The fact that the heart may start racing when one is excited or otherwise emotionally aroused may have contributed to this idea as well. In fact, the heart is not the organ that controls thoughts or emotions. The organ that controls those functions is the brain. An organ is a collection of tissues joined in a structural unit to serve a common function.
Organs exist in most multicellular organisms, including not only humans and other animals but also plants. In single-celled organisms such as bacteria, the functional equivalent of an organ is an organelle. The main tissue may be unique to that specific organ. The heart also includes nervous and connective tissues that are required for it to perform its major function.
For example, nervous tissues control the beating of the heart, and connective tissues make up heart valves that keep blood flowing in just one direction through the heart. The human body contains five organs that are considered vital for survival. They are the heart, brain, kidneys, liver, and lungs. If any of the five vital organs stops functioning, the death of the organism is imminent without medical intervention. Functionally related organs often cooperate to form whole organ systems.
Some of the organs and functions of the organ systems are identified in the figure. Each system is also described in more detail in the text that follows. Most of these human organ systems are also the subject of separate chapters in this book. Organs of the integumentary system include the skin, hair, and nails.
The skin is the largest organ in the body. It encloses and protects the body and is the site of many sensory receptors. The skeletal system consists of bones, joints, teeth. The bones of the skeletal system are connected by tendons, ligaments, and cartilage.
Functions of the skeletal system include supporting the body and giving it shape. Along with the muscular system, the skeletal system enables the body to move. The bones of the skeletal system also protect internal organs, store calcium, and produce red and white blood cells.
The muscular system consists of three different types of muscles, including skeletal muscles, which are attached to bones by tendons and allow for voluntary movements of the body. Smooth muscle tissues control the involuntary movements of internal organs, such as the organs of the digestive system, allowing food to move through the system. Smooth muscles in blood vessels allow vasoconstriction and vasodilation and thereby help regulate body temperature.
Cardiac muscle tissues control the involuntary beating of the heart, allowing it to pump blood through the blood vessels of the cardiovascular system. The nervous system includes the brain and spinal cord, which make up the central nervous system, and nerves that run throughout the rest of the body, which make up the peripheral nervous system.
The nervous system controls both voluntary and involuntary responses of the human organism and also detects and processes sensory information. The endocrine system is made up of glands that secrete hormones into the blood, which carries the hormones throughout the body. Endocrine hormones are chemical messengers that control many body functions, including metabolism, growth, and sexual development. The master gland of the endocrine system is the pituitary gland, which produces hormones that control other endocrine glands.
Some of the other endocrine glands include the pancreas, thyroid gland, and adrenal glands. The cardiovascular system also called the circulatory system includes the heart, blood, and three types of blood vessels: arteries, veins, and capillaries. The heart pumps blood, which travels through the blood vessels. The main function of the cardiovascular system is transport. The muscular system is comprised of the sum total of muscles throughout the body that move the skeleton, maintain posture through steady contraction, and generate heat through cell metabolism.
Humans have three types of muscle. The nervous system allows us to perceive, comprehend, and respond to the world around us. The female reproductive system encompasses all necessary female organs needed to conceive and bear a child.
The male reproductive system consists of a series of organs used during sexual intercourse and procreation. The primary organs are the gonads, or sex glands, which produce sperm.
In men, these are the testes. We break down some of the basics surrounding what masculinity is, how it harms men, and what we can do about it. Ruined orgasms are about control, domination, and power. And with the right partner s , these aspects of kink can all be super sexy.
Autosexual people are mainly sexually attracted to themselves. They typically experience little to no sexual attraction to other people. To embody a healthy sexual self, you must actively engage in yourself. It helps break it into stages: warm-up, action, climax, and reflection. Whether or not you use the term is up to you.
The heart and blood vessels are not the only organs circulating fluid around the body, and blood is not the only circulated fluid. The lymphatic system transports lymph a fluid using:. The lymphatic system is key for immunity, blood pressure regulation, digestion, and other functions. The lymphatic system is the drainage system of the body, carrying excess fluid, proteins, fats, bacteria, and other substances away from the cells and spaces between cells to be filtered, excreted, and recycled.
The lymphatic system also helps create and circulate vital cells that fight disease part of the immune system, which is covered below including lymphocytes, monocytes, and antibodies. The respiratory system contains the:. It's responsible for breathing , which is the controlled movement of air in and out of the body ventilation and the movement of oxygen and carbon dioxide into and out of the bloodstream respiration.
One of the least understood responsibilities of the respiratory system is to help regulate the body's pH balance. Carbon dioxide is made into carbonic acid, which the respiratory system can regulate through carbon dioxide levels.
When a patient has a condition that affects the body's acidity, respiratory rate and depth can be a sign of the problem.
The integumentary system is skin, which includes all the:. The integumentary system is unique because it is the only single-organ system. Skin is both an organ and the entire organ system. The endocrine system includes all the glands that secrete hormones into the bloodstream. The endocrine system mostly regulates metabolism and utilizes the products of digestion. The gastrointestinal GI system is colloquially known as the gut. It includes all the organs that carry food from where it enters to where it exits, including the:.
The GI tract and the endocrine system have a lot of interaction. The GI system also plays host to a very important nerve called the vagus nerve. This is the main contributor to the parasympathetic nervous system and has a lot to do with slowing metabolism, lowering heart rate and blood pressure, and stimulating the mechanics of digestion.
The urinary system is made up of the:. These organs work together to filter blood and remove toxins and waste from body tissues. The removal of excess fluid through the urinary system also helps to regulate blood pressure. The musculoskeletal system provides the framework and the engine for our movement, posture, and productivity. The three types of muscles in the body are:. Only striated muscle is in the musculoskeletal system. The nervous system includes the:.
The nervous system is incredibly detailed and includes the only tissue that isn't fed directly through contact with blood. The reproductive system is the only system that is split into two parts. Half of us have:. This is the only organ system that is not complete in any one body and requires another person or medical intervention to complete its mission.
The immune system is listed last because, while it has a vital function in the survival of both the person and the species, all of the organs that make up the immune system are borrowed from other organ systems. The immune system organs work like sailors on a navy ship: every sailor has a primary duty and is cross-trained for the safety of the vessel. The primary organs of the immune system are:. Because of the interplay between organs from various other systems, the immune system is one of the most complicated systems of all.
An organ system is used to define a group of organs that work together to perform complex bodily functions. For example, the organs in the gastrointestinal GI system each play a unique, important role in food digestion. Organs located in the nervous system include the brain, spinal cord, and the nerves connected to both of them. The nervous system can be thought of as the 'command center' of the body, since it is in charge of overseeing the body's systems.
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