Respiratory System Flashcards
(41 cards)
What are the major functions of the respiratory system?
- Supply body with oxygen for cellular respiration
- Dispose of carbon dioxide, a waste of cellular respiration
What process does respiratory system involve?
- Pulmonary ventilation (breathing): movement of air in and out of lungs
- External respiration: diffusion of gasses b/w blood and lungs
What process does circulatory system involve?
- Transport of O2 and CO2 in blood
- Internal respiration: diffusion of gasses b/w blood and tissues
What does upper respiratory system consists of?
Nose, nasal cavity, and the pharynx
What does lower respiratory system consist of?
Larynx, trachea, bronchi and lungs
What are the two zones of respiratory system?
- Respiratory zone: site of gas exchange (respiratory bronchioles, alveolar ducts, and alveoli)
- Conducting zone: transport gas to and from gas exchange sites. Cleanses, warms, and humidifies air
What are the functions of nose?
- Provide an airway for respiration
- Moistens and warms entering air
- Filters and clean inspired air
- Serves as a resonating chamber for speech
- Houses the olfactory/smell receptors
What do alveolar walls consist of?
- Single layer of squamous epithelium (type I alveolar cells)
- Scattered cuboidal (type II alveolar cells) secrete surfactant and antimicrobial proteins
What does surfactant secreted by type II alveolar cells do?
Reduces the surface tension to avoid lungs from collapsing
What is respiratory membrane made out of?
Layers of epithelial tissues and basement membranes.
What do alveolar pores do?
- Connect adjacent alveoli
- Equalize air pressure throught lung
- Provide alternate routes in case of blockages
What do alveolar macrophages do?
Keep alveolar surfaces sterile
What is a pleurae?
Thin, double layered serosal membrane that divides thoracic cavity into two pleural compartments and mediastinum
What is partietal pleura?
Membrane on thoracic wall, superior face of diaphragm, around heart and b/w lungs
What is visceral pleura?
Membrane on external lung surface
What is an atmospheric pressure?
The pressure exerted by air surrounding the body
760mm Hg at sea level = 1 atmosphere
Respiratory pressures are always described relative to ?
Atmospheric pressure (P atm): the pressure exerted by the air surrounding the body
What is the intrapulmonary pressure (P pul)?
The pressure in the alveoli (intra-alveolar pressure)
- Raises and falls with breathing but always equalizes with the atmospheric pressure eventually
- Pressure decreases as volume increases during inspiration
- Pressure increases during expiration
What is the intrapleural pressure (P ip)?
The pressure in the pleural cavity
- Pressure becomes negative during inspiration
- Always about 4mm Hg less than P pul.
- P ip is always negative relative to P pul and P atm
What causes negative intrapleural pressure?
- The lungs’ natural tendency to recoil
- The surface tension of the alveolar fluid
What is the transpulmonary pressure?
The difference between the intrapulmonary and intrapleural pressure (P pul - P ip)
- Keeps the lungs from collapsing
- The size of the transpulmonary pressure determines the size of the lungs
- The greater the transpulmonary pressure, the larger the lungs
What is Boyle’s Law?
The relationship b/w the pressure and volume of a gas has an inverse relationship
What is inspiration?
Active process involving inspiratory muscles (diaphragm and external intercostals)
- Diaphragm contacts and moves down
- External intercostals contract and lifts up and out rib cage
- Causes intrapulmonary pressure (P ip) to drop by 1mm Hg
- Due to the transpulmonary pressure, air flows into lungs, down its pressure gradient until P pul = P atm
- P ip lowers to 6mm Hg less than P atm
What is expiration?
Passive process
- Inspiratory muscles relax, thoracic cavity volume decreases, and lungs recoil
- Volume decrease causes intrapulmonary pressure (P pul) to increase by 1mm Hg
- P pul > P atm so air flows out of lungs down its pressure gradient until P pul = P atm
