Anatomy & Physiology II Unit Seven

Urinary System Functions Filter blood plasma so as to: ~ eliminate metabolic wastes ~ eliminate toxins ~ regulate body fluids ~ regulate electrolyte concentrations Activate vitamin D Produce hormones Maintain homeostasis

The Urinary System Right kidney Renal artery Right ureter Renal vein Urinary bladder Urethra

Internal urethral sphincter External urethral sphincter Urinary bladder The Urinary System Internal urethral sphincter External urethral sphincter Urethra Urethra

The Kidney Renal capsule Renal cortex Renal medulla Renal artery Renal vein Renal pelvis Ureter Renal pyramid Renal column Minor calyx Major calyx Renal papilla

The Nephron

The Nephron Glomerular capsule Efferent arteriole Afferent arteriole Distal convoluted tubule Proximal convoluted tubule Collecting duct Glomerulus Loop of Henle (descending limb) Loop of Henle (ascending limb) The Nephron

The Nephron

Nephron Functions Nephrons carry out three primary functions: * filtration * reabsorption and secretion * water conservation

Nephron Functions

Nephron Functions Filtration

Nephron Functions Filtration Sympathetic nerve Juxtaglomerular apparatus Efferent arteriole Distal convoluted tubule Afferent arteriole

Nephron Functions Filtration

Reabsorption & Secretion Nephron Functions Reabsorption & Secretion

Reabsorption & Secretion The Countercurrent Multiplier Nephron Functions Reabsorption & Secretion The Countercurrent Multiplier

Reabsorption & Secretion Nephron Functions Reabsorption & Secretion

Nephron Functions Water Conservation

Plasma Clearance Plasma clearance is the removal of waste products and excess molecules from the blood These waste products and excess molecules can be filtered through the glomerulus or secreted into tubules

Plasma Clearance Therefore the following equation is used to calculate plasma clearance Substance filtered = amount reabsorbed + amount excreted

Plasma Clearance Plasma clearance can be used to calculate GFR Inulin is a plant produced carbohydrate that is neither reabsorbed nor secreted by the kidneys

Plasma Clearance Therefore inulin can be used as a baseline to calculate GFR since the amount filtered will equal the amount excreted Once a baseline is established, comparisons can be made to the other substances that are filtered or secreted

Kidney Disorders Renal calculi - kidney stones - formed by precipitation of salt in the nephrons - causes may be linked to dehydration, inactivity or metabolic conditions - treatments range from watchful neglect to surgery

Kidney Disorders Cystitis - inflammation of the urinary bladder - causes include trauma, tumors, infection or urine retention - it is treated according to cause Gout - the deposition of uric acid crystals in the kidney tubules and in joints - caused by fat rich diet - treatment through diet and medication

Kidney Disorders Glomerulonephritis - Bright’s disease - inflammation of the glomeruli - results in excess filtration and even loss of function - autoimmune or bacterial in origin - treatments vary on cause

Kidney Disorders Incontinence - loss of control of voiding the urinary bladder - lost control of external urethral sphincter - natural in infants, but has a variety of causes in adults - treatment varies according to cause

Kidney Disorders Dialysis is the mechanical removal of wastes and excess materials from the blood Dialysis is used when the kidneys fail to function The blood is removed from the patient and sent through a machine that removes the wastes and excesses

Kidney Disorders The wastes and excesses are extracted by dialyzing solutions and selectively permeable membranes The blood is returned to the patient as it is filtered and cleaned

Kidney Disorders Dialysis can be short term or long term, but is always a stop-gap measure while waiting for the abatement of disease or a kidney transplant However helpful, it is time consuming, increases risk of infection and causes problems due to the use of anticoagulants