Urinary System 4 Flashcards
What is Acid-Base Balance?
The equilibrium between acidic and alkaline substances in the body, is crucial for maintaining various metabolic processes
What is a Base (Alkaline)?
Substances with a pH higher than 7 that help neutralize acids
What is Regulatory Hydrogen Balance?
The body’s regulation of hydrogen ion concentration, especially in arterial blood, to maintain a stable pH.
What is pH (Potential Hydrogen)?
A measure of how acidic or alkaline a solution is, determined by the concentration of hydrogen ions (H+). pH < 7 is acidic, pH > 7 is alkaline
What is Normal Arterial Blood pH?
7.35 - 7.45, a narrow range essential for enzyme activity and overall physiological function.
What is Alkalosis?
What is Acidosis?
pH Scale:
What is Chemical Buffering? (3)
- 1st line of defense.
- Immediate response
- Temporarily alters hydrogen levels – does not eliminate hydrogen from the body or add it to the body permanently
Chemical Buffering in response to alkalosis:
In response to alkalosis – H∙Buffer releases hydrogen and buffer (reaction to right)
Chemical Buffering in response to acidosis:
In response to acidosis – hydrogen binds buffer to form H∙Buffer (reaction to left)
What are 3 Types of Chemical Buffers?
Bicarbonate Buffer
Phosphate Buffer
Protein Buffer
What is Bicarbonate Buffer?
(In response to Alkalosis and Acidosis)
- Major extracellular buffer.
- In response to alkalosis- carbonic acid releases hydrogen and bicarbonate (reaction to right).
- In response to acidosis – hydrogen binds bicarbonate to form carbonic acid (reaction to left)
What is Phosphate Buffer?
(In response to Alkalosis and Acidosis)
- One of major intracellular buffers.
- In response to alkalosis – dihydrogen phosphate releases hydrogen and monohydrogen phosphate (reaction to right).
- In response to acidosis – monohydrogen phosphate binds hydrogen to form dihydrogen phosphate (reaction to left)
What is a Protein Buffer?
(In response to Alkalosis and Acidosis)
- One of major intracellular buffers.
- In response to alkalosis – protein releases hydrogen (reaction to right).
- In response to acidosis – protein binds hydrogen (reaction to left)
Respiratory Response to Acid-Base Balance:
- 2nd line of defense.
- Minutes to respond
What is a Breathing buffer?
(In response to Alkalosis and Acidosis)
- Alter ventilation – alters CO2 – alters hydrogen.
- In response to alkalosis – reduce ventilation to increase CO2 and increase hydrogen (reaction to right).
- In response to acidosis – increase ventilation to decrease CO2 and decrease hydrogen (reaction to left).
Renal Response to Acid-Base Balance:
- 3rd line of defense.
- Hours or days to respond
What is the First Renal Mechanism to Maintain Acid-Base Balance? (4)
Renal Mechanism 1: Reabsorption of Filtered Bicarbonate
- Cellular Production:
Epithelial Cells produce hydrogen ions (H+) and bicarbonate ions (HCO3-) - Filtration and Secretion:
Bicarbonate ions are filtered in the Interstitial Fluid & Hydrogen ions are secreted into the renal tubules - Bicarbonate Reabsorption:
Filtered bicarbonate ions from the Glomerulus accept the secreted hydrogen ions. This exchange process helps maintain acid-base balance by preventing excessive acidity in the body. It’s often referred to as the “reabsorption of filtered bicarbonate,” even though it’s not the exact same molecule that was filtered initially - Water and CO2 in the lumen most likely reabsorbed but could be excreted in urine if there is an excess
Renal Mechanism 1:
Reabsorption of Filtered Bicarbonate
What is the Second Renal Mechanism to Maintain Acid-Base Balance? (4)
Renal Mechanism 2: Reabsorption of Monohydrogen Phosphate and Excretion of Dihydrogen Phosphate
- Cellular Production:
Epithelial Cells in renal tubules produce both hydrogen ions (H+) and bicarbonate ions (HCO3-) - Filtration and Secretion:
Hydrogen ions are actively secreted into the renal tubules, where they bind Monohydrogen Phosphate ions (from glomerulus).
HCO3- is filtered into interstitial fluid - Reabsorption of Monohydrogen Phosphate
Forms Dihydrogen Phosphate ions (H2PO4-). Considered “new” bicarbonate reabsorbed (not involving filtered bicarbonate) - Dihydrogen Phosphate Excretion: Dihydrogen phosphate ions are produced in the renal tubules and excreted in the urine. This process helps remove excess hydrogen ions from the body, contributing to acid-base balance
Renal Mechanism 2:
Reabsorption of Monohydrogen Phosphate and Excretion of Dihydrogen Phosphate
What is the Third Renal Mechanism to Maintain Acid-Base Balance? (4)
Renal Mechanism 3: Reabsorption of Bicarbonate and Ammonium from Glutamine
- Glutamine (amino acid) can serve as a source of both bicarbonate ions (HCO3-) and ammonium ions (NH4+). Comes from glomerulus filtration, blood, or within the renal epithelial cells
- Reabsorption of Bicarbonate:
In this mechanism, a process is considered the reabsorption of “new” bicarbonate, similar to Mechanism 2. It doesn’t involve filtered bicarbonate directly. Instead, bicarbonate is generated from glutamine, which contributes to the body’s bicarbonate pool. This process aids in maintaining acid-base balance. - Ammonium ions are actively secreted into the renal tubules. These ammonium ions are then excreted in the urine. This process helps in eliminating excess ammonium from the body, which is an important aspect of acid-base regulation.
Renal Mechanism 3:
Reabsorption of Bicarbonate and Ammonium from Glutamine
