More lecture 9 qs Flashcards
Which two things assist in decreased vascular resistance with increased cardiac output?
Capillary recruitment and capillary distention
What is the primary reason for the fall in resistance with increased CO?
Capillary recruitment
Pleural pressure is more positive at what lung volume, high or low?
Low
What causes pulmonary vasoconstriction, high or low oxygen tension? What can this cause?
Low oxygen tension; hypoxia-induced pulmonary vasoconstriction
How does a negative pleural pressure affect vascular resistance?
High vascular resistance
Hypoxia-induced pulmonary vasoconstriction is characterized by what being high and what being low?
High CO2 and low blood pH
Generalized hypoxia is most likely seen with what?
Lung disease
Regional hypoxia is most likely seen with what?
Blood clots
An increase in alveolar ______ enhances filtration.
surface tension
What occurs when capillary filtration exceeds fluid removal?
Pulmonary edema
Hypoxia causes what in the pulmonary system?
Vasoconstriction
Where is ventilation the highest in the lungs?
Apex
An anatomic shunt or low regional ventilation/perfusion ratio are both causes of what?
Wasted blood
What is the main control of the respiratory center that sends impulses to the phrenic nerve and intercostal nerves?
Medulla
What keeps the alveoli dry?
Low pulmonary capillary hydrostatic pressure
Alveolar ____________________ enhances filtration
Alveolar ____________________ opposes filtration
surface tension; pressure
What pressure enhances filtration? (in the lungs)
Hydrostatic
What are the muscles of inspiration?
Diaphragm and intercostals
Mechanoreceptors (irritant, stretch, J receptors) send info where? Through what nerve?
Medulla and pons; vagus
The main control of the respiratory center is what?
Medulla
What muscles assist in the active expiration process?
Abdominal
What stimulates accessory muscle use and aids in forced breathing?
VRG
What stops the DRG from firing allowing for relaxation?
Pneumotaxic centers
What controls the depth on inspiration?
Apneustic centers
What is also called the inspiratory area?
DRG
Which receptor is the slowest?
J receptors/ Juxtapulmonary
Where do pulmonary stretch receptors fire to?
Medulla
How does the Hering-Breuer Reflex affect heart rate?
Stimulates heart rate to increase
What receptors are involved in the Hering-Breuer Reflex?
Pulmonary stretch receptors
Which receptors are rapidly adapting?
Irritant
What leads to severe bronchoconstriction in asthmatics?
Histamine stimulation of irritant receptors
What receptors line the respiratory epithelium?
Irritant
What receptors are located both within and outside of the lung?
Stretch
When are pulmonary J receptors stimulated? What do they then do?
When fluid volume increases, they stimulate increased respiratory rate
What innervates J receptors?
CNX
What receptors are adjacent to the alveoli and pulmonary capillaries?
Pulmonary J receptors
What two things can activate J receptors?
1) Physical engorgement of the pulmonary capillaries
2) Increased pulmonary interstitial volume
What modify the rate and rhythm of respiration maintained by the medulla?
Chemoreceptors
What is the most important factor for chemoreceptors?
PCO2
A high concentration of what is toxic to cells?
CO2
Where are central chemoreceptors?
Brain and brainstem
What happens to minute ventilation as PCO2 increases?
It increases
Where are peripheral chemoreceptors located?
Aortic arch and carotid arteries
What is the blood brain barrier permeable to?
CO2
List 2 things that the BBB is not permeable to
H+ and HCO3
What can influence the pH of CSF?
Blood PCO2
What does low CSF pH stimulate?
Respiratory centers in the medulla
What muscles are involved in hyperventilation?
Diaphragm and ICMs
Both increased and decreased PCO2 lead to what?
Firing of the peripheral chemoreceptors
True or false? Changes in tidal volume during slow wave sleep is called cheyne-stokes breathing.
True
What 3 things occur during stimulation of the VRG and DRG during exercise?
1) Increased ventilation
2) Increased RR
3) Increased depth
What falls and what rises during slow wave sleep?
Minute ventilation falls, PaCO2 rises (small amount)
How much of the body’s energy expenditure is used for breathing normally?
3%
What can pulmonary fibrosis cause?
Decreased pulmonary compliance
What condition increases airway resistance?
COPD
What condition decreases elastic recoil?
Emphysema
What causes increased work to be needed to establish pressure gradients?
Increased airway resistance (like COPD)
What causes more work to be required for increased depth and rate of breathing?
Need for increased ventilation (like exercise)
1) What causes more work to expand the lungs?
2) What causes more work to empty the lungs?
1) Decreased pulmonary compliance
2) Decreased elastic recoil
