FUNÇÕES RENAIS BÁSICAS: FILTRAÇÃO, REABSORÇÃO E SECREÇÃO | MK Fisiologia

Summary

In this video, Miriam explains the basic functions of the kidneys: filtration, reabsorption, and secretion. She breaks down how each process works, why they are important, and their relation to renal excretion. Filtration helps quickly remove substances from the body, reabsorption prevents the loss of vital nutrients and water, and secretion enhances the excretion of specific substances. The video emphasizes the balance between these processes, ensuring homeostasis in the body. Miriam simplifies complex physiology concepts, making it easier to understand kidney functions and their role in maintaining health.

Takeaways

• 😀 Filtration, reabsorption, and secretion are the three basic functions of the kidneys.
• 😀 Filtration refers to the movement of substances from blood into the Bowman's capsule in the nephron.
• 😀 The kidneys filter approximately 180 liters of fluid daily, but only 1.5 liters are excreted as urine.
• 😀 Reabsorption allows the kidneys to recover water and essential nutrients from the filtered fluid back into the bloodstream.
• 😀 99% of the filtered fluid is reabsorbed to maintain homeostasis and avoid the loss of essential substances like water and glucose.
• 😀 Secretion is the process where additional substances, not initially filtered, are actively moved from blood into the renal tubules for excretion.
• 😀 Filtration helps eliminate waste products and excess substances quickly from the body.
• 😀 Reabsorption helps conserve valuable resources like water and nutrients, preventing the need to drink excessively to maintain fluid balance.
• 😀 Secretion increases the excretion of specific substances, maintaining proper levels and avoiding accumulation of harmful compounds.
• 😀 These processes work together to maintain fluid balance, regulate concentrations of substances, and ensure the proper functioning of the body.
• 😀 Understanding filtration, reabsorption, and secretion is essential for comprehending how the kidneys support overall health and homeostasis.

Q & A

What are the three basic functions of the kidneys?

The three basic functions of the kidneys are filtration, reabsorption, and secretion.

How does filtration in the kidneys work?

Filtration, specifically glomerular filtration, involves the movement of water and other substances from the blood in the glomerular capillaries into the Bowman's capsule in the nephrons.

What is the purpose of reabsorption in the kidneys?

Reabsorption is the process where water and other substances that were filtered into the nephrons are transported from the tubular lumen back into the peritubular capillaries, returning them to the bloodstream.

What does secretion in the kidneys involve?

Secretion is the process where substances that were not filtered initially, but are transported from the blood in the peritubular capillaries into the lumen of the tubules, to be excreted in urine.

Why is the volume of filtrate in the kidneys so large (180 liters per day)?

The kidneys filter a large volume (180 liters) of fluid daily to ensure the rapid excretion of substances that need to be eliminated. A high filtration volume allows substances to be removed from the body efficiently.

How much urine is excreted by the body compared to the amount of filtrate?

Despite the kidneys filtering 180 liters of fluid daily, only about 1.5 liters of urine are excreted. This is because 99% of the filtrate is reabsorbed back into the bloodstream.

What is the importance of reabsorption in kidney function?

Reabsorption is crucial to prevent the loss of important substances like water and nutrients. For example, reabsorbing water helps maintain proper fluid balance, and reabsorbing nutrients like glucose prevents their unnecessary loss.

Why is it important to regulate the excretion of substances like water?

Regulating water excretion is important to maintain fluid balance in the body. If all the filtered water were excreted, the body would lose excessive amounts, requiring the consumption of 180 liters of water daily to maintain balance.

How do the kidneys handle glucose during filtration?

Glucose, a small hydrophilic substance, is filtered along with water but is completely reabsorbed back into the bloodstream. This ensures that glucose is not lost in urine, as it is an essential energy source.

What role does secretion play in the kidney's ability to excrete certain substances?

Secretion increases the excretion of specific substances that may not have been efficiently filtered. By actively transporting them into the tubules, the kidneys can ensure quicker elimination of these substances.