The Urinary System

Root Words

The Urinary System Paired kidneys A ureter for each kidney Urinary bladder Urethra

Main Functions of Urinary System Kidneys filter blood to keep it pure Toxins Metabolic wastes Excess water Excess ions Dispose of nitrogenous wastes and regulate water balance

Kidneys are retroperitoneal organs (see next slide) Behind the deep muscles of the back. Connective tissue and adipose tissue surround them Adrenal glands lie superior to each kidney (the yellow blob in pic) * *

Kidney has two regions Cortex: outer Medulla: inner House Renal Corpuscles Medulla: inner House Renal Tubule

Renal Arteries: Supply blood to the kidneys. Transports large amounts of blood, 15-30% Afferent Arterioles Final branch that supply blood for nephrons

Nephrons Functional unit of kidney, filters blood of waste and produces urine ~ 1 million nephrons in each kidney 2 parts: Renal Corpuscle and Renal Tubule

Renal Corpuscle Contains cluster of blood capillaries called Glomerulus – filters fluid Renal Tubule Fluid flows through and out of body

Glomerular Filtration Process of urine formation. Produces 180 liters of fluid every 24 hours Not all is excreted, some is reabsorbed through Tubular reabsorption (done through Renal Tubule)

Afferent Arterioles Blood entering Glomerulus Efferent Arterioles Blood leaving Glomerulus Bowman’s Capsule Membrane surrounding the Glomerulus

Filtration Process Sodium ions (Na+) are reabsorbed by active transport Negatively charged ions are attracted to Positively charged ions

Renal Calyx/ Calyces (Major and Minor) Chambers within the kidney that collect urine before moving on to the bladder

Urine Fluid byproduct as a result of body filtration and waste removal ~ 95% water Contains urea and uric acid Usually produces 0.6-2.5 liters a day

The Ureters Slender tubes about 25 cm (10 “) long leaving each renal pelvis One for each kidney carrying urine to the bladder

Internal Urethral Sphincter Micturition- Process of urination Bladder Muscular organ that stores urine and forces it into the urethra (tube that expels urine from bladder) Internal Urethral Sphincter Muscle group that controls urination Micturition- Process of urination

The Urethra Smooth muscle with inner mucosa Drains urine out of the bladder and body Male: about 20 cm (8”) long Female: 3-4 cm (1.5”) long Short length is why females have more urinary tract infections than males - ascending bacteria from stool contamination urethra Urethra____

Understand at least this much: Filtration a. Fluid is squeezed out of the glomerular capillary bed Resorption b. Most nutrients, water ad essential ions are returned to the blood of the peritubular capillaries Secretion c. Moves additional undesirable molecules into tubule from blood of peritubular capillaries

Polycystic Kidney Disease Cluster of fluid filled cysts develop on the kidneys. It is genetic and can be passed on From generation to generation.

Draw, label and color Figure 17.2 (a) & (b) on page 471.

For studying Parts of the kidney: 2. Efferent vessel 3. Renal artery 4. Renal vein 5. 6. Renal pelvis 7. Ureter 8. 9. Renal capsule 10. Inferior renal capsule 11. Superior renal capsule 12. Afferent vessel 13. Nephron 14. Minor calyx 15. Major calyx 16. Renal papilla 17. Renal column