Chapter 22: Respiratory System

What are the main functions of the respiratory system?

Supplies the body with oxygen and removes carbon dioxide.

What are the four processes of respiration?

1. Pulmonary ventilation (breathing)

2. External respiration (gas exchange in lungs)

3. Transport of respiratory gases

4. Internal respiration (gas exchange in tissues)

What are the two zones of the respiratory system?

• Conducting Zone: Air passages from nose to terminal bronchioles

• Respiratory Zone: Site of gas exchange (respiratory bronchioles, alveolar ducts, alveoli)

What organs are part of the upper respiratory tract?

Nose, nasal cavity, paranasal sinuses, and pharynx.

What are the functions of the nose?

Provides airway, moistens/warms air, filters, speech resonance, and olfaction.

What are the two types of mucosa in the nasal cavity?

• Olfactory mucosa (smell receptors)

• Respiratory mucosa (pseudostratified ciliated columnar epithelium with goblet cells)

What is the role of nasal conchae?

Increases air turbulence and deflects particles to mucus-coated surfaces

What are the three regions of the pharynx?

• Nasopharynx – air only, pseudostratified epithelium

• Oropharynx – food & air, stratified squamous

• Laryngopharynx – food & air, stratified squamous

What tonsils are found in the pharynx?

• Nasopharynx: Pharyngeal tonsils

• Oropharynx: Palatine and lingual tonsils

What are the functions of the larynx?

Voice production, open airway, routes air and food properly.

What structures allow sound production in the larynx?

Vocal folds – pitch changes with length, loudness depends on air force

What is the trachea supported by?

C-shaped cartilage rings to keep airway open.

What are the divisions of the bronchi?

• Primary (main) bronchi

• Secondary (lobar) bronchi: 3 right, 2 left

• Tertiary (segmental) bronchi

• Bronchioles < 1 mm

• Terminal bronchioles < 0.5 mm

How does tissue composition change along the bronchi?

• Cartilage rings → plates → none

• Epithelium: pseudostratified → simple columnar → cuboidal

• Smooth muscle increases

What structures are in the respiratory zone?

Respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli.

What are type I and type II alveolar cells?

• Type I: Simple squamous for gas exchange

• Type II: Cuboidal, secrete surfactant to reduce surface tension

What is the function of alveolar macrophages?

Remove debris and pathogens from alveolar surfaces.

What features help alveoli function effectively?

Elastic fibers, alveolar pores (for pressure equalization), and macrophages.

What causes air to move in and out of the lungs?

Pressure changes: air flows from high to low pressure

What happens during inspiration?

• Diaphragm contracts (pulls lungs down)

• External intercostal muscles contract (pulls lungs outward)

• volume increases; pressure decreases

What happens during quiet expiration?

• Diaphragm relaxes, pulls lungs up

• external intercostal muscles relax, pull lungs inward

• volume decreases and pressure increases

What muscles are involved in forced expiration?

Oblique and transversus abdominis muscles.

Forced expiration

• Diaphragm relaxes, pulls lungs up

• external intercostal muscles relax; pull lungs inward

• internal intercostals muscles contract; pulls lungs inward

• Lung volume decreases and pressure increases

Forced inspiration

• Diaphargm contracts; pulls lungs down

• external intercostal muscles contract, pulls lungs outward

• internal intercostal relax, pull lungs outward

• volume increases, pressure decreases

What muscles contract during forced inspiration

neck and back muscles