Endothelial and Epithelial Cells Flashcards
Where can endothelial and epithelial cells line in the human body?
- Epithelial cells line the internal and external parts of the body.
- Endothelium cells line the internal parts of the body.
Describe endothelial cells
- They line the inside of blood vessels and they grow in sheets.
- They have a semipermeable membrane, which allows certain substances to move in and out of the cell.
- They are classed as specialised epithelial cells.
What is intra- or extravasation?
- Endothelial cells regulating their barrier function to let cells in and out.
- They allow leukocytes to reach the site of infection.
Describe epithelial cells.
- They line internal and external parts of the body such as the skin, lungs, bladder and GI tract.
- They are kept in place by adhesion via an underlayer of proteins and glycoproteins.
- They are polar cells, they love water.
What is the basement membrane and where is it located?
- It is made out of proteins and glycoproteins.
- Supports tissues and helps cells to attach to it.
- Is located between the epidermis and dermis layers.
What are three characteristics of epithelial cells?
- Lateral surface: allows adjacent cells to interconnect with one another to form a tight pack.
- Basolateral surface: takes up metabolic waste into the cell.
- Apical surface: faces the lumen (inside space of a blood vessel).
What are the functions of endothelium cells?
- They coordinate blood homeostasis.
- Help in repairing damage by sensing tissue stress and sending new blood vessels to damaged areas.
- By providing new blood vessels , they can give cellular and nutritional support.
What are four functions of epithelial cells?
- Barrier/ protection: prevents unwanted movement of microbes and macromolecules into our bodies from the outside world.
- Absorption: transport substances that our body requires from the external environment to our bodies tissues.
- Lubrication: secrete mucus and fluids which minimises sheer stress; help move food down our oesophagus.
- Movement: some cells contain cilia and this allows the cells to move unwanted foreign particles in the trachea away from the lungs.
What are epithelial cell junctions?
- They join cells together and it helps the passage of substances into and out of the cells.
What is the paracellular pathway?
-It is the passage of substances across the intracellular space of epithelial cells.
-It is passive transport and results from diffusion.
- Under the control of tight junctions.
What is the transceullar pathway?
- The transport of cells through the cell membrane.
What is a stratified epithelial cell?
- It is layered cells.
- Multiple layers of epithelial cells stacked on top of one another.
What’s a simple epithelial cell?
- It is one cell thick.
What is a pseudo stratified epithelial cell?
- Columnar epithelial cells that are at different height, the nuclei are located at different heights.
What are the three shapes of epithelial cells and what do they look like?
- Columnar- tall
- Cuboidal- square
- Squamous- flattened/ scale like
Describe simple squamous epithelial.
- One cell thick epithelial.
- As they are flat and spread out, it provides a large surface area.
- Does not provide a lot of protection.
- An advantage of this type of tissue is that diffusion can take place as it is one cell thick.
What is transmembrane movement?
- Transmembrane movement is when molecules can move into and out of cells by either diffusion or active transport.
Describe simple cuboidal epithelial cells.
- Have increased cytoplasmic volume compared to squamous and columnar epithelial cells.
- Can be found in glands, the lining of kidney tubules.
Describe stratified squamous epithelial cells.
- Outer layer of the skin is made out of it.
- Multiple layers of the cells and the top layer are flat like and scale- like.
- Basal layer cells are more cuboidal.
- Cells on the top layer are continuously replaced by the cells underneath.
Describe keratinising stratified squamous epithelium.
- They produce keratin which is a protein.
- A specialised epithelial cell known as keratinocytes produces keratin.
- They originate at the stratum basale and then they move up the layers of the epidermis to the top layer.
The keratinocytes at the top layer are dead and this produces a dry surface which protects the underlying tissues.
Describe non-keratinising stratified epithelium cells.
- Occur in wet environments where abrasions are likely to occur.
-The ones that are present on the top layer are alive and they produce a moist surface.
-Hep to also protect the underlying delicate tissues from the external environment.
What is a transitional epithelium?
- A type of stratified epithelium which changes shape to allow an organ or a tube to increase and decrease in size.
What are ciliated cells?
Cells that have hair like projections on the surface and there are 200 cilia present on the surface of each cell.
The roles of these cells is to help substances to migrate across the epithelial layer.
Describe epithelial cells with microvilli.
- Some cells contain finger like protrusions and they are known as microvilli.
- They waft substances across the surfaces.
- Microvilli are shorter and wider compared to cilia.
- Can be found in the intestine and they increase the surface area for absorption.
