Lecture 4
Tissues
- Provide specific functions for the body
- Collection of cells that have the similar function
- 4 main types
o Epithelial tissues: protective coverings
and function in secretion and absorption
o Connective tissues: support soft parts and blind structures
o Muscular tissues: produce body movement
Skeletal
Cardias
Smooth
o Nervous tissues: conduct impulses to control and coordinate body activities
Epithelial Tissues
- Widespread throughout the body
- Cover organs and the body surface, line cavities and hollow organs and make up gland
- Have a free surface exposed to the outside or internally
- Anchored to underlying connective tissues by a basement
membrane
- Made up of tightly packed cells containing little intercellular
materials
- Readily divide
- Lack blood vessels, but are nourished by cells in underlying
connective tissues
- Function in production, secretion, absorption and excretion
o Classified by cell shape and the number of cell layers
Squamous - thin and flattened
Cuboidal - Cube-shaped
Columnar - Tall and elongated
Simple Squamous Epithelium
- Single and thin layer -> easy for diffusion and filtration
o E.g. In lung for oxygen and CO2 to diffuse
- Cells are tightly pack
- Cells have broad, thin nuclei
- Very delicate and can be damage easily
- This type is not good for protection
, Simple Cuboidal Epithelium
- Single layer cube shaped cells with centrally located
nuclei
- Found in kidney tubules, cover ovaries
- Function in urine formation in kidneys; and glandular
secretion
- Free surface faces lumen, a hollow channel
Simple Columnar Epithelium
- Single layer but with tall elongated cells
- Nuclei are located near the basement membrane
- Microvilli sitting on the same level
- Cells may be ciliated or non-ciliated
o Non-ciliated: line the uterus, stomach and
intestines where they protect underlying tissues,
secrete digestive fluids and absorb nutrient
o Ciliated: in the uterine tubes -> help move egg
cell towards the uterus
Pseudostratified Columnar Epithelium
- Cells appear layered due to varying positions of their
nuclei, but are not truly layered
o Cilia doesn't seem to be sitting on the same level
Cilia will move, like a swepper
- Goblet cell are scattered among the epithelial cells
o Goblet cell make mucus
- Cells vary in shape
- Found in passageways of the respiratory system
Stratified Squamous Epithelium (multi – layer)
- Design to protect underlaying cells
- Composed of squamous cells
- Cuboidal cells in the deeper layer divide and push the older
cells outward
- No blood vessels found
- Lines the mouth, esophagus, vagina and anal canal
- Keratinization will occur in outer layer of skin but not in area
which tissues remain moist and alive -> E.g. oral cavity,
esophagus, vagina
Tissues
- Provide specific functions for the body
- Collection of cells that have the similar function
- 4 main types
o Epithelial tissues: protective coverings
and function in secretion and absorption
o Connective tissues: support soft parts and blind structures
o Muscular tissues: produce body movement
Skeletal
Cardias
Smooth
o Nervous tissues: conduct impulses to control and coordinate body activities
Epithelial Tissues
- Widespread throughout the body
- Cover organs and the body surface, line cavities and hollow organs and make up gland
- Have a free surface exposed to the outside or internally
- Anchored to underlying connective tissues by a basement
membrane
- Made up of tightly packed cells containing little intercellular
materials
- Readily divide
- Lack blood vessels, but are nourished by cells in underlying
connective tissues
- Function in production, secretion, absorption and excretion
o Classified by cell shape and the number of cell layers
Squamous - thin and flattened
Cuboidal - Cube-shaped
Columnar - Tall and elongated
Simple Squamous Epithelium
- Single and thin layer -> easy for diffusion and filtration
o E.g. In lung for oxygen and CO2 to diffuse
- Cells are tightly pack
- Cells have broad, thin nuclei
- Very delicate and can be damage easily
- This type is not good for protection
, Simple Cuboidal Epithelium
- Single layer cube shaped cells with centrally located
nuclei
- Found in kidney tubules, cover ovaries
- Function in urine formation in kidneys; and glandular
secretion
- Free surface faces lumen, a hollow channel
Simple Columnar Epithelium
- Single layer but with tall elongated cells
- Nuclei are located near the basement membrane
- Microvilli sitting on the same level
- Cells may be ciliated or non-ciliated
o Non-ciliated: line the uterus, stomach and
intestines where they protect underlying tissues,
secrete digestive fluids and absorb nutrient
o Ciliated: in the uterine tubes -> help move egg
cell towards the uterus
Pseudostratified Columnar Epithelium
- Cells appear layered due to varying positions of their
nuclei, but are not truly layered
o Cilia doesn't seem to be sitting on the same level
Cilia will move, like a swepper
- Goblet cell are scattered among the epithelial cells
o Goblet cell make mucus
- Cells vary in shape
- Found in passageways of the respiratory system
Stratified Squamous Epithelium (multi – layer)
- Design to protect underlaying cells
- Composed of squamous cells
- Cuboidal cells in the deeper layer divide and push the older
cells outward
- No blood vessels found
- Lines the mouth, esophagus, vagina and anal canal
- Keratinization will occur in outer layer of skin but not in area
which tissues remain moist and alive -> E.g. oral cavity,
esophagus, vagina
