Search results
Results from the WOW.Com Content Network
The front edge usually has a wide black band. In the upper center is a characteristic large kidney-shaped marking (which can sometimes be a faint vertical line or V-shaped), from which it derives its common name. Immediately below it are two small but prominent black pits (fovea). At the posterior half is a series of faint transverse ridges. [1]
The cut was human-made in the 1950s and consists of rock that is roughly 450 million years old. [1] Maysville provides an opportunity to observe the stratigraphy of the formations present of the Ordovician time period.
The posterior end of the lower jaw bones contains a quadrate bone, allowing jaw extension. The anterior tips of the lower jaw bones are joined by a flexible ligament allowing them to bow outwards, increasing the mouth gape. [76] [77] The Pacific tree frog and the Baja California chorus frog are some of the only frog species that make a "ribbit ...
The unipapillary kidney with a single renal pyramid is the simplest type of kidney in mammals, from which the more structurally complex kidneys are believed to have evolved. [17] [6] [18] Differences in kidney structure are the result of adaptations during evolution to variations in body mass and habitats (in particular, aridity) between species.
For some time, the vagina is represented by a solid rod of epithelial cells. A ring-like outgrowth of this epithelium occurs at the lower end of the uterus and marks the future vaginal fornix. At about the fifth or sixth month, the lumen of the vagina is produced by the breaking down of the central cells of the epithelium.
Mesonephros develops after the pronephros, replacing it. The mesonephros is the final kidney in amphibians and most fish. In more advanced vertebrates , mesonephros develops during embryogenesis and is then replaced by the metanephros. [36] In reptiles and marsupials, it remains functional for some time after birth along with the metanephros.
The collecting duct system is the final component of the kidney to influence the body's electrolyte and fluid balance. In humans, the system accounts for 4–5% of the kidney's reabsorption of sodium and 5% of the kidney's reabsorption of water. At times of extreme dehydration, over 24% of the filtered water may be reabsorbed in the collecting ...
The right kidney sits just below the diaphragm and posterior to the liver. The left kidney sits below the diaphragm and posterior to the spleen. On top of each kidney is an adrenal gland. The upper parts of the kidneys are partially protected by the 11th and 12th ribs.