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thyroid gland  It is largest endocrine gland situated in the neck close to the trachea. The gland is butterfly or H shape and consists of two elongated oval lobes joined by a narrow band called isthmus. It is highly vascular organ and contains many spherical or oval sac-like follicles. Cells lining the thyroid follicles secrete … Read more

INTRODUCTION Mitochondria are cylindrical or sausage-shaped double membrane organelles distributed in the cytoplasm They are not easly visible under the microscope. Thus, they are stained by a vital stain Janus green to make them visible for observation. Mitochondria show a great degree of variability in their shape, size and number. Mitochondria are double-membraned organelles found … Read more

DISORDER (i) Myasthenia Gravis:- It is an autoimmune disorder in which the antibodies produced in the body start attacking its own body cells. The antibodies recognize the body cells as foreign material and start acting against it. In myasthenia gravis, the antibodies start attacking the acetylcholine receptors present on sarcolemma, due to  which the neurotransmitter … Read more

INTRODUCTION joints in human body Joints are structural arrangement where two bones articulate i.e., meet each other. The framework of the body consists of separate skeletal elements which are joined or articulate with one another by different types or joints. The joints are essential for the movement of different skeletal structures i.e., all the bones … Read more

Human Excretory system INTRODUCTION In human, excretory system consists of a pair of kidneys, one pair of ureters, a urinary bladder and a urethra. Kidneys Shape and size- Kidneys are reddish brown, bean- shaped situated between the levels of last thoracic and third lumber vertebrata close to the dorsal inner wall of the abdominal cavity. … Read more

human heart INTRODUCTION Human circulatory system, also known as the blood vascular system consists of a muscular chambered heart, a network of closed branching blood vessels and blood, the fluid which is circulated LABELLED HEART Structure of Human Heart Heart is located in the thoracic cavity, in between the two lungs, slightly tilted to the … Read more

INTRODUCTION Plastids are found in all plant cells in euglenoids etc. Depending upon their colour and pigments they contain, these are of three main types- leucoplasts, chromoplasts and chloroplasts.         1  Leucoplasts:- they are colourless plastids which generally occur near          the nucleus in non-green cells.They are variable in … Read more

INTRODUCTION The flower is the reproductive unit in the angiosperm. It is a modified shoot, meant for sexual reproduction. It consists of four whorls which are successively arranged on the thalamus or receptacle. Thalamus  is the swollen end of the predicel or the stalk. The four whorls present in a flower are calyx, corolla, androecium, … Read more

INTRODUCTION The ascending part of the plant axis which bears branches, leaves, flowers and fruits is called stem. It develops from plumule. Stem is differentiated into nodes and internodes. The region bearing leaves, present at regular intervals on the stem and its branches are called nodes  and the part of stem present between the two … Read more

INTRODUCTION Golgi Appratus • Golgi apparatus as a bustling sorting and distribution center within the cell. • He described it as a densely stained reticular structures present near the           nucleus of the cell. • Therefore, these were given the name Golgi bodies, after his name. • It is present in eukaryotic … Read more