Introduction
All living organisms are made up of tiny building blocks called cells, which are the smallest units of life. These cells combine to form tissues, which further unite to form organs and organ systems. So, what is tissue in science?
All biotic organisms in the world are classified into two major categories: unicellular and multicellular organisms.
In higher multicellular organisms such as dogs and human beings, cells cluster together to form groups that perform a particular function. Each group performs a specific function and is known as a tissue.
To put it simply, a tissue is a group of cells that play a similar role. These are present in both plants and animals and represent levels of organization in living organisms.
The study of tissues is called histology, and for plants, the subject is called plant anatomy.
Read on to know more about tissue and its types.
Classification of Tissues
Tissues form an intermediate organizational structure between cells and organ systems. Different groups of tissues with diverse functions group together to form an organ. In animals, therefore, a group of muscle cells combines together to form muscle tissue.
The classification of tissues in animals falls under four major categories. These are:
Connective tissues.
Muscle tissues.
Nervous tissues.
Epithelial tissues.
Before you learn more about what is the function of tissue, here’s a quiz for you to try:
Pop Quiz 1:
The study of tissues is known as ________.
Plant anatomy.
Morphology.
Histology.
Natural history.
Connective Tissues
In connective tissue, a group of cells separated by a non-living extracellular matrix combine to form a tissue. Connective tissues help provide mechanical strength, shape and rigidity to the organs and keep them in place. Examples of connective tissues include tendons, ligaments, bones, blood, adipose and areolar tissues. Further, there are three types of connective tissues. These are:
Skeletal Connective Tissue.
Fluid Connective Tissue.
Fibrous Connective Tissue.
Connective tissues have several different functions in the human body, namely:
They provide insulation and protection against cold to the body.
They help bind the organs together and provide mechanical support to them.
Connective tissues help transport gases, water, hormones, nutrients and waste materials within the body.
Muscle Tissue
Muscle tissues help us to perform different actions and engage in activities like walking, running and locomotion. There are three types of muscle tissue:
Skeletal muscles.
Cardiac muscles.
Visceral or smooth muscles that line the inner walls of organs.
Firstly, muscle tissues help us to maintain our posture. Secondly, they also aid in our involuntary and voluntary movements. For example, cardiac muscles help pump blood and regulate its flow in arteries and capillaries.
Muscle tissues can also be classified on the basis of the conscious control a person has over those muscles. On this basis, there are two types of muscles in existence which are - Voluntary muscles and Involuntary muscles. Voluntary muscles move according to the will of the person and involuntary muscles move freely irrespective of the will of the person.
Nervous Tissue
Nervous tissues are present in the central nervous system that comprises the brain and spinal cord. In the peripheral nervous system, nervous tissues make up the cranial and spinal nerves.
Nervous tissues perform several vital functions, such as:
They control and coordinate metabolic activities in the body.
They help transmit information within the body.
They help maintain stability and create an acute awareness of the environment around us.
They also help us respond to external stimuli.
These tissues also play a key role in the management of various emotions, memory, and the reasoning skills of an organism.
Epithelial Tissue
Epithelial tissues consist of cells that form the external covering of the body. These cover the organ surfaces such as the skin, the airways, the inner walls of our digestive tract as well as the reproductive tract.
Epithelial tissues provide support and mechanical strength to the cells and tissues. They also help in the transportation of materials through diffusion, secretion, and filtration.
Moreover, epithelial tissues such as the ones beneath our skin help us in sensory reception and protect us against pathogens and physical trauma. They also secrete hormones, mucus, and enzymes from various endocrine organs.
Now that you have gone through the classification of tissues, it’s time to revise a few concepts with the following exercise.
Classification of the tissue present in the plants
Plants also have various types of tissues and can be classified into two categories. The first is based on the parts of plants whose tissue is present in the plant and the second is on the basis of types of cells.
By the first category, the plant tissues can be classified into three major groups, these three groups are:
a) Epidermis Tissues: These tissues are present on the outer surfaces of the leaves.
b) Vascular Tissues: They help in the transportation of the various fluids and nutrients. They are generally present at the middle of the stem and trunk and are spread all over the plant's body.
c) Ground Tissues: Ground tissues are the ones that assist in the process of photosynthesis.
With the help of the second category, the plant tissue can be divided into two sub-categories.
a) Meristematic Tissues: These cells keep on producing new copies of themselves.
b) Permanent Tissues: These tissues have lost their ability to divide and recreate themselves.
Pop Quiz 2
What are the types of tissues?
Connective Tissues.
Nervous Tissue.
Epithelial Tissue.
Muscle Tissue.
All of the above.
Here is a classification of tissues chart to help you understand better.
(Image will be Uploaded soon)
Know more about topics related to tissue and types of tissue in our live classes, on the Vedantu app. Download study material from our range of revision notes and sample papers and make learning exciting.
FAQs on Classification of Tissues
1. How many Types of Tissues are There?
There are four types of tissues in animals. These are the connective tissues, the muscle tissues, the nervous tissues, and the epithelial tissues. For plants, the tissues can be divided into mainly two types- meristematic tissues and permanent tissues. Permanent tissue in the plants can be further divided into simple tissues and complex tissues.
The students can learn more about all these different types of tissue by referring to the high-quality study material provided on Vedantu.
2. What is the definition of Tissue?
A group of cells that play a similar role is called a tissue. In higher multicellular organisms such as human beings, cells cluster together to form groups that perform a definite function. Each group has a specific purpose and is known as a tissue.
The word “tissue” comes from the french word “tissu” which means “to weave” as the cells in a tissue seem like they are woven together to form a tissue. The study regarding the tissue is called “histology”.
3. Write down two functions of connective tissues.
Connective tissues help provide mechanical strength, shape, and rigidity to the organs and keep them in place. They provide insulation and protection against cold to the body. Connective tissues also have an important role in the transportation of gases, water, hormones, nutrients, and waste materials within the body. They also help in resisting different pathogens from entering the body. The connective tissues are also of various types such as bone ligaments, tendons, and cartilage.
4. What are the permanent tissues? and what are the different types of permanent tissues?
In plants, permanent tissues are those tissues in which the cells have lost their ability to divide and produce their own identical copies. The permanent tissues consist of both living and dead cells, all of which function in order to achieve a specific function, a specific function is dedicated to the one type of permanent tissue. Even the permanent tissue is further divided into two categories, these are -
a) Simple Permanent Tissues: These types of tissues comprise just a single type of cells and thus have a simpler structure.
b) Complex Permanent Tissues: They have many different kinds of cells included in the complex permanent tissues
5. What are the differences between the permanent tissues and meristematic tissue present in the plant?
The tissues present in the plant body can be classified in two ways. Classification of tissues under one of those ways divided the tissues into two categories, these two categories are- permanent Tissues and meristematic tissues. The difference between these two types of tissues, permanent Tissues, and meristematic tissues, are given below -
Meristematic tissues are the tissues that continuously divide and create new copies of themselves in order to participate in the plant's growth cycle. While the permanent tissues have lost their ability to divide and hence can not create new copies of themselves, their role in the plant's body is to carry out some specific functions that are dedicated to them.
New meristematic tissues originate directly from the meristematic tissue, and the permanent tissues also originate from the meristematic tissues.
Meristematic consists of only the living cells, but in some permanent tissue, dead and living cells are both included together.
