Tag: role of other organs in excretion

Since terrestrial animals do not have automatic access to either fresh or salt water, they must regulate water content in other ways, balancing off gains and losses.

Ammonia which is the major form of nitrogenous waste generated in the body is converted urea in the liver and excreted through the urine by the kidneys. Thus, the correct option is C.

The accessory excretory organs are:-

(A) Spleen - Primarily acts as blood filter. 

Metabolic wastes are substances left over from a metabolic process which cannot be used by the organisms and must, therefore, be excreted. This includes nitrogen compounds. The nitrogen compounds through which excess nitrogen is eliminated from the organism are called nitrogenous wastes. They are ammonia, urea, uric acid, and creatinine. 

The large intestine is the part of the digestive system. Whereas the excretory system of humans consists of two kidneys, two ureters, one urinary bladder, and one urethra. Urine is found in almost all excretory system parts(little or more).

The epidermis is composed of 4 or 5 layers depending on the region of skin being considered. The Malpighian layer (stratum malpighii) is defined as both the stratum basale and stratum spinosum. In spinous layer (stratum spinosum), keratinocytes become connected through desmosomes and start to produce lamellar bodies, from within the golgi, enriched in polar lipids, glycosphingolipids, free sterols, phospholipids and catabolic enzymes. Basal/germinal layer (stratum basale/germinativum) is composed of proliferating and non-proliferating keratinocytes, attached to the basement membrane by hemidesmosomes. Melanocytes are present, connected to numerous keratinocytes in this and other strata through dendrites. Merkel cells are also found in the stratum basale with large numbers in touch-sensitive sites such as the fingertips and lips. 

The sweat on the surface of the skin is evaporated by the body heat. As the water is evaporated by heat released from the body, the body cools off. Each gram of water on the body surface absorbs about 0.58 calories of energy before evaporating, which is a significant source of heat loss.

In humans, kidneys are the chief excretory organ, other than kidneys, lungs, liver, and skin also help in the elimination of excretory wastes. Lungs remove a large amount of carbon dioxide and the significant amount of water every day. The liver secretes bile containing substances like bilirubin, biliverdin, degraded steroid hormones, vitamins. Most of these substances pass along with digestive wastes. Skin contains sweat glands through which NaCl, the small amount of urea, lactic acid etc are secreted. The intestine is not an excretory organ but it is a digestive organ.

Cloaca is the posterior opening that serves as the only opening for the intestinal, reproductive and urinary tracts of all amphibians, birds, reptiles, and monotremes. They possess this orifice, from which they excrete both urine and feces, unlike most placental mammals, which possess two or three separate orifices for evacuation.