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Goodwin, M. (2022, July 14). How the immune system works. Medical News Today. https://www.medicalnewstoday.com/articles/320101

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1.) "A fully functional immune system can distinguish healthy tissue from unwanted substances. If it detects an unwanted substance, it will mount an immune response — a complex attack to protect the body from invaders. It also recognizes and removes dead and faulty cells" (Goodwin, 2022).
2.) "The immune system consists of a range of components, including:

white blood cells (leukocytes)

the spleen

the bone marrow

the lymphatic system

the thymus

the tonsils, adenoids, and appendix

White blood cells circulate in the blood and lymphatic vessels" (Goodwin, 2022).
3.) "The immune system becomes stronger on exposure to different pathogens. By adulthood, most people have had exposure to a range of pathogens and developed more immunity. Once the body produces an antibody, it keeps a copy so that if the same antigen appears again, the body can deal with it more quickly. Some diseases, such as measles, can be severe if they occur, which is why experts
Trusted Source recommend vaccination. If a person has the measles vaccine, they are unlikely to get the disease. If an unvaccinated person has measles once, it is also rare to get it again. In both cases, the body stores a measles antibody. The antibody is ready to destroy the virus next time it appears. This is called immunity" (Goodwin, 2022).

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1.) The reproductive system is a " organ system by which humans reproduce and bear live offspring" (Harrison, 2019).
2.) "The sex of a child is determined at the time of fertilization of the ovum by the spermatozoon. The differences between a male and a female are genetically determined by the chromosomes that each possesses in the nuclei of the cells. Once the genetic sex has been determined, there normally follows a succession of changes that will result, finally, in the development of an adult male or female" (Harrison, 2019).
3.) " Puberty marks the onset of increased activity in the sex glands and the steady development of secondary sexual characteristics" (Harrison, 2019).

The reproductive system is greatly affected by the immune system as a strong immune is critical for the safe development of the fetus/embryo.

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Wikipedia contributors. (2022, December 9). Endocrine system. In Wikipedia, The Free Encyclopedia. Retrieved 15:15, December 11, 2022, from https://en.wikipedia.org/w/index.php?title=Endocrine_system&oldid=1126432117

1.) "The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs" (Endocrine system, 2022).
2.) "A hormone is any of a class of signaling molecules produced by cells in glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour. Hormones have diverse chemical structures, mainly of 3 classes: eicosanoids, steroids, and amino acid/protein derivatives (amines, peptides, and proteins). The glands that secrete hormones comprise the endocrine system" (Endocrine system, 2022).
3.) "Hormones are used to communicate between organs and tissues for physiological regulation and behavioral activities, such as digestion, metabolism, respiration, tissue function, sensory perception, sleep, excretion, lactation, stress, growth and development, movement, reproduction, and mood" (Endocrine system, 2022).

Endocrine system is closest related to the reproductive system, as it controls sexual drive and growth & development.

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Wikipedia contributors. (2022, October 10). Human musculoskeletal system. In Wikipedia, The Free Encyclopedia. Retrieved 15:04, December 11, 2022, from https://en.wikipedia.org/w/index.php?title=Human_musculoskeletal_system&oldid=1115223294

1.) The musculoskeletal system " is an organ system that gives humans the ability to move using their muscular and skeletal systems" (Human musculoskeletal system, 2022).
2.) "The musculoskeletal system provides form, support, stability, and movement to the body" (Human musculoskeletal system, 2022).
3.) "There are three types of muscles—cardiac, skeletal, and smooth. Smooth muscles are used to control the flow of substances within the lumens of hollow organs, and are not consciously controlled. Skeletal and cardiac muscles have striations that are visible under a microscope due to the components within their cells. Only skeletal and smooth muscles are part of the musculoskeletal system and only the muscles can move the body. Cardiac muscles are found in the heart and are used only to circulate blood; like the smooth muscles, these muscles are not under conscious control. Skeletal muscles are attached to bones and arranged in opposing groups around joints. Muscles are innervated, to communicate nervous energy to, by nerves, which conduct electrical currents from the central nervous system and cause the muscles to contract" (Human musculoskeletal system, 2022).

The musculoskeletal system is closely related to the endocrine system as this controls how much muscles and bones grow.

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1.) The nervous system "conducts stimuli from sensory receptors to the brain and spinal cord and conducts impulses back to other parts of the body" (Nathan, 2020).
2.) " The central nervous system (the brain and spinal cord) and the peripheral nervous system (the nerves that carry impulses to and from the central nervous system)" (Nathan, 2020).
3.) "Movements can be organized at several levels of the nervous system. At the lowest level are movements of the viscera, some of which do not involve the central nervous system, being controlled by neurons of the autonomic nervous system within the viscera themselves. Movements of the trunk and limbs occur at the next level of the spinal cord. If the spinal cord is severed so that no nerve impulses arrive from the brain, certain movements of the trunk and limbs below the level of the injury can still occur. At a higher level, respiratory movements are controlled by the lower brainstem. The upper brainstem controls muscles of the eye, the bladder, and basic movements of walking and running. At the next level is the hypothalamus. It commands certain totalities of movement, such as those of vomiting, urinating and defecating, and curling up and falling asleep. At the highest level is gray matter of the cerebral hemispheres, both the cortex and the subcortical basal ganglia. This is the level of conscious control of movements.

The nervous system works in conjunction with the musculoskeletal system as they work together voluntarily and involuntarily to move muscles, organs, and limbs of the human body.

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1.) The respiratory system "takes up oxygen and expels carbon dioxide" (Heath, 2022).
2.)  "Atmospheric air is pumped in and out regularly through a system of pipes, called conducting airways, which join the gas-exchange region with the outside of the body" (Heath, 2022).
3.) "The interplay of respiration, circulation, and metabolism is the key to the functioning of the respiratory system as a whole. Cells set the demand for oxygen uptake and carbon dioxide discharge, that is, for gas exchange in the lungs. The circulation of the blood links the sites of oxygen utilization and uptake. The proper functioning of the respiratory system depends on both the ability of the system to make functional adjustments to varying needs and the design features of the sequence of structures involved, which set the limit for respiration" (Heath, 2022).

The respiratory system is directly influenced by the nervous system, as this controls the respiration without you having to think about inhaling and exhaling.

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human respiratory system, the system in humans that takes up oxygen and expels carbon dioxide.

The design of the respiratory system

The human gas-exchanging organ, the lung, is located in the thorax, where its delicate tissues are protected by the bony and muscular thoracic cage. The lung provides the tissues of the human body with a continuous flow of oxygen and clears the blood of the gaseous waste product, carbon dioxide. Atmospheric air is pumped in and out regularly through a system of pipes, called conducting airways, which join the gas-exchange region with the outside of the body. The airways can be divided into upper and lower airway systems. The transition between the two systems is located where the pathways of the respiratory and digestive systems cross, just at the top of the larynx.

The upper airway system comprises the nose and the paranasal cavities (or sinuses), the pharynx (or throat), and partly also the oral cavity, since it may be used for breathing. The lower airway system consists of the larynx, the trachea, the stem bronchi, and all the airways ramifying intensively within the lungs, such as the intrapulmonary bronchi, the bronchioles, and the alveolar ducts. For respiration, the collaboration of other organ systems is clearly essential. The diaphragm, as the main respiratory muscle, and the intercostal muscles of the chest wall play an essential role by generating, under the control of the central nervous system, the pumping action on the lung. The muscles expand and contract the internal space of the thorax, the bony framework of which is formed by the ribs and the thoracic vertebrae. The contribution of the lung and chest wall (ribs and muscles) to respiration is described below in The mechanics of breathing. The blood, as a carrier for the gases, and the circulatory system (i.e., the heart and the blood vessels) are mandatory elements of a working respiratory system ( see blood; cardiovascular system).

Morphology of the upper airways

The nose is the external protuberance of an internal space, the nasal cavity. It is subdivided into a left and right canal by a thin medial cartilaginous and bony wall, the nasal septum. Each canal opens to the face by a nostril and into the pharynx by the choana. The floor of the nasal cavity is formed by the palate, which also forms the roof of the oral cavity. The complex shape of the nasal cavity is due to projections of bony ridges, the superior, middle, and inferior turbinate bones (or conchae), from the lateral wall. The passageways thus formed below each ridge are called the superior, middle, and inferior nasal meatuses.

Characteristics of the Human Body

On each side, the intranasal space communicates with a series of neighbouring air-filled cavities within the skull (the paranasal sinuses) and also, via the nasolacrimal duct, with the lacrimal apparatus in the corner of the eye. The duct drains the lacrimal fluid into the nasal cavity. This fact explains why nasal respiration can be rapidly impaired or even impeded during weeping: the lacrimal fluid is not only overflowing into tears, it is also flooding the nasal cavity.

The paranasal sinuses are sets of paired single or multiple cavities of variable size. Most of their development takes place after birth, and they reach their final size toward age 20. The sinuses are located in four different skull bones-the maxilla, the frontal, the ethmoid, and the sphenoid bones. Correspondingly, they are called the maxillary sinus, which is the largest cavity; the frontal sinus; the ethmoid sinuses; and the sphenoid sinus, which is located in the upper posterior wall of the nasal cavity. The sinuses have two principal functions: because they are filled with air, they help keep the weight of the skull within reasonable limits, and they serve as resonance chambers for the human voice.

The nasal cavity with its adjacent spaces is lined by a respiratory mucosa. Typically, the mucosa of the nose contains mucus-secreting glands and venous plexuses; its top cell layer, the epithelium, consists principally of two cell types, ciliated and secreting cells. This structural design reflects the particular ancillary functions of the nose and of the upper airways in general with respect to respiration. They clean, moisten, and warm the inspired air, preparing it for intimate contact with the delicate tissues of the gas-exchange area. During expiration through the nose, the air is dried and cooled, a process that saves water and energy.

Two regions of the nasal cavity have a different lining. The vestibule, at the entrance of the nose, is lined by skin that bears short thick hairs called vibrissae. In the roof of the nose, the olfactory bulb with its sensory epithelium checks the quality of the inspired air. About two dozen olfactory nerves convey the sensation of smell from the olfactory cells through the bony roof of the nasal cavity to the central nervous system.

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Human respiratory system | Description, Parts, Function, & Facts

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Human respiratory system, the system in humans that takes up oxygen and expels carbon dioxide. The major organs of the respiratory system include the nose, pharynx, larynx, trachea, bronchi, lungs, and diaphragm. Learn about the anatomy and function of the respiratory system in this article.

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1.) The circulatory system "transports nutrients, respiratory gases, and metabolic products throughout a living organism, permitting integration among the various tissues" (Matthews, 2022).
2.) "The process of circulation includes the intake of metabolic materials, the conveyance of these materials throughout the organism, and the return of harmful by-products to the environment" (Matthews, 2022).
3.) "Many factors, such as temperature, oxygen supply, or nervous excitement, affect heartbeat and circulation. Blood circulation is controlled mainly via nerve connections, sensory receptors, and hormones. These act primarily by varying the heart’s pulse rate, amplitude, or stroke volume and by altering the degree of dilation or constriction of the peripheral blood vessels (i.e., those blood vessels near the surface of the body)" (Matthews, 2022).

The circulatory system works alongside the respiratory system because "The most widely distributed respiratory pigments are the red hemoglobins" (Matthews, 2020). This means both systems work to distribute and circulate oxygen through the body.

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1.) "The human digestive system consists primarily of the digestive tract, or the series of structures and organs through which food and liquids pass during their processing into forms absorbable into the bloodstream" (Hightower, 2022).
2.) "The system also consists of the structures through which wastes pass in the process of elimination and other organs that contribute juices necessary for the digestive process" (Hightower, 2022).
3.) "The liver is not only the largest gland in the body but also the most complex in function. The major functions of the liver are to participate in the metabolism of protein, carbohydrates, and fat; to synthesize cholesterol and bile acids; to initiate the formation of bile; to engage in the transport of bilirubin; to metabolize and transport certain drugs; and to control transport and storage of carbohydrates" (Hightower, 2022).

Digestion works alongside with the circulatory system because "Iron is necessary for the synthesis of hemoglobin, the oxygen-carrying compound of the red blood cells. It also has an important role as a cofactor in intracellular metabolism. The main dietary sources are meat, eggs, nuts, and seeds" (Hightower, 2022).