tissue
Definition
A tissue is a group of cells that are similar in structure and function. Tissues are the building blocks of organs, which are the functional units of the body.
The four main types of tissue in the body are:
- Epithelial tissue: Covers the body and lines its organs and cavities.
- Connective tissue: Holds the body together and provides support.
- Muscle tissue: Allows the body to move.
- Nervous tissue: Carries messages throughout the body.
Each type of tissue has its own unique properties and functions. For example, epithelial tissue is made up of cells that are tightly packed together, which helps to protect the body from infection. Connective tissue is made up of cells that are spread apart, which allows it to stretch and move. Muscle tissue is made up of cells that can contract and relax, which allows the body to move. Nervous tissue is made up of cells that can transmit electrical signals, which allows the body to communicate.
Tissues are organized into organs, which are the functional units of the body. For example, the heart is an organ that is made up of muscle tissue. The heart contracts and relaxes to pump blood throughout the body. The lungs are an organ that is made up of epithelial tissue. The lungs exchange oxygen and carbon dioxide with the blood.
The human body is made up of many different tissues and organs. These tissues and organs work together to keep the body alive and functioning.
How can the word be used?
The surgeon removed a small piece of tissue from the patient's liver.
Different forms of the word
Noun:
- a thin, soft, and often translucent layer of material, especially of animal or vegetable origin.
- a group of similar cells that together perform a specific function in an organism.
- a piece of absorbent paper used for blowing the nose or packing presents.
Verb:
- to form or arrange into a tissue.
Etymology
The word "tissue" comes from the Old French word "tissu", which means "woven".
The first recorded use of the word "tissue" in English was in the 14th century.
The word "tissue" is a French word, and it is not related to any other words in English.
Question
Where might you find tissue?
AQA Science Exam Question and Answer
Question:
Describe the structure and functions of epithelial tissue in the human body. Explain how the different types of epithelial tissue are adapted to their specific roles and environments. Provide an example of an organ where epithelial tissue plays a vital function.
Answer:
Epithelial tissue, a fundamental type of tissue in the human body, covers internal and external surfaces and lines various organs. It consists of tightly-packed cells arranged in layers, providing protection, absorption, secretion, and sensory perception.
There are several types of epithelial tissue, each adapted to its unique function and location. Simple squamous epithelium, found in the lungs' alveoli, is thin and suited for efficient gas exchange. Stratified squamous epithelium, forming the skin's outer layer, offers protection against mechanical stress and pathogens. Cuboidal epithelium, present in kidney tubules, facilitates absorption and secretion, while columnar epithelium, lining the intestines, increases surface area for nutrient absorption.
For instance, in the digestive system, the small intestine is lined with columnar epithelial cells covered in microvilli, tiny projections that enhance nutrient absorption. This adaptation increases the intestine's absorptive capacity, allowing for efficient digestion and nutrient uptake.
Epithelial tissue's diverse functions highlight its importance in maintaining tissue integrity and enabling vital bodily processes. The intricate structure of different epithelial types reflects their specific roles in various organs, emphasising how tissue specialisation contributes to the overall function of organs and systems within the human body.