Difference between cardiac muscles and striated muscles

Differences between simple eputhelium and compound epithelium

Earthworms are protandrous,i.e.,the tests mature earlier than the ovaries. Self fertilisation is not possible in them because of the relative position of the openings of male and female reproductive organs.

Sclerties The body of cockroach is externally covered by hard brown chitinous plates called sclerites, which constitute the exoskeleton.

Blood, Bone and cartilage are called connective tissue because
(i) they connect different tissues and organs
(ii) provide support to other structures of the animal body

The clitellum divides the earthworm's body into three basic regions
(i) Preclitellar Anterior 13 segments
(ii) Clitellar Only 3 segments
(iii) Postclitellar Last 84-104 segments

plasma protein maintains the pH of the blood by neutralising the strong acids and bases so it acts as acid base buffers

Haemoglobin contains a protein called globin and Fe2+ (ferrous)-porphyrin complex called haeme

Bone marrow cavity is present in long bones, such as humerus , femur , etc.

(i) Gap Junction 
(ii) Tight Junction
(iii) Adhering Junction

Young cartilage cells - Chondroblasts
Mature cartilage cells - Chondrocytes

Blood Vascular System. Pheretima exhibits a closed type of blood vascular system, consisting of blood vessels, capillaries and heart. Due to closed circulatory system, blood is confined to the heart and blood vessels. Contractions keep blood circulating in one direction. Smaller blood vessels supply the gut, nerve cord, and the body wall. Blood glands are present on the 4th, 5th and 6th segments. They produce blood cells and haemoglobin which is dissolved in blood plasma. Blood cells are phagocytic in nature. Earthworms lack specialised breathing devices. Respiratory exchange occurs through moist body surface into their blood stream.

In cockroach, there are two types of eyes, i.e., apair of simple eye and a pair of compound eyes. A compound eye has upto 2000 hexagonbal units called ommatidia. These are responsible for producing mosaic vision. The adjacent ommatidia are separated internally by the pigment cells. An ommatidium has two parts 
(i) Outer dioptoric or focussing part, which consisits of a corneal lens, two corneagen cells, a crystalline cone and four cone cells or vitrellae.
(ii) Inner receptive part has a spindle-shaped pigment contaning rhadome surrounded by eight retinulae which continue as nerve fibre.

Similarities between cardiac and skeletal muscles The cardiac and skeletal muscles both are made up of elongated fibres, which have numerous myofibrils. The myofibrils of the cardiac muscles have the same structure as those of skeletal muscle and are made up of actin and myosin filaments. The cardiac and skeletal muscles fibres have dark and light bands.

Malphighian tubules are the amin excretory organs of cockroach.

The entire body of cockroach is covered by a hard chitinous exoskeleton (brown in colour) made of touch plates called sclerites. These are formed of chitin, a polymer of acetone cocaine polysaccharide molecule. The exoskeleton protects the body and provides space for the attachment of muscles.

Epithelial Tissue
Epithelial tissues provide covering to the inner and outer lining of various organs. The cells of epithelial tissues are compactly packed with little intercellular matrix. There are two types of epithelial tissues:
(a) Simple Epithelium. Simple epithelium is composed of a single layer of cells and functions as a lining for body cavities, ducts, and tubes.
(b) Compound Epithelium. The compound epithelium consists of two or more cell layers and has protective function as it does in our skin. They cover the dry surface of the skin, the moist surface of buccal cavity, pharynx, inner lining of ducts of salivary glands and of pancreatic ducts.
On the basis of structural modification of the cells, simple epithelium is further divided into three types. These are:

1. Squamous. The squamous epithelium is made of a single thin layer of flattened cells with irregular boundaries. They are found in the walls of blood vessels and air sacs of lungs and are involved in functions, like forming a diffusion boundary.
2. Cuboidal. The cuboidal epithelium is composed of a single layer of cubelike cells. This is commonly found in ducts of glands and tubular parts of nephrons in kidneys and its main functions are secretion and absorption. The epithelium of proximal convoluted tubule (PCT) of nephron in the kidney has microvilli.
3. Columnar. The columnar epithelium is composed of a single layer of tall and slender cells. Their nuclei are located at the base. Free surface may have microvilli. They are found in the lining of stomach and intestine and help in secretion and absorption. If the columnar or cuboidal cells bear cilia on their free surface they are called ciliated epithelium. Their function is to move particles or mucus in a specific direction over the epithelium. They are mainly present in the inner surface of hollow organs like bronchioles and fallopian tubes.

Differences between male and female frog

Differences between male and female cockroach are