Bio 2312 E3

• The organs of the urinary system are the kidneys, ureter, bladder, and urethra.
• The kidneys produce urine
• The ureter transports the urine from the kidney to the bladder
• The urinary bladder temporarily stored urine prior to urination
• The urethra conducts urine to the exterior of the body.
• The female urethra is shorter than the males urethra
• The three functions of the urinary system are excretion, elimination, and homeostatic regulation
• The urinary system removes organic wastes from body fluids. It eliminates waste products. It regulates blood plasma volume and solute concentration.
• Increase of blood volume, increases blood pressure
• The key functions of the kidney are to concentrate filtrate by glomerular filtration, absorbs and retains valuable materials for use by other tissues such as sugar, water, and amino acids.
• The urinary tract includes the ureters, urinary bladder, and urethra
• Urination or micturition is the process of eliminating urine
• The homeostatic functions of the urinary bladder are 1. Regulates blood volume and blood pressure 2. Regulates plasma ion concentrations 3. Helps stabilize blood pH 4. Conserves valuable nutrients 5. Assists liver
• The kidneys are located on either side of the vertebral column and attach to the posterior wall of the abdominal cavity. They are retroperitoneal.
• The left kidneys lies superior than the right kidney because the liver lies on the right kidney
• On top of each kidney, there is an adrenal gland
• The kidneys are protected and stabilized by 3 concentric layers of connective tissues. 1) Fibrous capsule (closest to kidneys) 2) Perinephric fat 3) Renal Fascia (farthest layer)
• The hilum is the point of entry for the renal artery and renal nerves and a point of exit for renal vein and ureter
• The medulla has a renal papilla where urine goes to get to minor calyx
• The kidneys have an outer cortex and inner medulla
• There are two types of nephrons: cortical and juxtamedullary
• The kidney lobes is where urine is produced
• The renal hilum is composed of renal artery, vein, and nerve
• Trace the flow of urine from where it is produced to when it leaves urethra: Renal cortex -- pyramids -- renal papilla -- minor calyx -- major calyx -- renal pelvis -- ureter -- bladder -- urethra
• The nephron is the structural and functional unit of the kidney.
• The nephron consists of the renal tubule and renal corpuscle
• The renal tubule begins at the renal corpuscle and ends at the collecting ducts. It includes the PCT, loop of Henle, and DCT
• The renal corpuscle consists of the glomerular capsule (Bowman's capsule) and capillary network (glomerulus)
• The glomerulus is responsible for filtration of blood
• In glomerulus, blood is delivered via afferent arteriole and leaves in efferent arteriole
• The three functions of the renal tubule are to reabsorb useful organic nutrients and water from the filtrate, secrete waste products, and deliver urine to collecting ducts
• The nephron loop or loop of Henle extends partially into the medulla of the kidney
• Production and flow of urine in nephron: Renal corpuscle -- PCT -- loop of Henle -- DCT -- collecting duct -- renal papilla -- minor calyx -- major calyx -- renal pelvis -- ureter -- bladder --urethra
• Filtrate is called urine once its in the collecting duct
• Cortical nephrons produce most of the urine. They are located in the cortex of the kidney. They have a shorter loop of Henle and does not extend far into the medulla.
• Juxtamedullary nephrons are located in close proximity to the medulla. It has a longer loop of Henle that extends deep into renal pyramids. It functions in water conservation and forms concentrated urine.
• The filtration membrane consists of fenestrated endothelium, a dense layer, and filtration slits formed by podocytes
• Filtrations is caused by blood pressure. It is as a result of a bigger afferent arteriole compared to a smaller efferent
• In filtration, large solutes such as plasma proteins and blood cells cannot cross membrane of glomerulus
• The descending limb of Henle is permeable to H2O and water moves out of the limb