Acid/Base balance

Which ion are we looking at for acid/base balance?

hydrogen

neutral pH

7

physiologically normal pH

7.4

life is compatible between 6.8-8

Acidic Conditions

when the pH is lower than normal

Basic Conditions

when pH is higher than normal

What happens to the nervous system during acidosis?

results in depression of the central nervous system

patients are often disoriented, experience memory loss and dizziness, lose consciousness

What happens to the nervous system to alkalosis?

leads to overexcitability of the central nervous system

“Pins and needles” sensation, muscle cramping/spasm

Why are enzymes affected by pH?

denaturation can occur in high or low pH

Why are potassium ions impacted by pH and why does it matter?

K+ balance is closely related to the hydrogen balance

acidosis can cause high potassium levels→ this can disrupt cardiac function

What are the 3 main sources of hydrogen ions in the body?

carbonic acid formation- depends on presence of O2 in blood

inorganic acids produced during breakdown of nutrients- cellular respiration/metabolism

intermediary metabolism- breaks down the nutrients in food

What are the 3 main regulators of acidity in the body?

chemical buffer system- can take or give hydrogen ions depending on the solution they are in

respiratory pH control

renal pH control-tubular secretion of hydrogen ions in collecting ducts and distal tubules

What is a buffer system and how does it prevent wide wings in pH?

mixture in a solution of two chemical compounds that minimize pH changes when either an acid or base is added to or removed from the solution

minimizes changes in pH by binding with or yielding free H+

How do proteins act as buffers?

they contain both acidic and basic groups that can give up or take up H+

they are the most plentiful buffers of body fluids

Hemoglobin is the primary buffer system that protects against changes produced by what?

CO2

buffers the H+ generated from metabolically produced CO2 in transit between the tissues and the lungs

How do the lungs contribute to pH balance?

controls the rate of CO2 removal

second line of defense against changes in H+

What would happen to the lungs in the case of metabolic acidosis?

ventilation: increase

rate of CO2 removal: increase

rate of H+ generation from CO2: decrease

What would happen to the lungs in the case of metabolic alkalosis?

Ventilation: decrease

rate of CO2 removal: decrease

rate of H+ generation from CO2: increase

How do the kidneys contribute to pH balance?

by varying the extent of H+ secretion

mechanism of renal H+ secretion in the proximal tubule

they conserve or excrete HCO3-

Causes and Compensations of respiratory acidosis

causes: Arises from an increase in CO2, lung disease, depression of respiratory center by drugs or disease or holding one’s breath

compensations: kidneys are most important

Causes and Compensations of respiratory alkalosis

causes: Arises from a decrease in CO2, fever, anxiety, aspirin poisoning

compensations: chemical buffer systems liberate H+ to diminish the severity of the alkalosis

Cause and Compensations of metabolic acidosis

causes: associated with a fall in HCO3-, severe diarrhea, diabetes, strenuous exercise, uremic acidosis

compensations: by respiratory and renal mechanisms, chemical buffers

Causes and Compensations of metabolic alkalosis

causes: elevation in HCO3-, vomiting, ingestion of alkaline drugs

compensations: chemical buffer systems immediately liberate H+