Tissue the living fabrics
Tissues – groups of similar cells with common functions, usually of common embryonic
origin
4 types of tissue: epithelial tissue, connective tissue, muscle tissue, nervous tissue,
1. Epithelial tissue - serves as boundary between environments, protects, secretes,
absorbs and filters
- lining of digestive tract and other hollow organs
- epidermis of the skin
2 types by location; - covering or lining epithelium
externally – skin
internally – pleura, pericardium,
peritoneum
- glandular epithelium –secretory tissue in the glands
ex. thyroid gland
Functions: protection, absorption, filtration, excretion, secretion, sensory
reception
characteristics: - cells has polarity – apical part – may have cilia (trachea)
- may have microvilli (int)
- basal part- attached to the basal lamina
(Made up of glycoprotein and
collagens)
- composed of closely packed cell held together by tight junction
and desmosomes
- has reticular lamina under the basal lamina serving as support
(Basal lamina + reticular lamina = basement membrane)
- avascular but innervated
- high rate of regeneration
Lining epithelium:
classifications – based on number of layers – simple (single layer)
- stratified (2 or more layers)
- based on form or shape – squamous – flat
- cuboidal - cube
- columnar –column
Note: If stratified, the shape classification is based on the top
most layer
1. Simple squamous - cells are flat laterally, cytoplasm are sparse
describe -
functions – allow passage of materials by diffusion,
absorption, filtration, secretion
locations –
, 2. Simple cuboidal – forms walls of small ducts of glands and linings fo
renal tubules
- describe:
- functions: secretion, absorption
- location:
- 2 special names of simple squamous epithelium based on
the location: - endothelium – linings of blood vessels,
lymphatic vessels and heart
- mesothelium – linings of ventral cavities
3. Simple columnar – tall closely pack cells
- describe:
- functions: - absorption, conciliated but with microvilli
(intestine)
- propel mucus or reproductive cells, with
cilia (fallopian tube)
- location -
4. Pseudostratified columnar – nuclei of cell at different level
appear stratified but not
describe:
functions: secretion of mucus
propulsion of mucus
locations: 2 types – ciliated
- non ciliated
5. Stratified squamous – most widespread stratified epithelium
free surface (top most layer) are squamous
while the deeper layers are cuboidal and columnar
descriptions:
functions – protection in area subjected to pressure and
abrasion
locations –
Tissues – groups of similar cells with common functions, usually of common embryonic
origin
4 types of tissue: epithelial tissue, connective tissue, muscle tissue, nervous tissue,
1. Epithelial tissue - serves as boundary between environments, protects, secretes,
absorbs and filters
- lining of digestive tract and other hollow organs
- epidermis of the skin
2 types by location; - covering or lining epithelium
externally – skin
internally – pleura, pericardium,
peritoneum
- glandular epithelium –secretory tissue in the glands
ex. thyroid gland
Functions: protection, absorption, filtration, excretion, secretion, sensory
reception
characteristics: - cells has polarity – apical part – may have cilia (trachea)
- may have microvilli (int)
- basal part- attached to the basal lamina
(Made up of glycoprotein and
collagens)
- composed of closely packed cell held together by tight junction
and desmosomes
- has reticular lamina under the basal lamina serving as support
(Basal lamina + reticular lamina = basement membrane)
- avascular but innervated
- high rate of regeneration
Lining epithelium:
classifications – based on number of layers – simple (single layer)
- stratified (2 or more layers)
- based on form or shape – squamous – flat
- cuboidal - cube
- columnar –column
Note: If stratified, the shape classification is based on the top
most layer
1. Simple squamous - cells are flat laterally, cytoplasm are sparse
describe -
functions – allow passage of materials by diffusion,
absorption, filtration, secretion
locations –
, 2. Simple cuboidal – forms walls of small ducts of glands and linings fo
renal tubules
- describe:
- functions: secretion, absorption
- location:
- 2 special names of simple squamous epithelium based on
the location: - endothelium – linings of blood vessels,
lymphatic vessels and heart
- mesothelium – linings of ventral cavities
3. Simple columnar – tall closely pack cells
- describe:
- functions: - absorption, conciliated but with microvilli
(intestine)
- propel mucus or reproductive cells, with
cilia (fallopian tube)
- location -
4. Pseudostratified columnar – nuclei of cell at different level
appear stratified but not
describe:
functions: secretion of mucus
propulsion of mucus
locations: 2 types – ciliated
- non ciliated
5. Stratified squamous – most widespread stratified epithelium
free surface (top most layer) are squamous
while the deeper layers are cuboidal and columnar
descriptions:
functions – protection in area subjected to pressure and
abrasion
locations –
