THE TISSUE

 

What are Tissues?

In simple terms, tissue can be defined as a group of cells with similar shape and function are termed as tissues. They form a cellular organizational level, intermediate between the cells and organ system. Organs are then created by combining the functional groups of tissues.

 

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Let us learn in detail about the types of tissues in different organs.

The study of tissue is known as histology and study of disease-related to tissue is known as histopathology. The standard tools for studying tissues is by embedding and sectioning using the paraffin block.

Types of Animal Tissues

Animal tissues are grouped into four types:

• Connective Tissue
• Muscle Tissue
• Nervous Tissue
• Epithelial Tissue

The collection of tissues are joined in structural units to serve a standard function of organs. The primary purpose of these four types of tissue differs depending on the type of organism.

For example, the origin of the cells comprising a particular tissue type also differs.

Connective Tissues

They are the group of tissues made up of cells separated by non-living material, called as an extracellular matrix. This tissue provides shape to the different organs and maintains their positions. For example, blood, bone, tendon, adipose, ligament and areolar tissues. There are three types of connective tissue:

• Fluid Connective Tissue.
• Fibrous Conctive Tissue.
• Skeletal Connective Tissue.

Functions of Connective Tissue

The connective tissue functions by providing shape and maintains the position of different organs in the body. It functions as the primary supporting tissue of the body. Other important and the major functions of connective tissue in the body are:

1. Insulating.
2. Helps in binding the organs together and provides support.
3. It protects against the invasions of pathogens by their phagocytic activity.
4. Provides shape to the body, conserves body heat and also stores energy.
5. It is involved in the transportation of water,  nutrients, minerals, hormones, gases, wastes, and other substances within the body.

Also refer to – Blood – The Fluid Connective Tissue.

Muscle Tissue

They are involved in producing force and generating motion, either for the locomotion or for other body movements within internal organs. There are three types of muscle tissue:

• Skeletal Muscle – they  are typically attached to bones
• Cardiac Muscle – found in the heart.
• Visceral or Smooth Muscle – they are found in the inner walls of organs.

Functions of Muscle Tissue

Muscle tissues are associated with their movements including walking, running, lifting, chewing, picking and dropping objects, etc. The other major functions of muscle tissue in the body are:

1. Helps in maintaining an erect position, or posture.
2. Helps in the constriction of organs and blood vessels.
3. Involved in both voluntary and involuntary movements.
4. Involved in pumping blood and regulating the flow of blood in arteries.
5. Controls respiration by automatically driving the movement of air both into and out of our body.

Also Read:  Muscular Tissue.

Nervous Tissue

They are the main tissue components of the brain and spinal cord in the central nervous system. While, in the peripheral nervous system, the neural tissue forms the cranial nerves and spinal nerves.

Functions of Nervous Tissue

The nervous tissue forms the communication network of the nervous system and is important for information processing. The other major functions of nervous tissue in the body are:

• Response to stimuli.
• Stimulates and transmits information within the body.
• Plays a major role in emotions, memory, and reasoning.
• Maintains stability and creates an awareness of the environment.
• Nervous tissue is involved in controlling and coordinating many metabolic activities.

Also Refer:  Central nervous system.

Epithelial Tissue

They are formed by cells which cover the external parts of the body organs and lines the organ surfaces such as the surface of the skin,  the reproductive tract, the airways, and the inner lining of the digestive tract.

Functions of Epithelial Tissue

This tissue performs a wide variety of functions including:

1. Play a major role in sensory reception, excretion, filtration and other metabolic activities.
2. Provide mechanical strength and resistance to the underlying cells and tissue.
3. It is involved in the movement of materials through the process of filtration, diffusion and secretion.
4. Protects the internal organs against the invasions of pathogens, toxins, physical trauma, radiation, etc.

Epithelial tissues are also involved in secreting hormones, enzymes, mucus and other products from ducts and transporting it to the circulatory system.

Also Refer : Epithelial Tissue & Connective Tissue.

Types of Plant Tissues

The classification of plant tissues are mainly based on the two important criteria:

1. Based on the different part of plants.
2. Based on the different types of cells.

Plant Tissues are broadly categorized into three tissue systems. This classification is on the basis of parts of the plants they are present.

• Epidermis Tissues – cells formed from the outermost surface of the leaves.
• Vascular Tissues – involved in transporting fluid and nutrients internally.
• Ground Tissue – involved in producing nutrients by photosynthesis and preserve nutrients.

Plant tissue is divided into two types. This classification is on the basis of the types of cells, they comprise.

• Meristematic tissues.
• Permanent tissues.

Also, read Parts Of Plants.

Meristematic Tissue

They are the group of young cells, which consists of continually dividing cells and helps in the increase of length and width of the plant. There are different types of meristematic tissues, which are classified on the basis of positions, functions, plane of divisions, origin and development. The three main types of meristematic tissues depending on the occurrence of the meristematic tissue on the plant body are:

1. Apical Meristem.
2. Lateral Meristem.
3. Intercalary Meristem.

Functions of Meristematic Tissue

1. It is responsible for the growth of the new organs.
2. Involved in the movement of water and nutrition within the plants.
3. These tissues are responsible for both primary and secondary growth of the plant.
4. It is the outermost tissue, functions by providing protection from mechanical injury.
5. It gives rise to epidermis layer, cortex, endodermis, ground tissue and vascular tissue.

Explore more about Meristematic tissue.

Permanent Tissues

A group of cells which are similar in origin, structure and in function. They are involved in complete growth and differentiation during the ineffective of meristematic activity. There are three types of permanent tissues:

1. Simple Permanent Tissues.
2. Complex Permanent Tissues.
3. Special or Secretory Tissues.

Functions of Permanent Tissues

1. In aquatic plants, these tissues help in floating.
2. Stores food in the form of starch, proteins, oils and fats.
3. They provide hardness to fruits such as nuts, coconut, almond etc.
4. These tissues contain chloroplast which helps in carrying out photosynthesis.
5. Permanent Tissues are also involved in the Secretion, Transportation, and provides mechanical support to the plants.