Urinary System Flashcards
How many kidneys does a person have?
A person has 2 kidneys.
Name the four organs of the urinary system.
Kidneys
Ureters
Bladder
Urethra
How many ureters does a person have?
A person has two ureters.
Kidneys
A kidney is a bean-shaped, fist-sized organ where urine is formed.
Ureter
A ureter is a small, muscular tube that carries urine from the kidneys to the bladder.
Bladder
The bladder is an expandable organ that stores urine until it is expelled from the body.
Urethra
The urethra is a tube (longer in men than in women) that carries urine from the bladder to the outside of the body.
Give the five functions of the urinary system.
- Excretion of metabolic wastes
- Maintenance of water-salt balance
- Maintenance of acid-base balance
- Hormone secretion
- Reabsorb filtered nutrients and synthesize vitamin D
How is urea made?
Urea is made by the breakdown of amino acids in the liver.
How is uric acid made?
Uric acid is made by the breakdown of nucleotides.
How is creatinine made?
Creatinine is made by muscle cells from the breakdown of creatine phosphate.
What is excretion comprised of?
Excretion is mostly of nitrogenous wastes.
What does the water-salt balance help maintain?
The water-salt balance helps to maintain blood pressure.
Name two homeostatic mechanisms of the urinary system.
Water-salt balance
Acid-base balance
How do the kidneys maintain the acid-base balance?
The kidneys maintain the acid-base balance by excreting hydrogen ions and reabsorbing bicarbonate ions.
What is the blood pH maintained at?
The blood pH is maintained at 7.4.
Renin
A hormone secreted by the kidneys to allow the adrenal glands to secrete aldoesterone.
Aldosterone
Aldosterone is a hormone secreted by the adrenal glands that helps regulate the water-salt balance.
Erythropoietin
Erythropoietin is a hormone secreted by the kidneys to stimulate red blood cell production when blood oxygen is low.
Vitamin D
Vitamin D is a molecule that promotes calcium absorption from the digestive tract.
How does the urinary bladder work?
The urinary bladder stores urine, and sphincters keep it closed. An expandable wall contains a middle layer of circular fibers of smooth muscle and 2 layers of longitudinal smooth muscle. The lining of the transitional epithelium allows for expansion of mucosa, and filling activates stretch receptors which signal to the spinal cord.
Renal Cortex
An outer granulated layer of the kidneys.
Renal Medulla
The renal medulla is cone-shaped tissue masses called renal pyramids.
Renal Pelvis
The renal pelvis is a central cavity that is continuous with the ureter.
Nephrons
Nephrons are a microscopic functional unit of the kidney that produces urine. There are more than one million of these per kidney!
Name the three parts of the process of the nephron forming urine.
Glomerular filtration
Tubular reabsorption
Tubular secretion
Describe glomerular filtration.
Water, salts, nutrient molecules, and waste molecules move from the glomerulus to the inside of the glomerular capsule.
Describe tubular reabsorption.
Nutrient and salt molecules are actively reabsorbed from the convoluted tubules into the peritubular capillary network, and water flows passively.
Describe tubular secretion.
Certain ions and molecules (e.g., H+) are actively secreted from the peritubular capillary network into the convoluted tubules.
Kidney Stones
Kidney stones are hard granules formed in the renal pelvis due to UTIs, enlarged prostate, pH imbalances, or intake of too much calcium.
Uremia
High levels of urea and other waste substances in the blood that cause a serious condition when water and salts are retained due to extensive nephron damage.
Hemodialysis
Hemodialysis uses an artificial kidney machine to subtract and add substances to the blood as needed.
Continuous ambulatory peritoneal dialysis
Continuous ambulatory peritoneal dialysis uses the peritoneal membrane to filter the blood and allows a person to go about their normal life without interruption.
Kidney Replacement
A kidney replacement is when a single kidney is transplanted, with a high success rate.
