Lecture Notes: Understanding the Kidneys

Introduction

• Function of Kidneys: Two bean-shaped organs acting as internal sensors.
  • Balance fluid levels in body.
  • Detect waste in blood.
  • Release essential vitamins, minerals, and hormones.

Main Role of Kidneys

• Waste Disposal and Urine Formation:
  • Dispose of waste products.
  • Transform waste into urine.

Blood Filtration

• Blood Volume:

  • 8 liters of blood processes through kidneys 20-25 times daily.
  • Total filtration of about 180 liters every 24 hours.

• Blood Filtration Process:

  • Blood ingredients change with food and drink intake.
  • Continuous kidney activity required.

Structure of the Kidney

• Blood Entry:

  • Blood enters via branching arteries.

• Nephrons:

  • 1 million nephrons per kidney.
  • Act as filters and sensors.
  • Utilize glomerulus and tubule for filtration.

Filtration Mechanism

• Glomerulus:

  • Acts as a sieve, allowing certain ingredients through.

• Tubule Function:

  • Detects necessary ingredients for reabsorption.
  • Filters out waste products like urea.
  • Directs unwanted compounds to urine.

Urinary Pathway

• Ureters:
  • Long tubes that carry urine to bladder.
  • Dispose of waste completely.

Water Regulation

• Water Detection:
  • Excess water sent to bladder for removal.
  • Low water prompts reabsorption into bloodstream.
  • Affects urine color: Yellower when dehydrated.

Additional Kidney Functions

• Fluid Stabilization: Maintains body fluid levels.

• Hormonal Functions:

  • Activates vitamin D.
  • Secretes renin to raise blood pressure.
  • Produces erythropoietin for red blood cell increase.

Conclusion

• Essential Nature of Kidneys:

  • Prevents fluid and waste buildup.
  • Ensures smooth bodily function.
  • Life-sustaining role highlighted.

• Redundancy:

  • Presence of two kidneys provides backup.

Summary

• Kidneys are crucial for waste filtration, fluid regulation, and hormonal balance.
• They play an indispensable role in maintaining homeostasis within the body.