Lecture 18- Respiratory System Flashcards
Major functions of respiratory system
Supply blood with O2 for cellular respiration and dispose CO2
Functions in olfaction and speech
Four processes of respiration
Respiratory system:
Pulmonary ventilation (breathing)- movement of air into and out of the lungs
External respiration- exchange of O and CO2 between lungs and blood
Circulatory system:
Transport of O2 and CO2 in blood
Internal respiration- exchange of O2 and CO2 between blood and body tissues through blood vessels
Major organs in upper respiratory tract
Nose and nasal cavity
Parasail sinuses
Pharynx
Larynx
Major organs in lower respiratory tract
Trachea
Bronchi and branches
Lungs and alveoli
External nares
Nostrils
What is the nasal cavity lined with?
anterior nasal cavity is lined with skin containing sebaceous sweat glands, and hairs.
Remainder of nasal cavity is lined with two types of mucous membranes:
The olfactory mucosa contains receptors for smell.
The respiratory mucosa has scattered goblet cells, for mucus production.
Nasal conchae
Protrude into the nasal cavity from each lateral wall, increasing mucosal surface exposure in order to filter, heat and moisten air
What surrounds nasal cavity?
paranasal sinuses within the frontal, maxillary, sphenoid, and ethmoid
bones that serve to lighten the skull, warm and moisten air, and produce mucus.
Nasopharynx
ONLY air passageway and contains the pharyngeal tonsil, which traps and destroys airborne pathogens
Oropharynx
Air and food passageway that extends from the sot palate to the epiglottis and contains the palatine and lingual tonsils
Larygopharynx
Air and food passageway that lies directly posterior to the epiglottis, extends to the larynx and is continuous inferiorly with the esophagus
Larynx
attaches superiorly to the hyoid bone, opening into the laryngopharynx, and attaches inferiorly to the trachea.
Provides open airway, routes food and air into proper passageways and produces sound through vocal cords
What does the larynx consist of?
hyaline cartilages: thyroid, cricoid, arytenoid, corniculate, and cuneiform cartilages; and the epiglottis, which is elastic cartilage.
Epiglottis
designed to close off the larynx during swallowing to prevent food or liquids from entering the airways.
Glottis
term for the vocal folds and the medial space between them.
What does voice production involve?
intermittent release of expired air and the opening and closing of the glottis.
How is pitch of voice determined?
length and tension of the vocal folds change, pitch of the voice varies.
as tension increases, pitch becomes higher. Longer, thicker vocal folds vibrate more slowly and produce a lower pitched sound.
Loudness of voice is determined by force of air forced over vocal folds
Trachea (windpipe)
descends from the larynx through the neck into the mediastinum, where it terminates at the primary bronchi
What is trachea lined with?
ciliated pseudostratified columnar epithelium, designed to propel mucus upward toward the pharynx.
What supports the trachea?
C-shaped cartilaginous rings associated with the connective tissue submucosa, preventing collapse, while allowing the esophagus to expand normally during swallowing.
Trchealis
smooth muscle that decreases the trachea’s diameter during contraction, increasing the force of air out of the lungs.
Conducting zone
consists of right and left primary bronchi that enter each lung and diverge into secondary bronchi to each lobe of the lungs.
Secondary bronchi branch into several orders of tertiary bronchi, which branch into bronchioles.
What are the structural changes that occur when airways become smaller?
The supportive cartilage changes until it is no longer present in the bronchioles
The mucosal epithelium transitions from pseudostratified columnar, to columnar, and finally, to cuboidal in the terminal bronchioles.
The relative amount of smooth muscle in the walls increases, allowing significant changes in resistance to airflow in the smaller airways.
Respiratory zone
begins as the terminal bronchioles feed into respiratory bronchioles that terminate in alveolar ducts within clusters of alveolar sacs, which consist of alveoli.
What forms the respiratory membrane?
the capillary endothelium and the alveolar epithelium
What does the respiratory membrane consist of?
single layer of squamous epithelium type I alveolar cells, surrounded by a basal lamina.
Interspersed among the type I alveolar cells are cubodial type II alveolar cells that secrete surfactant to reduce surface tension in the lungs.
Alveoli
surrounded by elastic fibres, contain alveolar pores to allow airflow between adjacent alveoli, and have alveolar macrophages to phagocytose any foreign particles that get in.
