Banu's blog for school students

How many different types of cells are in the human body? There are about  200 different types of cells  in the body. Here are just a few examples: red blood cells (erythrocytes) skin cells neurons (nerve cells) fat cells Humans are multicellular, complex organisms. The cells inside our bodies are “specialized.” This means that each type of cell performs a unique and special function. For this reason, each of the 200 different types of cells in the body has a different structure, size, shape, and function, and contains different organelles. For example: Cells in the brain may be longer in shape so they can transmit signals more efficiently. Cells of the heart have more mitochondria because they need a lot of energy. Cells in the respiratory system are responsible for taking up oxygen and releasing carbon dioxide. All the cells work together to keep the human body running efficiently.

The arrangement of veins on the leaf lamina is called venation.  It is of two different types: RETICULATED venation: it is also called as web like venation. In this type, there is a central thick vein called midrib in the centre of the leaf . From the midrib arises lateral veins on both sides which inturn has small veinlets appearing like web. This type of venation is present in dicot plants. Ex. Rose, mango, peepal,etc PARALLEL venation: in this type, there is no midrib in the centre instead all the veins run parallel to each other on the whole leaf. Thus type of venation is present in monocot plants. Ex. All grass family plants like rice, wheat , jowar etc.