Urinary System Flashcards
Excretion
Removal of metabolic waste
Nitrogenous Waste
Urea, ammonia
Elimination
Removal of indigestible material, dietary fiber
Principal Organs
Lungs, liver, skin, kidneys
Lungs
Carbon dioxide and water vapor
Sweat glands
Excrete water and dissolved salts
Liver
Deamination of proteins is converted to urea
Kidneys
Control osmolarity of the blood, excrete numerous waste products and toxic chemicals, conserve glucose, salt, water
Nephrons
The functional unit of kidneys
Bowman’s Capsule
Bulb of nephrons, encapsulates a special capillary bed called a glomerulus
Three Regions of Kidneys
Outer cortex, inner medulla, renal pelvis
Coiled Tube Procession
Proximal convoluted tubule -> loop of Henle -> distal convoluted tubule -> collecting duct
Urine Formation
Filtration, Secretion, and Reabsorption
Filtration
Fluid and small solutes enter nephron, passive process driven by hydrostatic pressure
Secretion
Nephrons secrete waste such as acids, ions from the interstitial fluid by both passive and active transport
Reabsorption
Glucose, salts, amino acids, water are reabsorbed from the filtrate and returned to the blood, occurs in the proximal and is active, followed by passive water movement, forms urine
Glomerulus
Site of filtration, plasma and blood solutes are filtered and become the filtrate, based on size exclusion
Proximal Convoluted Tubule
Amino acids, glucose, vitamins, salts are reabsorbed along with water
Majority of Waste Products Excreted
H+, Urea, NH3, K+ (HUNK)
Loop of Henle
Descending (permeable to water), osmolarity gradient is crucial for urine concentration, Ascending (salt only)
Distal Convoluted Tubule
Reabsorption and secretion
Collecting Duct
Responsive to both aldosterone and antidiuretic hormone (ADH), area of high osmolarity
Countercurrent Multiplier System
A system in which energy is used to create a concentration gradient, exiting and re-entry of solutes such as Na+ and Cl-
Longer Loops of Henle
Build greater gradients via the countercurrent multiplier system
Aldosterone
Steroid hormone and upregulates the transport of sodium and potassium ions along the distal convoluted tubule and collecting duct, decreased excretion of Na+, more K+ excreted, decrease urine output
Antidiuretic Hormone
Affects water reabsorption by opening additional aquaporins, decrease urine output
Bicarbonate Buffer System
Maintains blood pH
Which region of the kidney has the lowest solute concentration
Cortex
In the nephron, amino acids enter the peritubular capillaries via
Reabsorption
Glucose reabsorption in the nephron occurs in the
Proximal Tubule
Urine is
hypertonic to the blood
