Tissues 1 Flashcards
What are the properties of epithelial tissues
- Covers surfaces
- Cells connected
- Separates compartments
- Cells define compartments
- Has a diversity of secondary functions
- Forms glands
What are properties of connective tissue?
- It connects
- Consists of few cells in extracellular matrix and fluid
- Varies from Liquid to solid
Give three examples of connective tissue
Blood
Bone
Adipose
What is the function and features of connective tissues?
- Long thin cells
- Contractile
- Cytoplasm packed with contractile apparatus
- Shortens lengths,
- Closes down spaces
What are the categories of muscle tissue
Skeletel
Smooth
Cardiac
What is the stretch of each muscle tissue
Skeletal & cardiac-Limited
Smooth- can stretch
What is nervous tissue important for?
Important in communication
What does nervous tissue consist of?
neurones and support cells (glee)
What does nervous tissue do?
- Receives, generates and transmits electrical signals
- Integrates information from around the body
What are the histological features of skeletal muscle?
- striated
- highly ordered arrangement of contractile proteins
- multiple nuclei per cell
What are the histological features of cardiac muscle?
- striated
- highly ordered arrangement of contractile proteins
- single nuclei per cell
What are the histological features of smooth muscle?
- non-stirated (smooth)
- less ordered arrangement of contractile protein
What do motor neurones consist of?
-cell body(soma)
-dendrites on cell body and terminal
axon and terminals
What do sensory neurones consist of?
- cell body at side of axon
- dendrites and receptor and terminal
- axon
Plasma membrane involved in what in nerve physiology
generation and conduction of action potentials
Endothelium
refers to cells that line the inside of blood vessels
N.B this is technically not just a type of epithelium as has vimentin not keratin
How does epithelial tissue maintain coverage of surfaces?
- Contact inhibition
- strong Cell-cell junctions allow them to stick together
- strong Cell-ECM junctions
what is a desmosome?
a cell-cell junction in which which cells stick together by a plaque of protein and filamentous proteins radiate out.
What is the purpose of a desmosome?
Firm anchorage
What type of junction is a desmosome?
cell-cell junction
What causes some desmosomes to be less strong than others?
some desmosomes lack plaque protein in centre
what type of junction is a tight junction?
cell-cell junction
what are desmosomes also know as?
adhering junctions or macula adherens
What is the function of a tight junction?
seals intercellular spaces
- prevents liquids leaking out or in
What is the tight junction also known as?
occluding junctions
What function do tight junctions serve in intestine?
seals intercellular junction between villus, preventing leak of digestive enzymes and bacteria into blood
what type of junction is a gap junction
A cell-cell junction
what is the function of a gap junction?
Cell to cell communication
what is another term for gap junction?
communicating junction and nexus
How do gap junctions allow for communication?
Holes in the membrane allow for the movement of small molecules (e.g. Calcium ion) which are involved in singling
What its an example of a gap junction?
cardiac muscle-due to gap junctions all heart muscle contracts together
What is the basement membrane composed of?
Basal Lamina, which sits on top of Reticular Lamina
What is a Hemidesmosomes
Half a desmosome
connecting epithelial cells to basal Lamina
Cell-ECM junctions
- Skin to basal lamina
- Blood vessel endothelium to basal lamina
- both use hemidesmosomes
Secondary roles of endothelium
- Thick to resist wear and tear (e.g. skin)
- Thin to allow diffusion
(e. g. lining of alveoli or “endothelium of blood vessels”-technically not epithelium) - Movement:Cilia
- Absorption:microvili
What are cilia ?
Finger like projections from the apical surface involved in movement
What does the apical surface face?
lumen or external environment
what does basal surface face ?
basement membrane
what is cilia made of?
9+2 arraignment of microtubules (made of tubulin) to give movement
how many cilia are there per cell?
100s
dimensions of a cilium
5-10 x 0.2 microns
where would cilia be found?
e.g. trachea
What are microvilli?
finger like projections from apical surface involved in absorption or secretion
dimensions of microvilli
0.5x <0.1 microns (smaller than cilia)
where would microvilli be found?
in small intestine on villus
what are microvilli made of
actin cytoskeleton +spectrin cross links
What is epithelial tissue good at
adaptive power (e.g. epidermal stem cells) reiterative power e.g. after skin cut
What does the function of epithelial tissue depend on
the cells and not the extracellular matrix
What is simple epithelia?
one cell thick
what is stratified epithelia?
multiple cells thick
what is Squamous epithelia?
thin layer
What lines the mouth and blood vessels?
Simple Squamous epithelium
what is cuboidal epithelia?
roughly cube-like, similar width as height as depth
what is columnar epithelia?
noticeably more long than wide
lining of gut and ovary is (….) epithelium
Columnar epithelium
What epithelial tissue is skin made of?
Stratified Squamous epithelia with stem cells at Bottom and keratin at top.
what epithelial tissue lines Salivary gland?
Stratified Cuboidal and Columnar
what are stratified transitional epithelium? and what are there functions
AN epithelia that:
only lines the bladder and most of urinary tract (some portions of urethra not lined)
- round
- flexible as bladder stretches a lot
- protective and impermeant to urine and its toxins
What are Pseudostratified c(olumnar) epithelium
Not stratified but appears stratified, with all cells touching basement membrane and hence cells all having different shapes.
The trachea for example has pseudostratified (columnar) epithelium
NB. rarely occurs in cuboidal or squamous tissue.
