BIOS 256 Week 4 Lab Instructions Urinary System

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Chamberlain University

BIOS-256: Anatomy & Physiology IV with Lab

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Kidney Week 4 Lab Instructions: Urinary System Activity

Introduction and Materials

In this activity, you will perform a kidney dissection to observe and identify key structures within the urinary system. You will need the following materials:

Kidney specimen
Dissecting tools

Procedure

Begin by removing any peripheral fat from the surface of the kidney using your fingers or a blunt probe.
Locate and identify the ureter, which originates at the renal hilum, the indentation on the medial side of the kidney.
Lay the kidney flat on the dissecting tray and make a coronal incision starting from the renal hilum. Proceed through the kidney’s entire length until you return to the hilum, ensuring to cut away from your body for safety.
After making the initial incision, continue cutting through the kidney to separate it into two equal halves.
Place both halves of the kidney on the dissecting tray.
Once dissected, identify the structures as labeled in Table 1.

Identification Table (Table 1)

Structure	Letter	Description
A. Pyramid or Renal Medulla	A	The inner region of the kidney, involved in urine formation.
B. Minor Calyx	B	Collects urine from the renal papilla.
C. Renal Pyramid	C	The triangular area of the medulla containing nephrons.
D. Renal Cortex or Fibrous Capsule	D	The outer region of the kidney, containing the renal corpuscles.
E. Renal Sinus	E	The space within the kidney that contains blood vessels and renal pelvis.
F. Renal Artery/Hilum	F	The entry point for blood vessels into the kidney.
G. Renal Column	G	Tissue between the renal pyramids.
H. Major Calyx/Interlobar Blood Vessels	H	Collects urine from the minor calyces.
I. Branch of Renal Pelvis	I	Connects to the major calyx, leading to the ureter.
J. Ureter	J	The tube that transports urine from the kidney to the bladder.

Critical Thinking Questions

1. Trace the path of urine from the renal papilla to the ureter

Urine flows from the renal papilla to the minor calyx, then to the major calyx, followed by the renal pelvis, and finally into the ureter.

2. Trace the flow of blood through the kidney, starting with the renal artery and ending with the renal vein

Blood flow begins with the renal artery, which branches into segmental arteries, interlobar arteries, arcuate arteries, and finally the glomerulus. After filtering, blood moves through the efferent arterioles, peritubular capillaries, interlobular veins, arcuate veins, interlobar veins, and ultimately the renal vein.

3. Trace the path of filtrate from the glomerulus to the collecting duct

Filtrate moves from the glomerulus to the proximal convoluted tubule, then through the nephron loop, followed by the distal convoluted tubule, and finally into the collecting duct.

4. List and describe at least five functions of the urinary system/kidneys

The urinary system has several essential functions, including:

Fluid regulation – The kidneys help regulate water retention and thirst.
Hormone release to control blood pressure – Through fluid regulation, the kidneys help maintain blood pressure by adjusting the volume of water in the bloodstream.
Removal of medications and waste products – The kidneys filter the blood, removing metabolic waste and excess water, which is then excreted as urine.
Maintain a balance of salts/electrolytes – The kidneys help regulate the balance of salts, particularly sodium, which affects blood volume.
Maintain pH and acid-base balance – The kidneys control the excretion of hydrogen ions and bicarbonate ions, which helps maintain the body’s pH balance.