7.1. Organ and Organ System

The basic tissues as you have learnt in earlier classes, organise to form organs which in turn associate to form organ systems in the multicellular organisms. Such an organisation is essential for more efficient and better coordinated activities of millions of cells constituting an organism.

In multicellular organisms, various basic tissues come together to create organs. These organs then work together to form organ systems. This organization is crucial because it allows for better coordination and efficiency in carrying out the many functions necessary for survival. Each type of tissue has specific roles, and when they band together, they create structures that perform more complex tasks than individual cells could manage.

Think of a sports team. Each player has a distinct role: a goalkeeper, defenders, midfielders, and forwards. When they work together as a team, they can execute strategies to win games, much like how different tissues create organs to carry out bodily functions.

Each organ in our body is made of one or more type of tissues. For example, our heart consists of all the four types of tissues, i.e., epithelial, connective, muscular and neural.

Every organ in the body has a specific composition of tissues that perform various functions. For instance, the heart is made up of epithelial tissue (which lines the heart), connective tissue (which supports and binds), muscular tissue (which allows the heart to contract and pump blood), and neural tissue (which coordinates heart functions). This diversity of tissue types is what allows organs to function effectively.

Consider a car engine. It consists of metal (structural parts), rubber (hoses), and electrical wiring (controls). Each component must function well individually but also work together for the engine to perform effectively.

When two or more organs perform a common function by their physical and/or chemical interaction, they together form organ system, e.g., digestive system, respiratory system, etc.

Organ systems are formed when different organs work together to perform a specific task. For example, the digestive system includes the mouth, stomach, and intestines, which collaborate to break down food and absorb nutrients. Each organ contributes uniquely, and their interactions ensure that the overall function is efficient.

Imagine a restaurant kitchen, where the chef (mouth) prepares, the stove (stomach) cooks, and the waiter (intestines) serves meals to customers. Each member works in tandem, contributing a part of the process to ensure diners enjoy their meal.

Cells, tissues, organs and organ systems split up the work in a way that exhibits division of labour and contribute to the survival of the body as a whole.

In biology, just like in any efficient workforce, tasks are divided among cells, tissues, organs, and organ systems. This division of labor means that each part, whether a single cell or a complex organ system, focuses on specific duties, allowing the organism to function optimally. This interconnectedness is crucial for the health and survival of the organism.

Think of a factory where each worker has a specific job—some assemble parts, others manage supplies, and some handle shipping. This way, the factory runs smoothly and produces products efficiently, similar to how division of labor works in living organisms.

We also notice, after some careful study that the complexity in organ and organ systems displays certain discernable trend. This discernable trend is called evolutionary trend (You will study the details in class XII).

As organisms have evolved over time, there has been a noticeable increase in the complexity of organs and systems. These trends can often reflect adaptations that allow organisms to survive in their environments. For instance, the respiratory system of fishes is different from that of mammals, showing adaptation to their respective environments.

Consider a cell phone that has evolved over the years. Early models only made calls, while modern smartphones combine calling, texting, internet browsing, and photography. This complexity reflects advancements in technology, much like evolutionary trends in biological organisms.

In this chapter, you are being introduced to morphology and anatomy of frog. Morphology refers to study of form or externally visible features. In the case of plants or microbes, the term morphology precisely means only this. In case of animals this refers to the external appearance of the organs or parts of the body. The word anatomy conventionally is used for the study of morphology of internal organs in the animals.

Morphology and anatomy are key concepts in biology. Morphology is the study of the form and structure of organisms, focusing on external structures. Anatomy, on the other hand, is the study of internal organs and systems. Understanding these helps in comprehending how organisms function and thrive in their environments.

It’s like knowing a car's exterior features (morphology) and also understanding the engine and systems inside it (anatomy). Just as knowing both aspects helps you appreciate how the car works, studying both morphology and anatomy helps us understand living organisms.

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