11 Bio Chapter Summary

Animal Tissue

Chapter Summary

  • There are four major types of animal tissues, viz. epithelial, connective, muscular and neural tissues.
  • Tissues which provide covering to the inner and outer linings of various organs are called epithelial tissue.
  • The epithelial tissues are further divided into two main types, viz. simple epithelium and compound epithelium.
  • The simple epithelium is composed of a single layer of cells. It is present in the lining of body cavities, ducts and tubes.
  • The compound epithelium is composed of more than one layer of cells. The compound epithelium serves the protective function.

  • There are three types of connective tissues, viz. loose connective, dense connective and specialized connective tissues.
  • The matrix of cartilage is solid and pliable and resists compression. The cells of cartilage are called chondrocytes.
  • The matrix of bones is hard and non-pliable. The bone cells are called osteocytes.
  • Blood is a fluid connective tissue. It contains plasma, blood cells and platelets.
  • A muscle is made of many long, cylindrical fibres which are arranged in parallel rays. The muscle fibres are composed of very fine fibrils; called myofibril.
  • The skeletal muscle is closely attached to skeletal bones. The voluntary movements are facilitated by skeletal muscles. Skeletal muscles quickly get tired.
  • The smooth muscle fibres are spindle-shaped. Smooth muscles are present in those organs which are not under our conscious control.
  • The muscles in the heart are called cardiac muscles. Cardiac muscles are multinucleated and have striations.
  • Neural tissue is made of neurons. Neurons are excitable cells.
  • When a neuron is stimulated, an electrical disturbance is generated. The electrical disturbance travels along its plasma membrane.
  • Earthworm is a reddish brown terrestrial invertebrate. It lives in the upper layer of moist soil. Pheretima and Lumbricus are the common Indian earthworms.
  • Periplaneta americana is the common species of cockroach. An adult cockroach is about 34 – 53 mm long. Wings extend beyond the tip of the abdomen in males. The body is segmented into three distinct regions, viz. head, thorax and abdomen.
  • In India, the most common species of frog is Rana tigrina. The frogs are cold-blooded or poikilotherms. The body of a frog is divisible into head and trunk.