kidney disection
Introduction to Kidney Anatomy and Dissection
Pigs are mammals, and their kidneys share similarities with human kidneys, allowing anatomical studies to provide insights into human anatomy.
Equipment Needed for Kidney Dissection
Essential Equipment:
Dissecting tray
Dissecting kit
Gloves
Specimen Handling:
Kidney specimens usually arrive in a plastic bag.
Carefully cut open the bag using scissors from the dissecting kit to remove the kidney.
Dispose of the plastic bag in regular trash.
Dispose of animal waste in a hazardous waste container.
Rinse off preservative solution in the regular sink.
Orientation and Position of the Kidney
The human cadaver abdomen displays visible kidneys.
Kidney Overview:
There are two kidneys: left and right.
The kidneys are classified as retroperitoneal, meaning they are located posterior to the peritoneum and outside the peritoneal cavity.
Anatomical Features of the Kidney
Vascular Structures:
Three main vessels emerge from the medial surface of the kidney, which has a bean shape:
Renal hilum: An indentation on the medial surface of the kidney, located on the left side.
Renal artery: Brings blood into the kidney.
Renal vein: Carries blood away from the kidney and is typically anterior to the renal artery.
Ureter: Transports urine away from the kidney to the urinary bladder and appears as a 'C'.
Directional Orientation:
The ureter travels inferiorly, establishing the superior (top) and inferior (bottom) reference points of the kidney.
The renal hilum indicates the medial surface, allowing identification of the lateral surface.
Connective Tissue Layers:
Three layers of connective tissue between the peritoneum and the kidney provide support and protection:
Renal Fascia: Adheres the kidney to the muscles of the posterior abdominal cavity (not visible in the current image).
Perirenal Fat Capsule: Surrounds the kidney to provide stability and additional protection (also not visible).
Fibrous Renal Capsule: A fibrous covering that protects the kidney from infection and provides cushioning, similar to a shrink-wrapped cut of meat.
Dissection Procedures
Preparation for Coronal Section
Understanding Coronal Section:
A coronal section (or frontal section) provides a clear view of the kidney's functional anatomy.
Steps for Making the Coronal Section
Holding the Kidney:
Firmly and carefully hold the kidney with the lateral surface facing up.
Incision:
Make an incision with a scalpel at the far end of the kidney, drawing the scalpel towards yourself.
Turn the kidney as necessary to complete the incision around it.
Continue incising deeper until you can separate the two halves of the kidney.
Internal Anatomy of the Kidney
Major Regions of the Kidney:
Renal Cortex: The outer shell just beneath the fibrous renal capsule.
Renal Medulla: The inner region deeper than the cortex, serving as the kidney's center portion.
Both regions contain renal parenchyma, which refers to the functional tissue of the organ.
Nephrons:
The microscopic urine-producing units located within the renal cortex and medulla (invisible in gross anatomical sections).
Renal Structure Description
Renal Pyramids:
The renal medulla appears to contain triangular structures, known as renal pyramids, which are actually three-dimensional.
Renal Papilla: The apex of each pyramid pointing toward the renal hilum and renal pelvis.
Calices and Sinus:
Each renal pyramid's papilla ends in a funnel-shaped minor calyx, collecting urine.
Minor calices from adjacent pyramids merge to form a major calyx, leading to the renal pelvis.
The space between the calices is designated as the renal sinus.
Observations of Vasculature
Vascular Injection Notes:
Specimen may be injected with colored substances (e.g., red latex for arteries, blue latex for veins) to help identify renal vasculature.
Interlobar Vessels:
Interlobar arteries and veins: Named for their location between the renal pyramids (considered as lobes of the kidney).
Arcuate arteries and veins: Form an arch over the bases of renal pyramids.
Summary of Vascular Features
Cortical Radiate Vessels:
Straight arteries and veins that radiate from the arcuate arteries/veins to the cortex are known as cortical radiate arteries and veins.
To prepare the kidney for dissection in proper chronological order, follow these steps:
Cut the Bag: Carefully cut open the plastic bag containing the kidney specimen using scissors from the dissecting kit.
Remove Kidney: Remove the kidney from the plastic bag.
Rinse Specimen: Rinse off any preservative solution from the kidney in the regular sink.
Orient Kidney: Identify the superior, inferior, medial (renal hilum), and lateral surfaces. The ureter travels inferiorly, establishing the top and bottom reference points, while the renal hilum indicates the medial surface.
The medically located indentation of the kidney is called the renal hilum.
Three main vessels emerge from the medial surface of the kidney at the renal hilum: the renal artery, which brings blood into the kidney; the renal vein, which carries blood away; and the ureter, which transports urine to the urinary bladder.
The ureter is one of the three main vessels emerging from the medial surface of the kidney at the renal hilum. Its function is to transport urine away from the kidney to the urinary bladder. It travels inferiorly, establishing the bottom reference point of the kidney.
There are three layers of connective tissue between the peritoneum and the kidney that provide support and protection:
Renal Fascia: Adheres the kidney to the muscles of the posterior abdominal cavity.
Perirenal Fat Capsule: Surrounds the kidney to provide stability and additional protection.
Fibrous Renal Capsule: A fibrous covering that protects the kidney from infection and provides cushioning.
The plastic bag that the kidney comes in can be discarded into the regular trash while the kidney itself will be discarded into the hazardous waste bin.