3. Draw a labelled diagram of the reproductive organs of an earthworm.

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1 1. Answer in one word or one line. (i) Give the common name of Periplanata americana. (ii) How many spermathecae are found in earthworm? (iii) What is the position of ovaries in cockroach? (iv) How many segments are present in the abdomen of cockroach? (v) Where do you find Malpighian tubules? (i) Cockroach (ii) Four pairs (iii) Ovaries in cockroach lie in the 4 th, 5 th and 6 th segments (iv) Ten segments (v) Malphigian tubules are found in insects. 2. Answer the following: (i) What is the function of nephridia? (ii) How many types of nephridia are found in earthworm based on their location? (i) Nephredia is the excretory organ present in earthworm. (ii) Three types of nephridia are found in earthworms: (a) Septal nephridia: Present on both sides of the intersegmental septa. (b) Integumentary nephridia: Attached to the lining of the body wall. (c) Pharnygeal nephridia: Found in the 4 th,5 th and 6 th segments. 3. Draw a labelled diagram of the reproductive organs of an earthworm. 1

2 4. Draw a labelled diagram of alimentary canal of a cockroach. 5. Distinguish between the followings (a) Prostomium and peristomium (b) Septal nephridium and pharyngeal nephridium Prostomium Peristomium 1.Prostomium is a lobe, which covers the mouth 1.Peristomium is the first body segment. at the anterior end. 2.Prostomium has a wedge to force open cracks in 2.The mouth is present in the peristomium. the soil. 2

3 3.It is sensory in function. Septal nephridium These are present on either side of the intersegmental septa from segments 15 th to the last. They open into the intestine. 3.It is commonly called as buccal segment. Pharyngeal nephridium These are present as paired tufts. They are present in the 4 th,5 th, and 6 th segement. 6. What are the cellular components of blood? The cells found in blood are called blood corpuscles. These are of three types, (i) Red blood corpuscles (ii) White blood corpuscles and (iii) Platelets. (i) Red blood corpuscles: Red blood corpuscles are also called erythrocytes. The red colour of erythrocytes is due to the presence of haemoglobin, a red coloured pigment with high affinity for oxygen. The shape and size of RBC s vary in different animals. The cells may be nucleated or nonnucleated. Actually, the nucleus is present in the RBCs of mammals initially, but when these cells finally differentiate and mature, the nucleus, mitochondria and endoplasmic reticulum degenerate. Such cells accommodate more haemoglobin for transportation of oxygen. About 4.8± 1.0 million RBCs per cubic millimetre of blood are found in adult women and 5.5± 1.0 million per cubic millimetre in adult men. Haemoglobin is a conjugated protein made up of globin and Fe 2+ containing a tetrapyrrole prophyrin ring called haeme. One molecule of haemoglobin binds to four molecules of oxygen. Erythrocytes also participate in transporting carbon dioxide from tissues to lungs. Carbon dioxide is mainly carried in both plasma and RBCs as bicarbonate. Carbon dioxide is also partly carried in combination with globin of haemoglobin. Erythrocytes have an average life span of about 120 days. (ii) White blood corpuscles: White blood corpuscles are also called leukocytes, as these are colourless. These are devoid of haemoglobin. Leukocytes are nucleated blood cells. The number of WBCs in adult humans is 7.5 ± 3.5 x10 3 per cubic millimeter of blood. WBCs are of two types - granulocytes and agranulocytes. On the basis of staining characteristics of cytoplasmic granules and shape of nucleus, granulocytes are of three types (a) neutrophils, (b) eosinophils and (c) basophils. Granules are in abundance in the cytoplasm. These are phagocytic in action. Eosinophils are larger in size and with bi-lobed nucleus and abundant coarse granules. Basophils release heparin and histamines in the blood. Heparin is a natural anticoagulant. Agranulocytes are non-granular white blood cells. The nucleus is non-lobulated. These are of two types, (a) lympocytes and (b) monocytes. Lymphocytes have a large and rounded nucleus. Due to this reason, cytoplasm forms a thin peripheral film. These are formed in the bone marrow and are differentiated in the same place or in the thymus. The primary function of lymphocytes is to produce antibodies against antigens or to kill the invading pathogens directly in the body. (iii) Blood platelets: Blood platelets are also called thrombocytes because they secrete thromboplastin. These are the smallest blood corpuscles. Blood platelets are non-nucleated, round or oval, biconvex disc-like bodies. Their number normally varies from 0.15 to 0.40 million per cubic millimetre of blood. They bud-off from the cytoplasm of very large megakaryocyte cells of the bone marrow. When a blood vessel is injured, platelets get clumped at the injured spot and release certain chemicals called platelet factors. The thromboplastin, a protein-phospholipid complex, released from the platelets at the site of injury is an important clotting factor in blood coagulation. The oozed out transparent fluid after coagulation of blood is called serum. It means, serum is blood without corpuscles and fibrin protein. 3

4 7. What are the following and where do you find them in animal body. (a) Chondriocytes (b) Axons (c) Ciliated epithelium (a) The intercellular material of cartilage consist of cells called Chondriocytes, they are enclosed in small cavities within the matrix secreted by them. (b) The neuron consist of a long fiber which originates from the cell body of the neuron and this is called axon. The distal ends of these are branched to synaptic junction. (c) Ciliated epithelium: These are columnar or cuboidal cells which bear cilia on their free surface. They are mainly present in the inner surface of hollow organs like bronchioles and fallopian tube. 8. Describe various types of epithelial tissues with the help of labelled diagrams. The various types of epithelial tissues are simple, compound and glandular epithelium. (i) Simple epithelium It is found generally on secretory and absorptive surfaces. It covers surfaces exposed to mechanical or chemical abrasions because it is not effective in protecting the underlying tissues. It is formed of a single layer of cells resting on the basement membrane. There are various types of simple epithelia. These are, squamous, cuboidal, columnar, ciliated and pseudostratified. (a) Squamous epithelium: Squamous epithelium consists of cells, which are thin, flat and polygonal having a prominent round or oval nucleus. The cells have irregular boundaries that fit closely into those of neighbouring cells. Its main function is protection of the underlying tissues. It forms the inner lining of lung, alveoli, blood vessels and peritoneum of the body cavity. (b) Cuboidal epithelium: Cubiodial epithelium is made up of cells, which are polygonal in outline but appear cubical or cuboidal in vertical section. In addition to protection, these cells participate in secretion, excretion and absorption. The cells of cuboidal epithelium in absorptive surfaces often bear microvilli at their free ends. This type of epithelium is found in proximal tubules of kidneys, lines of small salivary glands, pancreatic ducts, thyroid follicles and ovaries. (c) Columnar epithelium: Columnar epithelium is characterized by the presence of tall pillar-like cells, which resemble polygonal columns. The oval nucleus is generally present at the base of the cell. The function of columnar epithelium is secretion or absorption and it is found in the inner surface of the intestine, stomach and gall bladder. It also occurs in gastric and intestinal glands. The intestinal mucosa is lined by columnar epithelium, whose free ends are thrown into tiny finger-like projections. (d) Ciliated epithelium: Ciliated epithelium is formed of columnar or cubical epithelial cells that bear thin protoplasmic processes called cilia on their free surfaces. Such an epithelium is known as ciliated epithelium. The function of the cilia is to move particles, free cells or mucus in a specific direction over the epithelial surface. Ciliated epithelium lines the inner surfaces of some hollow organs such as fallopian tubes, nasal passages, bronchioles and small bronchi. 4

5 (e) Pseudo-stratified epithelium: Pseudo-stratified epithelium consists of ciliated or non-ciliated epithelium in which the cells are columnar and arranged in a single layer, but appears multi-layered because some cells are shorter than others. As a result, their nuclei become located at different levels giving a stratified appearance. This type of epithelium is therefore, called pseudo-stratified. (ii) Compound epithelium It consists of more than one layer of cells and gives a stratified appearance. Hence, these are also known as stratified epithelium. The cells may be of different shapes in different layers. The deepest layer of cells rests on a basement membrane. The morphology of the superficial layers varies in the different kinds of stratified epithelia. Compound epithelium may be stratified cuboidal, stratified squamous, stratified keratinized or transitional. The main function of this type of epithelium is protection to underlying tissues against mechanical, chemical, thermal or osmotic stresses. In stratified cuboidal epithelium, the superficial cells are cuboidal. It lines the inner surfaces of larger salivary and pancreatic ducts. Stratified squamous non-keratinized epithelium has several layers of interlinked cuboidal or columnar cells. Its cells lying closer to the underlying connective tissue, are cuboidal or columnar, but the superficial cells are flattened, thin-walled and squamous. They retain their nuclei. It covers moist surfaces such as buccal cavity, pharynx, oesophagus, cornea of eyes, etc. When the surface cells are dead and contain insoluble protein deposits, the tissue is called stratified squamous keratinized epithelium. This type of epithelium protects the epidermis of skin, hair, horn, nail, etc. Another type of compound epithelium is the transitional epithelium, which lines the inner surface of the urinary bladder, ureter, etc. Transitional epithelium is much thinner and more stretchable than the stratified epithelium. It has a single layer of cuboidal cells at the base, two to three middle layers of a large polygonal or pear-shaped cells and a superficial layer of large, broad, rectangular or oval cells. (iii) Glandular epithelia These are specialized epithelial cells that form glands. Glands produce a fluid secretion that is different from blood or any extra cellular fluid in its composition. Such secretions occur along with the synthesis of intracellular macromolecules such as proteins, lipids, complexes of carbohydrates and proteins or all the three types of macromolecules. The cells of glandular epithelia are generally columnar or cuboidal. The glandular epithelium can be classified into two types: (a) Unicellular consisting of isolated glandular cells and (b) multicellular - consisting of a cluster of cells. A gland, with a single unbranched duct is called a simple gland. The secretory part of the gland consists of epithelial cells arranged in the form of tubes or sacs or a combination of both. The duct is also made up of epithelial cells. Tubular gland, found in the human intestine, is an example of simple gland. A gland with a branched system of ducts is called a compound gland. In these glands, the secretory tubule or acinus may be coiled or branched and opens into the single duct of the gland. 5

6 9. Distinguish between (a) Simple epithelium and compound epithelium (b) Cardiac muscle and striated muscle (c) Dense regular and dense irregular connective tissues (d) Adipose and blood tissue (e) Simple gland and compound gland (a) Simple epithelium and compound epithelium Simple epithelium 1. This tissue is made up of a single layer of cells, resting on the basement membrane, e.g., squamous epithelium. Compound epithelium 1. This tissue is made up of many layers of cells and the deepest layer is attached to the basement membrane, e.g., stratified. (b) Cardiac muscle and striated muscle Cardiac muscle Striated muscle 1. They are called involuntary muscles. 1. They are voluntary because they can be moved at will. 2. They are found in the contractile tissue present 2. Most striated muscles are attached to bones by only in the heart. tendons. 3. The cells contract as a unit. When one cell 3. Each striated muscle is covered by a thin contracts, the signal stimulates the neighbouring elastic sacrolemma. cells. 4. They show any striation. 4. Alternate light and dark bands are present giving a striated appearance. (c) Dense regular and dense irregular connective tissues Dense regular connective tissue 1. In this tissue the collagen fibers are present in rows between many parallel bundles. Dense irregular connective tissues 1.These tissues have fibroblasts and many fibers that are oriented. 6

7 2. They are present in tendons, which attach skeletal muscles to bones and ligaments, which attach one bone to another. 2. These tissues are present in the skin. (d) Adipose and blood tissue Adipose tissue 1.These loose connective tissue are located beneath the skin. 2.The cells of these tissues are specialized to store fats which are formed by the conversion of excess of nutrient which are not used immediately. Blood tissue 1. Blood is a fluid connective tissue containing plasma, RBC, WBC, and platelets. 2. It is the main circulating fluid that helps in the transport of various substances. (e) Simple gland and compound gland Simple gland 1. These glands are made up of cells forming a single tube, which opens directly on the surface organ. Compound gland 1. These glands are made up of cells forming many alveoli. Each alveoli joins with the other ducts and finally empties its contents into one large duct, which leads to the surface. 10. Mark the odd one in each series: (a) Areolar tissue; blood; neuron; tendon (b) RBC; WBC; platelets; cartilage (c) Exocrine; endocrine; salivary gland; ligament (d) Maxilla; mandible; labrum; antennae (e) Protonema; mesothorax; metathorax; coxa (a) neuron (b) cartilage (c) ligament (d) antennae (e) coxa. 11. Mention briefly about the circulatory system of earthworm Earthworm exhibits a closed type of blood vascular system. This type of blood vascular system consists of blood vessels, capillaries and heart. 7

8 Due to closed circulatory system, blood is confined to the heart and blood vessels. Contractions of the body keep blood circulating in one direction. Smaller blood vessels supply the gut, nerve cord, and the body wall. Blood glands are present on the4th, 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 the moist body surface directly into the blood stream. 12. Draw a neat diagram of digestive system of frog. 13. Mention the function of the following (a) Ureters in frog (b)malpighian tubules (c) Body wall in earthworm (a) Ureters in Frog In frogs two ureters emerge from the kidneys. In male frog the ureters act as urinogenital duct which opens into the cloaca. It helps in passing the urine as well as the sperm to the exterior. In females the ureters and oviduct open seperately in the cloaca. The ureters excrete only the urine. (b) Malpighian tubules The malpighian tubules help in the removal of excretory products present in the haemolymph of the cockroach. (c) Body wall in the earthworm The moist body wall helps in respiration. The circular and the longitudinal muscles present below the cuticle along with the setae, which is embedded in the epidermal pits, help in the locomotion of the earthworm. 8

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