acid base balance

Water balance is controlled mainly by what hormone?

ADH (antidiuretic hormone)

What does ADH do?

Increases water reabsorption and reduces urine output

What happens to ADH levels when you are dehydrated?

ADH increases to conserve water

What happens to ADH levels when you are overhydrated?

ADH decreases to produce dilute urine

What organ contains the thirst center?

Hypothalamus

What hormone increases sodium (Na⁺) reabsorption?

Aldosterone

How does aldosterone affect water levels?

Water follows sodium, so water is reabsorbed too

What hormone lowers blood pressure by causing sodium and water loss?

ANP (Atrial natriuretic peptide)

Where in the nephron does ADH act?

Collecting duct

Where in the nephron does aldosterone act?

Distal convoluted tubule (DCT) and collecting duct

What is the most important extracellular electrolyte?

Sodium (Na⁺)

What is the most important intracellular electrolyte?

Potassium (K⁺)

Why is potassium so important?

It controls heart rhythm and muscle contractions

What happens with high potassium (hyperkalemia)?

Dangerous cardiac arrhythmias

What happens with low potassium (hypokalemia)?

Muscle weakness and irregular heartbeat

Which hormone increases potassium secretion?

Aldosterone

Which electrolyte is important for bones, muscle contraction, and clotting?

Calcium (Ca²⁺)

What hormone increases blood calcium?

PTH (parathyroid hormone)

What hormone decreases blood calcium?

Calcitonin

What electrolyte follows sodium to maintain osmotic balance?

Chloride (Cl⁻)

What electrolyte is the body's main buffer for pH?

Bicarbonate (HCO₃⁻)

What is the normal blood pH range?

7.35–7.45

What does acidosis mean?

Blood pH is too low (too acidic)

What does alkalosis mean?

Blood pH is too high (too basic)

What is the fastest system for controlling pH?

Chemical buffers

What is the main chemical buffer system?

Bicarbonate buffer system

How does the bicarbonate buffer work?

It binds or releases H⁺ to stabilize pH

How does the respiratory system raise pH?

Breathing faster to blow off CO₂

How does the respiratory system lower pH?

Breathing slower to retain CO₂

What does more CO₂ in the blood do to pH?

Lowers pH (acidosis)

What does less CO₂ do to pH?

Raises pH (alkalosis)

How do the kidneys fix acidosis?

Reabsorb more bicarbonate and secrete more H⁺

How do the kidneys fix alkalosis?

Excrete bicarbonate and retain H⁺

Which system is the slowest but most powerful for pH control?

The kidneys (renal system)

CO₂ and pH have what type of relationship?

Inverse relationship (↑ CO₂ = ↓ pH)

Bicarbonate (HCO₃⁻) and pH have what type of relationship?

Direct relationship (↑ HCO₃⁻ = ↑ pH)

What are the three main pH control mechanisms?

Chemical buffers, respiratory control, renal control

What organ removes CO₂ to regulate pH?

Lungs

What organ adjusts bicarbonate levels to regulate pH?

Kidneys