Flashcards in Urinary System Deck (34)
Name the four organs of the urinary system.
How many kidneys does a person have?
A person has 2 kidneys.
How many ureters does a person have?
A person has two ureters.
A kidney is a bean-shaped, fist-sized organ where urine is formed.
A ureter is a small, muscular tube that carries urine from the kidneys to the bladder.
The bladder is an expandable organ that stores urine until it is expelled from the body.
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.
1. Excretion of metabolic wastes
2. Maintenance of water-salt balance
3. Maintenance of acid-base balance
4. Hormone secretion
5. 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.
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.
A hormone secreted by the kidneys to allow the adrenal glands to secrete aldoesterone.
Aldosterone is a hormone secreted by the adrenal glands that helps regulate the water-salt balance.
Erythropoietin is a hormone secreted by the kidneys to stimulate red blood cell production when blood oxygen is low.
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.
An outer granulated layer of the kidneys.
The renal medulla is cone-shaped tissue masses called renal pyramids.
The renal pelvis is a central cavity that is continuous with the ureter.
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.
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.