Urinary System Chapter 5

A chemical system that resists changes in pH by absorbing or releasing hydrogen ions (H+).

The kidneys play a crucial role in regulating acid-base balance by removing hydrogen ions (H+) from the body and generating bicarbonate ions (HCO3-) to maintain blood pH within a normal range.

A major protein buffer found in red blood cells that helps maintain blood pH by absorbing excess hydrogen ions (H+).

The phosphate buffer system involves two forms of phosphate: dihydrogen phosphate (weak acid) and monohydrogen phosphate (weak base). The system helps maintain blood pH by absorbing or releasing hydrogen ions (H+), depending on whether a strong acid or a strong base is present.

The bicarbonate buffer system is crucial for maintaining pH in the extracellular fluid (ECF). It involves a weak acid (carbonic acid) and its conjugate base (bicarbonate). This system absorbs or donates hydrogen ions (H+) to maintain blood pH.

Increased hydrogen ion concentration (H+) in the blood, making it more acidic.

Decreased hydrogen ion concentration (H+) in the blood, making it more alkaline.

The process of maintaining a stable pH within the body fluids.

The measure of hydrogen ion concentration in a solution. A low pH indicates a high concentration of hydrogen ions (acidosis), while a high pH indicates a low concentration of hydrogen ions (alkalosis).

A buffer system that primarily involves proteins, which can act as both acids and bases to absorb or release hydrogen ions.

The process by which the respiratory system, primarily the lungs, helps regulate acid-base balance by adjusting the rate and depth of breathing to control carbon dioxide (CO2) levels in the blood.

A system that helps maintain stable blood pH levels, primarily by neutralizing acidic substances. It uses bicarbonate ions to buffer the acidity of metabolic wastes like lactic acid and ketone bodies.

A weak acid that's constantly produced in the body by metabolic activities, particularly cell respiration.

An ion that helps balance the pH levels in the blood. The bicarbonate-carbonic acid system relies heavily on this ion to buffer acidity.

The process by which the lungs remove CO2 (carbon dioxide) from the body, which helps regulate blood pH.

The chemical reaction where CO2 reacts with water to form carbonic acid.

Carbon dioxide (CO2) is a byproduct of metabolism that directly influences blood pH.

Hyperventilation removes CO2 from the blood, reducing carbonic acid (H2CO3) levels, making the blood more alkaline. This temporary alkalosis can be reversed by rebreathing exhaled air, which has a higher CO2 concentration, bringing blood pH back to normal.

Chemoreceptors, primarily sensitive to CO2 levels, are located in the walls of the aorta and carotid arteries. These sensors signal the brain to adjust the respiratory rate when CO2 levels change.

The medulla oblongata, a brain structure, contains chemoreceptors that detect changes in CSF pH. These receptors directly influence breathing rate to restore normal pH levels.

The kidneys regulate acid-base balance by excreting acidic or basic urine, with a normal pH range of 4.5 to 8.0. They maintain acid-base balance through three mechanisms: secretion of H+ ions, reabsorption of bicarbonate, and production of new bicarbonate.

In alkalosis, the kidneys fail to reabsorb all filtered bicarbonate, resulting in increased bicarbonate excretion, which effectively adds H+ to the extracellular fluid (ECF), bringing the pH back down.

In acidosis, the kidneys reabsorb all filtered bicarbonate and produce new bicarbonate, adding it to ECF and lowering ECF H+ concentration, bringing the pH back up.

For every bicarbonate ion reabsorbed by the kidneys, an H+ ion must be secreted. The proximal tubule is responsible for the majority (80-90%) of bicarbonate reabsorption and H+ secretion.

The descending and ascending thin limbs of the loop of Henle do not participate in bicarbonate reabsorption or H+ secretion.

The process where filtered bicarbonate ions react with secreted hydrogen ions (H+) forming carbonic acid (H2CO3), which then decomposes into CO2 and H2O.

CO2 easily diffuses across the tubular membrane, enters the tubular cell, and reacts with H2O under the influence of carbonic anhydrase generating a new H2CO3 molecule. This H2CO3 then breaks down into HCO3- and H+. The HCO3- diffuses through the basolateral membrane into the interstitial fluid, eventually entering the peritubular capillaries.

Two main mechanisms facilitate the movement of HCO3- across the basolateral membrane: 1. Sodium-bicarbonate co-transport, where sodium ions (Na+) and bicarbonate ions (HCO3-) are transported together, and 2. Chloride-bicarbonate exchange, where bicarbonate ions (HCO3-) swap places with chloride ions (Cl-).

The kidneys play a crucial role in maintaining acid-base balance by reabsorbing filtered bicarbonate in the proximal tubules and generating new bicarbonate in the distal tubules. Simultaneously, the kidneys secrete hydrogen ions (H+) into the urine.

The lungs, kidneys, and erythrocytes all work together to maintain the acid-base balance in the body, ensuring the pH stays within a narrow and healthy range.

The lungs are responsible for the exchange of gases between the body and the atmosphere. Carbon dioxide (CO2) generated by the body is transported in the blood as bicarbonate (HCO3-)

Hemoglobin, a protein found in red blood cells, contributes to CO2 transport. Hemoglobin also acts as a buffer, absorbing excess hydrogen ions (H+) released from carbonic acid (H2CO3).

The partial pressure of carbon dioxide (PCO2) measures the amount of CO2 in arterial or venous blood, providing an indication of the blood's acid-base status.