Connective Tissue Flashcards
State four functions of basement membranes.
(1) Provide physical binding of the epithelium to the underlying tissue and physical support.
(2) Control of epithelial growth and differentiation, they form a barrier to downward epithelial growth; this is only breached if epithelia undergo malignant transformation (cancer)
(3) Permit the flow of nutrients, metabolites and other molecules to and from an epithelium, as epithelium is devoid of blood vessels
(4) Where a cell layer acts as a selective barrier to the passage of molecules from one compartment to another (e.g. between the lumen of blood vessels and adjacent tissues), the basement membrane assumes a critical role in regulating permeability.
Name the type of collagen found in the basement membrane.
type IV collagen
Name two glycoproteins that binds the type IV collagen to the basal plasma membranes of epithelial cells.
laminin and nidogen (entactin)
Name three layers of the basement membrane as seen under electron microscopy.
- lamina lucida
- lamina densa
- lamina fibroreticularis
Name two diseases caused by disorders of basement membranes.
- Alport disease
- Goodpasture syndrome
Name three types of adipose tissue.
- White
- Brown
- Beige
State differences between white and brown adipose tissue. (5)
- WAT is unilocular whereas brown adipose tissue is multilocular.
- WAT cells have few mitochondria whereas BAT cells have numerous mitochondria.
- WAT - cytoplasm occurs as a narrow rim, and the nucleus of the cell is pressed near the margin, BAT - cytoplasm occurs throughout the cell, and the nucleus can be found at the centre of the cell
- WAT has few capillaries, BAT is highly vascularized
- WAT is an energy storage site, BAT is specialized for energy expenditure and thermogenesis
What stain is appropriate for reticular fibres?
silver stain
Where is dense irregular connective tissue found? (3)
reticular dermis of the skin, submucosa of GIT, sclera of the eye
Where is dense regular connective tissue found?
ligaments, tendons, aponeuroses
Give examples of resident and transient cells of connective tissues. (at least 4 each)
Resident cells: fibroblasts, myofibroblasts, macrophages (histiocytes), adipocytes, mast cells, stem cells
Transient cells: lymphocytes, monocytes, neutrophils, eosinophils, basophils, plasma cells
What is the function of fibroblasts?
They are responsible for synthesis of fibres and the ground substance.
What is the function of myofibroblast cells?
These are contractile cells. Their contractions play a key role in the closure of wounds during wound healing.
Marfan syndrome is a defect of which type of collagen?
collagen type I
Further notes:
Symptoms of Marfan syndrome include: Tall and slender build, disproportionately long arms, legs, fingers and toes, high-arched palate and crowded teeth, heart murmurs, extreme nearsightedness, an abnormally curved spine, flat feet …
