Lecture 3 Flashcards
What holds cells together?
Cell to cell adhesion molecules
Extracellular proteins
Internal-external scaffolding
Close proximity (pressure effect)
Difference between connective and epithelial tissue
Connective lots of extracellular matrix
Connective rarely do cells contact each other
Cells sparsely distributed
Matrix rich in fibrous polymers like collagen
Epithelia have cells bound together in sheets
What is the difference between parenchyma and stormal tissue?
Parenchyma is the functional tissue of an organ
Stromal tissue is the structural tissue of organs, generally connective
What is the primary cell of connective tissue?
Mesenchymal stem cell (mesoderm) and becomes a fibroblast
What is connective tissue made of?
Cells- primarily fibroblasts
Fibres- collagen, elastin, reticular
Ground substance- glucosaminoglycans such as hyaluronic acid
Function of fibroblasts?
Make extracellular matrix and collagen
Connective tissue functions?
Binding and support Protecting Insulating Separating tissue and organs Storing fuel and cells Transport of substances
What is paracellular transport?
When substances move between cells through tight junctions in the case of epithelium
What is the role of tight junctions?
To prevent larger molecules from moving through the epithelium and into deeper tissue layers.
What are endothelial cells?
Specialised epithelial cells that line blood vessels.
What are adhesion junctions?
Make a belt all the way through epithelial layer to keep cells together and also act as a barrier.
What is the strongest cell to cell adhesion?
Desmosomes- only adhesion found in epidermal cells
What is the role of gap junctions?
Important role in muscle contraction as allow the movement of calcium between cells in cardiac and smooth muscle.
Where are hemI-desmosomes found?
At the basal surface of epithelial cells. Anchor cell to basal lamina and prevent loss of epithelial cells.
What do all epithelial cell adhesion methods require to work?
Calcium
How do epithelial cells join to muscle?
Through connective tissue fibres
How does tissue adhere to other tissue?
Through connective tissue
How do cells of different types communicate?
Nerves and hormones
What is a mucous membrane or mucosa?
Combination of epithelium, basal lamina and lamina propia
What is the lamina propia?
Areolar connective tissue that sits under the basement membrane
What are the layers of the gi tract called?
Mucosa or mucous membrane Muscularis mucosa Submucosa Muscularis Serosa
What type of epithelium would you find in the oesophagus?
Stratified squamous non keratinised
What is the function of rugae in the stomach?
Folds of gastric mucosa that form longitudinal ridges in stomach and alert you when full
What epithelium do you find in the jujunum?
Simple columnar
What are plicae circulates?
Circular folds of mucosa and submucosa that project int the gut lumen.
What type of epithelium do you get in the large intestine?
Simple columnar
What is the big difference in structure between large and small intestine?
Large intestine has no villi.
Function of GI mucosa?
Movement f cents and expel waste
Prevent entry of pathogens
Provide lubrication
Why is the muscularis of the urethra thin?
Gravity will bring urine out, don’t need muscle to do it.
Function of fat in bladder?
Fat absorber for when it expands
Transitional epithelium in bladder?
Urothelium
Difference between urethra and bladder?
Bladder has transitional urethra has squamous and keratinised squamous at outlet. Mucus glands to prevent ingress of pathogens
Is the respiratory tract a true mucosal membrane?
No as its muscle layer is not smooth
Will foreign objects lodge more easily in the left or right lung?
The right as its a more vertical path down as no heart in the way
Epithelium of primary bronchi?
Pseudostratified ciliates columnar
What is the mucocilliary escalator?
Movement of material to oral cavity where it can be swallowed by wave motion of cilia
What is a mucous membrane?
Combination of epithelium, basal lamina and lamina propia
