Connective Tissue Flashcards
What is the extra cellular matrix (ECM) composed of?
structural fibers
fibrous proteins
Ground substance
What is the epimysium?
prominent and thick outer covering of muscles
- type of deep fascia
What are 5 examples of connective tissue?
- epimysium
- ligaments
- tendons
- capsules
- cartilage
- bone
- superficial fascia
- deep fascia
What are 3 functions of connective tissue?
- mechanical strength/ support for specialized tissues in organs
- Conduct and control exhange of nutrients, metabolites and signaling ligands
- different cell types in an organ
- cell types and blood vessels - Control behavior and function of cells in contact with ECM
- polarization and shape of epithelia
- guidance/ regulation of cell migration thru matrix
- proliferation, metabolism, differentiation
- defense against infection
- tissue formation, organization, modification
- inflammation, repair due to injury
What are the two types of cells in the ECM?
Core resident cells of CT family
Immigrant blood derived cells (mostly WBCs)
What are the 7 types of core cells of the ECM and what are their functions?
- Mesenchymal
- precursors of all connective tissue
- embryogenesis & adult stem cells - Fibroblasts
- most common in CT - Myofibroblasts
- from fibroblasts
- contractile function - Adipocytes
- store fat as energy - Osteoblasts & osteocytes
- make bone - Chondrocytes
- make cartilage - SOME smooth muscle
- walls of blood vessels
- can synthesize and secrete ECM components
- wound healing
What are 5 types of immigrant blood derived cells and what are their functions?
- Lymphocytes
- acquired immunity - Macrophage
- engulfing/ phagocytosing cells
- secrete and respond to many extra cellular signals - Neutrophils and eosinophils
- defense against microorganisms - Mast cells
- secretory
- promote swelling, allergic reactions - Osteoclasts
- phagocytic: bone reabsorption and remodeling
Name 3 functions of macrophages
- angiogenesis
- immune cell migration/ function
- fibroblast activation
- blood vessel permeability
- remodel damaged tissues
- remodel developing tissue/ organs
How do fibroblasts respond to tissue injury?
proliferate
severe injury: scar tissue = hypertrophy of fibroblast dependent connective tissue
How do fibroblasts contribute to the ECM?
several types
- responsible for enormous variation in ECM structure/ function
- IDd by immunohistological methods
Where do mesenchymal stem cells originate? What type of cells do they produce?
Bone marrow
NOT hematopoietic -> primary precursors of CT cells
Describe the structure and function of collagen. Why is it so diverse?
most abundant 3 intertwined polypeptide chains =>rigid triple helix (alpha chain) - 25 different alpha chains - 17 multimeric collagen types
How does fibrillar collagen assemble?
align head to tail in large bundles => fibrils
- stack bundles -> thickness
- strength
- resistance to tensile forces
- Banding pattern
MOST ABUNDANT (especially type I)
What type of collagen links fibrils together, and links collagen fibers to other tissues?
Fibril associated collagen
What does network-forming collagen do?
form thin fibers -> assemble as interlaced fibers -> form porous sheets
- found in basal laminae
- form filtration barriers
- Type IV