CAROLINA DISSECTION GUIDES

Mammalian Kidney Dissection

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Introduction

Mammalian kidneys are part of the urinary system, functioning with the ureter, urinary bladder, and tubular urethra. These organs remove unwanted cellular waste, excess salts, and toxins from the blood. The kidneys play a part in regulating water balance and pH levels in the mammalian body. They also help regulate blood pressure and red blood cell production. Dissecting a kidney allows you to trace the path of wastes and urine through the organ and better understand its function.

Time Icon

Total Time:

  • Time: 45–90 min
  • Span: 1 - 2 Class Periods
earth science

Ideal Group Size

  • 2 students per group

Safety Supplies

  • Gloves, Safety Glasses, Apron

Videos

Kidney External Anatomy

  1. Place the preserved pig kidney on your dissecting tray.
  2. Observe and feel the renal capsule (Figure 1). This structure encapsulates the kidney and is made up of dense, irregular connective tissue. It provides protection and helps maintain the shape of the kidney.
  3. Locate the hilus (Figures 1 and 2). This is an indentation where the ureter exits and blood vessels either enter or exit the kidney.
    1. The ureter is located within the adipose tissue that is attached to the hilus. It drains urine from the renal pelvis into the bladder.
    2. The renal artery and renal vein are also found in the adipose tissue of the hilus. The renal artery is located directly above the renal vein and has a slightly thicker wall. The renal artery supplies the kidney with blood, carrying water and wastes to be filtered and removed. After the blood has been filtered, many veins throughout the capsule converge into the renal vein, which returns the filtered blood to the body.
  4. Remove any adipose tissue attached to the renal capsule and hilus. Consult Figure 2 to ensure that you do not remove too much of the tissue around the ureter and the renal artery and vein.

Kidney Internal Anatomy

  1. Carefully make a lateral, longitudinal cut through the kidney and lay the 2 halves on the dissecting tray.
  2. Locate the cortex and medulla. The medulla lies below the cortex. Observe and record the appearance of each region.
  3. Look closely at the cortex section of the kidney. Locate the collecting ducts and follow them into the renal medulla (Figure 3). Urine is formed in microscopic structures called nephrons and then passed to the collecting ducts.

    Figure 3


  4. Locate the conical renal pyramids in the renal medulla (Figure 4). The base of each renal pyramid lies next to the cortex, while the tip forms the renal papilla. Urine in the collecting ducts travel through the renal pyramids to the renal papillae.
  5. Adjacent to the renal pyramids are the renal columns, that expand from the cortex through the medulla, composed of cortical tissue that has a granular texture similar to that of the cortex (Figure 4). The renal cortex, renal pyramids, and renal columns collectively are called the renal lobe. Urine passes through the renal lobe and is discharged through the renal papilla, the apex of the renal pyramids, into the minor calyx.

    Figure 4

     

  6. Locate a minor calyx, major calyx, and the renal pelvis. (Figure 5). Urine from a renal papilla empties into a minor calyx. Minor calyces merge to form major calyces. Major calyces merge to form the renal pelvis.
  7. Trace a path through the minor and major calyces and into the renal pelvis. Urine from the renal pelvis then drains urine into the ureter where it is transferred to the bladder.

    Figure 5


  8. After you have observed all the structures of the kidney, dispose of the specimen in accordance with local guidelines and your teacher’s instructions.
     
     
     

 

Safety Resources

Recommended Kit(s)

Recommended Specimen(s)

Recommended Dissection Supplies

Related Resources

General Dissection Resources

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