Saturday, 1 February 2014

Fish & Frogs Out Of Water

Water provides a refuge from temperature extremes.

For fish out of water, death is usually inevitable but for lung fish, they have certain adaptations to ensure their survival in hot surroundings. Their swim bladder forms a crude lump, allowing them to directly take in oxygen from the surrounding air and then they escape the heat by burrowing.

The lung fish first swallow the mud to excavate chamber and passes out through the gills. then coats itself in mucus. when mucus dries, it forms a body bag that seals off the fish from the drought. As conditions worsen, the lung fish shut down to wait for conditions to improve. When drought finally ends, rainwater releases it from suspended animation.

In other parts of the world where there are dry conditions as well, the desert frog also has adaptations to help it live. It can survive untombed for years as the layers of skin that forms on it a water proof barrier prevents the frog from drying out.

Another example will be the tawny devil which can survive for years without drinking water. It simply eats black ants and this is sufficient in providing all the moisture it needs.
In addition, it can collect water through capillary action. Its skin sucks out the liquid like blotting paper from the ground. For example, when humans need water, they can drink from the bladder of the desert frog and what little water is wasted when drinking will then be absorbed by the tawny devil. The darkening vein traces the network of channels which directs the water to the mouth of the tawny devil. Morning dew is also drunk this way.

Root Hair Cells Of Plants & Cells of Villi In Small Intestines

The function of root hair cells is to increase the ability to take in water and mineral salts so as to provide the plant with the nutrients that it needs. It has adaptations to ensure that it can fulfill its role to the best of its ability. Root hair cells have tiny hairs which are long and this creates a larger surface area that in turn leads to a greater absorption rate for water for example. A larger surface area also speeds up the rate of diffusion for the root hair cells, hence a more effective transportation goes on in the plant. The process of Active Transport also happens within the cells and this process involves water and minerals traveling from a lower concentration to a higher concentration. The minerals that travel from a lower concentration stem from the soil which the roots of the plant are in and the minerals of a higher concentration is from the plant itself. This is because the plant needs to get the maximum nutrients it can to carry out photosynthesis well. If all these processes happen, homeostasis will then be able to take place since we can observe water regulation by the root hair cells of a plant, meaning that it is their role to maintain a constant internal environment for the plant cells.

The function of the villi is also to increase the surface area for absorption in our small intestines, thus the small intestine is covered by millions of villi which have 4 layers and extend about 1 mm into the lumen. Once the molecules of amino acids, glucose etc. cross the epithelium that the small intestinal villi covers, these molecules diffuse into a capillary network and into our bloodstream. However, some molecules (mostly fats), are not transported into the small capillaries but into the lymphatic vessel.

Therefore, we can see that the similarities of root hair cells and the villi is that:
- Both absorb food in the simplest form (minerals and salt), albeit from different sources
- Both have adaptations to ensure a greater surface area for absorption of water and nutrients.
- Both ensure successful homeostasis through Active Transport and diffusion respectively.

Sunday, 19 January 2014

Regulation of Water In Our Bodies

During the course of OBS, our bodies went through many vigorous activities which caused a shift in the way our bodies functioned. That means that our bodies had to work hard to maintain the bodies so that we could carry out body processes and carry on normally.

Water was regulated through the process of homeostasis by our kidneys which maintained water balance in our bodies by controlling the water concentration of blood plasma. Water is usually taken in through eating and drinking and then released through sweating, peeing etc. Producing urine which is of different concentration is vital in maintaining the water balance.

For example, when the water level of our blood plasma is high, lesser water will be absorbed back into our blood stream and our urine will be more diluted. Our bodies had to work harder to keep this balance during OBS since water balance is affected by many various conditions, some of which include the amount of exercise, amount of water drunk, amount of salt intake and the external environment you are in.