Exploring the Excretory System: From Theory to Practice

Objectives

1. Identify and describe the organs of the excretory system and their functions.

2. Understand the functioning of the excretory system and the types of excreta released by the human body.

Contextualization

The excretory system is crucial for maintaining homeostasis in the human body, regulating the elimination of toxic substances and metabolic waste. For example, the kidneys filter approximately 180 liters of blood daily, producing about 1.5 liters of urine. Understanding the functioning of this system is essential for individual health and the development of medical technologies, such as dialysis, which saves lives.

Relevance of the Theme

Understanding the excretory system is fundamental in the current context, given the increase in kidney diseases and the growing need for qualified professionals in health and biotechnology. This knowledge is applied in areas such as nephrology, biomedical engineering, and the development of essential medical equipment for quality of life.

Kidneys

The kidneys are the main organs of the excretory system, responsible for filtering the blood and forming urine. They remove metabolic waste and toxic substances from the blood, as well as regulate the balance of water and electrolytes in the body.

• Main function: Blood filtration to remove waste and toxins.

• Urine production: Urine is formed in the nephrons, the functional units of the kidneys.

• Homeostasis regulation: Maintenance of balance of water, salts, and pH in the body.

Ureters

The ureters are narrow tubes that transport urine from the kidneys to the urinary bladder. Each kidney has a ureter that efficiently carries urine, preventing reflux and infections.

• Urine transport: Carry urine from the kidneys to the bladder.

• Peristalsis: Muscle movements that aid the flow of urine.

• Prevention of reflux: Valves in the ureters prevent urine from returning to the kidneys.

Urinary Bladder

The urinary bladder is a muscular organ that stores urine until it is eliminated from the body. It can expand and contract to accommodate different volumes of urine.

• Urine storage: Capacity to store up to 600-800 ml of urine.

• Control of urination: Urination reflex coordinated by the nervous system.

• Muscular structure: The bladder wall is made up of detrusor muscle, which helps in expelling urine.

Practical Applications

• Dialysis: A medical procedure that mimics the function of the kidneys, filtering the blood of patients with renal failure.
• Drug development: Research in nephrology to create drugs that improve kidney function or treat kidney diseases.
• Biomedical engineering: Creation of medical devices, such as dialysis machines and artificial kidney implants, to assist patients with excretory system problems.

Key Terms

• Excretory System: A set of organs responsible for the elimination of metabolic waste and maintenance of homeostasis.

• Homeostasis: The internal balance of the body, regulated by various systems, including the excretory system.

• Dialysis: A medical procedure that replaces the function of the kidneys, filtering the blood of patients with renal failure.

• Nephron: The functional unit of the kidneys, where blood filtration and urine formation occur.

Questions

• How can kidney function failure impact the overall health of the body?

• In what ways can knowledge of the excretory system be applied in careers in health and biotechnology?

• What are the current technologies that assist in the treatment of kidney diseases and how have they evolved over time?

Conclusion

To Reflect

The excretory system plays a vital role in maintaining homeostasis and eliminating metabolic waste from the human body. Understanding the organs that make up this system and their functions is essential not only for biology but also for various practical applications, including medicine and biotechnology. Reflecting on how problems in this system can affect overall health helps us value even more the importance of technological and medical advances, such as dialysis.

Mini Challenge - Excretory Challenge: Simulating Renal Function

In this mini-challenge, you will be a 'biomedical engineer' for a day and create a simple device that simulates the filtering function of the kidneys.

• Gather materials: coffee filters, sand, dyed water, plastic cups, funnel, and small stones.
• Build your filtration device: Place the coffee filter inside the funnel and position it over a plastic cup.
• Add a layer of small stones to the filter, followed by a layer of sand.
• Slowly pour the dyed water over the filter and observe the clean water coming out from the bottom of the funnel.
• Compare the filtered water with the initial water and discuss how this experiment relates to the function of the kidneys in the human body.