Anatomy - Organ and Organ System
The basic tissues organise to form organs which in turn associate to form organ systems in the multicellular organisms.
An organisation is essential for more efficient and better coordinated activities of millions of cells constituting an organism.
Every organ is made of one or more type of tissues. For example human heart consists of four types of tissues.
The complexity in organ and organ systems shows certain discernable trend and this discernable trend is called evolutionary trend.
The morphology refers to study of form or externally visible features. In the case of animals refers to the external appearance of the organs or parts of the body.
The word anatomy conventionally is used for morphology of internal organs in the animals. we will cover the morphology and anatomy of earthworm, cockroach and frog representing invertebrates and vertebrates.