Respiratory System Flashcards
Respiratory system
■ Cells produce energy:
■ for maintenance, growth, defense, and reproduction
■ through mechanisms that use oxygen and produce carbon dioxide
Oxygen
■ Is obtained from the air by diffusion across delicate exchange surfaces of lungs
■ Is carried to cells by the cardiovascular system which also returns carbon dioxide to the lungs
5 functions of the respiratory system
- Provides extensive gas exchange surface area between air and circulating blood
- Moves air to and from exchange surfaces of the alveoli
- Protects respiratory surfaces from outside environment
- Produces sounds
- Participates in olfactory sense
Organization of respiratory system
■ The respiratory system is divided into the upper respiratory system, above the larynx, and the lower respiratory system, from the larynx down
Respiratory tract
■ Consists of a conducting portion (zone):
■ from nasal cavity to terminal bronchioles
■ Consists of a respiratory portion (zone):
■ the respiratory bronchioles and alveoli
Alveoli
■ Are air-filled pockets within the lungs
■ where most gas exchange takes place
Respiratory Epithelium
■ For gases to exchange efficiently:
■ alveoli walls must be very thin (< 1 µm)
■ surface area must be very great (about 35 times the surface area of the body)
Respiratory mucosa
■ Consists of:
■ an epithelial layer
■ an areolar layer
■ Lines conducting portion of respiratory system
Lamina propria
■ Underlies areolar tissue
■ In the upper respiratory system, trachea, and bronchi:
■ contains mucous glands that secrete onto epithelial surface
■ In the conducting portion of respiratory system:
■ contains smooth muscle cells that encircle lumen of bronchioles
Alveolar epithelium
■ Is a very delicate, simple squamous epithelium
■ Contains scattered and specialized cells
■ Lines exchange surfaces of lungs
Respiratory defense system
■ Consists of a series of filtration mechanisms
■ Removes particles and pathogens
Components of respiratory defense system
■ Goblet cells and mucous glands:
■ produce mucus that bathes exposed surfaces
■ Cilia:
■ sweep debris trapped in mucus toward the pharynx
■ This results in a moving carpet of mucus called the mucus escalator
■ Filtration in nasal cavity removes large particles
■ Alveolar macrophages engulf inhaled particles that reach lungs
Upper respiratory system: nose
■ Air enters the respiratory system:
■ through nostrils or external nares
■ into nasal vestibule
■ Nasal hairs (Vibrissae):
■ are in nasal vestibule
■ are the first particle filtration system
Nasal cavity
■ The nasal septum:
■ divides nasal cavity into left and right
■ Mucous secretions from paranasal sinus and tears:
■ clean and moisten the nasal cavity
■ Pseudostratified ciliated columnar epithelium
■ Mucous and serous secretions contain lysozyme and defensins
■ Cilia move contaminated mucus posteriorly to throat
■ Superior portion of nasal cavity is the olfactory region:
■ provides sense of smell
Air flow
■ From vestibule to internal nasopharynx:
■ through superior, middle, and inferior meatuses
■ Nasal cavity opens into nasopharynx through internal nares
Meatuses
■ Constricted passageways that produce air turbulence:
■ warm and humidify incoming air
■ trap particles
Paranasal sinuses
■ In frontal, sphenoid, ethmoid, and maxillary bones
■ Lighten skull; secrete mucus; help to warm and moisten air
Palates
■ Hard palate:
■ forms floor of nasal cavity
■ separates nasal and oral cavities
■ Soft palate:
■ extends posterior to hard palate
■ divides superior nasopharynx from oropharynx
Nasal mucosa
■ Warm and humidify inhaled air for arrival at lower respiratory organs
■ Breathing through mouth bypasses this important step
Pharynx
■ A chamber shared by digestive and respiratory systems
■ Extends from internal nares to entrances to larynx and esophagus
Divisions of pharynx
■ Nasopharynx
■ Oropharynx
■ Laryngopharynx
Cartilages of larynx
■ 3 large, unpaired cartilages form the
■ larynx:
■ the thyroid cartilage
■ the cricoid cartilage
■ the epiglottis
Thyroid cartilage
■ with laryngeal prominence (Adam’s apple)
■ Is a hyaline cartilage
■ Forms anterior and lateral walls of larynx
■ Ligaments attach to hyoid bone, epiglottis, and laryngeal cartilages
Cricoid cartilage
■ Is a hyaline cartilage
■ Form posterior portion of larynx
■ Ligaments attach to first tracheal cartilage
■ Articulates with arytenoid cartilages