Connective tissue Flashcards
What are the embryological derivations of connective tissue?
- Mesoderm2. Ectoderm (neural crest)
Which CT cell possesses the cellular machinery for the synthesis and secretion of fibers and ground substance?
Fibroblast (active)
Do active fibroblasts typically divide?
No
Under which circumstances would an active fibroblast divide?
Wound healing (fibroplasia)
Which is another term for a quiescent fibroblast?
Fibrocyte
What is another term for a fibrocyte?
Quiescent fibroblast
What are some characteristics of a fibrocyte compared to a fibroblast?
- Smaller2. Spindle-shaped3. Fewer processes4. Eosinophilic cytoplasm5. Elongated and heterochromatic nucleus6. Nucleoli not visible
What is a myofibroblast?
Cell that possesses characteristics of fibroblasts and smooth muscle cell
Where are myofibroblasts commonly found?
Sites of wound healing
What is a Dupuytren’s contracture?
Ischemic damage to palmar aponeurosis, fibroblasts and myofibroblasts replace Type I collagen with Type III. Contracture at MP joints due to excess deposition of Type III collagen crosslinking with myofibroblasts
Which digits are most commonly affected in a Dupuytren’s conracture?
4th and 5th digits
Unilocular adipocytes are associated with what type of adipose tissue?
White adipose tissue
Which type of adipocyte has a signet ring appearance?
Unilocular adipocytes
What hormone is secreted by adipocytes to decrease appetite?
Leptin
What is the function of leptin?
Appetite suppression
What type of cell secretes leptin?
Adipocyte
What is lipodystrophy?
Loss of body fat
What is the term for loss of body fat?
Lipodystrophy
Which type of adipocyte contains a single large droplet not bound by a membrane by ensheated by vimentin fibers?
Unilocular adipocyte
Are multilocular adipocytes smaller or larger than unilocular adipocytes?
Smaller
Multilocular adipocytes have an abundance of what type of organelle?
Mitochondria
Is the nucleus displaced in multilocular adipocytes?
No
Is a mast cell a fixed or migratory CT cell?
Fixed
From where are mast cells derived?
Bone marrow
Where are mast cells usually located?
CT proper, adjacent to blood vessels and subepithelial layers of respiratory and GI tracts
Are mast cells found in nervous tissue?
No
Is a macrophage a fixed or migratory CT cell?
Fixed
What are the cytological characteristics of a macrophage?
- Oval nucleus2. Clumps of heterochromatin along nuclear envelope3. Typically indented4. Eccentrically positioned in cytoplasm
Which organelles are abundant in macrophages?
- Golgi2. rER3. Lysosomes
What are two functions of macrophages?
- Phagocytose cellular debris2. Antigen presentation (to lymphocytes)
From what cell lineage are plasma cells?
B cells
What are the cytological attributes of plasma cells?
- Large, ovoid2. Eccentrically located nucleus3. Clock face nucleus (heterochromatin dispersed around it)4. Very basophilic (a lot of rER)5. Prominent negative Golgi at light level
Which cell type has a clockface nucleus?
Plasma cell
Are antibodies secreted in a constitutive or regulated way by plasma cells?
Constiutive
In the ‘first wave’ of leukocyte infiltration, what cell type is most abundant?
Neutrophils
In the ‘second wave’ of leukocyte infiltration, what cell type is most abundant?
Monocytes
