Urinary System Chapter 5

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Questions and Answers

What is the primary role of the acid-base buffer system in the body?

To generate acids in the body

To combine with acids or alkalis to prevent changes in [H+] (correct)

To remove carbon dioxide from the body

To regulate body temperature

How does the respiratory center contribute to acid-base balance?

By producing more enzymes

By altering the rate of breathing to change [H+] (correct)

By excreting acids through urine

By increasing metabolic rate

Which buffer system is NOT one of the primary systems regulating [H+] concentration?

Renal buffer system

Gastrointestinal buffer system (correct)

Phosphate buffer system

Acid-base buffer system

What happens when pH levels drop in the body?

Acidosis occurs Signup and view all the answers

What is the effect of renal regulation in the acid-base balance?

Long-term adjustment of [H+] Signup and view all the answers

What does a high pH level indicate about [H+] concentration?

There is a lower concentration of [H+] Signup and view all the answers

Which of the following is NOT a characteristic of metabolic pathways affected by pH changes?

Cellular communication is enhanced Signup and view all the answers

Which buffer system works immediately to prevent large changes in [H+]?

Protein buffer system Signup and view all the answers

What is the ratio of bicarbonate ions to carbonic acid in blood when pH is normal?

20:1 Signup and view all the answers

How does the bicarbonate-carbonic acid buffer system respond when the concentration of H+ ions increases?

It produces carbonic acid and salt. Signup and view all the answers

What happens to blood pH when CO2 levels rise?

Blood pH decreases. Signup and view all the answers

Which chemical reaction occurs when sodium bicarbonate reacts with hydrochloric acid?

HCl + NaHCO3 → NaCl + H2CO3 Signup and view all the answers

How does the respiratory system help in acid-base balance?

By regulating extracellular fluid CO2 concentration. Signup and view all the answers

What do bicarbonate ions do when the concentration of hydroxide ions (OH−) increases in the blood?

They react to form water and bicarbonate. Signup and view all the answers

What happens to pulmonary ventilation when blood pH decreases?

It increases to expel more CO2. Signup and view all the answers

What is produced when carbonic acid reacts with a strong base like sodium hydroxide?

Water and bicarbonate. Signup and view all the answers

What physiological condition does hyperventilation primarily cause in the blood?

Increase in blood alkalinity Signup and view all the answers

Which mechanism do the kidneys utilize to control acid-base balance?

Secretion of H+ ions into the urine Signup and view all the answers

Where are peripheral chemoreceptors, which regulate respiratory rate based on CO2 levels, primarily located?

In the walls of the aorta and carotid arteries Signup and view all the answers

In response to decreased extracellular fluid (ECF) H+ concentration (alkalosis), what do the kidneys do?

Fail to excrete all filtered bicarbonate Signup and view all the answers

Where does the majority of bicarbonate reabsorption and H+ secretion occur in the kidneys?

Proximal tubule Signup and view all the answers

What is the primary function of central chemoreceptors in the regulation of breathing?

To detect changes in blood CO2 levels Signup and view all the answers

What happens to bicarbonate levels during acidosis in the kidneys?

Bicarbonate is fully reabsorbed and new bicarbonate is produced Signup and view all the answers

Rebreathing exhaled air into a paper bag is an effective method to remedy which condition?

Hyperventilation leading to alkalosis Signup and view all the answers

What percentage of filtered bicarbonate is reabsorbed in the thick ascending loop of Henle?

10% Signup and view all the answers

What mechanism is NOT involved in the secretion of H+ into the tubular fluid?

Potassium-H+ exchange Signup and view all the answers

How does bicarbonate combine with H+ in the renal tubule?

To form H2CO3 Signup and view all the answers

Which enzyme facilitates the reformation of H2CO3 from CO2 and H2O in tubular cells?

Carbonic anhydrase Signup and view all the answers

What are the two mechanisms for transporting HCO3– across the basolateral membrane?

Na+-HCO3– co-transport and Cl–-HCO3– exchange Signup and view all the answers

Which component of the body primarily facilitates gas exchange with the atmosphere?

Lungs Signup and view all the answers

How is carbon dioxide transported in the plasma generated from tissues?

As bicarbonate (HCO3–) Signup and view all the answers

Which statement about hemoglobin is incorrect regarding its role in acid-base balance?

It generates new bicarbonate in the proximal tubules. Signup and view all the answers

Which system is responsible for maintaining blood plasma pH within a normal range?

Kidneys and urinary system Signup and view all the answers

What is the role of hemoglobin in the protein buffer system?

To buffer hydrogen ions Signup and view all the answers

What happens when sodium monohydrogen phosphate (Na2HPO4) encounters a strong acid?

It becomes sodium dihydrogen phosphate Signup and view all the answers

Which of the following is NOT one of the three major buffer systems in body fluids?

Nitrate buffer system Signup and view all the answers

In which fluid compartment is the bicarbonate buffer system considered the most important?

Extracellular fluid Signup and view all the answers

When the concentration of hydrogen ions [H+] increases, which reaction is likely to occur with sodium dihydrogen phosphate?

NaH2PO4 + NaCl formation Signup and view all the answers

What is the function of the kidneys in acid-base regulation?

Excrete hydrogen ions and generate bicarbonate Signup and view all the answers

Which component of the phosphate buffer system acts as a weak base?

Sodium monohydrogen phosphate Signup and view all the answers

Study Notes

Urinary System 5

The urinary system is explained by Fadhloallah najih and edited by Mohammad Talib Abbood.
The presentation is part of the #MEDLOGIC_TEAM.

Objectives

Regulation of Acid-Base Balance
Defense Against Change in [H+]
- Acid-Base Buffer System
- Respiratory Center
- Kidneys
Buffer Systems of the Body
- Proteins Buffer System
- Phosphate Buffer System
- Bicarbonate Buffer System
Respiratory Regulation of Acid-Base Balance
Renal Regulation of Acid-Base Balance

Regulation of Acid-Base Balance

Metabolism depends on enzyme function, and enzymes are sensitive to pH.
Slight pH deviations can disrupt metabolic pathways and alter macromolecular structure and function.
Acid-base balance is crucial for homeostasis.

Regulation of Acid-Base Balance (Continued)

Acid-base balance regulates [H+] in body fluids.
Slight changes in [H+] significantly affect reaction rates in cells.
pH is used to express [H+].
Low pH indicates high [H+] (acidosis); high pH indicates low [H+] (alkalosis).

Defense Against Change in [H+]

Three primary systems regulate [H+] to prevent acidosis or alkalosis:
- Acid-base buffer system
- Respiratory center
- Kidneys
Acid-base buffer system immediately combines with acids or alkalis to prevent excessive [H+] changes (acts within seconds).
Respiratory center adjusts breathing rate to control CO2 removal, which affects [H+]. (adjusts within 1-15 minutes).
Kidneys excrete acid or alkaline urine to further regulate [H+] (adjusts within several minutes to days).

A. The Buffer Systems of the Body Fluids

Three major buffer systems:
- Protein buffer system
- Phosphate buffer system
- Bicarbonate buffer system

1- Protein buffer system

Hemoglobin is a crucial protein buffer in red blood cells.
Hemoglobin buffers hydrogen ions released during CO2 conversion to bicarbonate.
This process helps maintain normal pH and reverse in pulmonary capillaries.

2- Phosphate buffer system

Phosphates exist in blood as weak acid (dihydrogen phosphate) and weak base (monohydrogen phosphate).
Phosphate reacts with acids or bases to neutralize the changes in [H+].

3- Bicarbonate buffer system

Bicarbonate and carbonic acid are present in extra cellular fluids in a 20:1 ratio for normal blood pH.
This buffer system is highly efficient in preventing blood acidity changes.
Metabolic wastes (e.g. lactic acid, ketone bodies) are acids, so this buffer system is especially important.

B. Respiratory Regulation of Acid-Base Balance

The respiratory system controls extracellular fluid CO2 concentration by the lungs.
CO2 from metabolism diffuses into lungs, controlled breathing expels CO2 into atmosphere
CO2 combines with water, produces carbonic acid (H2CO3).
Exhaling CO2 reduces H2CO3 which reduces H+ concentration, thereby raising blood pH.
Increased or decreased breathing can offset acid-base imbalance.

B. Respiratory Regulation of Acid-Base Balance (Continued)

Chemoreceptors in the aorta and carotid arteries detect CO2 levels.
The brain's respiratory center adjusts breathing rate to maintain normal CO2 levels and pH..
The brain's pH can also affect breathing rate to regulate acid-base imbalance

C. Renal Regulation of Acid-Base Balance

The kidneys regulate extracellular fluid H+ concentration.
Kidneys can excrete either acidic or basic urine to control pH range between 4.5 and 8.0.
Kidney regulation of acid-base balance is accomplished by three fundamental mechanisms.

C. Renal Regulation of Acid-Base Balance (Continued)

Secretion of H+ ions into the urine
Reabsorption of filtered HCO3- from the urine back to the blood.
Production of new HCO3-.
Changes in ECF H+ can affect kidney function, like in alkalosis, failure to reabsorb bicarbonate leads to high H+ concentration. Acidic condition, the kidney does not excrete bicarbonate instead reabsorb all the filtered bicarbonate and produces new bicarbonate, which is added back to ECF, bringing H+ concentration back to normal.
Tubular segments differently reabsorb bicarbonate and secrete H+, about 80-90% of the process takes place in the proximal tubules, 10% in the thick ascending loop of henle and the rest in the collecting duct.
Filtered bicarbonate is not reabsorbed directly. Combining with secreted H+ makes CO2, which then combines with water. CO2 then converts back into bicarbonate which is reabsorbed into blood.

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Description

Explore the complexities of the urinary system in this quiz, focusing on the regulation of acid-base balance and its importance in maintaining homeostasis. Understand the roles of buffer systems, the respiratory center, and the kidneys in managing pH levels in the body.