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What are the 2 general types of connective tissue cells?
- Resdient cells
- Wandering cells
Describe the general category of wandering cells?
- Derived mostly from leukocytes
- move from different compartments
What are the cells contained in the wandering cell category
- Plasma cells
What are the cells in the resident cells category?
- Mesenchymal cells
- Reticular cells
- mast cells
is connective tissue mostly cell or ECM?
Name 3 functions of connective tissue (random 3 but here are 3 good ones)
- Diffusion of nutrients and wastes to and from cells to blood vessels
- tensile strength of body
connective tissue derives from what embryonic layer?
What are the 2 types of connective tissue stem cells that begin the 2 linneages
- undifferentiated mesenchymal cells
- heopoietic stem cells
Describe the mesenchymal cell` wher eis it found?
- Irregular shape with multiple processes
- Pluripotent reserve
- embryonic connective tissues or close to blood vessels in adults
Are there many mesenchymal cells in the adult?
No just a few for repair
Describe the connective tissue of an infant?
Very gelatinous, no fibres if there were fibres at this stage the body would not be very moldable
SHOULD GO OVER THE PICTURES IN THIS LECTURE SO HAVE AN IDEA WHAT YOUR LOOKING AT, MOST OF THE SLIDES ARE PICTURES
What is the function of the fibrocyte and blast?
To produce fivres that lend tensil;e strength such as collagen
Which stage actually produces the fibres in the fibrocyte or the fibroblast? What is unique betrween the relationship with these 2 cells?
- They can go back and forth
As compared to smooth muscle the fibrocyte/blasts look much more
Pink in colour and have a more spindly shaped NUCLEUS
What is bigger in connective tissue, the fibres or the cells creating the fibres
What does a reticular cell look like?
Similar to a mesenchymal cell, styar shaped in appearance
What does the reticular cell do?
- Produces collagen meshwork to hold things in place
- ex) the connective tissue surrounding individual cells
IS a reticular cell the same as a reticulocyte?
- Reticulocyte - RBC
- Reticular cell - connective tissue cell
What do adipose cells look like?
Rings with diamonds stacked on the side, very white in the center
Do adipose cells have lots of cytpoplasm? Where is it?
NO any remaining cytoplasm and nuclei are squished up against the cell membrane
Differentiate between a multilocular adipocyte and a adipocyte
- Multi = brown fat, instead of having 1 big fat droplet has many droplets and many many special mitochondria that produce only heat. important for babies and hibernating animals
- adipo = white fat
What is a mast cell?
- initiates allergic reactions in the body
- sits close to blood vessels
- don't stain well in H&E
Why don't mast cells stain well in H &E?
Lots of histamine granules
Which connective tissue cell causes anaphalactic shock?
What do macrophages get up to?
- Release of cytokines to attract neutrophils
- processes antigens for immunity
Why does a macrophage look like it has lots of holes within?
Cause it is phagocytising almost constantly. little projections coming out of the cell
What is a plasma cell?
Very very active B lymphocyte they go into tissues and produce tonnes of antibodies they have very prominent golgi
What is the ground substance made of?
- Multi adhesive proteins
Basically a lot of carbs and a protein core
Where does the ground substance get its hydrophilic nature?
What are 3 types of multi adhesive proteins found in the ground substance
How many types of glycosaminoglycans are there? Name them
- non sulfated - hyalouronic acid
- sulfated - chondroitin 4 sulfate and chondroitin 6 sulfate
- -dermatin sulfate
- -keratin sulfate
- -heparin sulfate
Describe where the following GAGs are found?
Chondrotin 4 sulfate
chondrotin 6 sulfate
- hyalouronic acid - umbilical chord, synovial fluid
- Chondrotin 4 sulfate - cartiledge bone skin
- chondrotin 6 sulfate - cartiledge skin
- dermatan sulfate - skin tendons
- heparin sulfate - lung liver
- keratin sulfate - cornea (1 type) cartiledge (other type)
Note: all types other tha H acid and keratin are found in the aorta
Describe the physical structure of the ground substance
- many proteoglycan monomers stuck onto a long hyaluronic acid, with collagen fibers jutting inbetween like railroad tracks
- A proteoglycan monomer is formed of mans GAGs surrounding a protein core
What are the three connective tissue fibers?
- Collagen fibers
- Reticular fibers
- Elastic fibers
What is the most abundant protein in the body?
collagen fibres are made up of?
Collagen bundles are made of? Which are made of?
The function and properties of collagen are?
Tensile and mechanical strength
Describe how collagen polypeptide strands become fibrils
- 3 proteins twist around eachother making a procollagen
- Added end to end and twisted together with other procollagen to make a fibril
What is at first stopping the procollagen from coming together end to end and forming fibrils? Where does it have to go to have it removed by what?
- terminal peptides inhibiting end to end interactions
- Has to leave the fibroblast or whatever cell is making it and in the connective tissue peptidyase cuts off the end
why do we see striations on collagen stuck together to make connective tissues?
Because when procollagen joins together end to end it does not actually touch, it leaves a small gap inbetween
What joins all the fibrils together?
Describe from a collagen polypeptide to a collagen bundle
What surrounds each fiber? Bundle? Tendon? What are these made of?
Collagen fibres themselves however just make a sheet and have collagen fibrils going in different directions so not so regulated
The fact that all fibres in a tendon run parralell to eachother lends to the tendons
Around each fibre as well as a endtendineum there is also a what? (squished like a triangle)
Fibroblasts present for repair and rejuvination
Do tendons heal fast?
There are more than 20 types of collagen, however 4 main groups, what are these groups? (what numbers for bonus marks)
- Fibril forming - 1,2,3,5,11
- Fibril associated - 9,12,14
- Anchoring fibril forming - 7
- Network forming - 4
Fibril forming collagen obviously makes fibrils but describe what type 1,2, and 3 do
- 1 = makes bundle
- 2 - makes cartidledge and bundles
- 3= lots of associated carbs stays as fibrils, becomes reticular fibres
fibril associated proteins do what? anchoring fibril forming collagen does what? Network forming collagen does what?
- help interactions between fibrils (glue)
- Network forming, as well as associated with basal lamina
- Associated with basal lamina
Does collagen stretch?
Most abundant collagen type?
Where do you find the elastic fibers around the larger blood vessels? Are they in contact with the blood?
No they are inbetween the endothelium and smooth muscle
Reticular fibers are also known as what type of collagen fiber?
Are reticular fibers actually fibers in reality?
Reticular fibers function is to?
Hold cells together,not so much tensile strength
Elastic fibers are secreted by the? And are made up of?
- Fibrillin, and elastin
elastic fibers tend to congregate into what type of formation?
How do elastic fibers connect?
Covalent bonds in cross linking
Where do elastic fibers get their elastic properties from?
The coily and bendy kinky nature of the fiber, when relaxed it goes into its super coiled form and then when stretched it stetches out
Connective tissue is classified based on what 3 criteria?
- Type of cells and fibers
- arrangement of fibers - direction they run
Why do tendons only have strength in one direction?
Cause they only run in one direction
Whjat are the three types of cells and fibers that we can classify connective tissue by?
- Elastic tissue
- Collagen tissue
- Reticular tissue
What are the two types of embryonic connective tissue?
- Mucous connective tissue
Do embryonic connective tissues tend to have high or low levels of connective fibres around them?
Low if any at all
How can you tell mesenchymal tissue from mucous connective tissue?
Cant without special stain to stain carbs on mucusous
Where do we find mucous connective tissue in adults?
Small amounts in umbilical chord other than that no where?
What would the mesenchyme look like?
Tsar shaped cells. lots of mitosis, cytoplasm stains poorly
What are the two designations given to the two ways connective tissue can run
- regular - parallel
- irregular - all over hell
What is loose irregular tissue used more for rather than its tensile strength?
Provides some space to hold onto fluid and provide nutriotion to surrounding cells
What would be your fibre to ground substance ratio in loose irregular connective tissue?
How can you identify dense connective tissue?
Must be in comparison to loose
Dense irregular connective tissue unline loose likely has more of a ______ function in all directions
tensile and mechanical strength
In dense connective tissue do we see a higher ratio fo cells or lower as compared to loose connective
lower much lower
regular connective tissue has tensile strength in? and often forms? they are all running the same?
- 1 direction
a tendon in terms of its connective tissue classification is a?
Dense regular tissue arranged at the end of a muscle
Elastic fibers typically make?
Why don't we refer to elastic sheets are regular or irregular?
Cause almost always more or less parrallel
An adipose tissue is?
A tissue that includes large amounts of adipose cells