Biology: Tissues.

 Biology.

Tissues.

Made By Hibat Khalid.

INTRODUCTION

Tissues are groups of similar cells that have a common function. It consists of a group of structurally and functionally similar cells and their intercellular material. Organs are formed by the functional grouping together of multiple tissues

Types of tissue

There are two types of tissues- Animal tissues and Plant tissues, they have their own types. First we will discuss plant tissue and then animal tissue.

Plant tissue

Plant tissue is a collection of similar cells performing an organized function for the plant. Each plant tissue is specialized for a unique purpose, and can be combined with other tissues to create organs such as leaves, flowers, stems and roots

1. Dermal Tissue

           Dermal tissue is found covering the younger primary parts of a plant. These    include leaves, roots, stems, flowers, fruits, and seeds. Plant parts that become woody no longer have dermal tissue as their outer layer because it is replaced by periderm, or cork.

2. Vascular Tissue

Vascular tissue is a complex conducting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally.

3. Ground Tissue

A ground tissue is a plant tissue other than those of the dermal tissues and the vascular tissues. It arises from the ground meristem. It fills in the soft parts of the plants, such as cortex, pith, pericycle, etc. 

4. Meristematic Tissue

A meristematic tissue is made up of small thin-walled cells, which may be spherical, oval or polygonal. These cells have a large nucleus, dense cytoplasm and a few small vacuoles. Unlike other cells, they have the ability to divide continuously to produce new cells. Meristematic tissue is responsible for the growth of the plant. All other types of tissues develop from meristematic tissue. 

                                                                                                                                                                                  

• Important point of Plant tissue.

1.  The cells are living, elongated and irregularly thick at the corners made of cellulose or pectin they have very less or no intercellular spaces   

2. Vascular tissue transports water, minerals, and sugars to different parts of the plant.

3. They are usually loosely packed, so that large spaces between cells (intercellular spaces) are found in this tissue

4. This tissue provides support to plants and also stores food.

5. Meristematic tissues, based on their location, are of three types namely: apical lateral and intercalary meristematic tissue. 

6. Xylem is a water conducting tissue.

7.  Phloem is a food conducting tissue.   

Animal Tissue

Animal cells are grouped together to form animal tissues. These tissues vary in their structure, function, and origin. The animal tissues are divided into epithelial, connective, muscular and nervous tissues.

1. Epithelial Tissue

This tissue covers the outer surface of the whole body. It also lines organs, cavities and other parts of the body.It forms the inner lining of blood and lymph vessels, and various ducts and tubes such as the bronchioles. It provides protection from injury and germs. It also helps in absorption.

2. Connective tissue

Connective tissue is the tissue that connects, separates and supports all other types of tissues in the body. Like all tissue types, it consists of cells surrounded by a compartment of fluid called the extracellular matrix. It has three types- Connective tissue proper, Skeletal tissue and Vascular tissue. It is also known as supportive tissue.

3. Muscular tissue

This tissue forms muscles, which not only helps us move various parts of our body, but helps us breath, digest food, get rid of waste, and so on. There are three types of muscular tissue- voluntary, involuntary, and cardiac.It is also referred to as myopropulsive tissue.

4. Nervous Tissue

Nervous tissue is composed of specialized cells called neurons, which transmit messages from all parts of the body to the brain and spinal cord, and vice versa. A neuron consists of the cyton, or cell body, a tail-like structure called axon, and dendrites.The cyton contains the nucleus and various organelles. The cytoplasm of a neuron is known as neuroplasm. Bunches of neurons form nerves. There are three types of muscular tissue- Voluntary, Involuntary, Cardiac muscles. 

• Important points of Animal tissue.

1. They cover the body, organs, blood vessels and all body cavities. 

2. Nervous tissue is made up of the nerve cells (neurons) that together form the nervous system, including the brain and the spinal cord.

3. Bone marrow is a soft connective tissue that produces blood cells. It is found inside the pores of bones.

4. Bone, blood, fat, and cartilage are all connective tissues.

5. Cardiac muscle is found only in the walls of the heart.

6. Connective tissues are made up of fibrous cells (Fibroblasts).