Introduction Differential permeability is defined as a property of cellular membranes that allows only selective substances to enter or leave the cell. This feature of cellular membranes helps to maintain a constant internal environment regardless of the changes in the external environment. Many ions, water, glucose, and carbon dioxide are constantly imported and exported from …
Introduction Neurons are specific cells of the Nervous system that are involved in transmitting signals from the brain and spinal cord to target cells of the body. It is estimated that the number of neurons in the human brain is about 80 billion. These neurons are classified into the following three types: Sensory neurons Interneurons …
Introduction In living cells, the plasma membrane or cell membrane is a selectively permeable barrier that allows selective substances to pass through it. Thus, it maintains different concentrations on both sides of the membrane. This gives rise to different electrical and chemical concentration gradients on the membrane surface which collectively form the electrochemical gradient. What …
Introduction to Action Potential Certain cells in the body are electrically active and can relay and sustain voltage fluctuations. These voltage fluctuations allow the propagation of signals and can be thought of as a means of communication between the cells. How these fluctuations come about is to a large extent dependent upon the cell membrane …
Introduction Hyperpolarization is said to be the final stage of an action potential after depolarization and repolarization in action potential, respectively. Many diseases and conditions may arise from dysfunctions and mutations in the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. These disorders include Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis among neurodegenerative disorders. Epilepsy is also seen …
Introduction Coordination of all the activities taking place within an organism is essential for the maintenance of life. This coordination among various cells of the body can be achieved in two ways; nervous coordination and chemical coordination. Chemical coordination is brought about by hormones. Hormones are the chemical substances capable of affecting the various chemical …
Introduction Nitrogen is the most abundant gas present in our atmosphere. It makes more than 70% of the gases present in the atmosphere of our planet. Being a component of organic compounds like proteins and nucleic acids, nitrogen is an important nutrient required for the normal growth and development of living organisms. The nitrogen cycle …
Introduction Nutrients are needed by organisms for their normal growth and development. Most organisms obtain nutrients from the surrounding environment. Animals get most of the nutrients in the form of food and air. Plants obtain nutrients present in the soil as well as air. The conservation of nutrients in the environment is essential for the …
Introduction Nutrients are the substances that are required by organisms for growth and development. A nutrient is defined as any substance that provides nourishment to the body and is essential for normal growth and development, reproduction, and survival of the organism. All organisms obtain nutrients from the environment surrounding them. The total amount of nutrients …
Introduction Organic compounds are those that are made up of carbon and hydrogen (hydrocarbons) and their derivatives. Organic compounds are the most widely spread chemical species present on earth. They are the molecules of life. All the life on this planet is dependent on various organic compounds found in the living systems. It was thought …
