Chapter 6 - Connective Tissue Flashcards
What is ECM made out of? (3)
- Fibers
- Amorphous Ground Substance
- Extracellular Fluid
Types of embryonic CT? (2)
- Mesenchyme
- Mucos CT
When does mesenchyme tissue develope?
Established early in embryo, only found in the mesoderm
What does mesenchyme tissue give rise to?
Various CT of the body
What does mesenchyme CT look like?
Small
Uniform
Spindle-shaped cells
3D cellular network
Viscous ground substance with lots of reticular fibers
What type of collogen is reticular fibers? Where are they found? What are they indicitive or?
Collagen III, very thin
Indiitive of immaturity (new wound) or of a low force area (ex protected in embyonic fluid)
What are the characteristics of mucous CT?
Loose network of collagen fibers
More fibers than mesenchyme
Type I collagen replaces reticular fibers of mesenchyme
Widley-spaced mesenchymal cells = appear fibroblast-like
What is worton’s jelly? Where is it found?
A specialized felatin-like ECM
In Mucous CT
Where is mucous CT found?
In the umbilical cord
What are the types of CT proper?
- Loose (areolar)
- Dense (could be irregular or regular)
What are the characteristics of loose CT?
Thin, sparse like collagen fibers
Lots of ground substance
What occurs at sites with loose CT?
Inflammatory and immune reactions
Where is loose CT located? (3)
- Under the epithelial layer
- Glands
- Small Blood Vessels
What function does fibrobast serve?
Fibroblasts makes all the fibers and ground substance in all CT proper
Why do immune responses happen in loose CT?
Loose CT is near blood vessels and the epithelium which is a survalence point for the immune system
What are the characteristics of dense CT?
Bundled, web-like collagen
Sparse cells
What does the irregular organization of collagen I in irregular dense CT promote?
Increasing the irregularities increases the strength of the CT and decreases tearing
What is the only cell type in dense CT?
Fiberblasts
Where is irregular dense CT found? (2)
- Submucosa
- Reticular (deep layer)
What are the characteristics of regular dense CT?
Ordered in dense collagen bundles
Minimmal ground substance
Where is dense regular CT found? What is it doing at each location? (3)
- Tendons - bind muscle to bone
- Ligaments - bind bone to bone
- Aponeuroses - anchor muscles to broad flattened tendons (ex on palm of hand or footpad)
Are there blood vessels in Dense CT?
No
What is the peratindinum? Where is is located? What is its purpose?
Surrounds fibers in DCT and is a collection of blood vessels, nerves, and LCT (?)
What two componets make DCT elastic?
Collagen I + elastic fibers
What are the 3 components of ECM?
- Fibers
- Ground Substance
- Tissue Fluid
What are the 2 main components of CT?
- Cells
- ECM
What are the two types of fibers found in CT?
- Collagen
- Elastic
What is the most abundent structural component of CT?
Collagen
What are the characteristics of collagen?
Felxible with high tensile strength
Ineslastic
What is a fribil?
The largest collogen strucute made of overlaopping collagen molecules
A collagen molecule is composed of 3 _ chains with every third amino acid being ______
Composed of 3 alpha chains
Third amino acid being glycine
List the ordered structure of collogen from smallest to largest
Amino acids
Triple amino chains
Collagen molecule
Stagered confirmation
Fibril
alpha chains vary in ____ and ______
size and composition
Fibrillar collagen from what kind of bundels?
Tight bundles
Type I, II, III, IV
Basement membrane forming collagen
Make net like structure
type IV
What are FACITS?
Fibular Associated Collagen with Interuppted Triple helices
No packing
Kink acts as connection
What are the 3 main steps of collagen synthesis? (2)
- Transcription and Translation
- Post Translation Modifications
- Assembly into Fibers
What post-translation modifications occur in collagen synthesis?
- Add hydroxyl gorups to Lys and Pro to make hydrogen bonds
- Gycolylation at N and C terminus and hydroxy-lysines
- Cleavage of globular ends by proteases
What happens if you don’t get the hydroxylation of pro and lys during collagen synthesis?
You decrease the amount of type I collagen which leads to weak bones, wounds that don’t heal, and teeth that bleed and fall out
What happens inf you don’t get the glycosylation of specific hydroxy-lys residues?
No covalent bonds in fibers, the collagen won’t hold its shpae which means you don’t get any fibrils
What types of collagen form the fibrillar core of type I collagen fibrils? What type is deposited on the fibrillar core?
Type V (dictate how think fibril will become - is a FACIT)
and XI
Type I deposited on fibrillar core
What type of collagen does type II collagen fibril associate with? What is its function?
Type IX
Type IX connect fiber to ECM components
What are the characteristics of reticular fibers?
aka type III collagen
narrow, branching fibrils
thread-like
mesh-like pattern
thin and wispy
Where are reticular fibers found? (5)
- Boundary of CT and epithelium
- Adipocytes, small blood vessels, nerves, muscle cells
- Embyronic tissue (mesemchyme)
- Hematopoietic and lymphatic tissue (anchoring point for lymph node attachment)
- Bone Marrow
What do elastic fibers allow tissues to do?
Stretch and expand
Are elastic fibers by themselves?
No, they are always in combination with collagen which gives them strength
What are the characteristics of elastic fibers?
Thinner than collagen
Branching patter froms a 3-D network
Where are elastic fibers located?
- Vertebral ligaments - hold the spinal cord together
- Larynx - vocal cords, you want gentel recoil back into position
- Elastic Arteries - you need it to expand and also come back into position
What are the two components of elastic fibers?
- Elastin - forms the central core
- jFibrillin-1 - microbril that forms substrate for elatin deposition
What two structural aspects of elastin fibers allow it to stretch and relax? (2)
- Desmosine covalently bonds to 4 molecules in the elasin which creates kinks
- Random coils due to hydrophobic glycine
What is Marfan’s syndrome? What is it caused by? What is present and what is lacking? Symptoms? What heart condition can this lead to?
Marfan’s syndrome is caused by a mutation in fibrilli-1 which causes there to be no microfibrils and so elastin doesn’t organize it self into elastic fibers
Tall, elongates fingers and arms, hallow chest
If there are no elastic fibers in the arota, overtime it won’t snap back into place which can cause an anerasym and aortic dissection which is when the aorta pulls away from the heart
What famous person is thought to have had Marfan’s syndrome?
Abraham Lincoln
What are the characteristics of ground substance?
Jello-like consistancy
Viscous, clear substance
High water content
What are the three major components of ground substance?
- Glycosaminoglycans (GAGs)
- Proteoglycans
- Multiadhesive glycoprotiens
What are GAGs?
long-chain unbranched polysaccharides with repeating disaccharide units
What are GAGs responsible for in the ground substance?
GAGs provide the physical properties of ground substance like its ability to disperse forces
It does becasue it is anionic. the negative chage draws in cations like Na which water follows and makes it like jello
Why do people dink bone broth?
It is high in CT which means its high in GAGs which are good fro your skin and hair
What is hyaluronic acid? What role does it play in the ground substance in ECM in CT?
Hyaluronic acid is the largest GAG by far,
it is a free floating carbohydrate chain
Forms ridgid rod-like structures and is the backbone for proteoglycan aggregates
What is a proteoglycan made out of? What is a principal characteristic?
Core protien + GAG
It is very anionic (so it draws in a lot of water)
What are multiadhesive glycoprotiens? Where are they found? What do they do?
They are found in the ground substance and help stabalize the ECM and link the ECM to cell surfaces
What four molecules (?) are types of multiadhesive glycoprotiens?
- Fibronectin (connect basement membrane)
- Laminin (connect basement membrane)
- Tenascin (found in embryonic mesemchyme)
- Osteopontin (connects to calcium in the bone which attracts phoshphates and leads to mineralization)
What does tissue fluid in ground substance carry? How quickly does it move?
Tissue fluid carries nutrients and oxygen
It moves slowly
What are the two overarching cell typs for CT tissue?
- Resident
- Transient - all immune cells
What are the four resident cells in CT?
- Fibroblasts and myofibroblasts (have contractile function like muscles)
- Macrophages
- Mast Cells
- Undifferentiated mesenchyme
What is the role of fibroblasts in CT?
They make everything: all the fibers and the ground substance
They are in every type of CT and they are the most abundant
How does the size and abundace of fibroblasts change in a wound?
They are more abundant and larger in wounds
They cause scar tissue (?)
What are 3 functions of macrophages?
- Phagocytosis
- Antigen presentation
- Cytokine production
While in tissues macrophages are called macrophages, but in the blood they are _____
Monocytes
What do mast cells do?
Secrete mediators of inflammation
Filled with basophilic granules with histamine, histadine, neprin
Where do mast cells develop? Where are mature mast cells located?
Mast cells develop in bone marrow from hemopoietic stem cell and mature after migrating to CT
Located: skin, hair follicles, glands
What do mesenchymal stem cells do?
They give rise to differentiated cells during repair and formation of new tissue (i.e. wound healitn, neovascularization)
What are transeint cells? What do they do?
They are cells that come and go from the CT
Primarily immune cells
Responsive to chemotactic signals that recruit cells form blood to CT
Identify the structure

Mesenchyme Cells
Identify the structure

Mesenchyme (Embryonic CT)
Identify the structure

Mesenchyme (embryonic)
Identify the structure

Mucous CT (embryonic)
Identify the structure

Mucous CT (embryonic)
Identify the structure

Loose CT (CT Proper)
Identify the structure

LCT (proper)
Identify the structure

LCT (proper)
Identify the structure

Irrecular DCT (proper)
Identify the structure

Regular DCT (proper)
Identify the structure

Regular DCT (proper)
Identify the structure

Regular DCT (proper)
Identify the structure

Regular DCT (proper)
Identify the structure

Top: Fibril
Packaging
Collagen molecule
Triple amino chain
amino acid chain, glycine is every 3rd aa
Identify the structure

Type I Collagen Fibril
Identify the structure

Type II Collagen Fibril
Identify the structure

Reticular Fibers (type III collagen fibers)
Identify the structure

Elastic Fibers
Identify the structure

Top: core protien
GAG
Hyaluronan
Overall: type I collagen fiber
Identify the structure

Top: Elastin
Microfibrils (fibrillin - 1)
Identify the structure

Marfan’s Syndrome
There is a lack of elastin organization on the left due to lack of fibrillin-I
Identify the structure

Top: GAG
Core protien
Identify the structure

Multiadhesive Glycoprotiens
Identify the structure

Fibroblasts
They are larger and more abundent in the bottom image because it is showing wound repair
Identify the structure

Fibroblasts
Identify the structure

Macrophages
Identify the structure

Macrophages
Identify the structure

Mast cells filled iwth basophillic granules
Identify the structure

mast cell with basophilic granules
Identify the structure

Mesenchymal Stem Cells
Identify the structure

Transient Cells
Identify the structure

Transient Cells