Respiratory System Flashcards
Resp System primary function
Gas exchange
- provide O2 for metabolism in the tissue
- remove CO2, the waste product of metabolism
3 step process of Resp System
Ventilation
- mechanical movement of air in and out of lungs
Diffusion
- move gas between lung and blood
Perfusion
- move blood from lung capillary to tissues
Chest wall and pleura
Visceral pleura
- membrane covers the lungs
Parietal pleura
- membrane lines the thoracic cavity
Pleural space
- between visceral and parietal pleurae
- contains lubricating fluid for membranes to slide against each other
- negative pressure
Bronchi
Have epithelial lining
Exocrine glands
- goblet cells: produce mucus
- ciliated cells: move secretions toward pharynx
Alveoli
Functional unit of the lung
Exchange of CO2 and O2
- epithelial cells: provide structure and surfactant
- surfactant: lipoprotein that lowers alveolar surface tension to keep lung expanded at end-expiration; produced at 26-27th week gestation
Pulmonary Circulation
Delivers nutrients to lung tissue
Provides O2 and CO2 for gas exchange
Lower pressure/resistance than systemic circulation
Pulmonary artery:
- divides into arterioles then capillaries
Alveolar membrane: thin membrane where gas exchange occurs
- changes in thickness of this membrane impairs gas exchange.
Pulmonary vein:
- drains the capillaries that are filled with oxygenated blood
Oxygen transport
- Diffuses across alveolar-capillary membrane
- Binds to hemoglobin
- Hemoglobin carries 98%-99% O2 in blood (oxyhemoglobin)
- Oxygen dissociates from hemoglobin for use by cells
Carbon dioxide transport
3 ways:
1. Dissolved in plasma as PCO2
2. Attached to hemoglobin as carbonic acid
3. As bicarbonate HCO3
More soluble than O2 and diffuses quicker
Respiration
Exchange of oxygen and carbon dioxide during cellular metabolism
Respiration Rate
Ventilators rate, breaths per min
Tidal Volume
Volume of air per breath (400-800mL/breath)
Effective ventilation (minute ventilation) = RR x tidal volume
Chest wall restrictions
Decrease tidal volume and inc RR
Can progress to hypercapnia
Pneumothorax
Air/gas in pleural space —> destroys negative pressure —> lung collapses
Primary: spontaneous, rupture of blob
Secondary: chest trauma to pleura and rupture of belt with patient with emphysema
Open pneumothorax
Pressure in pleural space = atmospheric pressure
Air enters with inspiration, leaves with expiration
Tension Pneumothorax
Pressure in pleural space > atmospheric pressure
- air enters with inspiration but cannot leave one way valve
- displaces heart/vessels to cause mediastinal shift
- life threatening