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1800-102-2727The 'Structural Organization in Animals' chapter discusses unicellular and multicellular organisms of the animal kingdom. The chapter talks about all the functions, such as respiration, digestion, and reproduction in unicellular organisms that are performed only by a single cell. Different groups of cells perform all the above basic functions inside the complex body of multicellular animals in an orderly manner.
All those animals who have complex body structures are made up of four basic types of tissues. These four tissues are placed in specific locations inside the body to develop organs, like the stomach, heart, kidney, and lungs. The topics of this chapter have been explained below.
This chapter concentrates on the specific set of functions that in multicellular organisms are performed by similar cells. Hence, this group of similar cells that carries out a particular function is called a tissue. In animals, tissues can be segregated into four different types: Connective, Epithelial, Nural, and Muscular. The arrangement of these complex animal tissues in a particular pattern and proportion helps in the formation of an organ in them.
When formed, these organs provide functionality through their chemical and physical interaction that comprises the organ system. Tissues, cells, organs, and organ systems in animals divide their operation in such a manner that clear division of labour and their contribution towards the survival of the body is visible. All these different animal bodies are very nicely portrayed in the chapter using animals, such as frogs, earthworms, and cockroaches, as examples.
NCERT Solutions for Class 11 Biology Chapter 7 Structural Organisation in Animals
Q1. Answer in one word or one line
(i). Give the common name of Periplaneta americana.
Answer:
The common name of Periplaneta americana is the cockroach.
(ii) How many spermathecae are found in earthworms?
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(iii) What is the position of ovaries in cockroaches?
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(iv) How many segments are present in the abdomen of the cockroach?
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(v) Where do you find Malpighian tubules?
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Q2. Answer the following
(i) What is the function of nephridia?
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(ii) How many types of nephridia are found in earthworms based on their location?
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Q3. Draw a labeled diagram of the reproductive organs of an earthworm.
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Q4. Draw a labeled diagram of alimentary canal of a cockroach.
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Q5. Distinguish between the following
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Q6. What are the cellular components of blood?
Q7. What are the following and where do you find them in the animal bodies.
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(b)Axon
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(c)Ciliated epithelium
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Q8. Describe various types of epithelial tissues with the help of labelled diagrams?
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(a)Simple epithelium: It is the single layer of cells that are in direct contact with the basement membrane. Simple epithelium is further subdivided into the following types:
(b)Simple squamous epithelium: It consists of a single layer of flat cells with irregular boundaries. Simple squamous epithelium is mostly found in the walls of the blood vessels and in the lining of alveoli.
(c)Simple cuboidal epithelium: It consists of a single layer of cube-like cells and is present in regions where secretion and absorption of substances take place such as the proximal convoluted tubule region of the nephron.
(d)Simple columnar epithelium: This epithelium is formed by a single layer of tall, slender cells with their nuclei present at the base of the cells. These generally possess microvilli on the free surfaces. Columnar epithelium forms the lining of the stomach and intestines. The major function of simple columnar epithelium is secretion and absorption.
(e)Ciliated epithelium: It consists of columnar or cuboidal cells with cilia on their free surfaces. They are present in bronchioles and oviducts from where they direct mucus and eggs in specific directions.
(f)Glandular epithelium: These are columnar or cuboidal cells involved in the secretion of substances. Glands are of two types, unicellular glands (goblet cells of the alimentary canal) and multicellular glands (salivary glands). They can be classified as exocrine (ductless glands) and endocrine glands (duct glands) based on the method through which they release enzymes.
(g)Compound epithelium: When the simple epithelium is consists of many layers of cells, it is called the compound epithelium. The compound epithelium is involved mainly in the function of providing protection and has a limited role in secretion and absorption. Examples of compound epithelium include the dry surface of the skin or moist inner lining of the buccal cavity, pharynx, pancreatic ducts, and the inner lining of ducts of salivary
glands.
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Q9. Distinguish between
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Q10. Mark the odd one in each series:
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(d)Maxilla; mandible; labrum; antennae
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(e)Protonema; mesothorax; metathorax; coxa
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Q11. Match the terms in column I with those in column II:
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Answer:
Column I - Column II
Q12. Mention briefly the circulatory system of earthworms.
Answer:
1. Blood- A colored respiratory pigment hemoglobin is found to be present in the plasma. Due to this, the color of the plasma is red. In the blood, only one type of blood corpuscles, the leucocytes are present in the blood of the earthworm.
2. Blood vessels- The blood vessels found in earthworms are as follows:
Dorsal blood vessels- These extend from one end of the body to the other. The blood flows in this vessel from behind to forward on the dorsal side of the alimentary canal. The dorsal blood vessel has valves that prevent the backward flow of blood.
Ventral blood vessels- These extend from one end to the other end of the body. It does not have any valves and the flow of the blood is from the anterior to the posterior end of the body. It is the major distributing vessel.
Sub-neural blood vessel- It runs from the posterior end of the body up to the 14th segment in front. It collects blood from the body wall and nerve cord. This blood is then sent to the dorsal blood vessel through commissural vessels.
Lateral oesophageal vessel- These are the paired blood vessels lying one on either ventrolateral side of the alimentary canal between the body wall and the alimentary canal in the first 14th segment.
Supra-oesophageal blood vessel- It is a single vessel that lies on the dorsal side of the alimentary canal between the 9th and 13th segments. It receives blood from the lateral oesophageal through two pairs of anterior loops and pours into two pairs of latero- oesophageal hearts present in the 12th and 13th segments.
Hearts and anterior loops- In earthworms, four pairs of tubular hearts are provided with valves. The anterior two pairs of the heart are known as the lateral heart and they lie in the 7th and 9th segments. They receive blood from the dorsal blood vessel and convey it to the ventral blood vessel. The posterior two pairs of hearts are situated in the 12th and 13th segments. These carry blood from the dorsal blood vessel and supra oesophageal vessel to the ventral blood vessel. Two pairs of anterior loops are present in the 10th and 11th segments.
3. Blood glands- These are situated in the 4th, 5th, and 6th segments and produce blood corpuscles and hemoglobin.
Q13. Draw a neat diagram of the digestive system of a frog.
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Q14. Mention the function of the following
a)Ureters in frog
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(b)Malpighian tubule
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(c)Body wall in earthworm
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