Kidney and Nephron Anatomy

Introduction

• Video by Earth, Registered Nurse (RN).
• Start of NCLEX review series on the renal system.
• Reminder to take the free quiz at the end of the video.

Kidneys Overview

• Two kidneys: right and left.
• Right kidney is lower due to the liver's position.
• Function: filter blood received via the renal artery and return it via the renal vein.
• Processes involved: filtration, absorption, secretion, and excretion.
• Produces filtrate that becomes urine, which travels through ureters to the bladder.

Kidney Anatomy

• Renal Capsule: Protective outer layer of the kidney.
• Renal Cortex: Outer layer of the kidney.
• Renal Medulla: Inner layer containing renal pyramids.
• Renal Pyramids: Striped appearance due to parallel nephrons.
• Renal Papilla: Tip of the pyramid.
• Calyces: Minor and major, where urine progresses.
• Renal Pelvis: Transfers urine to the ureter.
• Renal Columns: Contain branches of renal artery and vein.

Nephron Overview

• Functional unit of the kidney.
• Each kidney has millions of nephrons.
• Two main sections:
  • Renal Corpuscle: Responsible for filtration (Bowman’s capsule and glomerulus).
  • Renal Tubule: Responsible for reabsorption and secretion.

Nephron Anatomy

• Afferent Arteriole: Brings blood to glomerulus.
• Glomerulus: Network of capillaries facilitating ultrafiltration.
• Bowman’s Capsule: Collects filtrate.
• Efferent Arteriole: Carries blood away from glomerulus.
• Peritubular Capillaries: Assist in reabsorption and secretion.
• Vasa Recta: Specialized capillaries in the loop of Henle.

Filtrate Process

• Filtrate includes water, electrolytes, and waste (urea, creatinine).
• Reabsorption: Movement back into circulation (nutrients originally absorbed from food).
• Secretion: Movement of waste into tubules for excretion.

Detailed Nephron Function

• Proximal Convoluted Tubule: Major site for reabsorption (glucose, amino acids, sodium).
• Loop of Henle: Key site for water reabsorption and urine concentration. Located primarily in the renal medulla.
• Distal Convoluted Tubule: Further reabsorption and some secretion.
• Collecting Ducts: Final adjustments in urine composition.

Urine Pathway

• Flows from collecting ducts to renal papilla, into calyces, through the renal pelvis, ureter, bladder, and urethra.

Conclusion

• Encouragement to watch the next video on nephron physiology.
• Reminder to take the quiz and subscribe for more videos.