Secondary growth in thickness of root is due to the addition of new tissues by the activity of vascular cambium and cork cambium. Monocot roots do not show secondary growth. Dicot roots have radial and exarch vascular bundles. Conjunctive tissue is present between xylem and phloem. Activity of Cambium The conjunctive tissue becomes meristematic and … Read more
Due to continuous increase in the girth of the stem due to the activity of vascular cambium, great pressure is exerted on the outer cortex and epidermis. The epidermis will eventually get ruptured and hence new protective cell layers should be formed. This new layer is formed by the activity of another meristematic tissue called … Read more
Growth in length of the axis due to the activity of apical meristem is called primary growth. The increase in girth or thickness of the axis is called secondary growth. It is formed by the activity of the two lateral meristems, namely Vascular cambium and the Cork cambium. Vascular Cambium Dicot stems usually have open … Read more
Monocotyledonous leaf (Isobilateral / Equifacial Leaf) In monocot leaves, the internal structure of both upper and lower leaf surfaces look similar. Epidermis The epidermis is composed of barrel shaped parenchyma cells. It bears cuticle and epidermal hairs. In grasses, the epidermal cells are impregnated with silica. In these plants, some cells are modified into large, … Read more
Dicotyledonous Leaf (Dorsi-ventral leaf) A thin cross section of dicot leaf shows three main parts, namely epidermis, mesophyll and vascular system. Epidermis Epidermis covers the entire surface of a leaf. It is covered by a thick layer of cuticle. It is single layered and composed of closely packed cells. In some plants like Ficus, the … Read more
The heart can refer to as a complex muscle that pumps blood through the three divisions of the circulatory system like the coronary (vessels that serve the heart), pulmonary (heart and lungs), and systemic (systems of the body). Coronary circulation intrinsic to the heart does take the blood directly from the main artery (aorta) coming … Read more
Nausea and vomit are common signs and symptoms that may be caused by various conditions. Nausea and vomit are usually because of microorganisms inflammatory disease — often erroneously known as gastroenteritis — or the sickness of early pregnancy. Nausea is an uneasiness of the abdomen that always comes before vomit. Vomiting is that the forceful … Read more
The visceral nervous system also is known as the autonomic nervous system which controls many involuntary functions of the body like arterial blood pressure regulation, pupillary, and heart rate. A large amount of energy of this nerve goes to the psychological systems which require ongoing assessment and correction. The visceral or autonomic nervous system is … Read more
Osmoregulation is defined as the maintenance of constant osmotic pressure in an organism’s body fluids by controlling salt and water concentrations. Osmotic pressure is the measure of how water tends to move from one solution to another by osmosis. The greater the osmotic pressure of a given solution, the higher the tendency of water to … Read more
Proteins consumed by living organisms for growth mainly consist of nitrogen. The metabolism of proteins, therefore, forms nitrogenous waste materials in the body that could be toxic in high quantities. It is important for living organisms to excrete nitrogenous waste products such as ammonia, urea, and uric acid. Based on the type of nitrogenous waste … Read more