Nephron Function Flashcards

Questions and Answers

What is the Nephron?

The unit of the Kidney responsible for the production of urine in order to get rid of excess water and toxic waste products.

How many Nephrons are in each Kidney?

Approximately 1 million

What is the function of the Afferent Arteriole?

Blood enters the Glomerulus through this.

What is the function of the Efferent Arteriole?

Blood exits the Glomerulus through this. Signup and view all the answers

What is the Glomerulus?

A network of Capillaries. Signup and view all the answers

What happens as blood enters and exits the Glomerulus?

Components of the blood are filtered out into an area called the Bowman's Capsule. Signup and view all the answers

What is the first part of the journey where filtration takes place?

The Glomerulus Signup and view all the answers

What does normal filtrate contain?

Water (H2O), Sodium Chloride (NaCl) move together, Potassium (K), Bicarbonate (HCO3), Glucose, Amino Acids, Creatinine, Urea. Signup and view all the answers

What are Creatinine and Urea?

Waste products that should be removed from circulation before they become toxic. Signup and view all the answers

What occurs in the Proximal Convoluted Tubule?

Reabsorption of Potassium (K), Sodium Chloride (NaCl) (65%), Water (H2O) (65%), Amino Acids (100%), Glucose (100%), Bicarbonate (HCO3) (90%). Signup and view all the answers

How much Urea is reabsorbed into the blood at the Proximal Convoluted Tubule?

50% Signup and view all the answers

How does water (H2O) leave the Nephron?

By Osmosis. Signup and view all the answers

What is secreted in the Proximal Convoluted Tubule?

Uric Acid and Organic Acids. Signup and view all the answers

What is the function of the Loop of Henle?

Concentration of Urine. Signup and view all the answers

What is the Medulla in relation to the Nephron?

Highly salty as Sodium Chloride (NaCl) is actively pumped out. Signup and view all the answers

Is the Ascending Limb permeable to water?

No, it is impermeable to water (H2O). Signup and view all the answers

Is the Descending Limb permeable to water?

Yes, it is permeable to water (H2O). Signup and view all the answers

How does water leave the descending limb?

By Osmosis, due to the salty environment of the Medulla. Signup and view all the answers

Where does Sodium Chloride (NaCl) leave?

The Thin Ascending Limb and is actively pumped out of the Thick Ascending Limb. Signup and view all the answers

How much Sodium Chloride (NaCl) is reabsorbed from the Loop of Henle?

Approximately 25% Signup and view all the answers

What occurs in the Distal Convoluted Tubule?

Under the influence of Aldosterone, Sodium Chloride (NaCl) (5%) is reabsorbed. Signup and view all the answers

What is secreted into the Distal Convoluted Tubule?

Potassium (K) and Hydrogen Ions (H+). Signup and view all the answers

Is the Distal Convoluted Tubule normally impermeable to water?

Yes, but small amounts may be reabsorbed. Signup and view all the answers

How can you summarize the function of the Nephron?

The Proximal Convoluted Tubule = Reabsorption, The Loop of Henle = Secretion, The Distal Convoluted Tubule = the fine-tuning. Signup and view all the answers

What does the Collecting Duct reabsorb?

Urea, about 5% of the filtered Sodium Chloride (NaCl), and Water (H2O). Signup and view all the answers

What does Excretion/Urine contain?

Water (H2O), Sodium Chloride (NaCl), Potassium (K), Bicarbonate (HCO3), Creatinine, Urea. Signup and view all the answers

What happens at the end of the Collecting Duct?

Blood reabsorbs what is needed and any additional wastes are removed. Signup and view all the answers

What is Homeostasis?

Maintaining a stable internal environment. Signup and view all the answers

How do the Kidneys help to maintain Homeostasis in the body?

By regulating water balance, ion balance, and acid-base levels in fluids. Signup and view all the answers

Study Notes

Nephron Overview

Nephrons are the functional units of the kidneys responsible for urine production.
Each kidney contains approximately 1 million nephrons.

Glomerulus Function

Afferent arterioles supply blood to the glomerulus, while efferent arterioles carry blood away.
The glomerulus consists of a network of capillaries where filtering occurs.

Filtration Process

As blood passes through the glomerulus, components are filtered into the Bowman's capsule.
Normal filtrate includes water, sodium chloride, potassium, bicarbonate, glucose, amino acids, creatinine, and urea.

Waste Management

Creatinine and urea are waste products that must be eliminated to prevent toxicity.
Approximately 50% of urea is reabsorbed in the proximal convoluted tubule.

Proximal Convoluted Tubule (PCT)

In the PCT, key reabsorbed substances include potassium, sodium chloride (65%), water (65%), amino acids (100%), glucose (100%), and bicarbonate (90%).
Uric acid and organic acids are secreted in the PCT, aiding in waste removal.

Loop of Henle

The loop consists of a descending limb (permeable to water) and an ascending limb (impermeable to water).
The medulla is highly concentrated with salts, promoting water reabsorption via osmosis in the descending limb.
Approximately 25% of sodium chloride is reabsorbed in the loop, with active pumping occurring in the thick ascending limb.

Distal Convoluted Tubule (DCT)

Under aldosterone influence, the DCT reabsorbs approximately 5% of sodium chloride, water, and bicarbonate.
Potassium and hydrogen ions are secreted into the DCT.

Collecting Duct Function

The collecting duct reabsorbs urea, about 5% of filtered sodium chloride, and additional water.
At the end of the collecting duct, essential nutrients are reabsorbed while excess wastes are excreted.

Homeostasis Role

Homeostasis refers to the maintenance of a stable internal environment.
Kidneys contribute to homeostasis by regulating water balance, ion concentration, and acid-base levels in bodily fluids.

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Description

Explore the essential functions of the nephron, the basic unit of the kidney responsible for urine production and waste elimination. Test your knowledge on the structure and blood flow within the nephron through these flashcards.