Physiology Review Flashcards
Where in the brain is CO2 O2 and pH of arterial blood sensed?
Respiratory centers in the medulla
How is the metabolic demand of the body sensed by the peripheral chemoreceptors?
CO2, O2 and pH
Peripheral chemoreceptors send information along which nerve to the medulla for integration?
CN IX and X
What do the central chemoreceptors detect? Where does this send signals to?
pCO2
What is the respiratory center in the brain called? What does this do?
Central pattern generator
Generates spontaneous rhythmic discharge to keep the diaphragm functioning at a reasonable rate based on metabolic demands
What nerves does the central pattern generator send efferent signals to, to affect the respiratory muscles?
7 9 10 11 12
Where in the breathing control mechanism can the higher CNS exerts effects? Along what tracts does it send signals?
At the level of the spinal cord (bypasses the central pattern generator)
corticospinal tract
Along which tract does the ANS send signals to the diaphragm?
White matter of the spinal cord
The diaphragm sends afferent signals to the brain via which nerve?
CN X
What are the smallest airways that do not have alveoli?
Terminal bronchioles
Where does the majority of the resistance to airflow come from? Why?
The bronchus and the bronchioles
This is where smooth muscle is
What are the three major histological areas that comprise the conducting airways?
Inner mucosal surface
Smooth muscle layer
Outer connective tissue layer (cartilage)
Where is the airways is cartilage found?
Main bronchi
What type of epithelium covers the bronchial wall?
Ciliated pseudostratified epithelium
What are the main components of the bronchial wall?
Epithelium Smooth muscle cells Mucus glands CT Cartilage
What are the main components of the smaller bronchial walls?
Simple cuboidal epithelium
No cartilage
Is there cartilage in the bronchioles?
No
What are the four major obstructive lung diseases?
- Inflammation (bronchitis)
- Increased secretion (Asthma)
- Constriction of the smooth muscles
- Physical blockade (tumors)
What is the equation for the resistance to airflow?
R = {8nl / pi(r)^4 | n = viscosity of inspired air, l = length of airway, r = radius of the airway}
What happens with M3 activation in the lungs?
SM constriction
What happens with Beta 2 activation in the lungs?
SM relaxation
What is the most influential factor that controls resistance to airflow?
radius of the bronchiole
What are the three conditions that result in obstruction from the airway wall?
Asthma
Acute and chronic bronchitis
What is the pulmonary disorder that results in obstruction of the airway d/t a loss of lung parenchyma?
COPD
What are the pulmonary disorders that result in obstruction of the airway due to an obstruction in the airway lumen? (5)
bronchiectasis Bronchiolitis CF Epiglottitis Croup
Where does respiration take place?
At the respiratory unit
What comprises the respiratory unit?
Respiratory bronchiole
Alveolar ducts
Atria
Alveoli
What describes the capillary flow around the alveoli?
“sheet of flow”
What comprises the respiratory membrane?
The cell membrane between type I alveolar cells and the capillary bed
True or false: Like the tight junctions between endothelial cells, the junctions between endothelial cells are tight, not allowing much to pass through them
False–Unlike the tight junctions
between adjacent epithelial cells, which constitute a tight seal, the junctions between endothelial cells are leaky, allowing water and solutes to move back and forth between plasma and the interstitial space, the region between epithelial and endothelial basement membranes.
What are the components of the respiratory membrane?
- Surfactant
- Alveolar epithelium
- Epithelial BM
- Interstitial space
- Capillary basement membrane
- Capillary endothelial membrane
What is contained within the interstitial space in the respiratory membrane
Elastin and collagen (fibroblasts)
SM
Lymphatics
Capillaries
What is Goodpasture syndrome?
Autoimmune attack against type IV collagen in the kidneys and lungs, resulting in failure
What are the two major ways that pulmonary edema can result?
Damage to the respiratory membrane, or increased hydrostatic pressure in the capillaries
What happens with an increased deposition of collagen in the respiratory interstitial space?
harder to expand
What is the equation that relates to diffusion of gas across the respiratory membrane?
(dP)(A)(S) / d (MW)^0.5
A = surface area S = solubility of gas d = distance between two sides of the membrane
What are the factors that you can change clinically to alter the diffusion of gas across the respiratory membrane?
dP
What happens to dP in restrictive lung diseases?
Decreases
What are the factors that can affect d in the diffusion equation?
Pneumonia
Pulmonary edema
Which is more soluble in blood: CO2 or O2? What is the significance of this?
CO2
Needs a smaller partial pressure to enter the blood than oxygen does
What are the two major factors mentioned in class that can alter the surface area of the respiratory membrane?
Atelectasis
Tumor
What allows for the smooth movement between the visceral and parietal pleura?
1 mL of fluid
Which has stomata, the visceral or parietal pleura? What is the function of these?
parietal pleura
Serve as exit points for the pleural liquid, protein, and cells from the pleural space, to the lymphatics
What happens to the pleural capillaries in the visceral pleura during CHF? What does this cause?
Increased hydrostatic pressure
Causes a pleural effusion
What is the blood supply to the visceral pleura?
Bronchial circulation with venous return via the sub visceral pleural cavities
What is the blood supply to the parietal pleura?
branches of the intercostal arteries, with venous return via the bronchial veins
True or false: normally, there is a steady and balanced influx and efflux of fluid into the parietal space
True
What is the only significant barrier to solute and water exchange in the pleural space?
Pleural interstitium