Introduction

• major functions of the urinary system include :
  • eliminates ? from the body
  • regulates water , electrolyte , and acid-base balance of blood
  • regulates ? and ?
• structures of the urinary system include :
  • kidneys , ureters , urinary bladder , and urethra

The Kidneys

• help maintain ? by controlling the composition , volume , pressure , and pH of the blood
• located just above the waist between T12 and L3
• right kidney is lower than the left because of the ?
• major structures of the kidneys include the hilus , renal cortex , renal medulla , renal calyces , and renal pelvis
• Renal Hilus :
  • "door to the kidney"
  • area in which ureters , nerves , lymphatics , and blood vessels ?
• Renal Cortex :
  • ? of the kidney
• Renal Medulla :
  • ? to the cortex
  • formed by the ? ( cone shaped structures )
    • each pyramid has a ? ( pointed end of the pyramid )
      • tip faces toward the hilus
• Major and Minor Calyces :
  • drain urine into the ?

• Renal Pelvis :

  • funnel shaped tube that drains urine into the ?

• Blood Vessels of the Kidneys :

  • oxygenated blood is carried to the kidneys by way of the ?
    • branch off of the abdominal aorta
  • deoxygenated blood is carried away from the kidneys by way of the ?
    • empty into the inferior vena cava

Microscopic Anatomy of the Kidneys

• kidneys contain microscopic structures called ? ( each kidney contains over 1 million nephrons )
• nephrons help maintain homeostasis of the blood by :
  • getting rid of wastes ( in the form of urine )
  • returning needed materials to the blood
• each nephron is composed of a renal corpuscle and a renal tubule
• Renal Corpuscle :
  • composed of :
    • the ? ( Bowman's Capsule ) ( enlarged end of a nephron )
    • ? ( network of capillaries ) ( fenestrated )
  • as blood flows through the glomerulus , substances are filtered out of the blood plasma into the ?
  • the filtered substances that are now in the glomerular capsule are called ?
    • filtrate flows into the renal tubule
• Renal Tubule :
  • composed of the proximal convoluted tubule , loop of Henle , and distal convoluted tubule
    • Proximal Convoluted Tubule :
      • portion of the renal tubule that receives filtrate from the ?
• Loop of Henle :
  • center portion of the renal tubule
  • receives filtrate from the proximal tubule
  • consists of the ? and ?
• Distal Convoluted Tubule :
  • last portion of the renal tubule
  • receives filtrate from the loop of Henle
  • drains filtrate into the collecting ducts
    • collecting ducts unite to form ?
      • drain into the minor calyces
    • collecting ducts are not technically part of the nephron
    • minor calyces are the first place we can call the fluid "urine"

Blood Vessels Associated with Nephrons and Associated Structures

• Afferent Arteriole :
  • carries blood into the glomerulus
• Efferent arteriole :
  • smaller diameter than afferent
    • bottle-neck effect
  • carries blood out of the glomerulus
  • gives rise to the peritubular capillaries
• Juxtaglomerular Cells :
  • special smooth muscle cells forming cuff-like arrangement around the ? ( sphincter )
    • helps to maintain constant pressure
• Macula Densa :
  • senses changes in the flow of filtrate
  • specialized cells located in the part of the ? that lies between the afferent and efferent arterioles
• Juxtaglomerular Apparatus :
  • formed from the macula densa and juxtaglomerular cells
  • secretes ?
  • helps maintain a constant glomerular filtrate rate ( GFR )
• Peritubular Capillaries :
  • surround the proximal and distal convoluted tubules
  • give rise to the vasa recta
• Vasa Recta :
  • "straight vessel"
  • surround the ? of juxtamedullary nephrons
    • NOT associated with cortical nephrons

Ureters

• transport urine from the kidneys to the ?
• lined with transitional epithelium

Urinary Bladder

• right behind pubic symphysis
• ? ( average capacity of a bladder is 700 - 800 mL )
• lined with transitional epithelium

Urethra

• transports urine from the bladder to the ?
• the male urethra is longer than the female urethra ( 15 - 20 cm compared to 4 cm ) and transports both ? and ?
• proximal portion is lined with transitional epithelium

Urine Release

• average capacity of the bladder is 700 - 800 mL
• when the urine level reaches 200 - 400 mL , ? in the wall of the bladder send action potentials to the brain
• this leads to contraction of the ? ( smooth muscle ) and relaxation of the ? ( smooth muscle )
  • not ready to go ? ... don't worry , the ? is skeletal muscle

Urine Pathway

1. Minor Calyx
2. Major Calyx
3. Renal Pelvis
4. Ureter
5. Urinary Bladder

Histology Questions

• What is the function of transitional epithelium ?
  • To change ? to accommodate stretching of structure when full of urine
• What structures can you find in the renal cortex?
  • ? ( Bowman's Capsule + Glomerulus ) , ? , ? , ?
• What structures can you find in the renal medulla?
  • ? , ? , ?
• Is the Collecting Duct part of the nephron ?
  • ?
• Is the Loop of Henle part of the nephron ?
  • ?
• Name all parts of the nephron , include which parts are found in the renal cortex and which parts are found in the renal medulla
  • Cortex = ? , ? , ?
  • Medulla = ?

Kidney Stones

• Concentrated minerals found in the kidneys
• Pain in the side and back
• Pain during urination
• May be able to pass kidney stone or require surgery