文档介绍：Chapter 2 Epithelium
feature:
1) contain more cells and less extracellular ground substance
2) Polarisaton:
---free outer surface: face air or other things
---basal surface: face underlying CT, havebasement membrane
3)  Avascularity,but innervation:
---no blood vessels
---rich in nerve terminals
4) Having functions of protection, secretion, absorption excretion and sensory reception
1)  Covering epithelium: the epithelium which cover body surface or line the inner surface of body cavities, tubes and sac.
2)  Glandular epithelium: the epithelium which main function is secretion.
3)  Sensory epithelium: the epithelium which has special sensory function.
epithelium:
According to the number of layer and shape of cells
Simple epi.: ---simple squamous epi.
---simple cuboidal epi.
---simple columnar epi.
---pseudostratified ciliated columnar epi.
Stratified epi.: ---stratified squamous epi.
---stratified columnar epi.
---transitional epi.
1)      simple squamous epi:
---structural feature:
/one layer flattened cells, cell border are interdigitate
/with flattened ellipsoid nucleus
---distribution:
mesothelium: the simple squamous epi. which line the inner surface of body cavities such as thoracic, pericardiac and abdominal cavities.
endothelium: the simple squamous line the inner surface of cardiovascular and lymphatic system.
other place: alveoli,parietal layers of renal capsule.
---function: a) transport of materials
b) facilitates movement of viscera
2)      simple cuboidal epi.:
---structural feature:
one layer of cells, with same height and width(in side view) and hexagonal outline in surface view.
spherical centrally-located nucleus
---distribution: /the renal tubule
/thyroid
/the some ducts of mang glands
---main function: covering and secretion
3)      simple columnar epi.:
---structural features:
one layer of columnar cells,with basally lacated ovoid nucleus
goblet cell: sc