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The Urinary System EQ: What are the components and the function of the kindney ?. 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
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The Urinary SystemEQ: What are the components and the function of the kindney?
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 from blood • Regulate the balance of water and electrolytes, acids and bases
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 • House Renal Corpuscles • Medulla: inner • House Renal Tubule
Renal Arteries: • Supply blood to the kidneys. • Transports large amounts of blood, 15-30% • Branch into interlobar arteries, which supply blood for medulla and cortex. • 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
Bladder • Muscular organ that stores urine and forces it into the urethra (tube that expels urine from bladder) • Located in pelvic cavity, behind the pubis • Detrusor Muscle and Internal Urethral Sphincter • Muscle group that controls urination • Micturition- Process of urination
The Urethra • Smooth muscle with inner mucosa • Changes from transitional through stages to stratified squamous near end • 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 and 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.
LEFT SIDE ACTIVITYDraw, label and color Figure 17.2 (a) & (b) on page 471.