The Urinary System Kidney Functions 1 Your kidneys

The Urinary System

Kidney Functions (1) • Your kidneys filters 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 (2) • 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 (3) • 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 (4) • Cortex - the light colored, granular superficial region • Medulla - exhibits cone-shaped medullary (renal) pyramids

Major parts of the kidney and their function (4) 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 (5) 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 (6) • 200 liters! • The kidneys filter the body’s entire plasma volume 60 times each day

Parts of the nephron (7) 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