There can human physiology textbook pdf considerable variation in body water percentage based on a number of factors like age, health, weight, and sex. This is due to how fat tissue does not retain water as well as lean tissue.
These statistical averages will vary with factors such as type of population, age of people sampled, number of people sampled, and methodology. So there is not, and cannot be, a figure that is exactly the same for all people, for this or any other physiological measure. In the traditional BIA method, a person lies on a cot and spot electrodes are placed on the hands and bare feet. 20mA range current for safety. BIA has emerged as a promising technique because of its simplicity, low cost, high reproducibility and noninvasiveness. BIA prediction equations can be either generalized or population-specific, allowing this method to be potentially very accurate. Selecting the appropriate equation is important to determining the quality of the results.
For clinical purposes, scientists are developing a multi-frequency BIA method that may further improve the method’s ability to predict a person’s hydration level. New segmental BIA equipment that uses more electrodes may lead to more precise measurements of specific parts of the body. C is a coefficient for the expected percentage of weight made up of free water. In practice, the value rarely approximates the actual amount of free water required to correct a deficit due to insensible losses, urinary output, and differences in water distribution among patients. The amount of this water that is retained in animals is affected by several factors. Water amounts vary with the age of the animal. The site requires a paid subscription to access this page.
This page was last edited on 22 July 2017, at 21:37. Please continue to improve it and thanks for the great work so far! This page was last edited on 7 December 2017, at 12:07. Example of male and female anatomy from front and back.
These can be of several types, including direct and indirect. The complementary result for the X-chromosome follows, either a double or a single X. Often only the mean or mean difference between sexes is given. This may or may not preclude overlap in distributions. SRY is a gene which regulates sexual differentiation.
One set of 23 comes from the mother and one set comes from the father. Sperm also have only one set of 23 chromosomes and are therefore haploid. The sex chromosome in a human egg is always an X chromosome, since a female only has X sex chromosomes. In sperm, about half the sperm have an X chromosome and half have a Y chromosome.
If an egg fuses with a sperm with a Y chromosome, the resulting individual is male. If an egg fuses with a sperm with an X chromosome, the resulting individual is female. There are rare exceptions to this rule in which, for example, XX individuals develop as males or XY individuals develop as females. Chromosomes are not the final determinant of sex. In some cases, for example, chromosomally female babies that have been exposed to high levels of androgens before birth can develop masculinized genitals by the time they are born. There are other variations of sex chromosomes that lead to a variety of different physical expressions.
The X-chromosome carries a larger number of genes in comparison to the Y-chromosome. X-chromosome since females have two X-chromosomes while males have a single X and a Y chromosome. X-chromosome inactivation is random in the somatic cells of the body as either the maternal or paternal X-chromosome can become inactivated in each cell. Thus, females are genetic mosaics.
In the somatic cells of a developing female child, one of the X-chromosomes is shortened and condensed. The genes on this chromosome therefore can not be transcribed into an mRNA transcript and remain unread. X-chromosome is inactivated, resulting in two bar bodies. Sexual dimorphism in humans is the subject of much controversy, especially relating to mental ability and psychological gender. Although sex is a binary dichotomy, with “male” and “female” representing opposite and complementary sex categories for the purpose of reproduction, a small number of individuals have an anatomy that does not conform to either male or female standards, or contains features closely associated with both. The current estimated rate for intersexuality is about 1 in 1500 to 1 in 2000 births.