Urinary System

• URINARY SYSTEM FUNCTIONS


  1) Filtration/Excrection of body fluids

  2) Elimination of waste products

  3) Regulation/Stabilization of blood volume & compositon, pH level, & water & electrolytes
• Urinary system consists of

  2 kidneys (left & right), 2 ureters, 1 urinary bladder & 1 urethra
• Kidneys produce urine in order to

  maintain homeostasis
• Organ that transports urine toward the urinary bladder

  Ureters
• Organ that temporarily stores urine prior to elimination

  Urinary Bladder
• Organ that conducts urine to exterior

  Urethra
• Kidney location


  In Lumbar area, high on the posterior wall of the abdominal cavity
• Kidneys are surrounded by 3 layers which fuses with the covering peritoneum:

  1) Renal capsule

  2) Adipose Capsule

  3) Renal Fascia
• Renal Fascia


  Outermost layer of the kidney composed of dense irregular tissue; anchors kidneys and adrenal glands to the back of the body wall
• Adipose Capsule


  Located between renal fascia and renal capsule, a mass of fatty tissue surrounding each kidney that lies deep to the renal fascia, Protects and holds the kidney firmly in place within the abdominal cavity
• Renal capsule


  Fibrous supporting tissue capsule which adheres to the surface of the kidney & provides a barrier for infection & trauma
• Hilus


  Entry for renal artery and renal nerves and an exit for renal veins and ureter
• Nephrons


  functional units of the kidneys
• Renal Papilla


  The rounded tip of the medullary pyramids that empty urine into the minor calyx (the ducts in the pyramid)
• minor calyx


  A cup-shaped cavity at the base of the renal papilla, which drains urine from the renal papillae into the major calyx
• major calyx


  The cavity formed by the convergence of several minor calyces, which drain urine from the minor calyxes into the renal pelvis then through the ureter
• renal pelvis


  Funnel-shaped reservoir where major calyces converge, portion of the kidney that narrows to become the ureter.that collects and passes the urine.
• Ureters


  Pair of muscular tubes that act like valves and enter the urinary bladder via slit-like structures.
• renal lobe


  Consists of: A single renal pyramid, Its overlying area of renal cortex, One-half of each adjacent renal column
• Urine production ends with fluid entering the

  renal pelvis
• Bladder


  The elastic muscular organ that provides a reservior for urine storage and its walls are capable of great expansion b/c they are formed by the detrusor muscle
• detrusor muscle


  The underlying muscularis layer of the bladder composed of three layers of smooth muscle in the shape of a sphere which when contracted allows the expulsion of urine from the bladder.
• trigone of bladder


  a smooth-surfaced triangular area on the bladder floor made up by the 2 posterolateral ureteral openings and one opening at apex for the urethra; MOST COMMON SITE OF BLADDER INFECTION
• Internal Urethral Sphincter


  Circular smooth muscle that involuntarily controls passage of urine from the urinary bladder to the urethra by acting like a valve
• The urethra extends from the bladder to


  the exterior of the body then passes through the urogenital diaphram (an external voluntary spincter made of skeletal muscle)
• The urethra in men differs in

  length- longer and function (shared BTW reproductive & renal systems) compared to women- shorter urethra; only renal system functions
• Micturition reflex


  1. Stretch receptors are activated in the bladdder wall when the volume of urine reaches 200 to 300 mL. 2. Signals are sent along the sensory neurons to the cerebral cortex and to the micturition center in pons. 3. Micturition center sends nervous signals that cause contraction of the bladder and relaxation of internal urethral sphincter( parasympathetic system). The urination will take place if the voluntary control is undeveloped. Conscious control involves relaxation to the external sphincter; facilitated by voluntary contraction of abdominal and expiatory muscles. If urinaiton is not activated at the time of first reflex > micturition reflex will be activated again after another 200-300m: added urination will occur involuntariy between 500-600 mL
• bowman's capsule


  Double-walled cup shaped structure in the upper end of a nephron that encases the glomerulus and collects the filtrate from the blood.
• Renal Corpuscle


  The part of a nephron that consists of a glomerulus enclosed by a Bowmen's Capsule; site of production of filtrate
• The mechanism that establishes the medullary osmostic gradient depends most on the permeabitly properties of the

  A) loop of Henle

  B) glomerular filtration membrane

  C) collecting duct

  D) distal convoluted tubule

  Loop of Henle
• Urine passes through the

  A)renal hilum to the bladder to the ureter

  B) pelvis of the kidney to ureter to bladder to urethra

  C) glomerulus to ureter to renal tubule

  D) hilum to urethra to bladder

  Pelvis of the kidney to ureter to bladder to urethra
• Which of the following is associated with the renal corpuscle?

  A) a podocyte

  B) a vasa recta

  C) a fenestrated capillary

  D) an efferent arteriole

  a vasa recta
• An increase in the permeability of the cells of the collecting tubule to water is due to

  A) a decrease in the production of ADH

  B) an increase in the production of ADH

  C)an increase in the production of aldosterone

  D) an decrease in the concentration of the blood plasma

  an increase in the production of ADH
• The urinary bladder us composed of _______ epithelium

  A) transitional

  B) simple squamous

  C) stratified squamous

  D) pseudostratified columnar

  Transitional
• The kidneys are stimulated to produce renin_____

  A) when the peritubular capillaries are dilated

  B) when the pH of the urine decreases

  C) by a decrease in the blood pressure

  D) when specific gravity of urine rises above 1.10

  by a decrease in the blood pressure
• Blood vessels of the renal columns are called

  A) lobar

  B) segmental

  C) interlobar

  D) cortical radiate

  interlobar
• Which gland sits atop each kidney

  A) adrenal

  B) thymus

  C) pituitary

  D) pancreas

  adrenal
• The _____artery lies on the boundary between the cortex and medulla of the kidney

  A) lobar

  B) arcuate

  C) interlobar

  D) cortical radiate

  arcuate
• The glomerulus differs from other capillaries in the body in that it _____

  A) has a basement membrane

  B) is impermeable to most substances

  C) is drained by an efferent arteriole

  D) has a blood pressure much lower than other organ systems

  is drained by an efferent arteriole
• The descending limp of the loop of Henle_____

  A) is not permeable

  B) is freely permeable to sodium and urea

  C) pulls water by osmosis into the lumen of the tubule

  D) contains fluid that becomes more concentrated as it moves down into the medulla

  contains fluid that becomes more concentrated as it moves down into the medulla