The stucture of insect

The basal lamina:

• The innermost component of the integument
• An amorphous but selectively porous acellular layer that is attached by hemidesmosomes to the epidermal cells
• It is up to 0.5 μmthick and is produced mainly by the epidermis
• The chemical nature of the basal lamina is poorly understood though neutral mucopolysaccharide, glycoproteins, and collagen

The epidermis (hypodermis):

• More or less continuous sheet of tissue, one cell thick
• Responsible for secreting the bulk of the cuticle
• Its cells are flattened and intercellular boundaries are indistinct-During periods of inactivity
• The cells are more or less cuboidal, and their plasma membranes are readily apparent; one to several nucleoli, extensive rough endoplasmic reticulum, and many Golgi complexes are evident-During active
• At metamorphosis, the epidermal cells develop basal processes (“feet”) which can extend to become connected with the basal lamina and with other epidermal cells
• Epidermal cells also possess the ability to develop various forms of cytoskeletal extensions which can be used, for example, to draw tracheoles closer to the cell for increased oxygen supply, or to maintain intercellular contact as the cells migrate during wound healing and changes in body shape
• The cells often contain granules of a reddish-brown pigment, insectorubin, which in some insects contributes significantly to their color