Classify and describe epithelial tissue on the basis of structural modifications of cells.
There are two types of epithelial tissues namely simple epithelium and compound epithelium. Simple epithelium is composed of a single layer of cells and functions as a lining for body cavities, ducts, and tubes. The compound epithelium consists of two or more cell layers and has protective function as it does in our skin. On the basis of structural modification of the cells, simple epithelium is further divided into three types. These are (i) Squamous, (ii) Cuboidal and (iii) Columnar
• 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. The cuboidal epithelium is composed of a single layer of cube-like 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. 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.
• Compound epithelium is made of more than one layer (multi-layered) of cells and thus has a limited role in secretion and absorption. Their main function is to provide protection against chemical and mechanical stresses. 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.
The digestive system of a frog is made of the following parts. Arrange them in an order beginning from mouth.
Mouth, oesophagus, buccal cavity, stomach, intestine, cloaca, rectum, cloacal aperture
Correct the wrong statements among the following.
a. In earthworm, a single male genital pore is present.
b. Setae help in locomotion of earthworm.
c. Muscular layer in the body wall of earthworm is made up of only circular muscles.
d. Typhlosole is the part of intestine of earthworm.
Complete the following statement:
a. In Cockroach grinding of food particle is performed by
b. Malpighian tubules help in removal of
c. Hind gut of Cockroach js differentiated into
d. In Cockroach blood vessels open into spaces called
Match the following and choose the correct option.
| A. | Adipose tissue – | (i) | Nose |
| B. | Stratified epithelium | (ii) | Blood |
| C. | Hyaline cartilage | (iii) | Skin |
| D. | Fluid connective tissue | (iv) | Fat storage |
(a) A—(i), B—(ii), C—(iii), D—(iv)
(b) A—(iv), B—(iii), C—(i), D—(ii)
(c) A—(iii), B—(i), C—(iv), D—(ii)
(d) ‘ A—(ii), B—(i), C—(iv), D—(iii)
State the number of segments in earthworm which are covered by a prominent dark band or clitellum.
Why are neurons called excitable cells? Mention special features of the membrane of the neuron?
Stratified epithelial cells have limited role in secretion. Justify their role in our skin.
Match the followings and choose the correct answer.
| A. | Touch | (i) | Nasal epithelium |
| B. | Smell | (ii) | Foramen magnum |
| C. | Cranial nerves | (iii) | Sensory papillae |
| D. | Medulla oblongata | (iv) | Peripheral nervous system |
(a) A—(iii), B—(i), C—(ii), D—(iv)
(b) A—(ii), B—(i), C—(iv), D—(iii)
(c) A—(ii), B—(iv), C—(ii), D—(i)
(d) A—(iii), B—(i), C—(iv), D—(ii)
Write the functions in brief in column B, appropriate to the structures given in column A.
| Column A | Column B | ||
| a. | Nictitating membrane | i. | |
| b. | Tympanum | ii. | |
| c. | Copulatory pad | iii. | |
Common name of some animals are given in Column A, write their scientific name in Column B.
| Column A | Column B | |
| a. | Tiger | |
| b. | Peacock | |
| c. | Housefly | |
Special venous connection between liver and intestine, and between kidney and intestine is found in frog, what are they called?
Mention the function of the following:
(a) Ureters in frog
(b) Malpighian tubules
(c) Body wall in earthworm.
Write down the common features of the connective tissue. On the basis of structure and function, differentiate between bones and cartilages.
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.
Match the following and choose the correct answer.
| A. | Hermaphrodite | (0 | Produces blood cells and haemoglobin |
| B. | Direct development | (ii) | Testis and ovary in the same animal |
| G. | Chemoreceptor | (iii) | Larval form absent |
| D. | Blood gland in earthworm | (iv) | Sense of chemical substances |
(a) A—(ii), B—(iii), C—(iv), D—(i)
(b) A—(iii), B—(ii), C—(iv), D—(i)
(c) A—(i), B—(iii), C—(ii), D—(iv)
(d) A—(ii), B—(iv), C—(iii), D—(i)
Match the terms in column I with those in column II.
|
Column I |
Column II |
| (a) Compound epithelium (b) Compound eye (c) Septal nephridia (d) Open circulatory system (e) Typhlosole (f) Osteocytes (g) Genitalia |
(i) Alimentry canal (ii) Cockroach (iii) Skin (iv) Mosaic vision (v) Earthworm (vi) Phallomere (vii) Bone |
What are the following and where do you find them in animal body?
(a) Chondrocytes
(b) Axons.
(c) Ciliated epithelium
Structural organisation in animals attains different levels as cell—organ— organ system. What is missing in this chain? Mention the significance of such an organisation.
The body of sponges does not possess tissue level of organisation though it is made of thousands of cells. Comment.
Answer in one word or one line.
(i) Give the common name of Periplaneta 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?
Write the appropriate type of tissues in column B according to the functions mentioned in column A.
| Column A | Column B | ||
| a. | Secretion and absorption | i. | |
| b. | Protective covering | ii. | |
| c. | Linking and supporting framework | iii. | |
Frog is a poikilotherm, exhibits camouflage and undergoes aestivation and hibernation, how are all these beneficial to it?
Why nephridia in earthworm that are basically similar in structure classified into three types? Mention the names of each.
Classify and describe epithelial tissue on the basis of structural modifications of cells.
Answer the following.
(i) What is the function of nephridia?
(ii) How many types of nephridia are found in earthworm based on their location?