BIOS 256 Week 4 Lab Instructions Urinary System
Student Name
Chamberlain University
BIOS-256: Anatomy & Physiology IV with Lab
Prof. Name
Date
Kidney Week 4 Lab Instructions: Urinary System Activity
Lab Deliverables and Materials
All students are expected to complete Part A of the Week 4 lab, which focuses on the urinary system. This section contributes 30 points to the overall lab grade.
Materials Required:
- Kidney specimen (preferably from a preserved mammal)
- Dissection tools (e.g., scalpel, scissors, forceps)
- Dissecting tray
Please refer to the course syllabus under “Due Dates for Assignments & Exams” to confirm the submission deadline for this lab.
Activity: Kidney Dissection
The kidney dissection exercise is adapted from McGraw-Hill resources and includes hands-on practice with anatomical identification.
Dissection Instructions:
- Gently remove any superficial adipose tissue from the kidney using your fingers or a blunt instrument.
- Identify the ureter, which emerges at the renal hilum, the concave notch located on the kidney’s medial surface.
- Place the kidney flat on the dissection tray. Begin a coronal incision from the renal hilum, extending along the entire length of the organ and returning to the starting point.
- Carefully continue the incision to separate the kidney into two symmetrical halves.
- Arrange both halves with the interior surfaces facing up on the tray.
- Visually compare the dissected kidney with the reference diagram provided in your lab manual.
- Match and identify the anatomical structures labeled in the diagram using the information provided in Table 1 below.
- Proceed to answer the critical thinking questions.
Table 1: Identification of Kidney Structures (10 points)
| Letter | Structure Name |
|---|---|
| A | Renal pyramid / Renal medulla |
| B | Minor calyx / Renal papilla |
| C | Renal pyramid |
| D | Renal cortex / Fibrous capsule |
| E | Renal sinus |
| F | Renal artery / Hilum |
| G | Renal column |
| H | Major calyx / Interlobar blood vessels |
| I | Branch of renal pelvis |
| J | Ureter |
Critical Thinking Questions
1. Trace the path of urine from the renal papilla to the ureter. (5 points)
Urine exits the nephron at the renal papilla, then drains into the minor calyx, continues into the major calyx, flows into the renal pelvis, and finally passes into the ureter, which transports it to the bladder for temporary storage.
2. Trace the flow of blood throughout the kidney, starting with the renal artery and ending with the renal vein. (5 points)
Blood enters the kidney via the renal artery, which branches into segmental arteries. These divide into interlobar arteries, then pass into arcuate arteries, and further into cortical radiate (interlobular) arteries. Blood then flows into afferent arterioles, enters the glomerulus, and exits through efferent arterioles. From there, blood reaches either peritubular capillaries or vasa recta, depending on nephron type. The return path includes interlobular veins, arcuate veins, interlobar veins, and finally, the renal vein, which drains into the inferior vena cava.
3. Trace the path of filtrate, starting with the glomerulus and ending at the collecting duct. (5 points)
Filtrate forms in the glomerulus and enters the proximal convoluted tubule, where most reabsorption occurs. It then passes through the nephron loop (loop of Henle), followed by the distal convoluted tubule, and finally drains into the collecting duct, which carries it toward the renal papilla.
4. List and describe at least five functions of the urinary system/kidneys. (5 points)
- Regulation of Body Fluid Levels: Kidneys maintain hydration by adjusting water reabsorption and influencing thirst signals.
- Blood Pressure Regulation: Through the renin-angiotensin-aldosterone system (RAAS), kidneys modulate fluid balance and vascular resistance, directly impacting blood pressure.
- Excretion of Waste and Drugs: Metabolic byproducts such as urea, creatinine, and certain medications are filtered from the blood and excreted in urine.
- Electrolyte and Salt Balance: The kidneys fine-tune sodium, potassium, and other electrolytes, which helps regulate blood volume and nerve function.
- pH Homeostasis: By managing hydrogen and bicarbonate ion excretion or retention, the kidneys contribute to acid-base equilibrium in the blood.
References
Hall, J. E., & Guyton, A. C. (2021). Guyton and Hall Textbook of Medical Physiology (14th ed.). Elsevier.
BIOS 256 Week 4 Lab Instructions Urinary System
Marieb, E. N., & Hoehn, K. (2019). Human Anatomy & Physiology (11th ed.). Pearson Education.