Exchange And Transport Systems 2.5 Flashcards
Smaller animals have a _____ surface to volume ratio than larger animals.
Higher
What affects exchange into and out of an animal?
Body size: the rate of heat loss from an organism depends on its surface area, smaller organisms lose heat more readily.
Shape: animals with a compact shape have a smaller surface area relative to their volume - minimising heat loss from their surface area. Whether an animal is compact or not depends on the temp of it environment.
How are some small desert mammals adapted to minimise water loss?
Because they have a large SA:Volume ratio, they tend to lose more water as it evaporated from their surface. So they have kidney structure adaptations, so that they produce less urine.
Describe the system which fish use for gas exchange.
Fish use a counter current system, water containing oxygen enters the fish through its mouth and passes out through the gills. Each gill is made of lots of thin plates called gill filaments, which give a big surface area for exchange of gases. The gill filament are covered with lots of lamellae which also increase surface even more.the lamellae have lots of blood capillaries, blood flows through the lamellae in one direction and water flows over in the opposite direction, this maintains a large concentration gradient between blood and water.
Describe how insects use tracheae for gas exchange.
Air moves into the tracheae through spiracles. Oxygen travels down the concentration gradient towards the cells. CO2 from the cells moves down its own concentration gradient, towards the spiracles. The tracheae branch off into smaller tracheoles which have thin, permeable walls and go to individual cells, this means the oxygen diffuses directly into respiring cells. Insects use rhythmic abdominal movements to move air into and out of the spiracles.
Where do dicotyledons plants exchange gas?
At the surface of the Mesophyll cells
How can insects and plants control water loss?
Insects can close spiracles using muscles, they also have a waterproof, waxy cuticle all over their body and tiny hairs around their spiracles, which reduce evaporation.
If plants start to become dehydrated, the guard cells lose water and become flacid, which closes the pore.
Describe some adaptations of xerophytic plants.
Sunk stomata Curled leaves Layer of hairs on the epidermis A reduced number of stomata Waxy waterproof cuticles
Name the two main veins and arteries that are connected to the heart and what they carry.
Vena cava - deoxygenated blood towards the heart
Pulmonary vein - oxygenated blood towards the Heart
Pulmonary artery- deoxygenated blood from the heart
Aorta- oxygenated blood from the heart
What is the name of the artery and the vein which connects to the liver?
Hepatic vein- deoxygenated away from the liver to the heart
Hapatic artery - oxygenated blood towards the liver
What is the name of the vein that connects the gut to the liver?
Hepatic portal
What is the name of the artery and vein which connect to the kidneys?
Renal vein- deoxygenated blood from the kidneys
Renal artery - oxygenated blood to the kidneys
Arteries divide into smaller vessels called……?
Arterioles- their muscles contract to constrict blood flow, or relax to allow full blood flow depending on demand.
How is tissue fluid formed?
At the start of a capillary bed, nearest to the arteries, the pressure In the capillaries is the greater than the pressure in the tissue. This forces fluid out of the capillaries and forms tissue fluid. As fluid leaves the pressure decreases, and is lower at the end of the capillary bed. Due to fluid loss the water potential at the end of the capillary bed is lower than in the tissue fluid, so some re-enters the capillary by osmosis. Any excess liquid is drained of by the lymphatic system.
Why does water enter the roots by osmosis?
Because there is a higher water potential in the soil than the root hair cell.
