NCERT Solutions for Class 11 Biology Chapter 7 – Structural Organisation in Animals
Chapter 7 Structural Organisation in Animals is the animal counterpart to Chapter 6 and takes a close look at the different types of animal tissues, their structure, and how they are organised into organs and organ systems. This chapter also includes a detailed study of the morphology and anatomy of the cockroach (Periplaneta americana) — a topic that appears in CBSE practicals and NEET theory questions almost every year without fail. Must check the CBSE resources and NCERT Solutions.
Understanding animal tissues is not just a CBSE requirement — it is the foundation for advanced topics like physiology, reproduction, and genetics that come later in the syllabus. The four types of animal tissues — epithelial, connective, muscular, and neural — each have multiple sub-types with specific locations and functions that students must know. NCERT Solutions for Chapter 7 Structural Organisation in Animals on Myclass24 cover every NCERT question with comprehensive, accurate answers written to align with the latest CBSE marking scheme. Students across India, from states like West Bengal, Assam, Odisha, Jharkhand, Uttar Pradesh, and Delhi, studying under the CBSE board will find this resource essential for both theory and practical preparation.
Download PDF – NCERT Solutions for Class 11 Biology Chapter 7 Structural Organisation in Animals
Multicellular animals, unlike unicellular organisms, show division of labour — different cells specialise for different functions, giving rise to tissues, organs, and organ systems. A tissue is a group of cells with similar structure and function. An organ is formed by two or more tissue types working together. An organ system consists of multiple organs performing a coordinated function.
Epithelial tissue covers body surfaces, lines cavities, and forms glands. The cells are closely packed with little intercellular material and rest on a basement membrane. Types include simple squamous epithelium (lines blood vessels, air sacs of lungs — exchange), simple cuboidal epithelium (kidney tubules — secretion and absorption), simple columnar epithelium (lining of stomach and intestine — absorption; ciliated form lines respiratory tract and fallopian tubes), pseudostratified epithelium (nasal passage — appears multilayered but is single-layered), and stratified squamous epithelium (skin — protection against wear). Glandular epithelium forms glands — unicellular (goblet cells in intestine) or multicellular (salivary glands). Check out NCERT Solutions for Class 11 Biology and NCERT Solutions for Class 11 for the rest of the chapters.
| Epithelial Type | Structure | Location | Function |
| Simple Squamous | Flat, scale-like cells | Blood vessels, lung alveoli | Diffusion, filtration |
| Simple Cuboidal | Cube-shaped cells | Kidney tubules, ducts | Secretion, absorption |
| Simple Columnar | Column-like tall cells | Stomach, intestine lining | Absorption, secretion |
| Ciliated Columnar | Columnar with cilia | Trachea, fallopian tubes | Movement of particles/eggs |
| Stratified Squamous | Multiple flat layers | Skin, oesophagus | Protection from abrasion |
| Glandular | Secretory cells | Salivary glands, sweat glands | Secretion |
Connective tissue is the most abundant tissue in the body. It binds and supports other tissues. Unlike epithelium, connective tissue cells are loosely spaced in an extracellular matrix (ground substance + fibres). Types include loose connective tissue (areolar — fills spaces between organs; adipose — fat storage), dense connective tissue (tendons connect muscle to bone; ligaments connect bone to bone), cartilage (chondrocytes in lacunae; no blood supply; hyaline cartilage in trachea and joints), bone (osteocytes in lacunae; Haversian system; hard due to calcium phosphate), and blood (plasma + RBCs, WBCs, platelets — a fluid connective tissue).
Muscular tissue is made of elongated cells (muscle fibres) capable of contraction due to proteins actin and myosin. There are three types: skeletal (striated) muscle — attached to bones, voluntary, shows distinct striations; smooth (non-striated) muscle — found in walls of hollow visceral organs (gut, uterus, blood vessels), involuntary; and cardiac muscle — found only in the heart, striated like skeletal but involuntary, with intercalated discs between cells for synchronised contraction.
| Muscle Type | Striations | Control | Location | Nucleus |
| Skeletal / Striated | Present | Voluntary | Attached to skeleton | Multiple, peripheral |
| Smooth / Visceral | Absent | Involuntary | Gut, uterus, vessels | Single, central |
| Cardiac | Present | Involuntary | Heart wall | Single/double, central |
Neural tissue / Nervous tissue is composed of neurons (nerve cells) and neuroglia (supporting cells). A neuron has a cyton (cell body with nucleus), dendrites (receive impulses), and a single axon (transmits impulse away from cell body). The axon may be myelinated (faster impulse conduction, covered by myelin sheath) or non-myelinated. Neurons are excitable cells — they generate and transmit electrical signals (nerve impulses).
The cockroach (Periplaneta americana) is the key example studied in this chapter. It has a segmented body divided into head (6 fused segments, with compound eyes, antennae, and mouthparts), thorax (3 segments with 3 pairs of jointed legs and 2 pairs of wings — forewings are thick tegmina; hindwings are membranous), and abdomen (10 segments with spiracles for breathing). The alimentary canal runs from mouth through pharynx, oesophagus, crop, gizzard, stomach, intestine, and rectum to anus. Malpighian tubules (150–200 in number) act as excretory organs. The nervous system includes a brain (supra-oesophageal ganglion), sub-oesophageal ganglion, and ventral nerve cord with ganglia in each segment. Myclass24 NCERT Solutions for Chapter 7 provide complete answers on cockroach morphology and anatomy that are especially helpful for CBSE practicals and NEET questions.