24 Questions
What is the primary function of the respiratory system?
Exchange of respiratory gases (O2 and CO2) between the organism and the environment
What is the process of breathing in the respiratory system?
Breathing (ventilation), exchange of O2 for CO2, transport of gases (via bloodstream), exchange of CO2 for O2 (cellular level)
What is the function of the conducting portion of the respiratory system?
Conduction of air to the lungs
What is the function of the respiratory portion of the respiratory system?
Gas exchange at the alveoli
What is the function of the nasal cavity?
Modulation of the temperature of the inspired air
What is the function of the olfactory mucosa?
Olfaction
What is the epithelial type found in the vestibule of the nasal cavity?
Stratified squamous
What is the epithelial type found in the respiratory region of the nasal cavity?
Pseudostratified ciliated columnar
Which type of cells in the alveoli are responsible for manufacturing surfactant?
Type II pneumocytes
What is the primary function of the respiratory bronchioles?
To provide a pathway for air to enter the alveoli
What is the characteristic of the wall of respiratory bronchioles?
It is interrupted by outpocketings (alveoli)
What is the function of alveolar macrophages?
To remove dust and debris from the alveoli
What is the characteristic of alveolar ducts?
They have a linear arrangement of alveoli
What is the function of the pores of Kohn?
To regulate air pressure in the pulmonary segments
What is the characteristic of the alveolar sac?
It is a cluster of alveoli
What is the characteristic of the respiratory portion of the lung?
It is where gas exchange occurs
What is the unique feature of the tracheal cartilages in birds?
They form complete rings encircling the airway, overlapping and interlocking with adjacent rings.
What is the function of the secondary bronchi in the avian respiratory system?
They open into an abdominal air sac.
What is the characteristic of the air spaces (atria) in the avian respiratory system?
They contain smooth muscle and are lined by squamous cells.
What is the function of the tympaniform membranes in the avian respiratory system?
They are analogous to the mammalian vocal cords and vibrate during sound production.
What is the characteristic of the larynx in the avian respiratory system?
It is simple and devoid of vocal folds.
What is the function of the tertiary bronchi (parabronchi) in the avian respiratory system?
They interconnect the secondary bronchi.
What is the characteristic of the respiratory epithelium in the avian nasal cavity?
It is similar to the mammalian respiratory epithelium.
What is the characteristic of the trachealis muscle in the avian respiratory system?
It is absent, allowing for a more rigid trachea.
Study Notes
Respiratory System
- Primary function: exchange of respiratory gases (O2 and CO2) between the organism and the environment
- Process of respiration: breathing, exchange of O2 for CO2, transport of gases, and cellular exchange of CO2 for O2
Components
- Conducting portion: larger conduits (extrapulmonary) and smaller components (intrapulmonary)
- Respiratory portion: completely intrapulmonary
Conducting Portion
- Extrapulmonary regions: nasal cavities, pharynx, larynx, trachea, and bronchi
- Intrapulmonary regions: intrapulmonary bronchi, bronchioles, and terminal bronchioles
- Supported by a skeleton composed of bone and/or cartilage
Nasal Cavity
- Modulation of the temperature of the inspired air
- Olfactory mucosa: modified mucosa for olfaction
- 3 regions: vestibule, respiratory region, and olfactory region
Vestibule
- Rostral: relatively thick keratinized stratified squamous epithelium
- Midvestibule: thinner and non-keratinized epithelium
- Caudal: transition zone; stratified cuboidal to non-ciliated pseudostratified columnar epithelium
- Special features: vibrissae (tactile hair)
Respiratory Region
- Pseudostratified ciliated columnar epithelium with goblet cells
- Caudal 2/3 of nasal cavity proper
- Mucosity: epithelium with Clara cells and cuboidal cells, some with cilia
Respiratory Portion
- Begins with branches of the terminal bronchiole, known as respiratory bronchioles
- Wall is interrupted by outpocketings (alveoli)
Alveoli
- Single, sac-like space
- Primary structural and functional unit of the respiratory system
- Thin walls permit gas exchange
- Small outpouchings of respiratory bronchioles, alveolar duct, and alveolar sac
- Large number, frequently pressed against each other
- CT interstitium in between is eliminated
- Areas of close contact: air spaces communicate through an alveolar pore (pores of Kohn)
Alveoli Cells
- Type I pneumocytes: forms the lining
- Type II pneumocytes (septal cells): cells manufacturing surfactant, usually in regions where alveoli are separated by a septum
Other Cells in the Alveoli
- Alveolar Macrophage (Dust Cells): migrate between type I pneumocytes and enter the lumen, assist type II pneumocytes in uptake of surfactant
Avian Respiratory System
- Nasal cavity: epithelia similar to mammals
- Respiratory epithelium: groups of goblet cells form intraepithelial glands
- Infraorbital sinuses: drain into the nasal cavity, lined by respiratory epithelium
- Larynx: simple, devoid of vocal folds, produces little sound
- Syrinx: voice box, specialized region of the tracheobronchial junction, tympaniform membranes, analogous to the mammalian vocal cords, vibrate during production of sound
Avian Trachea
- Cartilages form complete rings encircling the airway, overlapping and interlocking with adjacent rings
- Trachealis muscle: absent
- Trachea does not undergo phasic changes in diameter during breathing
Avian Bronchi
- Extrapulmonary primary bronchi → intrapulmonary primary bronchi (mesobronchi) → terminates by:
- Opening into an abdominal air sac
- Secondary bronchi arising from each mesobronchi
- Tertiary bronchi (parabronchi) interconnect the secondary bronchi
- Air spaces (atria) – open into parabronchi, projecting tips of interatrial septa contain smooth muscle and are lined by squamous cells
- Air capillaries – arise from the base of the atria
This quiz covers the primary function and process of respiration, including breathing, gas exchange, and transportation of gases in the human body.
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