Animal Tissue - Structure & Types

Simply put, all animal cells are grouped under animal tissue. Animal tissues differ in their structure and origin, as well as morphological properties. Animal tissues are further divided into epithelial tissue, connective tissue, muscle tissue, and nerve tissue. Students need to know all the information about animal tissues and the important differences between plant and animal tissues, as tissues play an important role in the overall performance of bodily functions.

Animal tissue covers the cavities of the human body. Therefore, all students should know animal tissue types and their functions to clarify the idea of animal tissue culture by animal tissue types.

Types of Animal Tissue

There are four types of animal tissue :

1. Epithelial Tissue

2. Muscle Tissue

3. Connective Tissue

4. Neural Tissue

Epithelial tissue

The epithelium (Greek epi-on; the-nipple) is the layer of cells that covers the inner or outer surface. Epithelial tissue consists of compactly arranged cells with no intercellular matrix, forming continuous layers. Junctional complexes such as desmosomes and gap junctions help hold cells together. It has power or regeneration throughout life. It is avascular in nature. Epithelial cells rest on a basement membrane that contains the acellular, matrix protein collagen. Covers the external surface of the body and internal organs. It lines the body cavity. How it covers the outer surface of the skin, the inner lining of the mouth, the digestive tract, the nose, the lungs, etc. These are protective in nature.

Types of epithelial tissues

Epithelial Tissues are always located on the inner or outer surfaces of organs, and their functions largely depend on the exact position of their locations. These are of the following types:

• Squamous epithelium

Densely packed, these are thin, flat cells, mainly resembling the esophagus, blood vessels, alveoli, and the lumen of the mouth. The squamous epithelium can also be arranged in several layers, in which case it is called stratified squamous tissue. These tissues are usually found in the lining of the esophagus and skin.

• Cuboidal epithelium tissue

These are cubes, hence the name. The functions of cuboidal epithelial tissue found in renal tubules, salivary glands, nds, and sweat glands are secretory, protect, give, and absorptive. Multiple layers of cuboidal epithelium are calthe led stratified cuboidal epithelium and are found inside salivary glands and pancreatic ducts.

• Columnar epithelium tissue

Its protective epithelium has many layers of columnar cells, and only the most superficial cells appear truly columnar. This type of epithelium is rare. It is found in the mucus layer near the urethra and anus in men. It also lines the mammary ducts and epiglottis. Important functions of the columnar epithelium tissue include secretion and absorption.

• Cepitheliumithilium The columnarolumnar epithelium is often ciliated. It then becomes known as the ciliated epithelium. They are found in the lining of renal tubules, airways, and trachea. Their function is to help move materials in specific directions.

• Glandular epithelium tissue

These are majorly modified columnar epithelial tissues whose main function is secretion. They can be found in the sweat glands and tear glands.

Muscular tissue

Muscle tissue makes up the muscles in our body and can contract and relax. They are made up of muscle cells. Muscle cells are elongated fibers called muscle fibers that contain the contractile proteins actin and myosin. The contractile proteins they contain assist in contraction and relaxation, resulting in movement and locomotion.

Type of muscular tissue

• Skeletal muscle tissue( striated muscle tissue)

These muscles are attached to the skeleton and help it move. These muscles are also known as striated muscles because of their pattern of alternating light and dark bands. These bright and dark bands are sarcomeres, highly organized structures of actin, myosin, and proteins. They contribute to muscle contractility and extensibility. Skeletal muscle is a voluntary muscle made up of muscle fibers. 40% of our body weight is made up of skeletal muscle. All skeletal tissues contain myofibrils. Cells in these tissues are multinucleated. They are covered with blood vessels and many elongated mitochondria and glycogen granules. They move the organs of the body.

• Smooth muscle tissue

These are non-striated involuntary muscles controlled by the autonomic nervous system. Stimulates contractility of the digestive, urinary, reproductive, vascular, and respiratory systems. The actin and myosin filaments are so thin and randomly arranged that there are no striations. Cells are mononuclear and spindle-shaped.

• Cardiac muscle tissue

These can only be found in the heart. These are involuntary muscles, and the heart pumps blood by contracting the heart. Cardiomyocytes- cells of cardiac muscles, are striated. They are unicellular and lack a nucleus. The ends of the cells are connected and the connection is called the intercalated disc. Cells are connected by desmosomes.

Connective tissue

Connective tissue is a specialized tissue that holds and holds body tissues together. Connective tissue consists of a small portion of cells and a large amount of extracellular material that separates the cells. Two types of cells found in connective tissue include fibrocytes (or fibroblasts) and adipocytes, which are solid cells. In addition, the extracellular material that separates cells consists of three types of fibers: collagen fibers, reticular fibers, and elastic fibers.

Types of connective tissue

• Cartilage

Cartilage is a type of supporting connective tissue. Cartilage is a dense connective tissue composed of chondrocytes. Cartilage connective tissue includes hyaline cartilage, fibrocartilage, and elastic cartilage. The basal material of cartilaginous connective tissue is limited and varies from semi-rigid to flexible matrices.

• Bone

Bone is another type of supporting connective tissue. Bone, also known as bone tissue, is either compact (dense) or spongy (cancellous) and contains osteoblasts or osteocytes. Bone connective tissue is composed of collagen fibers and has a hard, mineralized matrix.

• Adipose

These can be found in the organs and skin. Composed of fat globules, their function is to insulate the body with the fat presence.

• Blood

Blood, also called vascular tissue, is a type of liquid connective tissue. Blood connective tissue contains three types of cells: red blood cells, white blood cells, and platelets. Blood connective tissue fibers are soluble proteins that are formed during clotting, and the extracellular substance that makes up blood connective tissue is liquid plasma.

• Elastic

Elastic connective tissue maintains blood pressure and promotes normal exhalation. They consist of chondrocytes and also of elastic fibers. The extracellular substance of the tissue consists of limited basal material and is built up in a flexible but firm matrix.

• Fibrous

Fibrous connective tissue provides strength and stiffness to the inner layer of the skin, allowing it to handle the forces of joint movement. It contains fibroblasts and is composed of fibrous fibers. It is a dense connective tissue composed of parallel or irregularly arranged fiber bundles with extracellular material and little cellular and basal material.

Nervous tissue

They are made up of neurons (nerve cells in the brain), and these tissues form the entire nervous system, including the spinal cord and the brain.

Types of nervous tissue

• Neuron

The functional unit of nerve tissue is the neuron or nerve cell. Each neuron has cytons, axons, and axon terminals. Cytons or cell bodies have dendrites. The cell body contains a nucleus and many Nissl granules. Neurons can be myelinated and unmyelinated. When myelin sheaths are present on axons, they aid in the rapid transmission of nerve impulses compared to unmyelinated neurons. Neurons do not divide. It helps relay nerve impulses to different parts of the body.

• Neuroglia

Neuroglia or glial cells are non-neuronal cells that reside above and between neurons, along with neurons in the CNS, ganglia, and retina. There are two types: microglia and macroglia.