Epithelia and Glands Flashcards
What are the four tissue types
- Epithelia
- Muscle
- Connective tissue
- Nerve
What are epithelia
Closely appose sheets of cells
What are the three primary germ layers
- ectoderm
- mesoderm
- endoderm
What does the ectoderm form
epidermis
What does the mesoderm form? And what does this line?
mesothelium (lines the pericardium, pleurae and peritoneum)
What does the endoderm form?
Lining of the GI tract
Where do we find epithelia? And it’s names
Epithelia- on surfaces
Endothelium- lining blood vessels
Mesothelium- lining body cavities
Basic characteristics of epithelia
- Entirely cellular
- Cell polarity
- specialised contacts between cells
- Lateral communication between cells
- basal lamina (basement membrane) separating from underlying tissue
- Call replacement, often rapid turnover
How are epithelia classified
- Number of cell layers
- Shape of cells in outermost layer
- Position of nuclei
- Transitional
- Ciliated
How can the number of cell layers be categorized?
- simple
- compound or stratified
How are shapes of cells in outermost layer categorized?
- squamous (flat)
- cuboidal
- columnar (longer than wide)
How can position of nuclei be categorized?
- Stratified
- pseudostratified (different nuclei position)
What is compound/stratified epithelia
More than one layer
What is transitional epithelia
Shape of cells changes according to need
What’s the function of simple epithelia
Absorption
Function of stratified epithelia
Protective
What are other functions of epithelia
- secretion
- sensory perception
- Movement of materials
- Wound repair
- Where are microvilli found
- Where are they anchored
- What do they do
- Apical plasma membrane
- In terminal web
- Increase surface area
- Where are cilia found
- What do they do
- apical surface
- Transport materials across surface
What sort of core do stereocilia have
Microfilament core- modified microvilli
What do basal infoldings do
Increase surface area
What are glands derived from
Epithelia
What are the two types of glands
Endocrine
Exocrine
How are glands formed
1) Cells from surface epithelium grow down into underlying tissue (called epithelial cord or tubule)
2) Then either endocrine or exocrine glands form
