Science Zone

WHY ARE GRASSHOPPERS GREEN DURING RAINY SEASON BUT BROWN DURING DRY SEASON

WHY ARE GRASSHOPPERS GREEN DURING RAINY SEASON BUT BROWN DURING DRY SEASON

Ever wondered why grasshoppers are green during the rainy season but brown during the winter. Well it's an adaptive coloration to escape from predators. They assume the green colour of green grasses d…

19 Feb 2015

SKIN AS BODY TEMPERATURE REGULATOR

<div xmlns='http://www.w3.org/1999/xhtml'>The skin as we all know is the largest organ in the body. Also with exception of the bones and cartilages, it's the toughest tissue in the body. It does live up to its status by carrying out numerous functions such as protection, excretion, storage of food, sensitivity, regulation of the body temperature, production of vitamin D through the early sunshine and so on. 
 
Today we are going to see how the skin regulates the body temperature especially in we homoiothermic animals; animals with constant body temperature. 
 
This is truly amazing as how the skin keeps the body temperature constant regardless of changes in external environment though the liquid tissue cell (blood) also plays a role at body temperature regulation. 
 
On a hot day or weather, there's usually an increase in the temperature of the environment and the skin carry out the following processes to get rid of excess heat and thus to keep the body temperature constant. 
 
VASODILATION: 
There is a dilation of the capillaries near the skin surface and a constriction of those in the deeper layer. The impact of this is a large volume of blood flow close to the surface of the skin such that there's a loss of heat via the three mood of heat transfer namely; conduction, convection and radiation. 
 
DECREASE IN METABOLIC RATE: There is a reduction in metabolic activity by the skin or body and this reduces the heat released by metabolic activity and thus heat production is reduced. 
 
LOWERING OF HAIRS: We usually notice that the hairs especially those on the hands and legs rise and fall. Yes they rise and fall. 
During hot days, the hair erector muscles relax causing the hairs to lie flat on the skin surface. This expose most of the air trapped by the hairs and also heat from the body is lost as the air evaporates. 
 
SWEATING: 
The sweat gland is usually active during hot periods and there's large sweat production. As the sweat evaporate from the skin, latent heat of evaporation is also extracted from the body hence the heat of the body is reduced. 
 
On a cold day or weather, the following processes are done by the skin to regulate the body temperature. 
 
RAISING OF THE HAIRS: 
The hair erector muscle contract to raise the hair and trap more air during a cold weather. Since air is a bad conductor of heat, the layer of air next to the skin acts as an insulator and prevent heat loss from the body and conserves the normal body temperature. 
 
VOSOCONSTRICTION: There's constriction of capillaries close to the skin surface and also a dilation of capillaries in deeper layer of the skin. This brings about small volume of blood flow near the skin surface and hence prevents loss of heat and conserves body heat or temperature. 
 
INCREASE IN METABOLIC ACTIVITY: The skin increases the metabolic activity of the body especially the respiratory activity of the liver that release large amount of energy and heat. This help to generate the heat necessary to keep the body's temperature from dropping during cold weather. 
 
SWEATING: 
THE sweat gland become inactive on a cold day and hence there is very little production of sweat that gets evaporated thereby conserving the latent heat of vaporization and rather use it to keep the body temperature constant by ensuring no drop 'in temperature rate throughout the body.</div>

SKIN AS BODY TEMPERATURE REGULATOR

The skin as we all know is the largest organ in the body. Also with exception of the bones and cartilages, it's the toughest tissue in the body. It does live up to its status by carrying out numerous …

04 Feb 2015

WHY WE URINATE MUCH AND OFTEN ON A COLD WEATHER OR DAY

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No one can claim that he's oblivious of the fact that we tend to urinate more and often during cold weather. Yes you heard me right! 
 
But why is it so? 
Well let me address the question once and for all. 
 
First! How does the body react during cold and hot weather with regard to even temperature distribution through out the body. 
 
But then when does one feel warm and cold? 
I mean how does the body cope with hemostasis, to sound less complex the regulation of the body's temperature in order to attain and maintain a fairly constant temperature rate. 
 
The blood and the skin see to that. 
The blood cell does its by even distribution of blood around the body to ensure an even body temperature. 
To be precise, the blood disperse the temperature of a particular part of the body to all other parts of the body. <a href="http://sciencezone12.blogspot.in/2015/02/skin-as-body-temperature-regulator.html/">The skin does its as body temperature regulator</a> 
 
The body is usually warm on a hot day as a result of heat from the sun and high metabolic activity in the body. When the body is warm, there's a stimulation for sweat production and this is due to the high metabolic activity of the liver which heats up the body. 
 
For the sweat to be evaporated from the body, latent heat of vaporization is derived from the body and thus the body's temperature is continually reduced as the sweat evaporate. 
This and cold weather bring about the sensation of cold stimuli while hot weather and high metabolic activity within the body lead to warm sensation we feel. 
 
Acknowledging this, it's also important to understand how the body dispose sweat in each atmospheric condition and thus why we urinate much and often during cold weather or atmospheric condition than the warm one. 
 
During hot weather, the skin helps the liver dispose excess salt or sweat produced by the sweat gland through body sweating because the sweat gland is highly active and produces high amount of sweat. 
 
Unlike hot atmospheric condition, the sweat gland is inactive during a cold day and produces very little sweat. The effect of this is a drastic reduction of heat or sweat loss through evaporation. Not only does this result to body heat conservation but also result to the skin not excreting excess salts or sweat and then the sweat become excreted by the liver as urine. 
That's why we urinate much and often on a cold weather or day.</div>

WHY WE URINATE MUCH AND OFTEN ON A COLD WEATHER OR DAY

No one can claim that he's oblivious of the fact that we tend to urinate more and often during cold weather. Yes you heard me right! But why is it so? Well let me address the question once and for al…

02 Feb 2015