Fluid-homeostasis and acid-base balances fully solved 2023/2024

Fluid-homeostasis and acid-base balances protein buffer system - correct answer most abundant buffer in body cells and plasma as the protein molecule functions are both a weak acid and a weak base • The weak acids in the carboxylic groups counteract rising pH • The weak bases in the amino groups counteract falling pH most important protein buffer - correct answer is hemoglobin • Carbon dioxide from the tissues diffuses into the erythrocyte and combines with water to form carbonic acid • Carbonic acid then dissociates into bicarbonate and hydrogen ions • The bicarbonate diffuses into the blood and is replaced by chloride ions (chloride shift) • The hydrogen ions are buffered by hemoglobin molecules (Bohr effect) which helps facilitate oxygen to be released at the tissues and reduces hemoglobin Most important buffer for maintain acid-base balance - correct answer in the blood is the bicarbonate-carbonic acid buffer system • Bicarbonate ions (HCO3 - ) acts as a weak base • Carbonic acid (H2CO3) acts as a weak acid Bicarbonate ions and carbonic acid are present in the blood - correct answer in a 20:1 ratio if the blood pH is within the normal range • With 20 times more bicarbonate than carbonic acid, this capture system is most efficient at buffering changes that would make the blood more acidic This is useful because most of the body's metabolic wastes are acids the respiratory system contributes to the balance of acid-bases - correct answer -in the body by regulating the blood levels of carbonic acid: How does the respiratory system regulate carbonic acid? - correct answer • CO2 in the blood readily reacts with water to form carbonic acid, and the levels of CO2 and carbonic acid in the blood are in equilibrium • When the CO2 level in the blood rises (as it does when you hold your breath), the excess CO2 reacts with water to form additional carbonic acid, lowering blood pH • Increasing the rate and/or depth of respiration allows you to exhale more CO2 reducing blood levels of carbonic acid and adjusts the pH upward increasing breathing - correct answer at rest to leads to a decrease in CO2 (and H+) causing a temporary increase in blood pH Decreasing breathing at rest leads to an increase in CO2 (and H+) causing a temporary decrease in blood pH renal regulation of the body's acid-base balance - correct answer addresses the metabolic component of the buffering system by controlling the blood levels of bicarbonate Even though, bicarbonate ions are essential for buffering pH in our blood the cells of the tubule are not permeable to bicarbonate ions • Instead we transport it as water and CO2 into the cells along the collecting duct which reformed into carbonic acid, which dissociates into bicarbonate and H+, and the new bicarbonate can be transported into the blood arterial blood pH - correct answer is typically restricted to a very narrow range of 7.35 to 7.45 person who has a blood pH below 7.35 - correct answer is considered to be in acidosis (actually, "physiological acidosis," because blood is not truly acidic until its pH drops below 7), and a continuous blood pH below 7.0 can be fatal person who has a blood pH above 7.45 - correct answer is considered to be in alkalosis, and a pH above 7.8 is fatal major effect from acidosis - correct answer is a depression of the central nervous system and has several symptoms, including headache and confusion, and the individual can become lethargic and easily fatigued In contrast the major effect of alkalosis is an over-excitability of the central and peripheral nervous systems and has symptoms including cognitive impairment (which can progress to unconsciousness), tingling or numbness in the extremities, muscle twitching and spasm, and nausea and vomiting