Kidney and Nephron Anatomy

Introduction

• Presenter: Earth, Registered Nurse from rn.com
• Part of the NCLEX review series on the renal system
• Reminder to access the free quiz at the end of the video

Kidneys Overview

• Two kidneys: right and left
  • Right kidney is slightly lower due to the liver above it
• Functions of the kidneys:
  • Filter fresh blood received from the renal artery
  • After filtration, send clean blood back through the renal vein
  • Processes: Filtration, absorption, secretion, and excretion
  • Produce filtrate that becomes urine
• Urine Pathway:
  • Filtrate moves through the ureter (one for each kidney) to the bladder
  • Exits through the urethra

Anatomy of the Kidney

• Renal Capsule: Outer protective layer
• Renal Cortex: Outer layer where initial processing occurs
• Renal Medulla: Inner layer, contains renal pyramids
  • Renal Pyramids: Striped appearance due to the structure of nephrons
  • Renal Papilla: Tips of the pyramids
  • Calyces (Calyx):
    • Minor and Major Calyces collect urine
  • Renal Pelvis: Leads to the ureter
• Renal Columns: Contain renal arteries and veins

Nephron Structure

• Nephron: Functional unit of the kidney
  • Millions per kidney
• Renal Corpuscle: Involves filtration
  • Bowman's Capsule and Glomerulus (capillary network)
• Renal Tubule: Involves reabsorption and secretion
  • Processes substances from filtrate back into circulation or secretes them into urine
• Blood Flow in Nephron:
  • Afferent Arteriole: Brings blood to the glomerulus
  • Efferent Arteriole: Takes filtered blood away and forms peritubular capillaries
  • Peritubular Capillaries: Assist in reabsorption and secretion

Processes in the Nephron

• Reabsorption:
  • Recapturing substances already absorbed once from the GI tract
  • Maintains balance (homeostasis) of water, electrolytes, waste
• Secretion:
  • Removal of waste products like urea, creatinine, and drugs
  • Transports these into the filtrate for excretion

Nephron Pathway

• Proximal Convoluted Tubule: Major site of reabsorption
  • Glucose, amino acids, sodium, chloride
• Loop of Henle:
  • Descending Limb: Mostly located in the renal medulla, hypertonic environment
  • Ascending Limb: Important for urine concentration
• Distal Convoluted Tubule: Further reabsorption and secretion
• Collecting Ducts: Final processing of urine

Urine Excretion Pathway

• From the collecting ducts through:
  • Renal Papilla → Minor and Major Calyces → Renal Pelvis → Ureter → Bladder → Urethra

Conclusion

• Preview of upcoming video on nephron physiology
• Encouragement to take the quiz and subscribe for more videos