Physiology (//; from Ancient Greek φύσις (physis), meaning "nature, origin", and -λογία (-logia), meaning "study of") is the scientific study of function]disambiguation needed[ in living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or Medicine, awarded since 1901 by the Royal Swedish Academy of Sciences.
The body fat percentage of a human or other living being is the total mass of fat divided by total body mass; body fat includes essential body fat and storage body fat. Essential body fat is necessary to maintain life and reproductive functions. The percentage of essential body fat for women is greater than that for men, due to the demands of childbearing and other hormonal functions. The percentage of essential fat is 2–5% in men, and 10–13% in women. Storage body fat consists of fat accumulation in adipose tissue, part of which protects internal organs in the chest and abdomen. The minimum recommended total body fat percentage exceeds the essential fat percentage value reported above. A number of methods are available for determining body fat percentage, such as measurement with calipers or through the use of bioelectrical impedance analysis.
The body fat percentage is a measure of fitness level, since it is the only body measurement which directly calculates a person's relative body composition without regard to height or weight. The widely used body mass index (BMI) provides a measure that allows the comparison of the adiposity of individuals of different heights and weights. While BMI largely increases as adiposity increases, due to differences in body composition, it is not an accurate indicator of body fat; for example, individuals with greater muscle mass will have higher BMIs. The thresholds between "normal" and "overweight" and between "overweight" and "obese" are sometimes disputed for this reason.]citation needed[
In biology, adipose tissue // or body fat or just fat is loose connective tissue composed mostly of adipocytes. In addition to adipocytes, adipose tissue contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular endothelial cells and a variety of immune cells (i.e. adipose tissue macrophages (ATMs)). Adipose tissue is derived from preadipocytes. Its main role is to store energy in the form of lipids, although it also cushions and insulates the body. Far from hormonally inert, adipose tissue has in recent years been recognized as a major endocrine organ, as it produces hormones such as leptin, estrogen, resistin, and the cytokine TNFα. Moreover, adipose tissue can affect other organ systems of the body and may lead to disease. Obesity or being overweight in humans and most animals does not depend on body weight, but on the amount of body fat—to be specific, adipose tissue]citation needed[. The two types of adipose tissue are white adipose tissue (WAT) and brown adipose tissue (BAT). The formation of adipose tissue appears to be controlled in part by the adipose gene. Adipose tissue, more specifically brown adipose tissue, was first identified by the Swiss naturalist Conrad Gessner in 1551.
A flush toilet is a toilet that disposes of human waste by using water to flush it through a drainpipe to another location. Flushing mechanisms are found more often on western toilets (used in the sitting position), but many squat toilets also are made for automated flushing. Modern toilets incorporate an "S", "U", "J", or "P" shaped bend that causes the water in the toilet bowl to collect and act as a seal against sewer gases. Since flush toilets are typically not designed to handle waste on site, their drain pipes must be connected to waste conveyance and waste treatment systems. A flush toilet may be euphemistically called a lavatory, a bog (UK), a pot (USA), a loo, a john, a water closet (abbreviated "W.C."), or simply "toilet".