1. Basal Lamina & Basement Membrane
Dr. Mah Jabeen Muneera
Associate Professor
Department of Anatomy
KEMU

3. LAMINA PROPRIA Connective tissue upon which epithelium rests
Support, provide nutrition, epithelium is avascular
Area of contact is increased by folds
BASEMENT MEMBRANE
Sheet of ECM intervenes between epithelium and lamina propria
Source
Function
Special stain (PAS)
Also present around glial cells, adipocytes & muscle cells
Not present around other CT cells

4. Basal lamina Evident by routine EM preparation
Composed of upper LAMINA LUCIDA (glycoproteins)
LAMINA DENSA on lower aspect

5. Components Laminin Type IV collagen, XV, XVIII, VII
Glycoproteins
Associated with integrins
Type IV collagen, XV, XVIII, VII
Entactin (Nidogen) & Perlecan, Agrin
Link the first two components
Proteoglycans ; hydrated,
negative charge controls ions

6. Tissue preparation by HPF method
HPF- high pressure freezing
Only lamina densa is present
Lamina lucida is considered to be an artifact

7. External lamina
In non epithelial cells

8. Formation of basal lamina
Self assembly of collagen type IV & Laminin
Calcium dependent polymerization

9. RETICULAR LAMINA FUNCTIONS: Support Barrier
Influence cellular activity e.g. proliferation, differentiation
BASEMENT MEMBRANE
PAS +ve layer
Visible by Light Microscope
Two basal laminae
One basal lamina & one reticular lamina

11. Attachment of basal lamina to underlying tissue
Anchoring fibrils
Mutations-dystrophic epidermolysis bullosa
Fibrillin microfibrils
Marfan’s syndrome
Projections of basal lamina

12. Functions Regulator of cell behavior Organ specific molecules
Structural attachment
Compartmentalization
Filtration
Tissue Scafolding (barrier against tumor cell invasion)
Regulation & signaling