Week 3 Flashcards
Upper tracts of respiratory system
Nose and nasal cavity
Pharynx
Larynx
Lower tracts of respiratory system
Trachea
Bronchial tubes
Alveoli
4 layers of trachea
Mucosa
Sub mucosa
Hyaline cartilage
Adventitia
Epithelium of primary secondary and tertiary bronchial tubes
Pseudostratified ciliated columnar epithelium with goblet
Epithelium of large bronchioles
Simple ciliated with some goblet
Small bronchioles
Simple ciliated with few goblet cells
Terminal bronchioles epithelium
Simple cuboidal
Structure of alveoli
Simple squamous epithelium (type I cells)
Alveolar wall and capillary wall form respiratory membrane (gases must diffuse across this)
Main premise of boyle’s law
If the volume of a gas is increased, its pressure decreases (and vice versa)
Mechanics of inflating lungs
To inflate lungs with external air, we must increase lung volume (boyle’s law) to reduce intrapulmonary/alveolar pressure.
Mechanics of exhalation
We must increase alveolar pressure by reducing lung volume. Once air pressure is lower than alveolar pressure, air is expelled from lungs
Structures that allow pulmonary ventilation
Rib cage
Diaphragm
External intercostals
Internal intercostals
Abdominals, obliques, scalenes, SCM
Muscles of Inhalation
Diaphragm
External Intercostals
Three different air pressures involved in breathing
Atmospheric
Alveolar
Intrapleural
Factors that effect pulmonary ventilation
Alveolar surface tension (pulls alveoli slightly inwards so must be overcome to expand their volume)
Lung Compliance( describes the ease of lung expansion - caused by the difference between intrapleural and alveolar pressure)
Airway Resistance (Resistance caused by walls of bronchial tubes- asthma and chronic bronchitis cause this)
4 categories of total lung volume
Residual volume
Tidal volume
Inspiratory reserve volume
Expiratory reserve volume
Residual Volume
Not all air expelled from lungs
Volume of air remaining in lungs after forced expiration
Tidal volume
Resting volume of air inhaled and exhaled
Represents air moved in one breath
Inspiratory Reserve Volume
Achieved during deep inhalation
Excess volume inhaled beyond normal tidal volumes
Expiratory reserve volume
Achieved during deep exhalation
Excess volume exhaled beyond normal tidal volume
Inspiratory Capacity
Inspiratory reserve volume + tidal
Maximum volume of air inhaled from normal
Functional Residual Capacity
Expiratory reserve volume + residual volume
Volume of air remaining in lungs after normal expiration
Vital Capacity
Inspiratory reserve volume + tidal volume + expiratory reserve volume
Maximum volume of air that can be inhaled/exhaled
Total lung capacity
Vital capacity+ residual volume
Partial Pressure
In a mixture of gases such as our atmospheric air, we can calculate the individual contribution to the total air pressure by a single gas.
Total air pressure is the sum of the partial pressures of all gases in a mixture
Partial Pressure in the Respiratory System
Partial pressure of oxygen must be higher in the alveoli compared to blood in the pulmonary capillaries (ensures oxygen diffuses into blood). Partial pressure of Co2 must be higher in the pulmonary capillary blood compared to alveoli.
Gas solubility
When a gas is in contact with a liquid, the dissolved gas is proportional to its partial pressure and solubility (Henry’s Law). A high PP and solubility will increase the amount of gas dissolved in solution.
Factors affecting oxyhaemoglobin saturation
Acidity
Carbon dioxide partial pressure
Temperature
Carbon dioxide methods of transportation
Bicarbonate ions (70%)
Carbamino compounds (23%)
Dissolved Co2- compounds (7%)
Where is PO2 highest in external respiration
Alveolar Air
Where is PCO2 highest in internal respiration
Tissue cell (45mmHg)
Vasoconstriction
Sympathetic nervous system activation
Epinephrine and norepinephrine
Hypertension
Vasodilation
Prostaglandins and histamines
ACE inhibitors
Sympathetic nervous system activation
the activation of the sympathetic nervous system enhances the respiratory system’s ability to meet increased demands for oxygen during stress or physical activity. It achieves this through mechanisms such as bronchodilation, increased respiratory rate, reduced mucous secretion, and improved airway patency.
Parasympathetic nervous system activation
parasympathetic nervous system activation generally results in bronchoconstriction, decreased respiratory rate, increased mucous secretion, and increased airway tone. These effects are aligned with the body’s needs during rest and relaxation, helping to maintain normal respiratory function and protect the airways.
