Two bean-shaped organs, each roughly the size of a fist, make up the kidneys. They are located One on either side of the spine, immediately below the rib cage.
Every minute, healthy kidneys filter roughly a half cup of blood, eliminating wastes and excess water to form urine. Urine travels from the kidneys to the bladder through two thin muscular tubes known as ureters, one on each side of the bladder. Urine is stored in your bladder. The urinary tract includes your kidneys, ureters, and bladder.
FUNCTIONS OF KIDNEY
The kidneys’ primary function is to maintain homeostasis. They maintain the body’s internal environment stable and pleasant by controlling fluid levels, electrolyte balance, and other elements. These organs are responsible for a variety of body processes
Excretion of waste
The kidneys filter out numerous waste materials, which are then excreted in the urine. The kidneys eliminate urea, which is produced by the breakdown of proteins, and uric acid, which is produced by the breakdown of nucleic acids, as well as medicines and their metabolites.
Reabsorption of nutrients
Tubules in the kidneys reabsorb nutrients from the blood and transfer them to where they will be most beneficial to health. They also aid to maintain homeostasis by reabsorbing other products like
Glucose
amino acids
chloride,
sodium,
magnesium,
and potassium.
Keeping the right pH
In humans, a pH range of 7.35–7.45 is considered appropriate. The body enters an acidemia or alkalemia condition at levels below or above this range, respectively. Proteins and enzymes break down and can no longer function in these states. This can be fatal in severe circumstances.
The kidneys and lungs help in maintaining the body’s pH balance. The lungs do this by regulating the amount of carbon dioxide in the bloodstream. The kidneys regulate pH by reabsorbing and generating bicarbonate from urine, which assists in acid neutralisation.
If the pH is tolerable, the kidneys can store bicarbonate and release it if the acid levels rise. By excreting acid, they can create new bicarbonate.
Osmolality regulation
The ratio between fluids and minerals in the body is measured by osmolality, which is a measure of the body’s electrolyte-water balance. Electrolyte imbalance is commonly caused by dehydration.
The hypothalamus in the brain sends a signal to the pituitary gland when the osmolality of blood plasma rises. Antidiuretic hormone is produced by this gland. The kidney responds to ADH by making many changes, including:
-
increasing the concentration of urine
-
increased resorption of water
-
admitting water back into the body, holding urea in the medulla of the kidney rather than excreting it, as this chemical draws in water
-
Keeping blood pressure in check
Regulating blood pressure
When blood pressure has to be regulated, the kidneys are in charge of making gradual adjustments.
They modify the fluid outside of cells to control long-term pressure in the arteries. Extracellular fluid is the medical name for this fluid. Hormones called vasoconstrictors force blood vessels to tighten.
These hormones assist in the absorption of sodium chloride, or salt, by the kidneys. As a result of this absorption, the extracellular fluid compartment expands and blood pressure rises. Anything that raises blood pressure, such as drinking too much alcohol, smoking, or being overweight, can harm the kidneys over time.
Secretion of active compounds
Several essential chemicals are released by the kidneys, including:
Erythropoietin: Erythropoietin is a hormone that regulates erythropoiesis, or the production of red blood cells. The liver also generates erythropoietin, although in adults, the kidneys are the primary producers.
Renin: Renin is an enzyme that helps in the control of artery expansion as well as the quantities of blood plasma, lymph, and interstitial fluid. Interstitial fluid is the major component of extracellular fluid, and lymph is a fluid that includes white blood cells that promote immune activity.
Calcitriol: Calcitriol is a metabolite of vitamin D that is hormonally active. It increases the amount of calcium that can be absorbed by the intestines as well as phosphate reabsorption in the kidney.
STRUCTURE OF KIDNEY
-The kidneys are found on either side of the spine, on the upper and lower sides of the abdomen (see diagram). The lower ribs help to protect them from damage.
-The kidneys are located deep within the abdomen and generally can’t be felt.
-A pair of bean-shaped organs make up the kidneys. A kidney is roughly 10 cm long, 6 cm broad, and 4 cm thick in adults. Each kidney weighs between 150 and 170 grams.
-Urine produced in the kidneys passes through the urinary bladder and then the ureters. Each ureter is a hollow tube-like structure made up of specific muscles that is roughly 25 cm long.
-The urinary bladder is a hollow organ made up of muscles that may be found in the lower and anterior abdomen. It serves as a urine reservoir.
-The bladder of an adult holds roughly 400-500 mL of urine, and when it is about full, a person feels compelled to pass urine.
During the urination procedure, the urine in the bladder is expelled through the urethra. The urethra in females is comparatively short, but it is substantially longer in males.
CONCLUSION
The kidneys are one of the body’s most important organs. Kidney failure can result in significant illness or even death. The structure and function of each kidney are complex.
They serve two purposes: to flush away dangerous and poisonous waste products, and to maintain the equilibrium of water, fluids, minerals, and chemicals (electrolytes such as sodium, potassium, and other electrolytes).