Class 11 Biology Structural Organisation In Animals Solution

Class 11 Biology Structural Organisation in Animals helps us understand how different tissues and organs work together in animals. The chapter explains the structure and function of epithelial, connective, muscular, and nervous tissues. It also introduces the anatomy of earthworm, cockroach, and frog.

By studying this chapter, students gain a clear understanding of how animal bodies are organized and how each part plays a vital role in survival and functioning. This chapter is essential for building a strong foundation in zoology and preparing for exams like NEET and CBSE boards.

Class 11 Biology Structural Organisation in Animals -Exercise Answers

1. What are the functions of areolar tissue?
Areolar tissue is a loose connective tissue found in animals. It acts as a packaging tissue between organs and under the skin. Its main function is to provide support and flexibility to tissues and organs. It also helps in repairing tissues, stores body fluids, and plays a role in defense by trapping bacteria and other harmful agents.

2. Define the term ‘tissue’.
A tissue is a group of similar or dissimilar cells that perform a specific function or a set of related functions. Tissues form the structural and functional units of an organ. In animals, there are four basic types of tissues: epithelial, connective, muscular, and nervous tissue.

3. Name the types of epithelial tissues present in animals.
The main types of epithelial tissues in animals are: 1) Simple epithelium – which includes squamous, cuboidal, columnar, and ciliated epithelium, and 2) Compound epithelium – which includes stratified epithelium and transitional epithelium.

4. Write short notes on the structure and function of columnar epithelium.
Columnar epithelium consists of tall and pillar-like cells that are arranged closely side by side. The nucleus is located near the base. This type of epithelium is mainly found in the inner lining of the stomach and intestine. It helps in absorption and secretion. In some places, it may have cilia on the surface, called ciliated columnar epithelium, which helps move mucus or other materials.

5. Differentiate between voluntary and involuntary muscles.
Voluntary muscles are under the control of our will. These muscles are striated, multinucleated, and found attached to bones, helping in movement. Involuntary muscles are not under our conscious control. They include smooth muscles (found in internal organs like intestines, stomach, and blood vessels) and cardiac muscles (found only in the heart). Smooth muscles are non-striated and spindle-shaped, while cardiac muscles are striated, branched, and have intercalated discs.

6. Describe the structure of neuron and explain the transmission of nerve impulse.
A neuron consists of three parts: the cell body (soma), dendrites, and axon. The cell body contains the nucleus and cytoplasm. Dendrites are short, branched extensions that receive impulses. The axon is a long fiber that carries impulses away from the cell body. The transmission of a nerve impulse begins when a stimulus is received by the dendrites. The impulse then travels through the axon as an electrical signal, which is transmitted to the next neuron or muscle cell across the synapse via neurotransmitters.

7. Differentiate between the three types of muscular tissues.
The three types of muscular tissues are: 1) Skeletal muscle – striated, voluntary, multinucleated, found attached to bones and helps in body movement. 2) Smooth muscle – non-striated, involuntary, uninucleate, found in internal organs like the stomach, intestines, and blood vessels. 3) Cardiac muscle – striated, involuntary, branched, and found only in the heart; it has intercalated discs that help in synchronized contraction of heart muscles.

8. What are the different types of connective tissues?
The different types of connective tissues are: 1) Connective tissue proper – areolar tissue, adipose tissue, and dense connective tissue. 2) Skeletal connective tissue – cartilage and bone. 3) Fluid connective tissue – blood and lymph. All these tissues connect, support, and bind different parts of the body and also play roles in transport, protection, and storage.

9. Describe the structure and function of bone.
Bone is a strong and rigid connective tissue made up of a dense matrix of collagen fibers embedded in calcium phosphate. It has bone cells (osteocytes) located in spaces called lacunae. Bones provide structural support to the body, protect internal organs, and help in locomotion. They also serve as a site for muscle attachment and store minerals like calcium and phosphorus.

10. Describe the structure and function of cardiac muscles.
Cardiac muscles are found only in the heart. These muscles are striated, branched, and have one nucleus per cell. They are connected by intercalated discs, which help in the coordinated contraction of heart muscle cells. Cardiac muscles are involuntary and are responsible for the continuous rhythmic beating of the heart throughout life.

11. What are the differences between cartilage and bone?
Cartilage is a soft and flexible connective tissue, while bone is hard and rigid. Cartilage cells (chondrocytes) are present in cavities called lacunae but do not have blood supply, so they heal slowly. Bone cells (osteocytes) are also in lacunae but bones are richly supplied with blood vessels, so they heal faster. Cartilage provides flexibility and support (like in the nose and ear), whereas bone provides strength, protection, and shape to the body.