Epithelial Cells Flashcards
What is extracellular matrix (ECM)?
material deposited by cells which forms the “insoluble” part of the extracellular environment
What is ECM generally composed of?
Fibrillar proteins (collagens, elastin) embedded in a hydrated gel (proteoglycans or ground substance)
What are some examples of poorly and highly organised ECM?
Poorly organised - Loose connective tissue
Highly organised - Tendon, bone, basal lamina
What are the 5 main cell types?
Connective
Contractile
Haematopoietic
Neural
Epithelial
Connective tissue examples
Chondrocytes (cartilage)
Osteocytes (bone)
Fibroblasts (many tissues)
Contractile tissue examples
Skeletal, Cardiac and Smooth muscles
Haematopoietic cell examples
blood cells
tissue-resident immune cells
bone marrow cells
Neural cell examples
Neurones and Glial cells
What is carcinoma?
Epithelial cell cancer
What is sarcoma?
Mesenchymal (connective and muscle) cancers
What is leukaemia?
Haematopoietic cancer (bone marrow cells)
What is lymphoma?
Haematopoietic cancer (lymphocytes)
What is neuroblastoma?
Neural cell cancer (neurones)
What is glioma?
Neural cell cancer (glial cells)
What is epithelial cell cancer called?
carcinoma
What are cancers of mesenchymal tissue called?
Sarcoma
What are the 2 types of haematopoietic cancers?
Leukaemia and Lymphoma
What are the 2 types of neural cancers?
Neuroblastoma and Glioma
Functions of Epithelial cells
transport, absorption, secretion, protection
How are epithelial cells classified?
According to their shape and layering
What type of epithelium is flattened, plate shaped?
Squamous
Name the epithelium (shape+layering)
Simple squamous
What type of epithelium is arranged in columns?
Columnar
Name the epithelium (shape+layering)
Simple columnar
What type of epithelium is cube-like?
Cuboidal
Simple cuboidal
What is the term given for multi-layered epithelium?
Stratified epithelium
What type of epithelium is found in lung alveoli?
Simple squamous
What type of epithelium is found in mesothelium (lining major body cavities)?
Simple squamous
What type of epithelium is found in endothelium lining blood vessels?
Simple squamous
What type of epithelium is this?
Simple squamous
What type of epithelium is found in ducts such as kidney collecting ducts?
Simple cuboidal
What type of epithelium is this?
Simple cuboidal
What type of epithelium is found in surfaces involved in absorption and secretion (e.g. enterocytes lining the gut)?
Simple columnar
What type of epithelium is this?
Simple columnar
What are the 2 sub-types of Stratified Squamous epithelium?
Keratinizing - dead cells due to kerating production, thicker, e.g. skin
Non-keratinizing - nuclei and organelles in-tact
What type of epithelium is found in mouth?
Stratified squamous epithelium
What type of epithelium is found in oesophagus?
Stratified squamous epithelium
What type of epithelium is found in anus?
Stratified squamous epithelium
What type of epithelium is found in cervix and vagina?
Stratified squamous epithelium
What type of epithelium is this?
Stratified squamous
Is this epithelium keratinizing or not?
Is this epithelium keratinizing or not?
What is pseudo-stratified epithelium?
Multi-layered like appearance but each cell is in contact with the basal lamina
Identify epithelium
Pseudo-stratified (columnar) epithelium
What type of epithelium is found in airways (trachea and bronchi)?
Pseudo-stratified columnar
What type of epithelium is found in various ducts in urinary and reproductive tracts?
Pseudo-stratified columnar
Identify apical and basolateral domains and junctions
Is this epithelium polarised?
Unpolarised, as ions move both in and out from both domains
Is this epithelium polarised?
Polarised, as ions move towards one direction from each domain
Which one is polarised?
One on the right is polarised
Why are the mitochondria in transport epithelia concentrated in the basal aspect of cells?
Provide ATP for active transport on the basal membrane
Identify the enterocytes and goblet cells within the villi epithelium
Identify the enterocytes and goblet cells within the villi epithelium
What is the brush-border in the gut lumen?
Formed by microvilli, rich in active transporters and channels for nutrient uptake
What are the 2 types of secretion?
Exocrine - into a duct or lumen
Endocrine - into the bloodstream
Is this a exocrine or endocrine secretory cell?
Exocrine as secretion is from the apical membrane
Is this a exocrine or endocrine secretory cell?
Endocrine as secretion is from the basal membrane into blood
What is the term used for dead epithelial cells being replaced by proliferation of stem cells?
Epithelial turn-over
Which cells replace the cells lost from the tips of intestinal villi?
Cells in intestinal crypts
Why do some chemotherapies cause gastrointestinal disturbances?
They inhibit cell proliferation which results in loss of the finger-like intestinal villi and flattening of the intestinal mucosa
What happens when there is too much epithelial cell proliferation in colon?
Increased number of cells lead to a tumour growth, in colon, called adenoma (polyp)
Why are the basal cells in epider not keratinized?
They are dividing cells and while migrating, they undergo a programme of differentiation that eventually leads to them flattening out and keratinising
What is the result of hyperproliferation of epidermal epithelial cells?
Formation of a thick hard layer on the skin
What can cause hyperproliferation other than pressure and abrasion?
Infectious agents, such as HPV, hijack the cellular machinery of stratified squamous epithelia and inducing increased cell proliferation
