Tag: other systems in the body

• The process of expelling waste from the organism is called excretion. Ammonia, urea and uric acid are the major forms of nitrogenous wastes excreted by the animals. Ammonia is the most toxic form and requires a large amount of water for its elimination, whereas uric acid, being the least toxic, can be removed with a minimum loss of water.
  
• The human excretory system consists of a pair of kidneys, ureter, urinary bladder and urethra.
  
• So, the correct answer is 'Excretion'.
  

One of the major organs of the excretory system are the kidneys. It's other major organ's are the urethra, sweat glands, lungs, and rectum. Gills in fish are part of the excretory system. The kidneys are very complex organs that play very important roles such as liquid waste is produced by the kidneys and stored in the muscular bladder. As blood flows through the capillaries, substances move from the blood through the capillary walls into the tubes. The urethra is a tube which connects the urinary bladder to the outside of the body. The urethra functions to both male and female bodies. It also functions as a passage for semen. There are two different types of sweat glands, the apocrine sweat glands, and the merocrine sweat glands. Both sweat glands contain muscle cells. Humans have two lungs, the left lung being divided into two lobes and the right with three. Lungs are what make you breathe and they also absorb water vapors. The rectum is about eight inches long and serves basically as storage for poop. 

The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals, including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species. It is within the uterus that the fetus develops during gestation, usually developing completely in placental mammals such as humans and partially in marsupials such as kangaroos and opossums. Two uteri usually form initially in a female and usually male fetus, and in placental mammals, they may partially or completely fuse into a single uterus depending on the species. In many species with two uteri, only one is functional. Ureter, urethra, and urinary bladder are parts of the excretory system.

Nitrogenous waste products are generated during the breakdown of proteins by the cells as they catabolize amino acids to obtain energy. During the process of deamination, enzymes remove the amino group as ammonia which is highly toxic even in small quantities. In humans, this is combined with carbon dioxide to give urea and uric acid, which is thrown out by the function of the kidneys in the form of urine. 

Renal physiology was described by Ludwig. Renal physiology is the study of the physiology of the kidney.

The liver is a large, meaty organ that sits on the right side of the belly. Weighing about 3 pounds, the liver is reddish-brown in color and feels rubbery to the touch. The liver has two large sections, called as the right and the left lobes. The gallbladder sits under the liver, along with parts of the pancreas and intestines. The liver and these organs work together to digest, absorb, and process food. 

Nephrons are the structural and functional units of the kidney, which is the primary organ of the excretory system.

The kidneys play a primary role in filtering the blood and excreting metabolic wastes, excess ions, and certain mineral salts such as carbonates and phosphates. While other organs like the skin and liver also have excretory functions, the kidneys are principally responsible for regulating and excreting these specific mineral ions.

Kidney is the main excretory organ in man. It helps in filtration of blood and maintains osmoregulation. Accessory organs of excretion are liver, lungs and skin. Lungs helps in excretion of carbon dioxide. Skin helps in secretion of oil, water and salts by sweat and sebaceous gland. Liver helps in excretion of bile. It also helps in formation of urea which is a major excretory product. So, the correct answer is option"kidneys."