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Development of organ systems |
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An organ system is a biological system consisting of a group of organs that work together to perform one or more functions. [1] Each organ has a specialized role in a plant or animal body, and is made up of distinct tissues.
Other animals have similar organ systems to humans although simpler animals may have fewer organs in an organ system or even fewer organ systems.
There are 11 distinct organ systems in human beings, [2] which form the basis of human anatomy and physiology. The 11 organ systems: the respiratory system, digestive and excretory system, circulatory system, urinary system, integumentary system, skeletal system, muscular system, endocrine system, lymphatic system, nervous system, and reproductive system. There are other systems in the body that are not organ systems—for example, the immune system protects the organism from infection, but it is not an organ system since it is not composed of organs. Some organs are in more than one system—for example, the nose is in the respiratory system and also serves as a sensory organ in the nervous system; the testes and ovaries are both part of the reproductive and endocrine systems.
Organ system | Description | Component organs |
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Respiratory system | breathing: exchange of oxygen and carbon dioxide | nose, mouth, paranasal sinuses, pharynx, larynx, trachea, bronchi, lungs and thoracic diaphragm |
Digestive and excretory system | digestion: breakdown and absorption of nutrients, excretion of solid wastes | teeth, tongue, salivary glands, esophagus, stomach, liver, gallbladder, pancreas, small intestine, large intestine, rectum and anus |
Circulatory system | circulate blood in order to transport nutrients, waste, hormones, O2, CO2, and aid in maintaining pH and temperature | blood, heart, arteries, veins and capillaries |
Urinary system | maintain fluid and electrolyte balance, purify blood and excrete liquid waste (urine) | kidneys, ureters, bladder and urethra |
Integumentary system | exterior protection of body and thermal regulation | skin, hair, exocrine glands, fat and nails |
Skeletal system | structural support and protection, production of blood cells | bones, cartilage, ligaments and tendons |
Muscular system | movement of body, production of heat | skeletal muscles, smooth muscles and cardiac muscle |
Endocrine system | communication within the body using hormones made by endocrine glands | hypothalamus, pituitary, pineal gland, thyroid, parathyroid and adrenal glands, ovaries and testicles |
Lymphatic system | return lymph to the bloodstream, aid immune responses, form white blood cells | lymph, lymph nodes, lymph vessels, tonsils, spleen and thymus |
Nervous system | sensing and processing information, controlling body activities | brain, spinal cord, nerves, sensory organs and the following sensory systems (nervous subsystems): visual system, olfactory system, taste (gustatory system) and hearing (auditory system) |
Reproductive system | sex organs involved in reproduction | ovaries, fallopian tubes, uterus, vagina, vulva, penis, testicles, vasa deferentia, seminal vesicles and prostate |
Plants have two major organs systems. Vascular plants have two distinct organ systems: a shoot system, and a root system. The shoot system consists stems, leaves, and the reproductive parts of the plant (flowers and fruits). The shoot system generally grows above ground, where it absorbs the light needed for photosynthesis. The root system, which supports the plants and absorbs water and minerals, is usually underground. [3]
Organ system | Description | Component organs |
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Root system | anchors plants into place, absorbs water and minerals, and stores carbohydrates | roots |
Shoot system | stem for holding and orienting leaves to the sun as well as transporting materials between roots and leaves, leaves for photosynthesis, and flowers for reproduction | stem, leaves, and flowers |
Anatomy is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to developmental biology, embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy and physiology, which study the structure and function of organisms and their parts respectively, make a natural pair of related disciplines, and are often studied together. Human anatomy is one of the essential basic sciences that are applied in medicine.
Biology – The natural science that studies life. Areas of focus include structure, function, growth, origin, evolution, distribution, and taxonomy.
Endocrinology is a branch of biology and medicine dealing with the endocrine system, its diseases, and its specific secretions known as hormones. It is also concerned with the integration of developmental events proliferation, growth, and differentiation, and the psychological or behavioral activities of metabolism, growth and development, tissue function, sleep, digestion, respiration, excretion, mood, stress, lactation, movement, reproduction, and sensory perception caused by hormones. Specializations include behavioral endocrinology and comparative endocrinology.
The endocrine system is a messenger system in an organism comprising feedback loops of hormones that are released by internal glands directly into the circulatory system and that target and regulate distant organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems.
A hormone is a class of signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physiology and behavior. Hormones are required for the correct development of animals, plants and fungi. Due to the broad definition of a hormone, numerous kinds of molecules can be classified as hormones. Among the substances that can be considered hormones, are eicosanoids, steroids, amino acid derivatives, protein or peptides, and gases.
Physiology is the scientific study of functions and mechanisms in a living system. As a subdiscipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out chemical and physical functions in a living system. According to the classes of organisms, the field can be divided into medical physiology, animal physiology, plant physiology, cell physiology, and comparative physiology.
The peripheral nervous system (PNS) is one of two components that make up the nervous system of bilateral animals, with the other part being the central nervous system (CNS). The PNS consists of nerves and ganglia, which lie outside the brain and the spinal cord. The main function of the PNS is to connect the CNS to the limbs and organs, essentially serving as a relay between the brain and spinal cord and the rest of the body. Unlike the CNS, the PNS is not protected by the vertebral column and skull, or by the blood–brain barrier, which leaves it exposed to toxins.
A sex organ, also known as a reproductive organ, is a part of an organism that is involved in sexual reproduction. Sex organs constitute the primary sex characteristics of an organism. Sex organs are responsible for producing and transporting gametes, as well as facilitating fertilization and supporting the development and birth of offspring. Sex organs are found in many species of animals and plants, with their features varying depending on the species.
The human body is the entire structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organs and then organ systems. They ensure homeostasis and the viability of the human body.
In biology, tissue is a historically derived biological organizational level between cells and a complete organ. A tissue is therefore often thought of as an assembly of similar cells and their extracellular matrix from the same embryonic origin that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues.
In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a function. Tissues of different types combine to form an organ which has a specific function. The intestinal wall for example is formed by epithelial tissue and smooth muscle tissue. Two or more organs working together in the execution of a specific body function form an organ system, also called a biological system or body system.
The sympathetic nervous system (SNS) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of the autonomic nervous system, and sometimes considered an independent system.
Epithelium or epithelial tissue is a thin, continuous, protective layer of compactly packed cells with a little intercellular matrix. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. Epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. These tissues also lack blood or lymph supply. The tissue is supplied by nerves.
A biological system is a complex network which connects several biologically relevant entities. Biological organization spans several scales and are determined based different structures depending on what the system is. Examples of biological systems at the macro scale are populations of organisms. On the organ and tissue scale in mammals and other animals, examples include the circulatory system, the respiratory system, and the nervous system. On the micro to the nanoscopic scale, examples of biological systems are cells, organelles, macromolecular complexes and regulatory pathways. A biological system is not to be confused with a living system, such as a living organism.
Phytomorphology is the study of the physical form and external structure of plants. This is usually considered distinct from plant anatomy, which is the study of the internal structure of plants, especially at the microscopic level. Plant morphology is useful in the visual identification of plants. Recent studies in molecular biology started to investigate the molecular processes involved in determining the conservation and diversification of plant morphologies. In these studies transcriptome conservation patterns were found to mark crucial ontogenetic transitions during the plant life cycle which may result in evolutionary constraints limiting diversification.
The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes of differentiated species often have significant differences. These differences allow for a combination of genetic material between two individuals, which allows for the possibility of greater genetic fitness of the offspring.
Fish physiology is the scientific study of how the component parts of fish function together in the living fish. It can be contrasted with fish anatomy, which is the study of the form or morphology of fishes. In practice, fish anatomy and physiology complement each other, the former dealing with the structure of a fish, its organs or component parts and how they are put together, such as might be observed on the dissecting table or under the microscope, and the later dealing with how those components function together in the living fish. For this, at first we need to know about their intestinal morphology.
This glossary of medical terms is a list of definitions about medicine, its sub-disciplines, and related fields.
A body is the physical material of an organism. It is only used for organisms which are in one part or whole. There are organisms which change from single cells to whole organisms: for example, slime molds. For them the term 'body' would mean the multicellular stage. Other uses: