Week 6: Connective Tissues 3 - Cells Flashcards
What are immature cells known as?
‘blasts’ = builders
What do immature cells do?
Immature cells are builders. They synthesis and secrete extracellular matrix (ECM). They can also divide and differentiate into mature cells.
What are mature cells known as?
Mature cells are known as ‘cytes’.
What are mature cells referred to as? What are their role?
Referred to as caretaker cells, i.e., maintain and monitor quality of extracellular matrix (ECM).
What is the role of structural cells?
Structural cells synthesis (e.g., fibroblasts) and store (e.g., adipocytes).
What is the role of defence cells?
Defence cells protect the body against invasion.
What are the main types of defence cells?
Main types seen are macrophages, mast cells, plasma cells, pericytes and white blood cells (lymphocytes, neutrophils and eosinophils)
Explain the difference between a fibroblast and a fibrocyte.
Fibroblast is the younger cell, more active in protein production and in producing the intercellular components, i.e., (connective tissue) fibres, amorphous ground substance (AGS). Fibrocyte is the more mature cell; produces less protein and maintains intercellular components. Fibrocytes are less metabolically active and can revert to active form (fibroblast) in connective tissue injury.
Fibroblast and fibrocyte appearance in H&E sections.
Only the nucleus can be seen (flattened, ovoid nucleus). Cytoplasm is indistinguishable from collagen.
Fibroblast and fibrocyte appearance in EM sections.
Long, cytoplasmic processes, features of protein producing and secreting cell.
What are the functions of fibroblasts and fibrocytes?
Produces all connective fibres and amorphous ground substance. They are also involved in repair: respond to injury by dividing and producing large amounts of collagen, i.e., form scar tissue. During healing, fibroblasts can form myofibroblasts that are responsible for contraction of scar tissue at a wound.
What is the appearance of adipoctyes/ fat cells under H&E?
Huge cell with a thin rim of cytoplasm surrounding a clear lipid droplet; peripheral nucleus.
How are adipocytes found?
They occur as single cells or clumped together to form adipose tissue (a loose connective tissue)
What examples of structural or storage cells?
Fibroblasts and adipocytes/ fat cells.
