Urinary system

Excretion of metabolic wastesExcretion of metabolic wastes

Kidneys

reddish brown, bean shaped, enclosed in a tough reddish brown, bean shaped, enclosed in a tough capsule. capsule.

2 – located in the right and left lumbar regions; 2 – located in the right and left lumbar regions; posterior to the parietal peritoneumposterior to the parietal peritoneum

remove remove metabolic wastes metabolic wastes from the blood and from the blood and excrete to outside; urea is from protein breakdownexcrete to outside; urea is from protein breakdown

Control rate of RBC formation Control rate of RBC formation Regulate blood pressure. Regulate volume, Regulate blood pressure. Regulate volume,

composition and pH of body fluids composition and pH of body fluids

Nephrons – functional unit of kidney

Blood vesselsBlood vessels renal arterierenal arteries – blood to kidneyss – blood to kidneys renal veinsrenal veins – blood away from kidneys – blood away from kidneys

Glomerulus - Glomerulus - where filtration occurs, fluid leaks where filtration occurs, fluid leaks out of blood. Is collected in out of blood. Is collected in Bowman’s capsuleBowman’s capsule

Proximal convoluted tubule, loop of Henle and Proximal convoluted tubule, loop of Henle and distal convoluted tubule all selectively pick up distal convoluted tubule all selectively pick up certain molecules from filtrate. (loop of Henle is certain molecules from filtrate. (loop of Henle is in the medulla, all the rest is in the cortex)in the medulla, all the rest is in the cortex)

Urine

Calyx on medial side of kidney collects Calyx on medial side of kidney collects what fluid is left after passing through what fluid is left after passing through nephrons; it is now urinenephrons; it is now urine 95% water, plus urea, electrolytes, amino 95% water, plus urea, electrolytes, amino

acidsacids kidneys can filter 45 gallons of fluid in kidneys can filter 45 gallons of fluid in

24 hours24 hours

Ureters

Tubes that extend from kidney to urinary Tubes that extend from kidney to urinary bladder bladder

peristaltic wavesperistaltic waves move urine to bladder move urine to bladder

Urinary Bladder

Stores urine and forces it into urethra - Stores urine and forces it into urethra - MicturationMicturation

Some muscles contract while others relax Some muscles contract while others relax Stretch receptors in bladder wall are Stretch receptors in bladder wall are

stimulated by distension stimulated by distension

Urethra

tube that carries urine from bladder to tube that carries urine from bladder to outsideoutside

Males – shares function with reproductive Males – shares function with reproductive system; long tubesystem; long tube

Females – only used for urinating, but much Females – only used for urinating, but much shorter, females get urinary tract infections shorter, females get urinary tract infections much more frequently than malesmuch more frequently than males

Kidney stones

Hard little rock-like formations that occur in Hard little rock-like formations that occur in the calyx of the kidneythe calyx of the kidney

Extremely painful when they pass through Extremely painful when they pass through the uretersthe ureters

Thought to be caused by too much protein Thought to be caused by too much protein in the dietin the diet

Ultrasound wavesUltrasound waves can shatter the stones can shatter the stones into smaller pieces if they are unable to passinto smaller pieces if they are unable to pass