Respiratory drive Flashcards
What is blood PH controlled by
H+ concentration
What is a normal Ph concentration
7.35-7.45
What is the result of too much H+
acidosis
How much CO2 do we produce each minute
200mL/min
Where does carbon dioxide come from
H2CO3 (waste product of cellular metabolism)
What is normal PaCO2
40mmHg
How much more soluble is CO2 than O2
20x more soluble
What does it mean for something to be a weak acid
more easily dissociates
What are the main determents of PH in the body
carbonic acid and pCO2
What is bicarbonate controlled by
the kidneys
What is a normal Bicarb level
22-26 mEq/L
What is hypoxia
low O2 in the peripheral tissue
What can cause hypoxia
increased O2 demand
Decreased Hgb carrying capacity
Decreased ability of O2 to reach specific tissue
What things are considered voluntary breathing
talking
singing
laughing
breath holding
Where are chemoreceptors located
centrally within the medulla
Where are O2 receptors located
in the periphery
Where are CO2 receptors located
periphery and centrally
What is hypercapnia
CO2 increases
pH becomes more acidic
What is hypocapnnia
CO2 drops
pH becomes alkalotic
What are the main chemoreceptors
O2
CO2
What do central chemoreceptors detect
pH of CSF
What can cause the chemoreceptors to become less sensitive
With chronic hypoxia (COPD)
At what level does are body care about the O2 level
PaO2<60mmHg
What are the respiratory centers within the brainstem
pneumotaxic center (pons)
Apneustic (pons)
Dorsal and ventral resp. group (Medulla)
What can trigger involuntary breathing
Pain
Emotion
disease
What does the pneumotaxic center do
modify breathing rhythm that is set forth by the dorsal and ventral respiratory groups
What helps with inspiration / expiration transition
pneumotaxic center
What does the Apneustic center do
Modify breathing rhythm that is set forth by the dorsal and ventral respiratory groups
Input from stretch receptors
primarily involved with inspiration
What does the dorsal respiratory group do
primary control of respiratory drive
Where things trigger the dorsal respiratory group
lungs
carotid
neural
(Chemical, mechanical, neuro)
*Drop in pH and PaCO2
What structure signals the calm breathing muscles to begin expiration
Dorsal respiratory group
What are the calm breathing muscles
diaphragm
external intercostals
When is the ventral respiratory group activated
times of increased effort
What group is the breathing pacemakers
ventral respiratory group
What hormone stimulates ventral respiratory group
dopamine
What stimulates the VRG to increase frequency of ventilation
DRG
How do the carotid chemoreceptors send respiratory stimuli to the medulla
glossopharyngeal nerve
How will aortic chemoreceptors send respiratory stimuli to the medulla
the vagus nerve
What do the lung receptors do
send AFFERENT stimuli to the dorsal respiratory group
When do the irritant receptors react
to noxious stimuli
Where are irritant receptors found and how do they work
conducting airway epithelium
trigger cough reflex
cause bronchoconstriction
What do stretch receptors do
assist with ventilatory rate/volume as the smooth muscle sense/react to over inflation/deflation
Who are the lung receptors most important in
babies and exercising results
What is the herring Breuer reflex
Stopping of inspiration
What do J receptors do
sense pulmonary capillary pressure
*Rapid shallow breathing
Which nervous system determines the diameter of the airway
ANS
What does the parasympathetic system do to the airways
constriction
What does the sympathetic system do to the airway
relaxation
What happens if a patient has a depressed CNS
pH will decrease because we are retaining CO2
What happens if a patient has anxiety
pH will increase because we are breathing off more CO2
What happens if a person has a neuromuscular disorder
pH will decrease because we are retaining CO2
What happens if a patient has diabetic ketoacidosis
pH decrease ill trigger respiratory center to breath faster/harder to breathe of CO2 to buffer the pH and bring pH closer to normal
what is FiO2
The amount of oxygen someone is receiving through different devices (%)
How much oxygen is in sea level / room air
21%
What is the partial pressure of oxygen
pressure exerted by a gas within the confined container
What is the PaO2 in the pulmonary artery
40mmHg
What is the PaO2 of the pulmonary vein
100mmHg
What is SaO2
percentage of hemoglobin sites bound to O2
How much oxygen can hemoglobin carry
4 O2 molecules
What is responsible for changing the Hgb form to open the overall configuration for O2 to bind
oxyhemoglobin
What is the most powerful respiratory stimuli
partial pressure O2 (especially <60mmHg)
What factors effect PaO2
Barometric pressure (760mmHg)
FiO2
How well ventilation occurs
humidity
What is an ABG the gold standard for evaluating
acid-base balance
oxygenation
ventilation
What are the indications for an ABG
Critically ill
respiratory conditions
metabolic disorders
What is an ABG sensitive to
Time (analyze ASAP)
Temp (Ice after draw)
What does the ABG tell us
pH
PO2
PCO2
HCO3
SaO2
degree of excess/deficit of base in blood
How do you calculate the anion gap
BMP/CMP
What are alternatives to an ABG
Venous blood gas
End-tidal CO2/capnography
What info do you get with a VBG
pH
HCO3 concentration
Why is pH control important
to maintain integrity of cells and enzymatic function
