Human Systems
Skeletal 
Muscular 
Nervous 
Endocrine 
Cardiovascular 
Lymphatic 
Respiratory 
Digestive 
Urinary 
Reproductive
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.
Female: The production of egg cells is the initial purpose of the female reproductive system; the second is to safeguard and feed the fetus until it is born.
Male: The production and deposit of sperm is the sole purpose of the male reproductive system. There is a lot of sexual differentiation in humans. Apart from variations in almost all reproductive organs, many variations usually arise in secondary sexual traits.
The kidneys, ureters, bladder, and urethra make up the human urine system, sometimes referred to as the urinary tract or renal system. The elimination of waste from the body, blood volume and pressure regulation, electrolyte and metabolite level control, and blood pH regulation are all functions of the urinary system.
KIDNEY: The kidneys are two blood-filtering, reddish-brown, bean-shaped organs.They are a multilobar, multipapillary variation of the mammalian kidney and typically show no outward evidence of lobulation. In adult humans, they measure approximately 12 centimeters (4+1⁄2 inches) in length and are situated on the left and right in the retroperitoneal area.
BLADDER: The bladder is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In placental mammals, urine enters the bladder via the ureters and exits via the urethra.
URETERS: Urine is transported from the kidneys to the bladder via smooth muscular tubes called ureters. The ureters of an adult person are normally between 20 and 30 centimeters long and 3 and 4 millimeters in diameter. They have an additional layer of smooth muscle in the lower third to help with peristalsis, and they are lined by urothelial cells, a type of transitional epithelium.
URETHRA: The tube that joins the urine meatus to the mammalian bladder is known as the urethra (plural: urethras or urethrae). When they urinate, placental mammals—both male and female—release urine through the urethra.
According to biology, an animal's nervous system is the extremely intricate portion that communicates signals to and from various bodily regions to coordinate movements and sensory data. When the body experiences environmental changes, the neurological system notices them and collaborates with the endocrine system to react to them.Between 550 and 600 million years ago, wormlike creatures gave rise to the earliest nervous tissue.
STRUCTURE: The nerves that originate from the brain and spinal cord and branch repeatedly to innervate every area of the body are called nerves, which are cylindrical bundles of fibers (the axons of neurons). Although nerves are big enough for the ancient Greeks, Romans, and Egyptians to have identified them, it wasn't until the ability to view them under a microscope that their interior structure was discovered.
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In vertebrates, the lymphatic system, also known as the lymphoid system, is an organ system that functions in tandem with the circulatory system and is a component of the immune system. It is made up of a vast network of lymphatic tissue, lymph nodes, lymphatic veins, and lymphoid organs. The clear fluid known as lymph is returned to the heart for recirculation by the lymphatic veins. The freshwater goddess "Lympha" is referenced in the Latin term for lymph, lympha.The lymphatic system is an open system in contrast to the closed circulatory system.The human circulatory system uses capillary filtration to remove plasma from the blood, processing 20 liters of blood on average every day.
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Primary lymphoid organs
The primary (or central) lymphoid organs generate lymphocytes from immature progenitor cells. The thymus and the bone marrow constitute the primary lymphoid organs involved in the production and early clonal selection of lymphocyte tissues.
secondary lymphoid organs
Mature naïve cells are maintained and an adaptive immune response is started by the secondary (or peripheral) lymphoid organs, which include the spleen and lymph nodes. Antigen-stimulated lymphocytes are activated in the secondary lymphoid organs.Clonal expansion and affinity maturation follow activation. When mature lymphocytes come into contact with their particular antigen, they recirculate between the blood and the secondary lymphoid organs.
Tertiary lymphoid organs
Tertiary lymphoid organs (TLOs) are abnormal lymph node-like structures that form in peripheral tissues at sites of chronic inflammation, such as chronic infection, transplanted organs undergoing graft rejection, some cancers, and autoimmune and autoimmune-related diseases.[22] TLOs are regulated differently from the normal process whereby lymphoid tissues are formed during ontogeny, being dependent on cytokines and hematopoietic cells, but still drain interstitial fluid and transport lymphocytes in response to the same chemical messengers and gradients.[23] TLOs typically contain far fewer lymphocytes, and assume an immune role only when challenged with antigens that result in inflammation. They achieve this by importing the lymphocytes from blood and lymph.[24] TLOs often have an active germinal center, surrounded by a network of follicular dendritic cells (FDCs).[25]
The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body. The process of digestion has three stages: the cephalic phase, the gastric phase, and the intestinal phase.
STAGES
The first stage, the cephalic phase of digestion, begins with secretions from gastric glands in response to the sight and smell of food. This stage includes the mechanical breakdown of food by chewing, and the chemical breakdown by digestive enzymes, that takes place in the mouth. Saliva contains the digestive enzymes amylase, and lingual lipase, secreted by the salivary and serous glands on the tongue. Chewing, in which the food is mixed with saliva, begins the mechanical process of digestion. This produces a bolus which is swallowed down the esophagus to enter the stomach.
The second stage, the gastric phase, happens in the stomach. Here, the food is further broken down by mixing with gastric acid until it passes into the duodenum, the first part of the small intestine.
The third stage, the intestinal phase, begins in the duodenum. Here, the partially digested food is mixed with a number of enzymes produced by the pancreas.
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.
In humans: The thyroid, parathyroid, pituitary, pineal, and adrenal glands, along with the (female) testicles and (male) ovaries, are the main endocrine glands in humans. Among other things, the thymus, pancreas, and hypothalamus are endocrine glands. (The pituitary and hypothalamus are neuroendocrine system organs. The pituitary gland, which is situated next to the hypothalamus in the brain, is responsible for connecting the endocrine and neurological systems. This is one of the hypothalamus's most significant roles.) By secreting certain hormones, other organs like the kidneys play a part in the endocrine system as well. Endocrinology is the study of the endocrine system and its diseases.
Animals and plants employ their respiratory systems, also known as respiratory apparatuses or ventilatory systems, to exchange gases. These biological systems are made up of particular organs and components. Depending on the organism's size, its living habitat, and its evolutionary background, the anatomy and physiology that enable this vary widely. The respiratory surface is internalized as the linings of the lungs in land animals. Millions of tiny air sacs, known as atria in birds and alveoli in mammals and reptiles, are responsible for gas exchange in the lungs. Because of their extremely robust blood supply, these small air sacs bring the air and blood into close proximity.
The skeletal system is made up of the bones that give structure to the human body. Bones protect and support vital organs and work with muscles to help the body move. Bone marrow is the soft inner part of many bones of the body.
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Skull
Vertebrae (bones of the spine)
Ribs and sternum
Clavicle and scapula
Humerus, ulna and radius (arms)
Pelvis (hipbones)
Femur, tibia and fibula (legs)
There are three distinct types of muscle: skeletal muscle, cardiac or heart muscle, and smooth (non-striated) muscle. Muscles provide strength, balance, posture, movement, and heat for the body to keep warm.
There are approximately 640 muscles in an adult male human body. A kind of elastic tissue makes up each muscle, which consists of thousands, or tens of thousands, of small muscle fibers. Each fiber comprises many tiny strands called fibrils, impulses from nerve cells control the contraction of each muscle fiber.
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The blood flows through your heart in the same way every time. Along the way, valves ensure that the blood is flowing in the proper direction.
Blood is carried by certain blood vessels (veins) to your heart and by other blood vessels (arteries) away from it. Additionally, your blood arteries remove waste products from your cells, such as carbon dioxide.
Your heart beats throughout the day and even while you sleep, pumping blood throughout your body. Your doctor can hear your heartbeat because of this. That sound is your heart beating normally. Approximately 2,000 liters of blood are circulated daily by your heart.
The purpose of the cardiovascular system is to ensure that your body eliminates unnecessary substances and receives the oxygen, nutrition, and other things it need.