The preferred test for detecting protein in the urine is a urine albumin-to-creatinine ratio urine ACR test, which shows the amount of albumin a type of protein in the urine. A urine albumin-to-creatinine ratio urine ACR test should be done at least once a year if the person has diabetes or high blood pressure, and every two years if the person has any of the other identified risk factors for developing chronic kidney disease.
Urinary System Anatomy Kidneys The kidneys are a pair of bean-shaped organs found along the posterior wall of the abdominal cavity. The left kidney is located slightly higher than the right kidney because the right side of the liver is much larger than the left side. The kidneys, unlike the other organs of the abdominal cavity, are located posterior to the peritoneum and touch the muscles of the back.
The kidneys are surrounded by a layer of adipose that holds them in place and protects them from physical damage.
The kidneys filter metabolic wastes, excess ions, and chemicals from the blood to form urine. Ureters The ureters are a pair of tubes that carry urine from the kidneys to the urinary bladder.
The ureters are about 10 to 12 inches long and run on the left and right sides of the body parallel to the vertebral column. Gravity and peristalsis of smooth muscle tissue in the walls of the ureters move urine toward the urinary bladder. The ends of the ureters extend slightly into the urinary bladder and are sealed at the point of entry to the bladder by the ureterovesical valves.
These valves prevent urine from flowing back towards the kidneys. Urinary Bladder The urinary bladder is a sac-like hollow organ used for the storage of urine. Urine entering the urinary bladder from the ureters slowly fills the hollow Homeostasis function of the kidney of the bladder and stretches its elastic walls.
The walls of the bladder allow it to stretch to hold anywhere from to milliliters of urine. Urethra The urethra is the tube through which urine passes from the bladder to the exterior of the body.
The female urethra is around 2 inches long and ends inferior to the clitoris and superior to the vaginal opening. In males, the urethra is around 8 to 10 inches long and ends at the tip of the penis.
The urethra is also an organ of the male reproductive system as it carries sperm out of the body through the penis. The flow of urine through the urethra is controlled by the internal and external urethral sphincter muscles. The internal urethral sphincter is made of smooth muscle and opens involuntarily when the bladder reaches a certain set level of distention.
The opening of the internal sphincter results in the sensation of needing to urinate. The external urethral sphincter is made of skeletal muscle and may be opened to allow urine to pass through the urethra or may be held closed to delay urination.
Urinary System Physiology Maintenance of Homeostasis The kidneys maintain the homeostasis of several important internal conditions by controlling the excretion of substances out of the body. Ions The kidney can control the excretion of potassium, sodium, calcium, magnesium, phosphate, and chloride ions into urine.
In cases where these ions reach a higher than normal concentration, the kidneys can increase their excretion out of the body to return them to a normal level. Conversely, the kidneys can conserve these ions when they are present in lower than normal levels by allowing the ions to be reabsorbed into the blood during filtration.
See more about ions. The kidneys also conserve bicarbonate ions, which act as important pH buffers in the blood. Osmolarity The cells of the body need to grow in an isotonic environment in order to maintain their fluid and electrolyte balance.
When a person consumes a large amount of water, the kidneys reduce their reabsorption of water to allow the excess water to be excreted in urine. This results in the production of dilute, watery urine. In the case of the body being dehydrated, the kidneys reabsorb as much water as possible back into the blood to produce highly concentrated urine full of excreted ions and wastes.
The changes in excretion of water are controlled by antidiuretic hormone ADH.
ADH is produced in the hypothalamus and released by the posterior pituitary gland to help the body retain water. When blood pressure is elevated, the kidneys can help to reduce blood pressure by reducing the volume of blood in the body. The kidneys are able to reduce blood volume by reducing the reabsorption of water into the blood and producing watery, dilute urine.
When blood pressure becomes too low, the kidneys can produce the enzyme renin to constrict blood vessels and produce concentrated urine, which allows more water to remain in the blood.
Filtration Inside each kidney are around a million tiny structures called nephrons. The nephron is the functional unit of the kidney that filters blood to produce urine.
Arterioles in the kidneys deliver blood to a bundle of capillaries surrounded by a capsule called a glomerulus. The liquid filtrate in the capsule flows through a series of tubules lined with filtering cells and surrounded by capillaries.
The cells surrounding the tubules selectively absorb water and substances from the filtrate in the tubule and return it to the blood in the capillaries. At the same time, waste products present in the blood are secreted into the filtrate.
By the end of this process, the filtrate in the tubule has become urine containing only water, waste products, and excess ions.Dialysis as Treatment of End-Stage Renal Disease FUNCTIONS OF THE KIDNEY AND PATHOPHYSIOLOGY OF RENAL FAILURE Function Salt, water, and acid-base balance Water balance Sodium balance Potassium balance.
Note: DCT = distal convoluted tubule; PCT = proximal convoluted tubule Kidney function. The primary function of the kidneys is to help maintain homeostasis by regulating the composition (including pH) and the volume of the extracellular fluid.
The urinary system, also known as the renal system, produces, stores and eliminates urine, the fluid waste excreted by the kidneys. The kidneys make urine by filtering wastes and extra water from. Each kidney contains around 1 million individual nephrons, the kidneys’ microscopic functional units that filter blood to produce urine.
The nephron is made of 2 main parts: the renal corpuscle and the renal tubule. The kidney is a bean-shaped structure with a convex and a concave border. A recessed area on the concave border is the renal hilum, where the renal artery enters the kidney and the renal vein and ureter leave.
The kidney is surrounded by tough fibrous tissue, the renal capsule, which is itself surrounded by perirenal fat, renal fascia, and pararenal fat. Homeostasis can be defined as a property of an organism or system that helps it maintain its parameters within a normal range of values.
It is key to life, and failures in homeostasis can lead to.