Tag: biology

Greenhouse effect refers to the absorption of the sun's radiations by the atmospheric gases like carbon dioxide and trapping of these radiations within the atmosphere. These are subsequently reflected onto the earth's surface and cause an increase in the global temperature, called global warming. So, greenhouse effect is related to the global warming caused by the accumulation of greenhouse gases like carbon dioxide, methane, sulphur tetrafluoride etc.

El Nino is a climate cycle, occurring after 5-8 years in the Pacific ocean which globally impacts weather pattern. The cycle begins when warm water in the western tropical Pacific Ocean shifts eastward along the equator toward the coast of South America. The cold counterpart of El Nino is called La Nino. The weakening of the trade winds which results in pushing of warm surface water to the west and less cold water to the east cause the effect of El Nino.

Greenhouse gases such as carbon dioxide, methane, nitrous oxide, water vapours trap heat radiating from earth towards space making the earth warmer. The increased amount of these gases block Heat from escaping and they present in the earth's atmosphere for more than their expected period. Scientist attributes the cause of global warming to such semi-permanently existing gases 'forcing' climate change.

Carbon dioxide is a greenhouse gas. It absorbs the long wavelength infrared radiations. The chemical bond between carbon and oxygen absorb infrared light very well and traps the heat from escaping, so they are considered to be opaque to the infra-red rays as these cannot pass across the carbon dioxide. Carbon dioxide molecules vibrate on receiving energy from the photon and allows molecules to capture the infrared photons (radiation). 

The spleen plays important roles in regard to red blood cells and the immune system. It removes old red blood cells and holds a reserve of blood, which can be valuable in case of hemorrhagic shock, blood loss and also recycles iron. It purifies the blood and helps the immune system to recognize and attack foreign antibodies and disease. The spleen is composed of the red and white pulp. The white pulp produces and grows immune cell as well as blood cells. On the other hand, the red pulp is responsible for purifying the blood and removing dead or old blood cells.

Essentially, the spleen is a storage container and filter for blood, though it is part of the lymphatic system. In fact, it’s the largest lymph node in the body. One of its tasks is to remove harmful bacteria and viruses in the blood stream. Its other major task is removing or storing certain blood cells. The spleen is composed of two primary regions namely, red pulp and white pulp. The red pulp makes up for little more than three-fourth of the spleen. A region designated marginal zone is a transition area that separates it from the white pulp. Red pulp is red because it has many small cavities (sinusoids) where the spleen stores blood in case of injury or other situations where the body needs extra blood. This blood reserve has a high count of platelets, an essential component for blood coagulation to help stop bleeding. In liver, kidney and heart blood can not be stored. Thus, option A is correct.

The lymphatic system returns excess interstitial fluid to the blood. Of the fluid that leaves the capillary, about 90 percent is returned. The 10 percent that does not return becomes part of the interstitial fluid that surrounds the tissue cells. It helps in exchange of gasses, nutrients and removes the metabolic waste. It is devoid of RBC. So, the correct answer is option B.

The lymphatic system returns excess interstitial fluid to the blood. Of the fluid that leaves the capillary, about 90 percent is returned. The 10 percent that does not return becomes part of the interstitial fluid that surrounds the tissue cells. It helps in exchange of gasses, nutrients and removes the metabolic waste. It is devoid of RBC. It contains fewer proteins than plasma and lacks RBC.  So, the correct answer is option A.

Lymph is watery clear fluid or colorless because it lacks red blood cells (erythrocytes). It consists of plasma and white blood cells (leucocytes) only.

WBCs are divided into leucocytes and lymphocytes. Lymphocytes are further divided into macrophages and monocytes. These cells help in the engulfment of any foreign particles inhaled or ingested by our body. Lymphocytes are considered as soldier cells of our body. A Large proportion of these cells is found in the lymphatic system wherein the lymph is present. Thus lymph provides immunity. So, the correct answer is option A.