Question
Given structure is not found in which of the following
| A. |
Epididymis |
| B. |
Bronchi |
| C. |
Oviduct(Fallopian tube) |
| D. |
Ependyma |
|
Correct Answer � A Explanation |
 |
Answer: A Epididymis
Marked structure in the given image is Cilia
Epididymis is lined by pseudostratified columnar epithelium with stereocilia
* Difference between cilia, stereocilia and microvilli:
These luminal surface specializations have distinct functions:
Cilia are motile and move material in a direction parallel to the epithelial surface;
Microvilli increase a cell’s surface area and are absorptive;
Stereocilia also increase the luminal surface area and are absorptive (but in the inner ear, stereocilia serve as sensory transducers).
The ultrastructural cores of microvilli and stereocilia are similar (bundled microfilaments), but in the light microscope, cilia and stereocilia appear to be the more similar structures.
Both the cilia and stereocilia are individually (barely) discernable because there are fewer of them per cell than there are microvilli on the surface of an absorptive cell.
The microvilli of absorptive cells are usually shorter (about 1 micrometer in length) than cilia and so tightly packed that they often form a solid-looking band (the striated border, or brush border) on the luminal surface of the absorptive epithelium.
Marked structure in the given image is Cilia
Stereocilia tend to clump together distally like a paint brush, whereas the shorter cilia do not. Furthermore, as a reflection of the ultrastructural differences between cilia and stereocilia, a dark line of basal bodies appears in the apical cytoplasm beneath the cilia.
With regard to relative height, the cilia are shorter (less than a quarter of the height of the cell) and more uniform in length than the stereocilia (which are more than half the height of the cell).
Epididymis is lined by pseudostratified columnar epithelium with stereocilia
Difference between cilia, stereocilia and microvilli:
These luminal surface specializations have distinct functions:
Cilia are motile and move material in a direction parallel to the epithelial surface;
Microvilli increase a cell’s surface area and are absorptive;
Stereocilia also increase the luminal surface area and are absorptive (but in the inner ear, stereocilia serve as sensory transducers).
The ultrastructural cores of microvilli and stereocilia are similar (bundled microfilaments), but in the light microscope, cilia and stereocilia appear to be the more similar structures.
Both the cilia and stereocilia are individually (barely) discernable because there are fewer of them per cell than there are microvilli on the surface of an absorptive cell.
With regard to relative height, the cilia are shorter (less than a quarter of the height of the cell) and more uniform in length than the stereocilia (which are more than half the height of the cell).
Stereocilia tend to clump together distally like a paint brush, whereas the shorter cilia do not. Furthermore, as a reflection of the ultrastructural differences between cilia and stereocilia, a dark line of basal bodies appears in the apical cytoplasm beneath the cilia.
The microvilli of absorptive cells are usually shorter (about 1 micrometer in length) than cilia and so tightly packed that they often form a solid-looking band (the striated border, or brush border) on the luminal surface of the absorptive epithelium.
