histology Flashcards
Terminal bronchioles are larger and are part of the conducting portion of the respiratory system, while respiratory bronchioles are smaller and are part of the respiratory part of the respiratory system. Both contain _______, ______, and _____.
smooth muscle, club cells, and NO glands
The epithelium of respiratory bronchioles compared to terminal bronchioles is transitioning from ______ to ______, ciliated cells and goblet cells (what few there are) are appearing/disappearing, and access to alveoli is beginning to appear.
columnar to cuboidal
Club (Clara) cells divide (with some differentiating to form ciliated cells), ______ and _______, a process that is carried out by _________ enzymes in their abundant smooth endoplasmic reticulum (SER).
secrete glycosaminoglycans, and metabolize airborne toxins; cytochrome P450
In general, the presence of club cells indicates respiratory bronchiole, which marks the transition from the ________ to ________.
conducting portion to the respiratory portion of the respiratory system
respiratory bronchiole are lined by ________ epithelium that contain mostly club (Clara) cells and some ciliated cells, except where their walls are interrupted by alveoli.
simple cuboidal
alveoli, the sites where gas exchange occurs and where the lining abruptly changes to a ________ composed of highly attenuated ______ cells.
simple epithelium; squamous
__________ epithelium is located in the trachea.
pseudostratified ciliated columnar; The layer is composed of ciliated columnar cells, short (basal) cells, and goblet cells, all of which rest on the basement membrane.
Goblet cells are, as the name suggests, goblet-shaped and are filled with large secretory granules containing mucinogen droplets, which are secreted onto the epithelial surface to trap inhaled particles. At the lower set of arrows, note how thin the cell is (like the stem of the goblet) and identify the nucleus.
microtubules; Ciliated cells have long, actively motile cilia (seen here as small circles when cut in cross section) that beat toward the mouth. They move inhaled particulate matter trapped in mucus toward the oropharynx, thus protecting the delicate lung tissue from damage. Cilia contain a core of longitudinally arranged microtubules (seen here as little dots in a 9+2 doublet arrangement).
2= Type II pneumocytes
Type II pneumocytes (type II alveolar cells, great alveolar cells, granular pneumocytes or septal cells) are ______ epithelial cells, form ______ with adjacent cells, and are most often found near septal intersections. They bulge into the alveolus and have a free surface that contains short microvilli around their peripheral borders. These cells are able to divide and regenerate both types of alveolar pneumocytes. Most importantly, type II pneumocytes synthesize __________, which is stored in ____________.
cuboidal; tight junctions; pulmonary surfactant; cytoplasmic lamellar bodies
Equalization of pressure between alveoli; Alveoli are separated from each other by interalveolar septa that may contain one or more alveolar pores (pores of Kohn). These pores permit equalization of pressure between alveoli.
Division and regeneration of pneumocytes
Continuous (somatic) capillaries contain numerous pinocytic vesicles. Continuous capillaries lack fenestrae and have a continuous basal lamina. They are located in nervous tissue, muscle, connective tissue, exocrine glands, and the lungs.
Type I pneumocytes (type I alveolar cells) cover about 95% of the alveolar surface and form part of the blood-gas barrier where exchange of oxygen and carbon dioxide occurs. They have an extremely thin cytoplasm that may be less than 80 nm thick, form tight junctions with adjacent cells, may have phagocytic capabilities, and are not able to divide (although there is disagreement on this). The blood-gas barrier permits the diffusion of gases between the alveolar airspace and the blood. Oxygen passes from alveolus into capillary, and carbon dioxide passes from the capillary blood into the alveolus.
These are lamellar bodies within type II pneumocytes. Pulmonary surfactant consists of phospholipids and at least four proteins. It forms tubular myelin (a network configuration) when it is first released from these lamellar bodies. It then spreads to produce a monomolecular film over the alveolar surface, forming a lower aqueous phase and a superficial lipid phase. Pulmonary surfactant reduces the surface tension of the alveolar surface, permitting the alveoli to expand easily during inspiration and preventing alveolar collapse during expiration.
microvilli
Alveolar macrophages (alveolar phagocytes, dust cells) are the principal mononuclear phagocytes of the alveolar surface. They remove inhaled dust, bacteria, and other particulate matter trapped in the pulmonary surfactant, thus providing a vital line of defense in the lungs. They migrate to the bronchioles after filling with debris. From there, they are carried via ciliary action to the upper airways, eventually reaching the oropharynx, where they are either swallowed or expectorated. They may also exit by migrating into the interstitium and leaving via lymphatic vessels. Alveolar macrophages also secrete elastase.
The secondary and tertiary bronchi are also known as the intrapulmonary bronchi and arise from the primary bronchi (which are extrapulmonary). The secondary, or lobar, bronchi are the branches within the three lobes of the right lung and the two lobes within in the left lung. The tertiary, or segmental, bronchi are the branches with 8-10 bronchopulmonary segments of each lung. The walls of these bronchi contain irregular cartilage plates and are lined by respiratory epithelium (but no respiration or gas exchange occurs in respiratory epithelium depsite its name). Spiraling smooth muscle bundles separate the lamina propria from the submucosa, which contains seromucous glands.
how many capillaries appear in this photo ?
20
C
5
what is the function at the cell below?
all of hte above
Curschmann’s spirals are formed from strands of mucus
Charcot-Leyden crystals are derived from eosinophils
