Tissues 1 Flashcards
what are tissues composed of?
Cooperative assemblies of cells and extracellular matrix
what are organs?
cooperative assemblies of tissues
describe epithelial and connective tissue in terms of the following
1) contact between cells
2) apico basal polarity
3) ECM
1) Cells are intimately connected to each other via junctions in epithelial cells. Cells have few contacts with each other in CT
2) Epithelial has apico-basal polarity, connective has no apico basal polarity
3) Epithelial has little ECM and Connective has large ECM
what are 5 major types of tissue
Epithelial, connective, nervous, muscle and blood/lymphoid tissue
Epithelia lines what areas and forms what?
Lines external body surfaces, internal body cavities and tube organs that communicate with exterior
Form secretory parts of glands and their ducts, components of sensory organs. The brain arsises from an epithelium in the embryo
What are the 6 different variations in cell morphology and arrangement in epithelia?
Simple Straitifed Pseduostrat Columnar Cuboidal Squamous
Name the types of epithelia used for the following areas
1) blood vessel
2) thyroid
3) intestine
4) skin
5) bladder
6) respiratory tract
1) simple squamous
2) simple cuboidal
3) simple columnar
4) stratified squamous
5) transitional
6) ciliated pseduostratified
What are functions of epithelia?
Protection from mechanical, abrasion, environmental stresses, water-proof and thermoregulation
The skin (epidermis) has
1) how many layers
2) produces what
3) what structure?
1) multilayered
2) keratins
3) interdigitations of dermis, conenctive tissues
The respiratory epithelium has what properties and lines where?
1) Lines air conducting tubes t lungs
2) secretes mucus
3) cell specialisation such as cilia and goblet cells
How does cystic fibrosis happen?
Genetic defect of chloride channel where there is abnormal export from ER leads to change in mucus properties.
Genetic defect of cilia, dyenin genes results in what?
Immotile cilia, recurrent respiratory disease in children
Primary ciliary dyskenesia, kartageners syndrome is what?
A defect in dynein heavy chain and causes situs inversus and male sterility in addition to high susceptibility of lung infectins
The intestinal tract and kidney tubules use epithelia to do what?
Absorb from lumen of organs
The intestine has what made up of epithelia?
Villi Membrane specialisations (microvilli, brush border) Secrete mucus (Defect in cystic ibrosis leads to GIT/pancreatic problems)
The gut epithelium allows for what
Absorption of nutrient molecules
The apical and basal membranes for the gut epithelium must have what and desrcibe this
Must have different properties
Apical has active transport channels which allow for an increase of glucose uptake
The basal membrane has passive channels and trasnporter proteins which allows for diffusion of glucose to blood.
What in the gut epithelium is present to prevent backflow of molecules
Special cell to cell junctions
Describe the properties the apical and basal membranes have in epithelia. How are the organelles localised?
They are polar
The apical membrane allows for absorpion, secretion, specialisations such as mmicrovilli and cilia
Basal membrane allows for adhesion to ECM, secretion into sub-mucos.
Asymmetric localisation of organelles which reflects function
Epithelial cell junctions are characterised by what type of contacts?
Close cell contacts
What are the different type of junctions for epithelia
Tight, adheren (Desmosomes), gap and focal contacts (Hemidesmosomes)
Explain the following type of cell junctions
1) Tight
2) Adheren
3) Desmosome
4) Gap junction
5) Hemidesmosomes
6) Actin linked cell matrix junction
1) Seals gap between epithelial cells
2) connects actin filament bundle in one cell with that in the next cell
3) connects intermediate filaments in one cell to those in the next cell
4) allows passage of small water soluble molecules from cell to cell
5) Anchors intermediate filaments in a cell to ECM, so anchors basal
6) Anchors actin filaments in cell to ECM, so anchors basal
Tight junctions
1) near where?
2) prevents what across epithelium?
3) separates what so shows what property?
4) essential to maintain what
5) what are the proteins for this junction
6) what allows for strong links to form between the cells
7) an increase in bands causes an increase of what due to what?
1) near the apical surface
2) prevents leakage of molecules
3) separates different membrane domains so shows polarity
4) essential to maintain cell apico basal polarity
5) claudin and occludin in adjoining cells
6) the proteins in tight junctions which forms sealing strands
7) increase in bands causes increase impermeability due to many noncovalent bonds
How can the effectiveness of tight junctions be shown ?
Experiments with tracer molecules show how effective tight junctions are at preventing movement of molecules between cells. Permeability varies.
Adherens junctions
1) link what
2) involve what type of molecules and what is the interaction between these molecules?
3) describe how moelcules from 2) interact with each other
4) What area of the cadherin repeat interacts with the repeat of the other cell?
5) The answer from 2 links to the actin filament via what? and name them
6) one of the answers from 5) functions in growth factor signalling, which one?
7)
1) link the actin filaments in the cell cytoskeleton
2) Involve homophilic interactions between cell adhesion molecules called cadherins
3) Ca2+ interacts with the cadherin domains to form hinge regions between the cadherin domains which allows for stabllisation
4) The N terminal of the cadherin repeat interacts with the n terminal of the other repeat and the calcium stabilises the repeats
5) via linker/adaptor proteins
Beta and alpha catenin, p120 cetnin, ycatenin and vinculin
6) b catenin
