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The physical substance of the human organism, consisting of live cells and extracellular components and organised into tissues, organs, and systems, is referred to as the human body.
Humans are, without a doubt, animals—more specifically, members of the order Primates, which is a subphylum of the phylum Chordata and belongs to the order Vertebrata. The human-animal, like all chordates, has a bilaterally symmetrical body that is defined by a dorsal supporting rod (the notochord), gill slits in the region of the pharynx, and a hollow dorsal nerve cord at some time during its development. The first two of these characteristics are only present during the embryonic stage in humans; the notochord is replaced by the vertebral column, and the pharyngeal gill slits are completely gone at this time. In humans, the dorsal nerve cord serves as the spinal cord, and it remains in place throughout life. The human body, which is characteristic of the vertebrate form, contains an internal skeleton that includes a backbone of vertebrae, which is characteristic of the vertebrate form. The human body has traits that are typical of mammalian structure, such as hair, mammary glands, and highly developed sense organs, among others.
However, beyond these superficial similarities, there are some significant distinctions. Among the animals, only humans have a largely two-legged (bipedal) posture, which has had a significant impact on the overall mammalian body plan. (Even the kangaroo, which moves quickly on two legs, walks on four and uses its tail as a “third leg” when standing.) Furthermore, the human brain, and notably the neocortex, is by far and away the most highly developed of any animal’s brains in the world. Many other mammals, such as chimpanzees and dolphins, are as clever as humans, but none have reached the level of intelligence that we have attained as a species.
Chemical composition of the body
Chemically, the human body is mostly composed of water and organic substances, which include lipids, proteins, carbohydrates, and nucleic acids, among other things. Extracellular fluids (such as blood plasma, lymphatic fluid, and interstitial fluid) and intracellular fluids (such as the cells themselves) contain water. It functions as a solvent, without which the chemistry of life would be impossible to perform. The average human body contains approximately 60% water by weight.
Lipids- including fats, phospholipids, and steroids, are important structural components of the human body and play important roles in its function. Fats act as a form of energy storage for the body, and fat pads also serve as insulation and shock absorbers, among other functions. Phospholipids and the steroid molecule cholesterol are two of the most important components of the membrane that surrounds every cell in the body.
Proteins are also a fundamental structural component of the body’s cells and tissues. Proteins, like lipids, play a crucial role in the structure of the cell membrane. Furthermore, protein is found in extracellular materials such as hair and nails, among other things. Collagen, the fibrous, elastic material that makes up a large portion of the body’s skin, bones, tendons, and ligaments, is also a protein. Proteins are also involved in a variety of physiological functions in the body. In particular, enzymes, which are cellular proteins that catalyse the chemical reactions that are required for life, are extremely vital.
In the human body, carbohydrates are used mostly as fuel, either as simple sugars that circulate through the bloodstream or as glycogen, which is a storage component located in the liver and muscles. Carbohydrates are also found in the urine and stool. A small amount of carbohydrates can also be found in the membranes of cells; however, in contrast to plants and many invertebrate animals, humans have a relatively little amount of structural carbohydrate in their bodies.
Nucleic acids are the building blocks of the body’s genetic material. Deoxyribonucleic acid (DNA) is the genetic material that holds the body’s hereditary master code, which contains the instructions that each cell must follow in order to function properly. DNA, which is passed down from parents to children, is responsible for determining the inherited features of each unique human. The nucleic acid ribonucleic acid (RNA), which comes in a variety of forms, aids in the execution of the instructions recorded in DNA.
Various inorganic minerals are found in the body, along with water and organic compounds, as well as other elements. Calcium, phosphorus, sodium, magnesium, and iron are the most abundant elements in the body. Calcium and phosphorus, in the form of calcium-phosphate crystals, make up a significant portion of the body’s bone structure. Calcium and sodium are both found in small amounts as ions in the blood and interstitial fluid. The presence of phosphorus, potassium, and magnesium ions in the intercellular fluid, on the other hand, is abundant. All of these ions are essential for the body’s metabolic functions to function properly. Iron is mostly found in red blood cells as a component of haemoglobin, which serves as an oxygen-transporting pigment. Cobalt, copper, iodine, manganese, and zinc are some of the other mineral constituents of the body that are present in minute but required proportions, as are other trace elements.
Organization of the body
The cell is the fundamental living unit of the human body—and, by extension, of all living things. With some exceptions, the human body is made up of trillions of cells, each of which is capable of growth, metabolism, response to stimuli, and – in some cases – reproduction. Despite the fact that the human body has over 200 different types of cells, they may be divided into four basic categories. Fundamental tissues of the human body are composed of four basic cell types and their extracellular materials: (1) epithelial tissues, which cover the body’s surface and line the internal organs, body cavities, and passageways; (2) muscle tissues, which are capable of contraction and comprise the body’s musculature; (3) nerve tissues, which conduct electrical impulses and comprise the nervous system; and (4) connective tissues, which are composed of widely spaced c cells and comprise the connective tissue network. (Bone and blood are considered to be specialised connective tissues, in which the intercellular matrix is hard in one and liquid in the other, respectively.)
Among the nine major organ systems in the body are diverse organs and tissues that operate together as a functional unit to perform certain functions. In the following sections, we discuss the primary parts and primary functions of each of the systems. In addition to protecting the body from hazardous microbes and chemicals, the integumentary system also limits water loss from the body:-
The integumentary system is made up of the skin and its accompanying tissues.
The musculoskeletal system (also known as the muscle system and the skeletal system) comprises skeletal muscles and bones (with around 206 of the latter in adults), and it is responsible for moving the body and protecting its interior organs.
The respiratory system, which is made up of the breathing passages, lungs, and muscles of respiration, is responsible for obtaining from the air the oxygen required for cellular metabolism and for returning to the air the carbon dioxide that is produced as a waste product of this metabolic process.
The circulatory system, which is composed of the heart, blood, and blood vessels, circulates a transport fluid throughout the body, supplying the cells with a constant supply of oxygen and nutrients while also transporting waste products such as carbon dioxide and toxic nitrogen compounds away from the body. This system also eliminates unwanted or extra food by excreting it as faecal waste.
The digestive system is made up of the mouth, oesophagus, stomach, and intestines. It breaks down food into useful components (nutrients), which are then absorbed through the blood or lymph.
The excretory system, which is comprised of the kidneys, ureters, urinary bladder, and urethra, is responsible for the removal of harmful nitrogen compounds and other wastes from the circulation.
The nervous system, which is composed of the sensory organs, the brain, the spinal cord, and nerves, transmits, integrates, and interprets sensory information, as well as transmitting impulses that cause the necessary muscle or glandular responses to occur.
In addition to hormone-secreting glands and tissues, the endocrine system serves as a chemical communications network for the coordination of numerous physiological activities.
The reproductive system, which is comprised of the male and female sex organs, is responsible for allowing reproduction and, as a result, ensuring the survival of the species.
Conclusion
Anatomy is concerned with the description of the form, or the appearance of body structures at various levels. The organ systems of the human body must communicate with one another in order for the body to remain alive and function appropriately. Organ systems must communicate with one another in order for this to happen. The autonomic nervous system and the endocrine system are in charge of this function. The circulatory system, the respiratory system, the lymphatic system, and other systems all have a role in human health, and the interactions between these systems can be beneficial or detrimental to the individual. It is possible to decide the appropriate care for each unique patient and their specific symptoms if you understand how the systems interact with one another.
