Exam 5: Chapter 18 Flashcards
what is hypoxia?
low blood O2
what is hypercapnia?
high blood CO2
what is the equation representing CO2 conversion into bicarbonate ion?
CO2 + H2O = H+ + HCO3-
which has a higher pressure of O2, alveoli or pulmonary capillaries?
alveoli
(alveoli –> pul. cap.)
which has a higher pressure of CO2, alveoli or pulmonary capillaries?
pulmonary capillaries
(alveoli <– pul. cap.)
which has a higher pressure of O2, the cells or systemic capillaries?
systemic capillaries
(systemic capillaries –> cells)
which has a higher pressure of CO2, the cells or systemic capillaries?
cells
(systemic capillaries <– cells)
how does a higher altitude effect pressure gradients in the lungs?
atmospheric pressure is lower than normal
-pressure gradient in the lungs is less strong
-decreases diffusion
what is hypoventilation?
lower volumes of air entering the alveoli
what are three ways that hypoventilation can occur?
-decreased lung compliance
-increased resistance
-CNS depression (alcohol poisoning, drug overdose)
what happens to diffusion when the concentration gradient increases?
diffusion increases
what happens to diffusion when surface area increases?
diffusion increases
-emphysema (destroys alveoli)
what happens to diffusion when permeability increases?
diffusion increases
-fibrotic lung disease
what happens to diffusion when distance increases?
diffusion decreases
-pulmonary edema (fluid in lungs)
what happens to diffusion when resistance increases?
diffusion decreases
-asthma
which has better O2 solubility, the alveoli or capillaries?
alveoli
which is more soluble, CO2 or O2?
CO2
which has a higher partial pressure, RBC or cells?
cells
what in the RBC binds O2?
hemoglobin
-iron+O2 = oxyhemoglobin (HbO2)
-COOPERATIVE (changes shape so it can bind to other O2)
what happens to the Hb-O2 binding affinity when O2 increases?
increases Hb-O2 binding affinity
-Law of Mass Action: drive the unbinding too!
what happens to Hb-O2 binding affinity when plasma O2 partial pressure increases?
increases Hb-O2 binding affinity
what does the plasma O2 partial pressure determine?
the % saturation of Hb
what happens to O2 when Hb levels decrease?
decrease in O2 transported
what happens when the oxyhemoglobin curve shifts right?
decrease in Hb-O2 binding affinity
what happens to Hb-O2 binding affinity when temperature increases?
decreases Hb-O2 binding affinity
what happens to Hb-O2 binding affinity when CO2 levels increase?
decreases Hb-O2 binding affinity
what happens to Hb-O2 binding affinity when pH levels increase (basic)?
increases Hb-O2 binding affinity
-due to lesser amounts of CO2
what happens to Hb-O2 binding affinity when 2,3-BPG levels increase?
decreases Hb-O2 binding affinity
what is the process of O2 entering the body once it is in the alveoli?
- alveoli
- dissolved in plasma
- enters RBC and binds to Hb
- leaves RBC and dissolves in plasma
- enters cell
what are the three ways CO2 is transported?
- dissolved in plasma
- bound to Hb (carbaminohemoglobin)
- converted to bicarbonate (MAJORITY)
what is the process of CO2 getting converted to a bicarbonate in the RBC?
- converted using carbonic anhydrase in the RBC
- HCO3- exits RBC and goes into the plasma, Cl- goes into the RBC (antiporter)
- HCO3- goes back into the RBC and the rxn reverses back into CO2
- CO2 goes into the alveoli
- partial pressures push CO2 out of the body
what respiratory muscles are skeletal muscles?
internal and external intercostals
-can move voluntarily
what muscles does the medulla control?
both inspiratory and expiratory muscles
-contains the DRG, PRG, and VRG
what is the nucleus tractus solitarius (NTS)?
contains the dorsal respiratory group (DRG)
what is the dorsal respiratory group (DRG)?
controls muscles of inspiration
how does the DRG send its output?
through phrenic nerve (controls diaphragm) and intercostal nerves (controls intercostal muscles)
what is the pontine respiratory groups (PRG)?
help decides how quickly DRG neurons fire
-smooth rhythm
-located in the pons (depth of ventilation)
what is the ventral respiratory group (VRG)?
contains the pre-botzinger complex and other areas
what does the pre-botzinger complex do?
has pacemaker cells that control rhythm of respiration
-controls firing fate of PRG
what do the other areas in the VRG do?
controls active breathing muscles
controls expiration
what happens to ventilation with a low O2, high CO2, and low pH?
increase ventilation
-get rid of CO2
what happens to ventilation with a high O2, low CO2, and high pH?
decrease ventilation
-we need more CO2
what are peripheral chemoreceptors?
receptors that detect changes in O2, CO2, and pH
-located outside the CNS in the carotid and aortic arteries
what is the process of the peripheral receptors when O2 is low?
- low O2
- close K+ channels
- depolarization
- Ca2+ entry
- NT release
- brain
- increases ventilation
we need a large change in O2 to trigger this
what are central chemoreceptors?
receptors that detect changes in CO2 (pH)
what is the process of central chemoreceptors when CO2 is high?
- high CO2
- peripheral receptors
- BBB (blood brain barrier)
- CO2 -> HCO3-
- increases H+ (decrease pH)
- central chemoreceptors
- increase ventilation
what are some protective reflexes in the respiratory system?
-physical injury or irritation (constriction, sneezing, coughing)
-overinflation (Hering-Breuer Response)
what is the Hering-Breuer Response?
- increase in tidal volume (overinflation)
- activates mechanoreceptors (stretch)
- info sent to brain
- terminate inspiration
how does the cerebrum and hypothalamus control the respiratory system?
works through the brainstem
-breath rate & depth
-we have some voluntary control of this (breathing techniques)
how does the limbic system control the respiratory system?
emotions! (fear, excitement)
-bypasses brainstem!!!
do we always have voluntary control of our respiratory system?
NO!
-eventually the medulla’s chemoreceptors take over
“you can only hold your breath for so long”
