Biology · Structural Organisation in Animals · NEET
The four basic animal tissues are: (1) Epithelial tissue - covers and lines body surfaces and organs; (2) Connective tissue - links, supports and packs organs (it has plenty of matrix between cells); (3) Muscular tissue - contracts to cause movement; (4) Neural tissue - carries messages as electrical signals. NCERT (Class XI, Structural Organisation in Animals) says our heart contains all four types. Remember: only these four exist in every animal, no matter how complex the body is.
A tissue is a group of similar cells that work together for one function (for example, all the cells of muscular tissue). An organ is made of two or more tissue types working together for a bigger job. Example: the heart is one organ but it contains all four tissues - epithelial (lining), connective (support), muscular (pumping) and neural (control). So the order goes cell to tissue to organ to organ system.
Blood is grouped as connective tissue because connective tissue is defined by cells scattered in a lot of extracellular matrix. In blood, the cells (RBCs, WBCs, platelets) float in a fluid matrix called plasma. So blood connects and links body parts by transporting things between them. It is a specialised (fluid) connective tissue. NEET loves this: if a question asks 'which is not a connective tissue', blood, adipose and cartilage are connective, but neuroglia is not.
No. Neuroglia (glial cells) are supporting cells of NEURAL tissue, not connective tissue. They support and protect neurons in the nervous system. In NEET 2022, the answer to 'which is not a connective tissue?' was neuroglia, exactly because students confuse 'supporting' with 'connective'. Supporting neurons is a neural-tissue job, so neuroglia belongs to neural tissue.
Epithelial tissue is the covering and lining tissue. It forms a sheet of tightly packed cells with very little matrix, sitting on a basement membrane, and it covers the outside of the body and lines the inside of hollow organs, ducts and cavities. Its jobs include protection, secretion and absorption. This is different from connective tissue, which has abundant matrix and does not form protective linings the same way.
Which type of tissue correctly matches with its location?
Which of the following is not a connective tissue?
Try the real previous-year questions from this chapter — each with the answer and a full solution.
For NEET Class XI, you only need to know that all animals have these four basic tissues (epithelial, connective, muscular, neural) and what each one does. Detailed germ-layer origin is not the focus of this chapter, so concentrate on the function and location of each tissue.
The heart is the standard NCERT example of an organ made of all four tissue types - epithelial, connective, muscular and neural. This line appears directly in the NCERT text, so it is a common one-liner in exams.
Use ECMN: Epithelial (covers/lines), Connective (links/supports), Muscular (moves), Neural (signals). Then attach one keyword to each - Epithelial = lining, Connective = matrix, Muscular = contract, Neural = message. Most tissue questions are just asking you to match one of these four to a location or a feature.
