Chapter 7 Structural Organisation in Animals Solutions
Question - 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?
Answer - 1 : -
(i) Cockroach
(ii) Four pairs of spermathecae are found in the 6“ to 9th segments (one pair in each segments).
(iii) Cockroach includes a pair of ovaries, that lie laterally in the 2nd to 6th abdominal segments of abdomen.
(iv) Ten
(v) At the junction of midgut and hindgut. 100-150 yellow coloured thin filamentous ring is present in earthworm, which is called malpighian tubules.
Question - 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?
Answer - 2 : -
(i) Nephridia are the minute openings found in all segments excepts the first two and their function is to discharge of nitrogenous waste.
(ii) There are three types of nephridia –
(i) Septal nephridia – Present on both the sides of intersegmental septa of segment 15 to the last that open into intestine.
(ii) Integumentary nephridia – Attached to the lining of the body wall of segment 3 to the last that open on the body surface.
(iii) Pharyngeal nephridia – Present as three paired tufts in the 4th, 5th and 6th segments.
These three different types of nephridia are almost similar in structure.
Question - 3 : - Draw a labelled diagram of the reproductive organs of an earthworm.
Answer - 3 : - 
Question - 4 : - Draw a labelled diagram of alimentary canal of a cockroach
Answer - 4 : - 
Question - 5 : - Distinguish between the following:
(a) Prostomium and peristomium
(b) Septal nephridium and pharyngeal nephridium
Answer - 5 : -
a) Prostomium andperistomium
| Prostomium | Peristomium |
| Small, fleshy lobe, serves as a covering for the mouth and as a wedge to force open cracks in the soil wherein the earthworm crawls. | It is the crescentic aperture at the anterior end of the first segment of the earthworm comprising the mouth |
b) Septal nephridiumand pharyngeal nephridium
| Septal nephridium | Pharyngeal nephridium |
| Found at the anterior and posterior surface of septa occurring after segment 15 in earthworm | Found in three pairs in the 4th, 5th and 6th segments located on either side of the alimentary canal |
| Excretory matter is discharged into the lumen of the alimentary canal | Excretory matter is discharged into the gut, in the pharynx or buccal cavity |
Question - 6 : - What are the cellular components of blood?
Answer - 6 : -
Blood consists of plasma, red blood cells (RBCs), white blood cells (WBCs) and platelets.
Question - 7 : - What are the following and where do you find them in animal body.
(a) Chondrocytes
(b) Axons
(c) Ciliated epithelium
Answer - 7 : -
(a) Chondrocytes:
These are the cells found in cartilage connective tissue. The number of chondrocytes found in cartilage determine how bendy the cartilage is chondrocytes produce and maintain the cartilage matrix. It is present in the tip of the nose, pinna of ear, joints between vertebral column, etc.
(b) Axon:
It is the longest processes of a neuron, that conducts the impulse away from the cell body. They are present in all nerve fibres.
(c) Ciliated epithelium:
When cuboidal or columnar epithelial cells bear cilia, they are called as ciliated epithelium.
Ciliated epithelium is found in the living of respirator tract, bronchioles and fallopian tube. It contains goblet cells, which secretes mucus.
Question - 8 : - Describe various types of epithelial tissues with the help of labelled diagrams.
Answer - 8 : -
Epithelial tissues
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 :
(i) Simple epithelium
(ii) Compound epithelium
(i) Simple epithelium :
Composed of single layer of cells and functions as a lining for body cavities ducts and tubes. It is further divided into three types on the basis of structure modifications-
(a) Squamous epithelium – It is made of a single layer of flattened cells with irregular boundaries.
It is found as a lining for body cavities, ducts and tubes such as in the walls of blood vessels and air sacs of lungs.
Functions – It helps in forming a diffusion boundaries.
(b) Cuboidal epithelium – It is made of single , layer of cube-like cells. It is commonly found in ducts of glands and tubular parts of nephrons in kidneys. Specialized cuboidal cells are capable of producing gametes found in gonads called germinal epithellium.
Functions- It helps in secretion and absorption and also in moving particles or mucus in a specific direction over the epithellium.
(c) Columnar epithelium – It is composed of a single layer of tall and slender cells. Nuclei are located at base.
Its free surface may have microvilli.
It is found in lining of stomach and i intestine.
Functions – It helps in secretion and absorption.
Question - 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
Answer - 9 : -
a. Simple epitheliumand compound epithelium
| Simple epithelium | Compound epithelium |
| Composed of one layer of cells | Consisting of many layers of cells |
| They are involved in the function of absorption and secretion | They are involved in the protection |
| Present in the stomach lining and intestine | Present in the lining of the buccal cavity and pharynx. |
| Cells rest on basement membrane | Cells of the lowermost layer rest on the basement membrane |
b. Cardiac muscle andstriated muscle
| Cardiac muscle | Striated muscle |
| They are involuntary in function, never gets fatigued | They are voluntary in function, hence gets fatigued sooner |
| They are found in heart | Found in triceps, limbs and biceps |
| Branched fibers | Unbranched fibers |
| Uninucleated | Multinucleated |
c. Dense regular anddense irregular connective tissues
| Dense regular connective | Dense irregular connective tissue |
| Collagen fibres are present in rows between parallel boundless fibres | Consists of Fibroblasts having several fibers that are differently oriented |
| Regular patterns of fibers observed | Irregular patterns of fibers observed |
| They are present in tendons and ligaments | They are present in the skin |
d. Adipose and bloodtissue
| Adipose tissue | Blood tissue |
| It is made of collagen fibres, fibroblasts, macrophages and adipocytes | It consists of RBC, WBC, platelets and plasma |
| It is a loose connective tissue | It is a fluid connective tissue |
Question - 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
Answer - 10 : -
(a) Neuron
(b) Cartilage
(c) Ligament
(d) Antennae
(e) Protonema