The structure of the abdominal wall is similar in principle to the thoracic wall. There are three layers, an external,internal and innermost layer. The vessels and nerves lie between the internal and innermost layers. The abdomen can be divided into quadrants or nine abdominal regions.Pain felt in these regions may be considered to be director referred abdominal wall made up of smooth muscles.

ATPase enzyme is located in the myosin cross bridgeheads. Actin forms the light orI- Band. Actin slides over myosin during contraction. Troponin protein is involved in establishing connection with myosin cross bridges.Actin is not involved in muscle contraction. It is also an ATPase (an enzyme) which is activated by Ca²⁺ and Mg²⁺ions. Hence, ATPase enzyme is located in myosin.

Hyaline cartilage is firm but slightly elastic with clearmatrix. It is present in larynx, trachea, bronchi, nose.Elastic cartilage occur in external ear. Calcified cartilage occurs in suprascapula. Fibrous cartilage occurs in intervertebral discs

Simple epithelium is a tissue made of a single layer of compactly arranged cells all of which rest over a non cellular basement membrane.

Ootheca of cockroach contains sixten fertilized egg in two rows.

Antennaee of cockroach bears tactile and olfactory receptors and are sensitive to touch and smell.

All body tissue receive oxygen directly through tracheoles.

The total number of ganglia in ventral nerve cord of cockroach is nine pairs,i.e., three pairs thoracic and six pairs abdominal.