tailieunhanh - Digital histology an interactive cd atlas with review text phần 2

Không lông mi Thành phần cốt lõi của actin microfilaments diện tích bề mặt tăng hiện tại trên các tế bào lót mào tinh hoàn và ống dẫn tinh trong đường sinh sản nam ➢ lông mao nhiều tóc như phần mở rộng từ bề mặt của tế bào; 7-10 micron chiều cao cao co thể cử động dể dang ; | 3. Epithelial Tissues 23 Are present in large numbers on each cell and collectively are called a brush or striated border Contain a core of actin microfilaments Are relatively nonmotile Increase surface area for absorption Prominent on cells lining the digestive tract and proximal tubules in the kidney Stereocilia Large nonmotile microvilli not cilia Contain a core of actin microfilaments Increase surface area Present on cells lining the epididymis and ductus deferens in the male reproductive tract Cilia Multiple hair-like extensions from free surface of the cell 7-10 microns in height Highly motile beat in a wave-like motion Function to propel material along the surface of the epithelium . in the respiratory system and the oviduct of the female reproductive system Core of a cilium is called the axoneme in which nine pairs of microtubules surround a central pair of microtubules 9 2 arrangement . The axomene of each cilum originates from a basal body that is located at the apex of the cell and is composed of nine triplets of microtubules. Cell Junctions Specialized structures of the plasma membrane that Attach and anchor cells Establish apical and basolateral membrane domains by sealing adjacent plasma membranes Provide channels for ionic and metabolic coupling Not restricted to epithelial cells cell junctions occur however in large number in epithelial tissues to resist the physical forces acting on the cells. Types 24 Digital Histology FIGURE . Cell junctions and surface specializations. Tight junction zonula occludens Belt-like barrier junction around apex of the cell Provides close apposition of adjacent plasma membranes and occludes the intercellular space Functions Prevents diffusion of material between the intercellular space and the lumen of the organ Establishes apical and basolateral membrane domains in the cell by preventing the lateral migration of proteins in plasma membrane Adherent junctions Attach cells to each other and anchor them to the .