The Urinary System

Kidney Functions Your kidneys filter 200 liters of your blood daily, allowing urinary excretion of toxins, metabolic wastes, and excess ions Kidneys also regulate the volume and chemical makeup of the blood Kidneys maintain homeostatic balance between water and salts, and acids and bases

Associated excretory organs & functions Urinary bladder – urine reservoir 2 ureters – urine transportation to bladder from kidneys Urethra – urine transport from bladder to outside world

Tissue layers supporting the kidney Renal capsule – fibrous capsule that prevents kidney infection Adipose capsule – fatty mass that cushions the kidney and attaches it to the body wall Renal fascia – outer layer of dense fibrous tissue that anchors the kidney

Major parts of the kidney and their function Cortex - the light colored, granular superficial region Medulla - exhibits cone-shaped medullary (renal) pyramids

Major parts of the kidney and their function continued Renal pelvis - flat, funnel-shaped tube lateral to the hilum within the renal sinus A hilum is part of an organ where structures such as blood vessels and nerves enter. The hilum of kidney is the medial depression for blood vessels and ureter to enter the kidney chamber (admits the renal artery, vein, ureter, and nerves)

Urinary infections UTIs Pyelitis - Acute inflammation of the pelvis of the kidney, caused by bacterial infection. the renal pelvis, the central part of the kidney is where urine accumulates before discharge. It is more common in women than in men.

Pyelonephritis pyelonephritis is when a urinary tract infection has reached the pyelum (pelvis) of the kidney Symptoms include: Loin pain, often severe Fever and shivers Blood-stained urine Foul-smelling and cloudy urine Painful and frequent urination Nausea and vomiting

Volume of blood filtered daily 200 liters! The kidneys filter the body’s entire plasma volume 60 times each day

Parts of the nephron A normal kidney contains 800,000 to one million nephrons Renal corpuscle consists of Glomerulus – a tuft of capillaries associated with a renal tubule Bowman’s capsule – a cup-like sac that houses the glomerulus

Glomerulus inside Bowman’s capsule together called Renal Corpuscle

Renal Tubule PCT - Proximal convoluted tubule – reabsorbs water and solutes from filtrate & secretes substances into it Loop of Henle – part of the PCT that is hairpin shaped DCT - Distal convoluted tubule – functions more for secretion than reabsorption

Renal Tubule continued Collecting tubule and collecting duct Receive filtrate from many tubules giving a striped appearance As collecting ducts reach renal pelvis, fuse to form large papillary ducts Ducts deliver urine into minor calyces via papillae of pyramids