These tissues are one-celled in thickness and are of the following types: Cells are pentagonal with a distinct nucleus. This tissue forms the superficial layer of the skin.
Tissue is a group of similar cells having a common origin that act together in the performance of a particular function. Early during development, the cells of the growing embryo differentiate into three fundamental embryonic tissues called germ layers namely ectoderm, mesoderm and endoderm.
These germ layers, in turn, differentiate into different cell types and tissues that are characteristic of the vertebrate body. Most animal cells are surrounded by a narrow space filled with extracellular or intercellular fluid.
This forms the immediate environment of the cell. From this fluid, the cell receives all the material needed by it and also transfers the waste materials produced by it to this fluid.
In adult vertebrates and also in most invertebrates, there are four principal kinds of tissues. They are epithelial, muscular, connective and nervous tissues. The epithelial tissues originate from ectoderm, mesoderm and endoderm layers. They are mainly concerned with protection, secretion, absorption, excretion and reproduction functions.
The muscular and connective tissues are of mesodermal origin. If muscular tissue helps in the movement of parts and locomotion, the connective tissue assists in attachment, support, protection, storage and transport.
The ectoderm derived nervous tissue controls and coordinates the conduction of nerve impulses.
Epithelial Tissues or Epithelia sing. The tissue that covers the outside of the body and lines organs and cavities within the body is called epithelial tissue or epithelium. The epithelia are derived from all three germ layers.
The epidermis derived from ectoderm constitutes the outer portion of the skin. The inner surface of the digestive tract is lined by an epithelium derived from endoderm.
The inner surfaces of the body cavities are lined by epithelia derived from mesoderm. The epithelial tissues consist of variously shaped cells.
The epithelial cells are closely arranged forming a single layer or multiple layers. The intercellular spaces between the cells are practically absent. The epithelial cells are held together by very little amount of intercellular matrix containing a carbohydrate derivative called hyaluronic acid.
The epithelial cells always rest on a thin non-cellular basement membrane consisting of glycoproteins and collagen fibres. The basement membrane is formed of two layers — outer thinner basal lamina secreted by the epithelial cells, and inner thicker fibrous reticular lamina secreted by the underlying connective tissue.
The neighbouring epithelial cells are held together by 3 types of intercellular junctions as shown in the figure such as tight junctions, adhering junctions and gap junctions.
The tight junctions prevent the leakage of substances, the adhering junctions cement the adjoining cells with desmosomes, interdigitation, etc. The epithelial tissues are non-vascular.(b) Stratified Epithelial Tissue: It is a compound tissue and many layered in thickness.
It is composed of a basal layer called the Malpighian layer. This tissue is found in the skin of mammals and conjunctiva of the eye. II. Connective Tissues: The cells of this tissue are known as corpuscles and secrete a ground substance – the matrix.
Various organs of an animal body are made up of four types of animal tissues: Epithelial tissue, Muscular tissue, Connective tissue; and; Nervous tissue; Classification of Animal Tissue.
1. Epithelial Tissue: Epithelial tissue is made up of epithelial cells which form the . The epithelial tissues originate from ectoderm, mesoderm and endoderm layers. They are mainly concerned with protection, secretion, absorption, excretion and reproduction functions.
The muscular and connective tissues are of mesodermal origin. Jul 31, · All connective tissues except blood tend to secrete structural proteins called collagen or elastin.
There are different types of connective tissues like Loose Connective tissue, Dense Connective tissue, and Specialized Connective tissue. Muscular tissue. This animal tissue is again divided into three types which are cardiac, smooth, and skeletal.
The main difference between plant and animal tissue is their functions; plant tissues provide structural support to the plant whereas animal tissues help the locomotion. Classification of (Animal) Tissue Types – Epithelial Tissue, Connective Tissue, Muscular Tissue, Nervous Tissue, Available here.
Accessed 28 Aug. Image Courtesy: 1. Connective tissues' most common function are to bind and support other tissues in the body. Muscle tissue is responsible for nearly all types of body movement.
The function of nervous tissue is to sense stimuli and transmit signals in the for of nerve impulses from one part of the animal to the other.