Acid Base Balance I Flashcards
What is the effect on pH if hydrogen ion concentration increases
pH decreases
What is the pH of arterial blood
7.45
What is the pH of venous blood
7.35
What is pH sensitive
ion channel function
Why is potassium regulated within narrow limits
regulate the excitability of cells and membrane potential
What is affected by fluctuations in H+ levels
enzyme activities, potassium levels, excitability of muscle and nerves
Name an alkali pH value in the body
pancreatic secretions
Name an acidic pH value in the body
gastric secretions
What does metabolism generate
carbon dioxide
What is the pH of carbon dioxide
acidic
break down of what…. can generate hydrogen ions
proteins
What systems are involved with acid base balance
blood and tissue buffers, respiration, and renal
Which system is the fastest to react
blood and tissue buffers
Which system is the only mechanism for extrusion of acid/alkali
renal system
How does the respiratory system help with acid base balance
changes CO2 levels in the body
Where are buffers for acid base balance present
blood, extracellular fluid, intracellular fluid, urine
Name some examples of buffers
haemoglobin, bicarbonate, inorganic phosphate
What is the most important buffer
bicarbonate
What diseases might cause respiratory acidosis
asthma attack, emphysema and COPD
What happens when there is too much carbon dioxide in the body
pH becomes more acidic, bicarbonate concentration is high
Describe the pH and bicarbonate in respiratory acidosis
acidic pH, high bicarbonate concentration
What are the pH and bicarbonate levels in respiratory alkalosis
alkaline pH, low bicarbonate concentration
Under what circumstances would you have respiratory alkalosis
panic attacks or hyperventilation
What are the pH and bicarbonate levels in metabolic acidosis
acidic pH and low bicarbonate levels
What causes metabolic alkalosis
excess bicarbonate
what are the pH and bicarbonate levels is metabolic alkalosis
high pH and high bicarbonate levels
What is hypoxia
low partial pressure of oxygen
What is hypercapnia
high partial pressure of carbon dioxide
What is acidosis
acidic pH
What do chemoreceptors control
breathing
What is the function of chemoreceptors
detect and control blood gas composition
What do chemoreceptors keep constant
partial pressure of oxygen, carbon dioxide and pH
What are the two types of chemoreceptors
peripheral and central
What type of system are chemoreceptors involved in
negative
What do hypoxia, hypercapnia and acidosis all increase
ventilation
What does increased ventilation in response to hypoxia , hypercapnia and acidosis cause
increased partial pressure of oxygen, decreased partial pressure of oxygen, increased pH
Where are peripheral chemoreceptors found
carotid and aortic bodies
What is the main stimulus for peripheral chemoreceptors
fall in partial pressure of oxygen - hypoxia
Which chemoreceptors are discrete and specific
peripheral chemoreceptors
What nerves do peripheral chemoreceptors send signals via
sinus, vagus and glossopharyngeal nerves
What is the receptor cell type in peripheral chemoreceptors
Glomus cell
What is anoxic condition
no oxygen
What happens when Glomus cells go into anoxic condition
gradual depolarisation of membrane potential, action potentials, activation of nerves
What supports the glomus cells
type II cells
What do glomus cells detect
oxygen
What is the phenotype of Glomus cells
neuronal
True or False - peripheral chemoreceptors have high blood flow rate and high metabolic rate
TRUE
Where are glomus cells present
carotid bodies
What can adjust the sensitivity of glomus cells
carbon dioxide and pH
What is the effect of increasing oxygen on glomus cell firing
decreases action potential firing
