Ch 7Structural Organization in Animals — Class 11 Biology, concept-first.

Every organ in an animal's body is built from just four basic kinds of tissue, and the first of these is epithelial tissue — the tissue that covers external body surfaces and lines internal cavities,…

Connective tissue is, by both volume and distribution, the most abundant tissue type in the vertebrate body, and it is defined by a feature exactly opposite to that of epithelium: rather than cells pa…

Muscular tissue is the tissue specialised for producing movement through contraction. Its cells, called muscle fibres because of their elongated shape, contain two contractile proteins, actin and myos…

Nervous tissue is the fourth and last of the four fundamental animal tissue types, and it is specialised not for covering, packing or contracting, but for rapidly receiving a stimulus and conducting a…

Having surveyed the four basic tissue types that build every animal organ, this chapter now turns to how those tissues are assembled into the complete organ systems of a real animal, using the frog —…

Like other vertebrates, the frog's digestive system is a continuous alimentary canal running from the mouth to a terminal opening, together with a set of associated glands that secrete digestive juice…

The frog possesses a closed circulatory system, meaning blood is at all times confined within a continuous system of vessels, driven by a muscular pump — the heart — that lies within a thin protective…

As an amphibian, the frog spends part of the year submerged in water and part of the year active on land, and correspondingly it does not rely on a single respiratory organ the way a fish (with gills…

The frog's nervous system, like that of other vertebrates, is organised around a central nervous system — the brain and spinal cord — connected to the rest of the body by a peripheral system of crania…

The frog's reproductive system, like its respiratory system, is closely tied to its amphibious life cycle, since fertilisation and the earliest stages of development both take place in water rather th…

This chapter has worked through animal structural organisation at two levels: first the four basic tissue types that are the common building blocks of every animal organ, and then, using the frog as t…