The net movement of molecules from a low concentration to a high concentration (against concentration gradient) using energy (released from ATP). Molecules will move in or out via Protein Carriers (in the cell membrane)
Concentrations of substances are at the same level as the body e.g. 4g- 8g of carbohydrate per 100cm3 of drink. As it is the same concentration, only some water moves from the gut to the body by osmisis but some sugar is also absorbed. Used for hydration and fuel replacement.
Net movement of water (only) from a high concentration to a low concentration through a semi-permeable membrane.
- Plants take up water and minerals from the soil through roots
- Water flows up stem into leaves
- Water exits plant by evaporating in the leaves then water vapour deffuses through the stomata
- The flow of water from the roots to the leaves is called the transpiration stream
- Evaporation is more rapid in dry, hot, windy or bright conditions.
Concentrations of dissolved substances are higher than in the body e.g. 8g+ of suger per 100cm3 of drink. These provide high sugar levels for absorption. Often called power drinks, they are for supplying fuel to muscles. Can cause sugar rush then a crash, which causes problems
Concentrations of disolved substances are lower than in the body e.g 4g of carbohydrate per 100cm3 of drink. as it is more dilute than blood, water moves from the gut into the body quickly by osmosis. Used for hydration.
Rate of Transpiration
Importance of Hydration
- Fluids protect organs with a liquid buffer
- Water and ions are needed for temperature regulation
- Fluids keep face features and other organs moist e.g. lungs, skin, nose, mouth
- Mineral ions are carried around the body dissolved in water
- Fluid lubricates joints
- Substances such as glucose, for respiration, are carried dissolved around the body to the muscles. Once oxygen leaves blood cells, it travels to muscles in water and so does carbon dioxide as it moves from muscles to blood.
Every heart beat, ventricals contract and force blood out of the heart and into the arteries
- Leaves left ventrical
- Carries oxygenated blood to your body tissues
- Simialr arteries branch off from it to take blood to the head and brain and the body organs
- Leaves the right ventrical
- Takes deoxygeated blood back to lungs
Blood is forced out of venticals at high pressure spurts. To cope, artery walls contain: elastic fibres, so they can stretch; muscle fibres, to withstand high pressures and maintain pressure; a folded inner lining that can expand as the walls stretch with each spurt and narrow lumen (space inside artery) to maintain pressure.
- Carry blood back from body tissue to the heart
- Blood under low pressure
- Lumen is wide to allow low resistance to blood flow
- Walls are thin as they don't have to withstand high pressures
- Walls contan less muscles and fewer elastic fibres than arteries
- Inner lining is smooth
- Veins surrounded by skeletal muscles. When legs contract, this hels to push blood up to your heart
- Have valves to prevent backflow
- The Vena Cava brings deoxygenated blood back to the right atrium
- The pulmonary veins bring oxygenated blood from lungs to left atrium
Problems with Arteries
With age, arteries become narrower, typically due to diet and in particular, saturated fats. Fatty deposits form under the lining and obstructs the lumen. This can reduce blood flow and cause a clot. If this occurs in a coronary artery, supplying the heart muscle, you would have a heart attack
- A stent can be inserted into a narrowed/blocked artery. It makes the lumen wider again, easing the blood flow.
- A stent is a narrow mesh tube that is inserted in the blood vessel and travels to the narrowing.
- It then expands and pushes the artery walls back, expanding the lumen.
The intercostal muscles (muscles between ribs which raise ribcage by contracting and lower it by relaxing) contract, expanding the ribcage outwards and upwards.
The diaphragm (sheet of muscle that sperates lungs form abdominal cavity. Pulled down to cause inhalation) contracts, pulling downwards to increase the volume of the chest.
Pressure inside the chest is lowered and air is sucked into the lungs.
The intercostal muscles relax, the ribcage drops inwards and downwards.
The diaphragm relaxes, moving back upwards, decreasing the volume of the chest.
Pressure inside the chest increases and air is forced out.
Man made heart that can replace a human heart if the heart has severe heart disease/damage/failure and a suitable donor cannot be found (often shortage)
Replicates the function of the heart but causes clotting within it, so only short term measure till donor is found
Biological Valves - human donor or animal
- Do not damage red blood cells
- Harden over time
- Might need replacing
Mechanical Valves - man made
- Strong and durable
- Damage red blood cells
- Anti-blood clotting drugs need to be taken
- Possible to hear valves opening and closing