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Nat. Review chpt. 15
Urinary system
Question | Answer |
---|---|
Kidney | Main organ of the urinary system, located behind the peritoneum in the lower thoracic and upper lumbar region, against the posterior wall of the abdominal cavity, responsible for filtering the blood and producing urine |
Functions of the kidney | Filtration of blood to remove wastes, excess salts, and toxins, production of urine to excrete unwanted materials, maintenance of water balance for the body, regulation of acid-base balance, production of hormones |
Retroperitoneal | Located behind the parietal peritoneum |
Hilus | Concave area on the medial aspect of the kidney, where the renal artery, renal vein, and ureter come into or out of the kidney |
Renal capsule | Outer layer of tissue surrounding the kidney, functions as a protective membrane to encapsulate the kidney |
Renal cortex | Outer zone of the kidney |
Renal medulla | Inner zone of the kidney, contains the renal pyramids |
Renal pyramids | Triangular areas in the kidney that contain nephrons, the apex of each renal pyramid contains many papillae where urine can drain out of the nephron |
Nephron | Functional unit of the kidneys, removing wastes and extra fluids from the blood |
Papillae | Little opening |
Calyces (major and minor) | Inlets on the renal pelvis that collect the urine from the renal pyramids |
Renal pelvis | Expansion of the ureter inside the kidney, collects urine from the calyces and directs it down the ureters |
Glomerulus | Network of capillaries where filtration of blood takes place |
Glomerular capsule | Bowman's capsule |
Bowman's capsule | Surrounds and encapsulates the glomerulus, receives the filtrate forced out of the glomerulus that will eventually become urine |
Proximal convoluted tubule | First segment of the nephron tube, reabsorbs about 65% of the water, reabsorbs many nutrients and secretes substances such as histamine and some drugs into the urine |
Nephron loop | Loop of Henle |
Loop of Henle | Includes the descending and ascending limbs |
Descending limb | Permeable to water only, absorbs about 15% of the reabsorbed water from the filtrate |
Ascending limb | Permeable to salts only, absorbs sodium and chloride from the filtrate |
Distal convoluted tubule | Last segment of the nephron before the collecting duct, reabsorbs sodium, potassium, and about 10% of the reabsorbed water when activated by antidiuretic hormone |
Collecting duct | Tubule that takes filtrate from the distal convoluted tubule out through the papillae and into the minor calyces where it becomes urine, reabsorbs about 10% of the reabsorbed water when activated by antidiuretic hormone |
Ureters | Long tubes that conduct urine from each kidney to the urinary bladder |
Urinary bladder | Holding pouch for urine located at the bottom of the pelvic cavity behind the symphysis pubis, lined with transitional epithelial tissue to allow for distension, has an average capacity of 3-3.5 cups, contains a layer of smooth muscle to help expel urine |
Micturition | Urination |
Urethra | Tube that transports urine out of the bladder, varies in length for males and females, also used in the male reproductive system to transport semen |
Internal urethral sphincter | Involuntary smooth muscle, located around the neck of the bladder where the urethra emerges |
External urethral sphincter | Voluntary skeletal muscle, located below the internal urethral sphincter |
Normal constituents of urine | Water, nitrogenous wastes, electrolytes, yellow pigment |