Respiratory system Flashcards
The respiratory system can be functionally classified into
-a conducting portion, consisting of airways that deliver air to the lungs, and
-a respiratory portion, consisting of structures within the lungs in which oxygen in the inspired air is exchanged for carbon dioxide in the blood.
what structures are in the conducting respiratory system
nose, nasopharynx, larynx, trachea, bronchi,
and bronchioles of decreasing diameters, including and ending at the terminal bronchioles.
what is the function of the structures of the conducting zone
These structures
-warm,
-moisten, and
-filter the air
before it reaches the respiratory components, where gas exchange occurs
comment on nasal cavities
A septum in the midline is divided into the right and left nasal cavities and the anterior part of the structure is supported by cartilage and the posterior part is supported by cartilage and bones.
The nares are the nostrils; their outer portions are lined by THIN SKIN. They open into the vestibule.
The nasal cavity consists of three parts: vestibule, respiratory section, olfactory section
comment on the vestibule
The vestibule is the first portion of the nasal cavity, where the epithelial lining becomes nonkeratinized. Posteriorly, the lining changes to pseudostratified ciliated columnar epithelium with goblet cells.
a. The vestibule contains vibrissae (thick, short hairs), which filter large particles from the inspired air.
b. It has a richly vascularized lamina propria (many venous plexuses) and contains seromucous glands.
comment on the respiratory section of the nasal cavity
-The medial wall of this section has a septum with a smooth surface.
-Lateral walls are recessed.
-The epithelium laying on the surface is a Pseudo-stratified squamous epithelium.
-Lamina propria of a loose connective tissue rich in blood vessels.
-This layer, which contains serous and mucous glands, continuous with perichondria of cartilage and periosteum of bone
comment on the olfactory epithelium
(1) The olfactory epithelium is located in the roof of the nasal cavity, on either side of the nasal septum and on the superior nasal conchae.
(2) It is a tall, pseudostratified columnar epithelium consisting of olfactory cells, supporting (sustentacular) cells, and basal cells.
(3) It has a lamina propria that contains many veins and unmyelinated nerves and houses Bowman glands.
comment on the 3 cells seen in the olfactory epithelium
-Olfactory cells are bipolar nerve cells characterized by a bulbous apical projection (olfactory vesicle) from which several modified cilia extend (the cilia are receptors for odour perception)
-Supporting (sustentacular) cells:
(a) possess nuclei that are more apically located than those of the other two cell types.
(b) have many microvilli and a prominent terminal web of filaments.
-Basal cells
(a) rest on the basal lamina but do not extend to the surface.
(b) form an incomplete layer of cells.
(c) are believed to be regenerative for all three cell types
what is the function of bowmans glands on the olfactory epithelium.
Bowman glands produce a thin, watery secretion that is released onto the olfactory epithelial surface via narrow ducts. Odorous substances dissolved in this watery material are detected by the olfactory cilia.
The secretion also flushes the epithelial surface, preparing the receptors to receive new odorous stimuli.
what is the epithelium of the vestibule
stratified squamous keratinized
what is the epithelium of the respiratory section of the nasal cavity
pseudostratified ciliated columnar
what is the epithelium of the olfactory section of the nasal cavity
pseudostratified ciliated columnar
comment on the nasopharynx
- The nasopharynx, the posterior continuation of the nasal cavities, becomes continuous with the oropharynx at the level of the soft palate.
- It is lined by pseudostratified ciliated columnar epithelium with goblet cells, whereas the oropharynx and laryngopharynx are lined by stratified squamous nonkeratinized epithelium.
- The lamina propria of the nasopharynx, located beneath the pseudostratified ciliated columnar epithelium. It contains MUCOUS and SEROUS glands as well as an abundance of lymphoid tissue, including the pharyngeal tonsil.
- When the pharyngeal tonsil is inflamed, it is called an adenoid.
COMMENT ON THE EPIGLOTTIS
-It is an elastic cartilage of the larynx.
-It is lined by stratified squamous epithelium on the lingual surface.
-Pseudostratified ciliated columnar epithelium lines the laryngeal side.
-Serous and mucous glands are localized in lamina propria.
comment on the larynx
- a. The larynx connects the pharynx with the trachea.
b. The wall of the larynx is supported by hyaline cartilages (thyroid, cricoid, and lower part of arytenoids) and elastic cartilages (epiglottis, corniculate, and tips of arytenoids).
c. The wall also possesses skeletal muscle, connective tissue, and glands. - -The vocal cords consist of skeletal muscle (the vocalis muscle), the vocal ligament (formed by a band of elastic fibres), and a covering of STRATIFIED SQUAMOUS NONKERATINIZED EPITHELIUM.
-Inferior to the vocal cords, the lining epithelium changes to Pseudostratified ciliated columnar epithelium, which lines air passages down through the trachea and intrapulmonary bronchi.
- Vestibular folds (false vocal cords) lie superior to the vocal cords.
These folds of loose connective tissue contain glands, lymphoid aggregations, and fat cells.
They are covered by stratified squamous nonkeratinized epithelium.
