urinary 3

Question 1

deficencies

Answer 1

Correct Definitions:
Oliguria = 100 to 400 mL/day

Anuria = Less than 100 mL/day

So:

If someone produces 150 mL/day, that’s oliguria.

If they produce 50 mL/day, that’s anuria.

💡 Easy Way to Remember:
Oliguria = “Oli” means few → low but not absent urine (100–400 mL/day)

Anuria = “An” means none → almost no urine (<100 mL/day)

Let me know if you’d like a chart or memory trick!

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Question 2

tubular reabsorption

Answer 2

What Is Tubular Reabsorption?
Tubular reabsorption is the process by which the kidney reclaims useful substances (like water, glucose, amino acids, and certain ions) from the filtrate (the fluid filtered from the blood in the glomerulus) and returns them to the bloodstream.

🔁 Where It Happens:
Begins: Immediately when filtrate enters the proximal convoluted tubule (PCT)

Mostly happens in:
✅ Proximal convoluted tubule
➕ Some continues in the distal convoluted tubule and collecting duct

✅ Water is reabsorbed passively by osmosis
Yes! Water follows sodium and other solutes that are actively reabsorbed.

It moves from the filtrate into the blood where solute concentration is higher.

This does not require ATP — it’s passive.

✅ Sodium (Na⁺) is reabsorbed actively
Sodium is pumped out of the tubule cells into the blood using the sodium-potassium pump.

This pump requires ATP.

Sodium movement often drives the reabsorption of other substances (like glucose and amino acids).

✅ Amino acids and glucose are also reabsorbed actively, but:
They use secondary active transport (called co-transport) with sodium.

ATP is indirectly used to maintain the sodium gradient.

✅ Ions (like K⁺, Ca²⁺, Cl⁻):
Some are reabsorbed actively (like calcium and potassium).

Chloride ions (Cl⁻) often move passively, following sodium due to electrical attraction — so not all ions are active.

lective transport means:

The body reabsorbs what it needs.

Substances with no carriers (or that are in excess) stay in the filtrate and are excreted in urine.

There are abundant carriers for useful substances, like glucose and amino acids, so they are usually completely reabsorbed (unless blood levels are abnormally high).

🩺 Why It Matters:
Prevents loss of essential nutrients and water

Keeps the internal environment (homeostasis) balanced

Ensures only waste products and excess substances are excreted

Question 3

tubular secretion

Answer 3

Tubular Secretion: What Happens?
Instead of reclaiming substances from the filtrate back into the blood (reabsorption), tubular secretion moves substances from the blood into the filtrate.

These substances are then eliminated in urine.

🚚 Substances commonly secreted include:
Hydrogen ions (H⁺) — helps regulate blood pH by removing excess acid.

Potassium ions (K⁺) — helps control potassium balance and prevents dangerous buildup in blood.

Creatinine — waste product not fully filtered initially, so secretion helps remove it.

Certain drugs and toxins — actively secreted to be cleared from the body.

⚙️ Why is tubular secretion important?
Removes substances not filtered enough by the glomerulus.

Helps maintain acid-base balance by secreting hydrogen ions.

Controls potassium levels to prevent hyperkalemia.

Provides a way for the body to excrete drugs and toxins efficiently.

Summary:
Tubular secretion = Blood → Tubule → Urine (getting rid of extra or unwanted substances).