Exam Four - Pulmonary 3 Flashcards
hypoxia
too little oxygen
hypercapnea
increased concentration of co2
to avoid hypoxia and hypercapnia, the body responds to these 3 regulated variables…
o2, co2, pH
hypoxic hypoxia
low arterial P02
anemic hypoxia
decreased total amount of O2 bound to hemoglobin
ischemic hypoxia
reduced blood flow
histotoxic hypoxia
failure of cells to use o2 because cells have been poisoned
normal arterial and venous level of o2
95a, 40v
normal arterial and venous level of co2
40a, 46v
normal arterial and venous level of pH
7.4a, 7.37v
breathing is ___ of air into and out of the lungs
bulk flow
low alveolar PO2 ___ oxygen uptake
decreases
t or f. low alveolar po2 if inspired air has abnormally low oxygen content
true, higher altitude decreases PO2
low alveolar po2 if alveolar ventilation is inadequate
hypoventilation,
hypoventilation can be caused by:
- decreased lung compliance
- increased airway resistance
- CNS depression
diffusion rate is related to
surface area x concentration gradient x barrier permeability
1/distance^2
what are 3 pathological changes that adversely affect gas exchange
- surface area (emphysema)
- diffusion barrier permeability (fibrotic lung disease)
- diffusion distance (edmea)
what are the acronyms we use for symptoms of hypoxia
early rat
late to bed
(peds use FINES)
emphysema
destruction of alveoli means less surface area for gas exchange
fibrotic lung disease
thickened alveolar membrane slows gas exchange. loss of lung compliance may decrease alveolar ventilation
pulmonary edema
fluid in interstitial space increases diffusion distance. arterial Pco2 may be normal due to higher co2 solubility in water
asthma
increased airway resistance decreases alveolar ventilation
movement of gases is directly proportional to
- pressure gradient of the gas
- solubility of the gas in liquid
- temperature
with temperature constant, the amount of gas that dissolves in a liquid depends on…
the solubility of the gas and the partial pressure of the gas
fick equation can be used to
estimate oxygen consumption
what is the fick equation
oxygen consumption (Qo2) = CO x (arterial o2 - venous o2)
oxygen binding obeys the law of mass action, so what happens if you increase oxygen
shift to the right
Hb + o2 -> HbO2
oxygen binding obeys the law of mass action, so what happens if you decrease oxygen
shift to the left
Hb + o2 <- HbO2
if you are at rest, will most of your oxygen be bound to hemoglobin or unbound?
bound
if you are exercising vigorously, will most of your oxygen be bound to hemoglobin or unbound
unbound
true or false, hemoglobin increases oxygen transport
true
What factors influence oxygens ability to bind to hemoglobin
pH, temperature, Pco2
if pH decreases, temp increases, and concentration of co2 increases, will you have an increase or decreased affinity of O2 to hemoglobin?
decreased, more O2 is released and represents and increase in metabolic activity
2,3-BPG shifts saturation curve to the _____
right (chronic hypoxia increased RBC production of 2,3-BPG)
true or false, fetal hemoglobin grabs O2 and holds onto it easier
true
carbon dioxide is transported in these 3 ways
- dissolved in plasma (7%)
- bound to hemoglobin (23%)
- converted to HCO3 (70%)
neural networks in the brain stem behave like a _______
central pattern generator
respiratory neurons in the ________ control inspiratory and expiratory muscles
medulla
neurons in the ___ integrate sensory info and interact with medullary neurons to influence ______
pons, ventilation
rhythmic pattern of breathing arises from a neural network of _________
spontaneously dischargin neurons
t or f? ventilation is subject to continuous modulation by chemoreceptor and mechanoreceptor linked reflexes and higher brain centers
true
What are the 3 groups of neurons in the medulla that control breathing?
- dorsal respiratory group
- pontine respiratory group
- ventral respiratory group
dorsal respiratory group is located in the _______ and controls _______
Nucleus tractus solitaries (NTS), muscles of inspiration (diaphragm)
pontine respiratory group is the…
integrating center for sensory afferents
ventral respiratory group (VRG) is important for
basic pacemaker activity, active expiration and greater than normal inspiration
medullary chemoreceptors monitor
co2
peripheral chemoreceptors are located in the __________, use specialized ______ cells. O2 must fall below _____ to trigger reflex
carotid bodies
glomus
60 mmhg
decreased po2, increased hydrogen ions and increased pco2 initiates ___ in ventilation
increase
central chemoreceptors are located in ______, respond to changes in _________ by detecting
CNS/medulla
PCO2
hydrogen ion concentration
central chemoreceptors monitor CO2 in the
CSF
hering - breuer inflation reflex
stops you from breathing in so much that you pop your lungs
t or f, limbic system can affect breath rate and depth
true (emotion)
t or f, you cannot override chemoreceptor reflex
true
