Welcome to Biology Notes Online! We are the BNO Team, dedicated to providing high-quality, accessible biology study notes for students and teachers alike. Our goal is to simplify complex biological concepts and present them in an easy-to-understand format, entirely free of charge. Whether you're preparing for exams, teaching a class, or simply passionate about biology, our comprehensive notes are designed to support your learning and teaching journey.
Urinary casts are small, cylinder-shaped, tube-shaped particles that can be detected by a microscopic analysis of urine. Casts are the only kidney-specific components discovered in the urine sediment. It is believed that Tamm-Horsfall mucoprotein (uromodulin) released by renal tubular epithelial cells forms the fundamental matrix of all casts. Any components present in the tube filtrate, … Read more
The male reproductive system includes a number of hormones and organs that are involved in reproduction. These hormones and organs can be found either inside or outside of the pelvis. Organs of the Male Reproductive System External male reproductive structures: Internal male reproductive organs: External male reproductive structures The scrotum contains the testes, epididymides and … Read more
What is Ear? Definition of Ear The ear is a sensory organ responsible for hearing and maintaining balance in the body. It consists of the outer ear, middle ear, and inner ear, and it converts sound waves into electrical signals that can be interpreted by the brain. Anatomy of Ear – Structure of Ear The … Read more
What is Skeletal system? Definition of Skeletal system The skeletal system is the framework of bones, joints, and cartilages that provides support, protection, and facilitates movement in the human body. Types of Skeletal Systems There are three main types of skeletal systems found in different organisms: hydrostatic skeleton, exoskeleton, and endoskeleton. Each type of skeletal … Read more
What is skeletal muscle? Definition of skeletal muscle Skeletal muscle is a type of voluntary muscle tissue that is attached to the bones and responsible for movement and various bodily functions. Properties Of Skeletal Muscle Skeletal muscles possess several important properties that contribute to their function and enable them to perform various tasks: These properties … Read more
Muscle twitch, the brief and transient contraction of a muscle fiber, is a fundamental event in muscle physiology. Understanding the characteristics of muscle twitches provides insights into the intricate mechanisms that govern muscle function. This article delves into the key aspects of muscle twitch, focusing on motor units, summation, and tetanus. Muscle twitches are initiated … Read more
What is Eye? Definition of Eye The eye is an organ of the visual system that detects light and enables organisms to see by converting light into electrical signals that are sent to the brain for processing. Anatomy Of Eye – Structure of Eye The eye is typically round in shape, but it appears convex … Read more
The nervous system relies on neurons to carry out various functions, ranging from basic motor reflexes to complex processes such as memory formation and decision-making. Unlike human communication through words and body language, neurons communicate through electrical and chemical signals. Similar to a committee member, a single neuron typically integrates and processes information from multiple … Read more
What is Neuromuscular junction? Definition of Neuromuscular junction A neuromuscular junction is a specialized connection between a motor neuron and a muscle fiber, where signals from the nervous system are transmitted to the muscle, resulting in muscle contraction. Structure of a Neuromuscular Junction The structure of Neuromuscular junction can be broadly divided into three parts: … Read more
What is Reflex Action? Definition of Reflex Action Reflex action is an automatic and rapid response to a stimulus that occurs without conscious control or thought. It involves the activation of sensory neurons, interneurons, and motor neurons to produce a quick and stereotyped response, often for the purpose of self-preservation or protection. Types of reflex … Read more
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