Unit 2 Exam (Respiratory) Flashcards
Pulmonary ventilation
Moving air into and out of the lungs
External respiration
Gas exchange between the lungs and the blood
Transport
Transport of oxygen and carbon dioxide between the lungs and tissues
Internal respiration
Gas exchange between systemic blood vessels and tissues
What is included in the respiratory zone?
Bronchioles, alveolar ducts, alveoli
What is included in the conducting zone?
All other structures (nose, nasal cavity, pharynx, trachea)
Air passages undergo ____ orders of branching in the lungs
23
Parietal pleura
Covers the thoracic wall and superior face of the diaphragm, continues around heart and between lungs
Visceral pleura
Covers the external lung surface
Are the two pleura physically connected to one another?
NO
What surrounds alveoli?
Fine elastic fibers
Air-blood barrier
Respiratory membrane (Alveolar and capillary walls) with fused basal laminas
Alveolar walls are made up of…
single layer of type I epithelial cells (90%)
What do the alveolar walls secrete?
Surfactant
Purpose of surfactant
To reduce surface tension and prevent alveoli from sticking together
Atmospheric pressure
Weight of the air outside the lungs = 760 mmHg at sea level
Intrapulmonary pressure
Pressure within the alveoli (or inside the lungs)
Intrapleural pressure
Pressure within the pleural space (creates a slight vacuum; NEGATIVE)
Transpulmonary pressure
Difference between intrapulmonary and intrapleural, keeps lungs from collapsing
Two forces trying to pull the lungs away from the thoracic wall
Elasticity and surface tension
Good surface tension
Between pleura
Bad surface tension
In the alveoli
Clinical name for lung collapse
Atelectasis
Boyle’s law
P=1/v (volume increases, pressure decreases and vice versa)
Three main factors of airway resistance
Diameter of the bronchioles, lung compliance, surface tension of alveoli
Lung compliance
The ease with which lungs can be expanded
Tidal volume
Air that moves into and out of the lungs with each breath (about 500 ml)
Inspiratory reserve volume (IRV)
Air that can be inspired forcibly beyond the tital volume (2100-3200 ml)
Expiratory reserve volume (ERV)
Air that can be evacuated from the lungs after a tidal expiration (1000-1200 ml)
Residual volume
Air left in the lungs after strenuous expiration (1200 ml)
Obstructive pulmonary disease
Increased airway resistance
Restrictive disorders
Reduction in the total lung capacity from structural or functional lung changes
Anatomical dead space
Volume of the conducting respiratory passages (150 ml)
Alveolar dead space
Alveoli that cease to act in gas exchange due to collapse or obstruction
Minute ventilation rate (MVR)
Measures the TOTAL amount of air flowing into or out of the respiratory tract in 1 minute
Alveolar ventilation rate (AVR)
Frequency x (TV-dead space) in ml/min
Factors influencing gas exchange
partial pressure gradients and gas solubilities, ventilation-perfusion coupling, structural characteristics of respiratory membrane
Dalton’s law of partial pressure
Separate contribution of each gas in a mixture
Henry’s law
A gas in contact with a liquid will dissolve in that liquid in proportion to its partial pressure
Bohr effect
Declining pH (acidosis) weakens the hemoglobin-oxygen bond
Three forms that can transport CO2
Dissolved in plasma (7-10%), chemically bound to open spot on hemoglobin (20%), bicarbonate ion in plasma (70%)
Chloride shift
To counterbalance outrush of bicarbonate ions from RBCs, chloride ions rush in from the plasma into the cytoplasm to ensure charge remains constant!
Ventral respiratory group (VRG)
Modulator
Dorsal respiratory group (DRG)
Sets base rate
Pontine respiratory group (PRG)
Adapts breathing to special situations (eg. crying, sleeping, speaking, etc.)
Formula for MVR
tidal volume x respiratory rate
