Connective tissue Flashcards
Main function of connective tissue:
Regulation
What do macrophages do?
- Phagocytosis
- Angiogenesis
- Cytokine signaling
What are the 3 classes of collagen?
- Fibrilar collagen (long cables)
- Fibril-associated collagen
- Network Forming Collagen
What is the role of Fibrillar collagen?
Collagen Type I
Rope like structures that promote tensile strength.
What does Fibril-associated collagen do?
Link collagens fibers together or to other tissue components.
What does network forming collagen do?
Collagen Type IV
Help make up the basal lamina.
Where does triple helix assembly occur for collagen?
Intracellularly.
Why are N-telo peptides important?
Their levels in Urine and blood are used to diagnose CT diseases.
Fragments also initiate formation of collagen fibrils, and catalytic bonding between collagen molecules.
What makes elastic fibers?
Elastin and Fibrilin fibers.
Marfan’s is caused by a defect in…
Fibrilin protein and therefore elastic fibers.
What are 3 important properties of GAGs?
- Highly - charged
- Rigid extended structure–> gel formation
- Activate or inactivate other proteins.
What makes the Ground substance?
- Proteoglycans
- Other proteins and glycoproteins.
- Solutes and H2O
What are the 3 steps in Tissue repair?
- Inflamation in blood clotting (increased perm of H2O and cells)
- Proliferation Phase(fibroblasts activated and divide. ECM is produced)
- Remodeling (macrophage recruitment)
Cartilage that grows at the surface via mesenchymal stem cell growth is
Appositional growth.
What do osteocytes do?
Modify matrix and sense it as well. They have long processes that extend through canaliculi.
They can signal for bone growth.
What do osteoblasts secrete?
Osteoid and matrix vesicles.
Matrix vesicles contain Ca and PO4.
Where do osteoclasts come from?
Monocytes (macrophages) in the blood that differentiate in bone marrow.
What role do osteoclasts play in the body?
- Degrade cartilage and bone matrix
- Recruit blood vessels(angiogenesis) and other “bone cells”
- Recruit nerves
T/F Bone marrow can have interstitial growth.
False. Bone only grows at the surface via appositional growth.
Describe the formation of a long bone:
Begins as a cartilage model which grows interstitially and appositionally.
Ossification begins to occur at the center of the long bone (primary ossification). This recruits nerves, blood vessels, and bone cells.
Secondary ossification occurs later at the epiphyseal growth plate.
Where does the majority of ca mobilization occur?
Endosteum.
Think of all the surface area.
Which hormone increases blood Ca levels?
Parathydoid
think that the calcium “va para el tyroid.”
What 4 things stimulate bone formation?
- Short range signals (such as BMPs)
- Long Range signals (calcitonin/PTH)
- Mechanical stress
- Neuronal Stimulation
