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A gland is an organ which produces and releases substances that perform a specific function in the body. There are two types of gland. Endocrine glands are ductless glands and release the substances that they make (hormones) directly into the bloodstream. These glands form part of the endocrine system and information on them is included … Read more
What Are Isotopes? Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numbers) due to different numbers of neutrons in their nuclei. While all isotopes of a given element have almost the same chemical properties, they … Read more
What is heat? Heat is the form of energy majorly due to temperature differences or increase in molecular kinetic energy. In other words, heat is energy transferred from one system to another solely by reason of a temperature difference between the systems. Heat exists only as it crosses the boundary of a system and the … Read more
In humans each lung is encased in a thin membraneous sac called the Pleura, and each is connected with the trachea (windpipe) by its main bronchus (large air passageway) and with the heart by the pulmonary arteries. Each Pleura can be divided into two parts: Visceral pleura-envelops the lung. Parietal pleura- covers the internal surface … Read more
Octahedral Complexes Octahedral complexes have six ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. Octahedral molecular geometry describes the shape of compounds wherein six atoms or groups of atoms or ligands are symmetrically arranged around a central atom. The octahedron has eight faces, hence the prefix octa-. An example of … Read more
What Is Endosmosis? When a cell is placed in a hypotonic solution, the water move inside the cell causing it to swell or bulge. This movement of water inside a cell is known as endosmosis. This happens because the solute concentration of the surrounding solution is less than that inside the cytoplasm of the cell. … Read more
Thick and thin blood smears are commonly used to determine whether a person has malaria or not. If one test is negative and no parasites are found, there will be repeated blood smears every 8 hours for a couple of days to confirm that there is no malaria infection. Blood smears are most often taken … Read more
Velocity is a rate of change of the position of an object within a certain time range. There are two different types of velocity: angular velocity and linear velocity. Linear velocity is the rate of change of the position of an object that is traveling along a straight path. Any object that moves has a linear velocity. On … Read more
Nephridium is unit of the excretory system in many primitive invertebrates and also in the amphioxus; it expels wastes from the body cavity to the (usually aquatic) exterior. The evolution of nephridia encouraged tissue specialization by eliminating the need for all cells of an organism to be in contact with seawater for diffusion of metabolic wastes. Nephridia … Read more
What Is Starch? Starch is the most important source of carbohydrates in the human diet and accounts for more than 50% of our carbohydrate intake. It occurs in plants in the form of granules, and these are particularly abundant in seeds (especially the cereal grains) and tubers, where they serve as a storage form of … Read more