PREFINAL: RESPIRATORY SYSTEM Flashcards
2 COMPONENTS OF RESPIRATORY SYSTEM
Conducting portion
Respiratory portion
The conducting portion, which consists of the___(7)
nasal cavities, pharynx, larynx, trachea, bronchi (Gr. bronchos, windpipe), bronchioles, and terminal bronchioles
The respiratory portion, where the system’s main function of gas exchange occurs, consisting of_____(3)
respiratory bronchioles, alveolar ducts, and alveoli
• The left and right nasal cavities each have two components: the external,
dilated vestibule and the internal nasal cavity.
• Skin of the nose enters the nares (nostrils) partway into the vestibule and includes sweat glands, sebaceous glands, and coarse, moist vibrissae (hairs), which filter out particulate material from inspired air. Within the vestibule, the epithelium loses its keratinized nature and undergoes a transition to typical pseudostratified columnar epithelium which also lines the nasal cavities.
• The nasal cavities lie within the skull as two cavernous chambers separated by the osseous nasal septum.
NASAL CAVITIES
The left and right nasal cavities each have two components:
the external, dilated vestibule and the internal nasal cavity.
Extending from each lateral wall are three bony shelflike projections called
conchae, or turbinate bones
The thin mucus layer produced by these glands and goblet cells serves to trap particulate and gaseous air impurities that are then removed. The secretions also contain immunoglobulin A (IgA) from
plasma cells in the lamina propria.
Small seromucous glands
Small seromucous glands: The thin mucus layer produced by these glands
and goblet cells serves to trap particulate and gaseous air impurities that are then removed. The secretions also contain __________ from
plasma cells in the lamina propria.
immunoglobulin A (IgA)
Epithelium on the middle and inferior conchae is ________ the roof of the nasal cavities and the superior conchae are covered with specialized olfactory epithelium.
respiratory epithelium
Most of the nasal cavities and conducting portion of the system is lined with mucosa having ciliated
pseudostratified columnar epithelium commonly known as _______.
respiratory epithelium
5 CELLS OF RESPIRATORY EPITHELIUM
Ciliated columnar cells
Goblet cells
Brush cells
Small granule cells (or Kulchitsky cells)
Basal cells
are the most abundant, each with 250-300 cilia on its apical surface.
Ciliated columnar cells
are also numerous and predominate in some areas with basal nuclei and apical domains filled with granules of mucin glycoproteins.
Goblet cells
are a much less numerous, columnar cell type, in which a small apical surface bears sparse, blunt microvillus. Brush cells are chemosensory receptors resembling gustatory cells, with similar signal transduction components and synaptic contact with afferent nerve endings on their basal surfaces
Brush cells
are difficult to distinguish in routine preparations but possess numerous dense core granules 100-300 nm in diameter. Like enteroendocrine cells of the gut, they are part of the diffuse neuroendocrine system (DNES) (see Chapter 20). Like brush cells, they represent only about 3% of the cells in respiratory epithelium.
Small granule cells (or Kulchitsky cells)
are mitotically active stem and progenitor cells that give rise to the other epithelial cell types
Basal cells
The olfactory chemoreceptors for the sense of smell are in the olfactory epithelium, a specialized region of
the mucous membrane covering the superior conchae at the roof of the nasal cavity.
OLFACTORY EPITHELIUM
OLFACTORY EPITHELIUM 3 CELL MAJOR TYPES
Olfactory neurons
Supporting cells
Basal cells
are bipolar neurons present throughout this epithelium. The axons leave the epithelium and unite in the lamina propria as very small nerves that then pass to the brain through foramina in the cribriform plate of the ethmoid bone. There they form the olfactory nerve (cranial nerve I) and eventually synapse with neurons in the olfactory bulb of the brain.
Olfactory neurons
are columnar, with narrow bases and broad, cylindrical apexes containing the nuclei and extending microvilli into the fluid layer. The supportive role of these cells is not well understood, but they express abundant ion channels, which help maintain a microenvironment conducive to olfactory function and survival.
Supporting cells
are small, spherical, or cone-shaped cells near the basal lamina. These are the stem cells for the other two types, replacing the olfactory neurons every 2-3 months and support cells less frequently.
Basal cells
The loss or reduction of the ability to smell, _________, respectively, can be caused by traumatic damage to the ethmoid bone that severs olfactory nerve axons or by damage to the olfactory epithelium caused by intranasal drug use.
anosmia or hyposmia
• are bilateral cavities in the frontal, maxillary, ethmoid, and sphenoid bones of the skull. They are lined with a thinner respiratory epithelium having fewer goblet cells.
• The lamina propria contains only a few small glands and is continuous with the underlying periosteum.
• communicate with the nasal cavities through small openings; mucus produced there is moved into the nasal passages by the activity of the ciliated epithelial cells.
PARANASAL SINUSES
is an inflammatory process of the sinuses that may persist for long periods of time, mainly because
of obstruction of drainage orifices.
Sinusitis
Chronic sinusitis and bronchitis are components of primary ciliary
dyskinesia, or _______, an inherited genetic disorder characterized by defective ciliary action.
Kartagener syndrome
• The nasal cavities open posteriorly into the nasopharynx, the first
part of the pharynx.
• The nasopharynx is continuous caudally with the oropharynx
(throat), the posterior part of the oral cavity leading to the larynx and
esophagus.
• the nasopharynx lining is respiratory epithelium, and its mucosa
contains the medial pharyngeal tonsil and the openings of the two
auditory tubes which connect to each middle ear cavity.
PHARYNX
• The larynx is a short (4 cm × 4 cm) passage for air between the pharynx and the trachea.
• Its rigid wall is reinforced by hyaline cartilage (in the thyroid, cricoid, and the inferior arytenoid cartilages)
and smaller elastic cartilages (in the epiglottis, cuneiform, corniculate, and the superior arytenoid cartilages),
all of which are connected by ligaments. In addition to maintaining an open airway, movements of these cartilages by skeletal muscles participate in sound production during phonation.
LARYNX
VOICE BOX
Larynx
a flattened structure projecting from the upper rim of the larynx, serves to prevent swallowed food or fluid from entering that passage.
EPIGLOTTIS
EPIGLOTTIS Its upper, or lingual, surface has
stratified squamous epithelium
EPIGLOTTIS at variable points on its laryngeal surface this epithelium undergoes a transition to
ciliated pseudostratified columnar (respiratory) epithelium