Body Systems
Respiratory System
Allows gas exchange between cells and the environment. Includes trachea and lungs. The respiratory system takes oxygen from the environment and converts it into a form that cells can use. In humans, that means that our lungs take in oxygen, and rapidly diffuse it into the blood. The lungs accomplish this by passing large amounts of blood over gas exchange membranes; the body's whole blood volume passes over these membranes about once per minute! It could be argued that the respiratory system is one of the body's most important. Without oxygen to fuel cellular respiration, cells begin to die within minutes. This is the real reason why heart attacks are deadly; although the heart is part of the circulatory system, not the respiratory system, it is responsible for transporting oxygen from lungs to our cells. When the circulatory system stops working, our tissues begin to die from lack of oxygen. The lungs also expel carbon dioxide - a waste product of cellular respiration which could otherwise build up to toxic levels.
Renal/Urinary System
Cleans dissolved waste products from the blood and excretes them. Includes kidneys and bladder.The renal/urinary system keeps our body healthy by removing dangerous waste products from our blood, and expelling them from our body in the form of urine. All blood is passed through the kidneys, where special filters allow dangerous substances to pass out of the bloodstream, while keeping helpful substances in. The waste liquid that's filtered out by the kidneys is stored in the bladder until the body expels it..
Digestive System-Digestive system is the food processing system of human body. The whole digestive system is in the form of a long, hollow, twisted and turned tube, called the alimentary canal, which starts from the oral cavity and ends at the anus. The overall process of digestion and absorption of food occurs in this tube. The tube is divided into different parts on the basis of structure and function of each part.
-Functions-Digestion and absorption of food -Necessary Organs Of the digestive system: 1)ORAL CAVITY-It is the cavity of mouth, irregular in shape, contains tongue, teeth and salivary glands, 2)ESOPHAGUS-Muscular tube passing the food from pharynx to stomach 3)STOMACH-Muscular, hollow and dilated part of alimentary canal, involved in both mechanical and chemical digestion of food, secretes strong acid and enzymes to aid in digestion of food 4)SMALL INTESTINE-Lies between stomach and large intestine, majority of digestion and absorption takes place here, About 5 meters in length 5)LARGE INTESTINE-Second-to-last part of alimentary canal, main function is to absorb water from indigestible food. 6)ANUS-Last part of alimentary canal, opens to outside for egestion of food, controls the expulsion of feces -Accessory Organs of the digestive system: 1)LIVER-Produces bile for emulsification of fats 2)Gallbladder-Stores bile produced by the liver. 3)PANCREAS-Secretes pancreatic juice containing different digestive enzymes into the small intestine 4)SALIVARY GLANDS-Salivary glands produce saliva, which moistens the mouth to help a person chew and swallow food 5)TEETH-Chewing and mastication of food 6)TONGUE-Rolling and lubrication of food -The food taken by human beings is digested into simpler molecules that can be absorbed into the blood and utilized for various functions of human body. As the digestive system is the only route of intake of nutrients (in normal conditions), therefore necessarily all the nutrient requirements of human body are fulfilled by this system alone. If the digestive system is impaired for some reason, health of the affected individual will seriously decline.
Endocrine System- is a regulatory system of human body.It associates the nervous system in controlling body functions. The control of body function by the nervous system is called nervous coordination and the control of body functions by the endocrine system is called chemical coordination. For a detailed explanation of the difference between nervous coordination and chemical coordination visit "". The control of body functions by the endocrine system is a long term control system. All the necessary changes and adaptations of the body, required for the long term control of a specific function, are influenced by the hormonal system.
-Separated into two categories: 1) TYPICAL ENDOCRINE GLANDS: These glands have primary function of producing hormones for human body. Typical endocrine glands include; -PITUITARY GLAND-Master galnd of the body, It has two lobes, Present at the base of brain in form of a protrusion, Secretes 9 different major hormones -THYROID GLAND-One of the largest glands of body, Found in neck below the thyroid cartilage, Mainly controls body metabolism, Secretes 3 different hormones -PARATHYROID GLANDS-Four in number, located behind the thyroid gland, produce parathormone -ADRENAL GLANDS-Found attached to the kidneys, Consists of two parts; Cortex and Medulla, Adrenal cortex produces 3 different hormones and adrenal medulla produces 4 different hormones 2) ORGANS HAVING SECONDARY -ENDOCRINE FUNCTION: These organs primarily belong to some other system of the body but have a secondary function of producing hormones. They include; -PANCREAS(Hormones of Pancreas)-Primarily an organ of digestive system, produces 4 different hormones including Insulin and Glucagon -Gonads-Primarily organs of reproductive system, a)Testes in males produse testosterone, b)Ovaries in females produce Estrogens and Progesterone -KIDNEYS (Hormones of Kidneys)-Primarily an organ of Excretory system, Produces 4 different types of hormones -LIVER (Hormones of Liver)-Primarily a metabolic organ of human body, produces 3 different types of hormones
Nervous System
Allows perception, emotion, thought, and rapid response to the environment. Includes brain and nerves. The nervous system allows us to sense stimuli such as light, sound, smell, and touch from our environment. It also allows rapid communication of stimuli within our body, such as sensations of pain, illness, and wellness. It also gives us the brain - a huge central processing unit that combines these stimuli into unified experiences, and performs tasks such as recording memories, producing emotional responses, and thinking. The last important function of the nervous system is to allow our brain to send signals to back to our body, enabling us to respond to environmental stimuli. The brain can be thought of as the control center that receives data, analyzes it, and then commands the body to respond. The nervous system accomplishes all of this using highly specialized cells called neurons, which can transmit signals extremely fast by firing electrochemical potentials. In order to fire these signals, neurons must use huge amounts of energy - as much as 25% of the calories we eat are used by the nervous system to allow us to perceive, feel, think, and respond! Some scientists believe that human ancestors were not able to become smart until we were able to meet the huge energy needs of a big brain. Our ancestors were able to meet these needs by becoming good hunters, good cooks - which makes food easier to digest - and eventually developing agriculture.
Musculoskeletal system
Allows the body to move on command. The musculoskeletal system has a very important role: it allows us to move! Vertebrates move by using the leverage of muscles on bones. Each of our bones can be thought of as a lever, ready to move part of our body; our muscles contract to apply force to these levers, according to the commands of our brains. This may seem simple compared to what the rest of our body systems do, but we would not get far without our muscles and bones. Literally! Our muscles and bones allow us to collect food, water, and other life essentials; and to escape from danger! If humans were a sedentary, unmoving species like sea sponges, we would never be able to get enough calories to feed our big brains!
Reproductive System
Allows the production of offspring. Includes ovaries, uterus, mammary glands (breasts), penis, and testes. The reproductive system is not essential to individual survival, but it is essential for the survival of the species. After all, a species whose members couldn't reproduce would not last very long! In humans, there are two very different reproductive systems: the male system, which is concerned primarily with producing sperm and finding mates; and the female system, which must prepare for pregnancy, childbirth, and baby care for reproduction to be successful. The female reproductive system is a particularly fascinating study in the way body systems work together to ensure our survival. Throughout the course of a woman's monthly cycle, her body uses four different hormones - most of which are produced by her ovaries - to decide when and whether her body should prepare for pregnancy. The major effects of the reproductive hormones are on the reproductive organs themselves, which must bring eggs for maturity and prepare uterine lining, rich in blood vessels, to nurture a possible embryo. But other effects are also seen in other organ systems. As a woman's cycle progresses, her hormones may effect her body temperature; blood flow; and even her appetite and her attraction to the opposite sex, to ensure that all the right resources are in place at the right time. Women in some parts of the world have been known to develop bizarre eating habits due to the demands of their reproductive cycle. In areas with poor nutrition, for example, the monthly shedding of blood-rich uterine lining can cause deficiencies of the minerals found in blood. As a result, women in these areas may actually eat clay from the ground to ensure these minerals are replenished! Their bodies, through some set of chemical signals, simply know what to do. We may not see such clear examples of our body systems interacting on a daily basis; but the organs and tissues that make up our body systems are always communicating, and working together, to keep us and our species alive and healthy.
Cardiovascular/Circulatory System-Perfectly functioning Cardiovascular system is so important for human body, that if it stops for a minute, rapid death will occur. The flow of blood is necessary for existence of life. If the flow of blood is stopped, life will stop. Heart is the main organ of cardiovascular system and it is responsible for distributing blood all over human body.
Components: -HEART-Hollow muscular organ providing the force for flow of blood throughout human body -BLOOD VESSELS-Pathways of blood flow in human body, hollow tubes, of 3 types 1)Arteries-Carry blood away from heart to other body parts, very muscular and elastic 2) Capillaries-Microscopic blood vessels where exchange of nutrients with tissues take place 3)Veins-Carry blood towards the heart from other body parts, their walls are thinner as compared to corresponding arteries. -BLOOD-Special type of body tissue that is in fluid form, consists of the following components; 1)Plasma 2) Blood Cells A)White Blood Cells B) Red Blood Cells C) Platelets
Integumentary System
Covers the body and regulates its exchange with the outside world. Includes skin, hair, nails, sweat, and other glands which secrete substances onto the skin. Like our bones and muscles, the job of our skin may seem mundane - but it is very important! Skin keeps our other organs in, and everything else out. Skin is our body's first line of defense against bacteria, viruses, injuries, and more. It also controls how much heat and water our body loses to the environment, allowing us to sweat. Even goosebumps are part of our skin's regulation system; the tightening of the skin raises our fine hairs upright, trapping warm air close to our skin. The skin is a surprisingly complex material, which scientists have not been able to reproduce artificially. This is because it is a living tissue, which is constantly maintained by the nourishing circulatory system underneath; and by a number of glands on the outside of our skin, which secrete oils and other substances that keep our skin from drying and cracking. Fun fact: skin is also the largest organ in the body. Or perhaps we should say, the largest organ on the body.
Lymphatic System/Immune System
Fights infection. Includes lymphatic vessels which permeate the body. Every living thing needs to be able to fight infection. This is because for every organism that's made of delicious carbohydrates, proteins, and lipids; there's another organism that wants to eat it. Some of these organisms are big predators, but most are microscopic pathogens that can easily fit inside us, instead of fitting us inside of them. In the case of animals, we have white blood cells that can specifically target and destroy invading pathogens. These white blood cells are made in our bone marrow and stored in our blood and our lymphatic systems. The lymphatic system is a circulatory system separate from the cardiovascular system that that carries water, white blood cells, and other substances. It does not have red blood cells or platelets. Because it is not the body's main carrier of oxygen, lymph can move more slowly than the bloodstream - giving the white blood cells more time to find and attack invaders. "Lymph nodes" are nexuses in the lymphatic system where white blood cells can cluster and attack invading pathogens. Sometimes when we're sick, our lymph nodes - such as those behind the ears, under the jaw, and in the armpits and groin- can become painful and swollen as our immune systems fight the infections in these nodes. Our immune systems are very, very good at their jobs. If you want to know how good, look at patients with severely compromised immune systems. People without functioning immune systems can contract fatal infections just from walking around in everyday environments without protection; prolonged lack of an immune system is usually fatal.
Digestive System
Ingests food and breaks it down into usable nutrients. Excretes solid waste products. Includes the mouth, esophagus, stomach, and intestines. The digestive system takes in food and processes it to obtain useful nutrients. One of the most important purposes of food is to serve as cellular fuel; carbohydrates, proteins, and fats can all be used by our cells to as sources of the energy they need to stay alive. We can also get other important nutrients from food, such as essential amino acids (amino acids our bodies can't make themselves), good fats, and vitamins and minerals that our cells need to keep their machinery in good working order. When food enters the body, it is first chewed by the mouth to break it down into a mush that stomach acids can penetrate. In the stomach, it is treated with acids and special enzymes that break the food's components down into more useful forms. Finally, it passes through the intestines: being squeezed through the huge surface area of the intestines' narrow tubes ensures that as many useful nutrients are extracted from the food as possible. The liver helps by releasing substances that assist the stomach and intestines in breaking down food, and by breaking down toxic substances in the blood. Once these nutrients have been extracted from foods, they are distributed to the body's cells by the circulatory system. The digestive/excretory system also expels solid waste components of our food that our body can't use in the form of fecal matter.
Cardiovascular/Circulatory System
Moves materials between body systems, including oxygen, nutrients, hormones, and waste products. Includes the heart, arteries, and veins.The cardiovascular system is a highly efficient system for moving substances around the body. The body's entire blood volume takes about a minute to circulate - making this a truly high-speed expressway for distributing oxygen, nutrients, messages, and removing waste. The heart is the central pump of the circulatory system, sending blood to throughout the body at very high speeds. To ensure that we get enough oxygen, the heart even pumps blood through a special circuit to send large amounts of blood through the lungs quickly. The arteries are the oxygen-delivery system that carry oxygenated blood through the body at high speeds and pressures. Arteries don't merely contain the blood; they have walls of smooth muscle which contract to help the blood keep going, even far away from the heart. This is why injuries to arteries are so dangerous; if an artery is injured, the body's whole blood volume can drain out through it very fast! The veins return blood to the heart after its oxygen has been removed. The blood in veins moves a bit slower and at lower pressures. At the finest level of the circulatory system, tiny blood vessels called capillaries carry blood all throughout the tissues. By passing blood flow close to every cell, the capillaries ensure efficient delivery of needed substances. Most bleeding from superficial cuts comes from blood seeping from these tiny, often microscopic, blood vessels. In addition to oxygen and nutrients, the circulatory system also transports chemical messages, such as hormones, around the body. This allows the adrenal glands, for example, to send messages that cause our whole body to prepare for fight or flight. Lastly, of course, the circulatory system performs the vital task of carrying waste products away from our cells. It delivers carbon dioxide to the lungs, and other toxins to the liver and kidneys to be destroyed or excreted.
Endocrine System
Secrets chemical signals that allow body systems to act cooperatively sa needed. Includes hormone-producing tissues of the pineal gland and pituitary gland in the brain; the thyroid gland; the adrenal glands; the pancreas; and the ovaries and testes.The endocrine system consists of a number of tissues that send out chemical messages - called 'hormones' - to the rest of the body. Each of these messages has its own unique purpose, to which the body's other systems respond accordingly. The endocrine system allows the body to respond to environmental changes, and to other types of survival changes, such as the need to reproduce. Some examples of messages sent by the endocrine system are: Fight or flight - When a threat appears in the environment, the adrenal glands secrete adrenaline. In answer to this chemical message, the heart pumps blood faster; breathing deepens to take in more oxygen; and the nervous system sharpens perception and memory formation. Other changes also occur to make the body ready to fight or flee from a potential threat. Reproductive signals - When the body is ready to reproduce, the ovaries or testes send chemical messages that affect other organs, including the brain. For the female reproductive system, preparing the uterus for pregnancy involves a complex cascade of chemical messages that repeat on a monthly cycle. Hungry or full - When the body is hungry, your stomach releases a hormone that tells the brain and other organ systems to start seeking food. When the body is full, on the other hand, another set of hormone messengers go out telling the body it can stop eating.