Railway Science (Biology – Excretory System)

Neurons are the cells that make up the brain and the nervous system. Excretion - Process where all the metabolic wastes (carbon dioxide, water and nitrogenous products like urea, ammonia and uric acid) are removed from the body. Kidney - Bean shaped structure.
Main function - filter the blood that runs inside the human body to create urine. Nephrons - Functional unit of the kidney. Weight (120 -170 g). Location - between the levels of last thoracic and third lumbar vertebra close to the dorsal inner wall of the abdominal cavity.

Cartilage is a connective tissue that provides support and flexibility to various parts of our body. Cartilage is found in the nose (hyaline cartilage), ear (elastic cartilage ), larynx (thyroid cartilage ) but not in the kidney. Renal tubules and corpuscles in the kidney are formed by Cuboidal epithelium tissue.

Nephron: Basic, functional and structural unit of a kidney. The kidney has more than eight lakh nephrons. Nephron produces urine during the excretion of waste. It is composed of the glomerulus and the renal tubule.
The primary function of nephron is removing all waste products including the solid wastes, and other excess water from the blood, converting blood into the urine, reabsorption, secretion, and excretion of numerous substances.

The following are the ways by which excretory products are removed by the plants: The excess water is removed by the process of Transpiration. Carbon dioxide during night is removed through the stomata.
Metabolic waste of plants is stored in the leaf cell vacuole which is removed by shedding of leaves. Resin and gum extrudes out of the bark.

Tissue - Group of cells that possess a similar structure and perform a specific function. Types of animal tissue: Epithelial tissue - Large sheets of cells covering all the surfaces of the body.
Connective Tissue - Support and connect different tissues and organs of the body, Originate from the mesoderm (the middle germinal layer of the embryo). Example - adipose tissue, cartilage, bone, blood, and lymph.
Muscular tissue - Capable of contraction and is associated with the various movements of animals, Made up of thin and elongated cells (muscle fibers). Nervous tissue (consists of nerve and glial cells) - Monitors and regulates the functions of the body, found in the brain, spinal cord, and nerves.

Dialysis using an artificial kidney is based on the principle of Diffusion, convection and osmotic pressure.

Urine passes through the ureter from the kidneys to the bladder. The urethra is the tubular path that connects the bladder to the body's exterior, allowing urine to exit the body.
Renal tubule - It is one of the millions of tiny tubes in the kidneys that returns nutrients, fluids, and other substances that have been filtered from the blood.

Creatinine is a waste product made by muscles as part of regular, everyday activity. Normally, kidneys filter creatinine from the blood and send it out of the body through the urine. A creatinine level of greater than 1.2 mg/dL for women and greater than 1.4 mg/dL for men may be an early sign that the kidneys are not working properly.

Collecting duct system of the kidney consists of a series of tubules and ducts that physically connect nephrons to a minor calyx or directly to the renal pelvis. Nephron - A basic anatomical and the functional unit of the kidney. Each nephron includes glomerulus (Region b) and tubule. The nephrons work through a two-step process - the glomerulus filters the blood, and the tubule returns needed substances to the blood and removes wastes.

Nephron is the functional unit of Kidney. Components of a Nephron