Kidney

• kidney anatomy is intricate, designed to efficiently filter blood, remove waste, maintain electrolyte balance, and regulate blood pressure.
• Each kidney is a bean-shaped organ, approximately the size of a fist, located on either side of the spine, just below the rib cage.
• The kidneys are part of the upper urinary tract and play a crucial role in the body’s urinary system.

External Anatomy

1. Location

   • The kidneys are retroperitoneal organs, meaning they are located behind the peritoneum (the lining of the abdominal cavity).
   • They lie on either side of the vertebral column, with the right kidney positioned slightly lower than the left due to the presence of the liver.

2. Size and Shape

   • Each kidney is approximately 12 cm (4.5 inches) long, 6 cm (2.5 inches) wide, and 3 cm (1.2 inches) thick, resembling a large bean.

3. Renal Capsule

   • A tough, fibrous membrane surrounding each kidney, protecting it from trauma and infection.

4. Renal Hilum

   • The medial indentation where the renal artery enters, and the renal vein and ureter exit the kidney. It acts as a gateway for blood vessels and nerves.

Internal Anatomy:

1. Renal Cortex

   • The outer layer of the kidney, granular in appearance, containing glomeruli, proximal and distal convoluted tubules, and blood vessels.

2. Renal Medulla

   • The inner layer, consisting of 10 to 18 renal pyramids. These cone-shaped tissues house the loops of Henle and collecting ducts. The apex of each pyramid, called the renal papilla, points towards the renal pelvis.

3. Renal Columns

   • Inward extensions of cortical tissue separating the renal pyramids. These columns provide a path for blood vessels to enter and exit the cortex.

4. Renal Pelvis

   • A funnel-shaped space in the center of the kidney that collects urine from the major calyces and channels it into the ureter.

5. Calyces

   • The renal pelvis is divided into major calyces, which further divide into minor calyces. These cup-shaped structures enclose the tips of the renal pyramids, collecting urine and draining it into the renal pelvis.

Blood Supply:

1. Renal Arteries

   • Branches of the abdominal aorta that deliver oxygenated, nutrient-rich blood to the kidneys.

2. Renal Veins

   • Carry deoxygenated, filtered blood from the kidneys back to the inferior vena cava.

• The kidneys receive a significant amount of blood flow, essential for their filtration and excretion functions.

Microscopic Structure:

• Nephrons

  • The functional units of the kidney, with approximately 1 to 1.5 million nephrons per kidney.
  • Each nephron contains a glomerulus (a capillary bed that filters blood) and a renal tubule, where the filtrate is processed and converted into urine.

Thank you for reading from Firsthope's notes, don't forget to check YouTube videos!