transport | when substabces are absorbed against the concentration gradient (low to high concentration) |
| phloem tubes | . transport food . transport goes in both directions |
| xylem tubes | take water up . carry water from the roots to the stam and leaves |
| transpiration | loss of water from a plant . caused by evaportation and diffusion of water in leaves . creates shortage of water in leaves so as a result more water is drawn up through the xylem tubes |
| osmosis | the movement of water molecules through a partially permeable membrane from an area of high concentration to low concentration |
| Breathing in ... | intercostal muscles and diaphragm contract thorax volume increces pressure decreaces |
| Breathing out ... | intercostal muscles and diaphragm relax thorax volume decreaces pressure increaces |
| gas exchange | diffusion through cell membranes |
| alveoli specialised for gas exchange | large surface area moist lining thin walls good blood supply |
| villi | . inside small intestine . increace surface are so more food is absorbed . good blood supply .thin walls, 1 cell thick |
Want to create your own Flashcards for free with GoConqr? Learn more.