Organs
Organs and How They Function
Your organs perform specialized jobs that keep your body functioning, but they do not work independently. The liver, heart, brain, lungs, kidneys and other organs constantly exchange blood, oxygen, nutrients, hormones and chemical signals. A problem in one organ can therefore affect several others. This page introduces the major organs, explains what each one does, and answers practical questions about how problems develop, what signs may matter and what different health assessments can and cannot tell you.
Liver
The liver processes nutrients, regulates stored energy, produces bile, manages cholesterol and helps remove substances the body does not need. Because it performs so many jobs, liver problems can affect blood sugar, digestion, circulation and overall metabolic health.
Heart
The heart pumps blood through the lungs and the rest of the body. This continuous circulation delivers oxygen and nutrients, carries hormones and other signals, and removes carbon dioxide and waste. Heart health depends on the condition of the blood vessels as well as the heart itself.
Brain
The brain coordinates thought, memory, emotion, movement and the senses. It also helps regulate breathing, heart rate, sleep, appetite and other functions that continue without conscious effort. Brain health is closely connected to circulation, metabolism, sleep and the health of the rest of the body.
Lungs
The lungs bring oxygen into the body and remove carbon dioxide. They work closely with the heart, blood vessels and breathing muscles to supply every organ and tissue. Lung function can be affected by smoking, infection, environmental exposure, physical conditioning and conditions elsewhere in the body.
Kidneys
The kidneys filter the blood, remove waste and regulate fluid, minerals and acid balance. They also help control blood pressure, support red blood cell production and maintain bone health. Kidney damage can develop gradually, with few obvious symptoms during its earlier stages.
Pancreas
The pancreas supports both digestion and blood sugar regulation. It produces enzymes that help break down carbohydrates, fats and proteins, along with hormones such as insulin and glucagon that help control how the body uses and stores energy. Because of these dual roles, pancreatic health connects the digestive and metabolic systems.
Digestive Tract
The digestive tract carries food from the mouth through the esophagus, stomach and intestines. Along the way, food is broken down, nutrients and water are absorbed, and waste is prepared for elimination. Its function depends on coordinated movement, digestive secretions, nerves, hormones and intestinal microbes.
Skin
The skin is the body’s largest organ and its primary protective barrier. It helps keep harmful organisms and substances outside the body, prevents excessive fluid loss, regulates body temperature and provides the sensations of touch, pressure, pain and temperature. The skin also participates in immune defense, wound repair and vitamin D production. Changes in the skin may reflect a local problem, environmental exposure or a condition affecting another part of the body.
Other Organs
The gallbladder, spleen, bladder and reproductive organs perform important specialized functions that connect with the body’s larger systems. This section introduces organs not covered in the main boxes and provides room to add deeper explanations as the resource grows.
LIVER
The liver helps manage energy, nutrients, digestion, cholesterol, medications and waste. Because it performs so many functions, liver problems may affect several parts of your health and can develop before you notice obvious symptoms.
What does your Liver do in the body?
Your liver processes nutrients absorbed from food and decides whether they should be used, changed, stored or released. It produces bile to help digest fats, makes proteins needed for blood clotting and fluid balance, regulates cholesterol, stores glucose as glycogen, and helps process medications, alcohol and other substances.
The liver does not work alone. It continually exchanges materials and signals with the digestive tract, pancreas, kidneys, heart and other organs.
Why can liver problems develop without obvious symptoms?
The liver has considerable reserve capacity and can continue performing its essential work even when some injury or scarring is present. Early liver disease may therefore cause no symptoms or only vague changes, such as fatigue, that have many possible explanations.
More recognizable symptoms, including jaundice, abdominal swelling, confusion or easy bleeding, may not appear until liver disease is advanced. This is why your medical history, metabolic risks, laboratory results and imaging may matter even when you feel well.
What is metabolic fatty liver disease?
Metabolic fatty liver disease develops when excess fat accumulates in the liver in association with metabolic risks such as type 2 diabetes, insulin resistance, abdominal obesity, high triglycerides or high blood pressure. The current medical name is metabolic dysfunction-associated steatotic liver disease, or MASLD.
Fat in the liver does not always progress. In some cases, however, it is accompanied by inflammation and liver-cell injury. Continued injury can lead to fibrosis, which is the formation of scar tissue. The amount of fibrosis is generally more important to long-term liver outcomes than the presence of fat alone.
Can your liver enzymes be normal when liver disease is present?
Yes. AST and ALT may rise when liver cells are injured, but normal results do not prove that your liver contains no excess fat, inflammation or fibrosis. They are useful pieces of information, not a complete assessment of liver health.
This matters particularly if you have type 2 diabetes, previously diagnosed fatty liver or several metabolic risk factors. Your PCP can decide whether your history warrants further evaluation even when routine liver enzyme results are normal.
For a closer look at what normal results may miss, read: Normal Liver Enzymes: What Can They Miss?
How can your PCP assess liver fat and fibrosis?
Different assessments answer different questions. Ultrasound may detect liver fat but can miss milder fat accumulation. FIB-4 uses your age, AST, ALT and platelet count to estimate whether advanced fibrosis is unlikely or whether further evaluation may be needed. It does not diagnose fatty liver.
FibroScan can estimate liver stiffness and liver fat. Other assessments may be considered when initial results are uncertain or suggest increased risk. You do not need to choose or arrange the tests yourself. Ask your PCP what, if anything, is appropriate based on your medical history and existing results.
The Heart
Your heart is a muscular pump that keeps blood circulating throughout your body. Working with your blood vessels and lungs, it delivers oxygen and nutrients to your tissues and carries carbon dioxide and other waste products away. Changes in the heart’s rhythm, pumping strength, valves, or blood supply can affect every organ in the body.
What does your heart do?
Your heart is a muscular pump that keeps blood moving continuously through your lungs and the rest of your body. The right side receives blood that has already circulated through the body and sends it to the lungs, where carbon dioxide is released and oxygen is collected. The left side then receives the oxygen-rich blood and pumps it out through the aorta to your organs, muscles, brain, and other tissues.
The heart adjusts its output according to what your body needs. It generally pumps more blood during physical activity, illness, stress, or increased demand and less while you are resting or sleeping. This requires the heart muscle, valves, electrical system, blood vessels, lungs, and nervous system to work together.
When the heart cannot pump effectively, the effects may be felt throughout the body. The brain, kidneys, liver, muscles, and other organs all depend on a steady supply of oxygenated blood.
How does blood move through your heart?
The heart contains four chambers. The two upper chambers are called the right and left atria, and the two lower chambers are called the right and left ventricles.
Blood returning from the body enters the right atrium and moves into the right ventricle. The right ventricle pumps it through the pulmonary arteries to the lungs. After receiving oxygen, the blood returns through the pulmonary veins to the left atrium. It then enters the left ventricle, the heart’s strongest pumping chamber, which sends it through the aorta and into the body.
Four valves help control this movement. They open when blood needs to pass forward and close to help prevent it from flowing backward. If a valve becomes narrowed, does not close properly, or allows blood to leak backward, the heart may have to work harder to maintain circulation. Over time, this can affect the heart’s pumping ability.
What controls the rate and rhythm of your heartbeat?
Your heart has an internal electrical conduction system that coordinates each heartbeat. The signal normally begins in a group of specialized cells called the sinoatrial, or SA, node, located in the right atrium. The SA node is often described as the heart’s natural pacemaker.
The electrical signal moves through the atria, causing them to contract and push blood into the ventricles. It then pauses briefly at the atrioventricular, or AV, node before traveling through the ventricles. This carefully timed sequence allows the ventricles to fill before they contract and pump blood to the lungs and body.
Your heart rate changes throughout the day in response to physical activity, sleep, stress, temperature, illness, medications, hormones, and signals from the nervous system. If electrical signals begin in the wrong place or do not travel normally, the heart may beat too quickly, too slowly, or irregularly. These disturbances are called arrhythmias. Some are harmless, while others require medical evaluation or treatment.
Can heart disease develop without obvious symptoms?
Yes. Some heart conditions can develop gradually without producing clear symptoms. High blood pressure and narrowing of the coronary arteries may be present for years before a person realizes there is a problem. Some abnormal heart rhythms also cause few or no noticeable symptoms. In certain cases, the first recognized event may be a heart attack, heart failure, or a serious arrhythmia.
This is why the absence of chest pain does not necessarily prove that the heart and blood vessels are healthy. Blood pressure, cholesterol, blood sugar, smoking history, kidney function, physical activity, family history, age, and other factors contribute to cardiovascular risk.
Routine medical care can help identify changes before they become emergencies. Depending on a person’s symptoms and risk factors, assessment may include blood-pressure measurements, laboratory tests, an electrocardiogram, imaging, or other testing. New symptoms such as chest pressure, unexplained shortness of breath, fainting, or a marked decline in physical capacity should not be dismissed simply because they are mild or intermittent.
BRAIN
The brain is the body’s primary control and communication center. It interprets information from your senses, supports thought, memory and emotion, directs movement, and helps regulate automatic functions such as breathing, heart rate and sleep. Brain health depends on a steady supply of oxygen and nutrients and is closely connected to circulation, metabolism, sleep and the health of the rest of the body.
What are the major parts of the brain, and what do they do?
The brain contains several interconnected regions that perform different but overlapping jobs. The cerebrum is the largest part. It supports conscious thought, language, memory, planning, sensory interpretation and voluntary movement. Its outer layer, the cerebral cortex, is divided into regions that specialize in functions such as vision, hearing, touch and decision-making.
The cerebellum, located toward the back of the brain, helps coordinate balance, posture, timing and smooth, accurate movement. It also contributes to learning movements that become more automatic with practice.
The brainstem connects the brain with the spinal cord. It helps regulate essential functions that usually occur without conscious effort, including breathing, heart rate, swallowing and sleep-wake activity.
These regions do not operate independently. Walking across a room, holding a conversation or remembering an appointment requires several areas to exchange information and coordinate their activity.
How does the brain communicate with the rest of the body?
The brain communicates through billions of nerve cells called neurons. Neurons receive, process and transmit information using electrical impulses and chemical messengers. The point where one neuron communicates with another cell is called a synapse. At many synapses, chemicals called neurotransmitters carry the signal across the small space between cells.
Messages travel between the brain and body through the spinal cord and an extensive network of nerves. Sensory nerves carry information toward the brain, allowing you to detect light, sound, temperature, pressure, pain and body position. Motor nerves carry instructions from the brain and spinal cord to muscles, producing movement.
Other nerve pathways regulate functions that you do not have to control consciously, including heart rate, digestion, breathing patterns and blood-vessel activity. Communication can be disrupted when neurons, their protective coverings, blood supply or connecting pathways are damaged. The effects depend on where the disruption occurs and which networks are involved.
How do circulation and metabolic health affect the brain?
The brain requires a continuous supply of oxygen and nutrients delivered by the blood. Although it represents only one part of the body, it has substantial energy needs. Healthy blood vessels help maintain the circulation that brain cells require to communicate, repair themselves and perform their many functions.
Conditions that damage blood vessels can also affect the brain. High blood pressure, diabetes, high cholesterol, heart disease and stroke have all been connected with poorer cognitive health or increased risk of vascular brain injury. The effects may occur suddenly, as with a stroke, or accumulate gradually through damage to small blood vessels.
Brain health is therefore not separate from heart and metabolic health. Managing blood pressure, blood sugar and cholesterol; remaining physically active; obtaining adequate sleep; avoiding smoking; and reviewing medications and health conditions with a clinician may support both cardiovascular and cognitive health. These steps cannot guarantee that cognitive decline will be prevented, but they address factors known to affect the brain’s blood vessels and overall function.
What brain-related symptoms require immediate medical attention?
Sudden neurological changes can indicate a stroke or another medical emergency. Warning signs include sudden weakness or numbness of the face, arm or leg, especially on one side; facial drooping; difficulty speaking or understanding speech; sudden confusion; loss of balance or coordination; sudden vision changes; or a severe headache with no known cause.
Call 911 immediately if these symptoms appear. Do not wait to see whether they improve and do not drive yourself to the hospital. Emergency medical personnel can begin assessment and care while arranging transportation to an appropriate facility.
Symptoms that disappear after a few minutes may still represent a transient ischemic attack, sometimes called a mini-stroke. A TIA is not harmless simply because the symptoms resolve. It can be a warning of a future stroke and requires prompt medical evaluation.
When symptoms begin, note the approximate time. Some stroke treatments are highly time-dependent, so rapid recognition and emergency care may reduce brain damage and disability.
LUNGS
The lungs bring oxygen into the body and remove carbon dioxide produced by its cells. Inside millions of tiny air sacs called alveoli, oxygen passes into the bloodstream while carbon dioxide moves from the blood into the lungs to be exhaled. The lungs work closely with the heart, blood vessels, brain, diaphragm and other breathing muscles to supply every organ and tissue with the oxygen needed to function.
What happens inside your lungs when you breathe?
When you inhale, the diaphragm contracts and moves downward while muscles between the ribs help expand the chest. This creates space for air to enter through the nose or mouth, travel down the windpipe and move through branching airways inside the lungs.
At the ends of the smallest airways are millions of microscopic air sacs called alveoli. These air sacs are surrounded by tiny blood vessels called capillaries. Oxygen from inhaled air passes through the thin walls of the alveoli and enters the blood. At the same time, carbon dioxide moves from the blood into the alveoli so it can leave the body when you exhale.
When you breathe out, the diaphragm and other breathing muscles usually relax, reducing the space inside the chest and pushing air out. This exchange continues automatically throughout the day and night, adjusting as your body’s needs change.
How do your lungs and heart work together?
The lungs place oxygen into the blood, but the heart is responsible for moving that blood through the body. Blood that has delivered much of its oxygen to the tissues returns to the right side of the heart. The heart then pumps it to the lungs, where carbon dioxide is released and oxygen is collected.
The oxygen-rich blood returns to the left side of the heart, which pumps it to the brain, kidneys, muscles and other organs. If either the heart or lungs cannot perform its part effectively, the body may not receive enough oxygen or remove carbon dioxide efficiently.
This close relationship is why heart and lung problems can produce similar symptoms, including shortness of breath, reduced exercise capacity, fatigue and swelling. Breathlessness does not automatically identify which organ is responsible. A healthcare professional may need to consider the lungs, heart, blood, breathing muscles and other possible causes together.
Can lung disease develop before obvious symptoms appear?
Yes. Some lung conditions develop gradually, and early changes may cause no symptoms or only mild symptoms. A person may unconsciously reduce activity, walk more slowly or avoid stairs and then attribute the change to aging or being out of shape rather than recognizing increasing breathlessness.
Early warning signs may include a persistent cough, frequent mucus production, wheezing, repeated respiratory infections, chest tightness or becoming short of breath during activities that were previously comfortable. These symptoms have many possible causes and do not necessarily mean that a person has a serious lung disease, but persistent or worsening changes deserve medical attention.
COPD is one example of a condition that may produce few symptoms during its early stages. Smoking is a major risk factor, but lung health can also be affected by secondhand smoke, air pollution, occupational exposures, infections, asthma, allergies and other medical conditions.
How can a healthcare professional assess how well your lungs are working?
Assessment usually begins with your symptoms, medical history, smoking and exposure history, physical examination and oxygen level. Depending on the concern, a clinician may order imaging, blood tests or pulmonary function tests.
Spirometry measures how much air you can forcefully exhale and how quickly you can exhale it. It can help identify airflow obstruction associated with conditions such as asthma or COPD. Lung-volume testing measures how much air the lungs can hold, while a diffusion-capacity test evaluates how effectively oxygen moves from the lungs into the blood. Some people may also undergo an exercise or walking test to see how breathing and oxygen levels respond to activity.
A normal oxygen reading at rest does not answer every question about lung health. Test selection and interpretation depend on the person’s symptoms and risks. Severe breathing difficulty, blue or gray lips, confusion, chest pain or a feeling that you cannot get enough air requires urgent medical attention.
How can smoke and ash exposure affect your lungs?
Smoke contains gases and very small particles that can irritate your airways and travel deep into your lungs. Exposure may cause coughing, wheezing, chest tightness or difficulty breathing, and it can worsen asthma, COPD and other existing lung conditions.
For practical steps to take after exposure, read: After Significant Smoke or Ash Exposure.
KIDNEYS
The kidneys continuously filter the blood, removing wastes and excess water to produce urine while returning substances the body still needs to the bloodstream. They also regulate fluid, minerals and acid balance; help control blood pressure; stimulate red blood cell production; and support bone health. Because kidney function affects circulation, nerves, muscles and many other tissues, kidney damage can create problems throughout the body.
How do the kidneys filter your blood and make urine?
Each kidney contains about one million microscopic filtering units called nephrons. Every nephron has a cluster of tiny blood vessels called a glomerulus and a connected tubule. As blood passes through the glomerulus, water and small molecules move into the tubule while blood cells and most proteins remain in the bloodstream.
The tubule then performs a careful sorting process. It returns most of the water, minerals and nutrients the body still needs to the blood while allowing wastes, excess minerals, acids and unwanted fluid to remain. What is left becomes urine.
Urine flows from each kidney through a tube called a ureter and is stored in the bladder until it leaves the body. The kidneys filter far more fluid than becomes urine because most filtered water and useful substances are reclaimed rather than discarded.
Why are diabetes and high blood pressure important to kidney health?
Diabetes and high blood pressure are the two most common causes of chronic kidney disease in adults. Persistently elevated blood sugar can damage the small blood vessels and filtering structures inside the kidneys. As that damage progresses, the kidneys may become less effective at removing wastes and may allow albumin, a protein that should generally remain in the blood, to leak into the urine.
High blood pressure can also damage the kidneys’ delicate blood vessels. At the same time, damaged kidneys may retain excess sodium and fluid or have difficulty regulating blood pressure. This can create a cycle in which high blood pressure worsens kidney damage and declining kidney function makes blood pressure more difficult to control.
Managing blood sugar and blood pressure cannot eliminate every cause of kidney disease, but it can reduce two major sources of continuing kidney damage.
Can kidney disease develop without obvious symptoms?
Yes. Early chronic kidney disease often produces no noticeable symptoms. The kidneys have substantial reserve capacity, and the remaining healthy nephrons may compensate when some filtering ability has been lost. A person may therefore feel well even while kidney damage is developing.
Symptoms are more likely to appear as kidney function declines. They may include swelling in the feet or ankles, changes in urination, fatigue, nausea, itching, muscle cramps, shortness of breath or difficulty concentrating. However, these symptoms are not specific to kidney disease and can have many other causes.
Because symptoms may appear late, blood and urine testing is particularly important for people with diabetes, high blood pressure, heart disease, a family history of kidney disease or other risk factors. Feeling normal does not necessarily establish that the kidneys are functioning normally.
What tests help assess kidney health?
Two key measurements are commonly used together. A blood test is used to estimate the glomerular filtration rate, or eGFR, which describes how effectively the kidneys are filtering the blood. The estimate is generally calculated using the blood level of creatinine along with other information.
A urine albumin-to-creatinine ratio, or UACR, checks whether albumin is leaking into the urine. Albumin in the urine can indicate damage to the kidney’s filtering structures even when the eGFR has not declined substantially. Conversely, a reduced eGFR may reveal impaired filtering even when a routine urine test appears unremarkable.
One abnormal result does not always establish chronic kidney disease. Illness, dehydration, medications and other circumstances can temporarily affect results, so repeat testing may be needed. Looking at both eGFR and urine albumin over time provides more information than relying on either measurement alone.
PANCREAS
The pancreas performs two very different but closely connected jobs. It releases digestive enzymes into the small intestine to help break down carbohydrates, fats and proteins. It also releases hormones into the bloodstream, including insulin and glucagon, that help keep blood sugar within a usable range. Pancreatic problems can therefore affect digestion, nutrient absorption, blood sugar regulation and overall metabolic health.
How does the pancreas help digest food?
The pancreas produces digestive enzymes and releases them into the small intestine after you eat. These enzymes help break down carbohydrates, fats and proteins so their nutrients can be absorbed and used by the body. The pancreas also releases bicarbonate, which helps neutralize stomach acid as food enters the small intestine.
If the pancreas does not produce or deliver enough enzymes, food may not be completely digested. This is called exocrine pancreatic insufficiency. Possible signs include bloating, abdominal discomfort, diarrhea, greasy or foul-smelling stools, unintended weight loss and deficiencies of certain vitamins. Because these symptoms can have many causes, testing is needed before assuming the pancreas is responsible.
How does the pancreas regulate blood sugar?
The pancreas contains specialized cells that release hormones directly into the bloodstream. Insulin helps move glucose from the blood into cells, where it can be used for energy or stored for later. Glucagon has the opposite effect: it signals the liver to release stored glucose when blood sugar begins to fall.
These hormones work together throughout the day to keep blood sugar within a usable range. If the pancreas produces too little insulin, or the body does not respond to insulin effectively, blood sugar can remain elevated. Pancreatic inflammation, surgery and other pancreatic conditions can also interfere with hormone production and contribute to diabetes.
Can pancreatic problems develop without obvious symptoms?
Yes. Some pancreatic problems can develop gradually or cause symptoms that are easy to attribute to other conditions. Chronic pancreatic inflammation may be difficult to recognize in its early stages, and pancreatic cancer may not produce noticeable symptoms early in the disease.
Symptoms that warrant medical attention include persistent upper abdominal pain—especially pain that spreads to the back—recurrent nausea or vomiting, unexplained weight loss, greasy stools, jaundice, dark urine or an unexplained change in blood sugar. These symptoms do not necessarily mean that pancreatic disease is present, but they should not be ignored.
There is no single test that evaluates every function of the pancreas. The appropriate assessment depends on whether the concern involves digestion, blood sugar regulation, inflammation or a structural abnormality. A healthcare professional may begin with symptoms, medical history, medications, alcohol and tobacco exposure, family history and a physical examination.
Blood tests may measure glucose, A1C, lipase, amylase and signs of inflammation or nutritional deficiency. A stool elastase test may be used when inadequate digestive-enzyme production is suspected. Ultrasound, CT, MRI or endoscopic ultrasound may be needed to examine the pancreas and nearby ducts. Results must be interpreted together because one normal test may not rule out every pancreatic condition.
How can a healthcare professional assess pancreatic function?
There is no single test that evaluates every function of the pancreas. The appropriate assessment depends on whether the concern involves digestion, blood sugar regulation, inflammation or a structural abnormality. A healthcare professional may begin with symptoms, medical history, medications, alcohol and tobacco exposure, family history and a physical examination.
Blood tests may measure glucose, A1C, lipase, amylase and signs of inflammation or nutritional deficiency. A stool elastase test may be used when inadequate digestive-enzyme production is suspected. Ultrasound, CT, MRI or endoscopic ultrasound may be needed to examine the pancreas and nearby ducts. Results must be interpreted together because one normal test may not rule out every pancreatic condition.
DIGESTIVE TRACT
The digestive tract carries food from the mouth through the esophagus, stomach, small intestine and large intestine. Along the way, food is broken down, nutrients and water are absorbed, and the remaining waste is prepared for elimination. This process depends on coordinated muscle movement, digestive secretions, nerves, hormones and intestinal microbes. When one part is not working properly, symptoms may appear elsewhere in the digestive system or affect nutrition and overall health.
How does food move through the digestive tract?
Digestion begins in the mouth, where chewing breaks food into smaller pieces and saliva begins processing it. After you swallow, coordinated muscle contractions move the food through the esophagus and into the stomach. The stomach mixes it with acid and digestive enzymes, producing a semiliquid mixture that gradually enters the small intestine.
Most digestion and nutrient absorption occur in the small intestine with help from the pancreas, liver and gallbladder. The large intestine absorbs much of the remaining water and minerals. It also contains microorganisms that act on material the body did not digest earlier. What remains is formed into stool and stored in the rectum until it is eliminated.
Why can digestive symptoms have so many different causes?
Many digestive conditions produce similar symptoms. Abdominal pain, bloating, nausea, heartburn, diarrhea and constipation may result from food choices, an infection, medication, inflammation, altered muscle movement or a disorder involving communication between the gut and brain. Symptoms can also originate in the liver, gallbladder or pancreas rather than the digestive tract itself.
The location and timing of a symptom provide useful clues but may not identify its cause. A healthcare professional may consider when symptoms began, whether they are related to meals, how bowel habits have changed, what medications you take and whether warning signs are present. Persistent or recurring symptoms deserve evaluation instead of being attributed automatically to stress, aging or a particular food.
How do nerves, hormones and intestinal microbes affect digestion?
The digestive tract does not work as a simple pipe. Nerves coordinate swallowing, muscle contractions, digestive secretions and the movement of food. Hormones released by cells in the stomach and intestines help regulate appetite, digestion and the rate at which food moves through the system. The digestive tract also communicates continually with the brain.
Trillions of microorganisms live primarily in the large intestine. Collectively called the gut microbiome, they interact with food, the intestinal lining and the immune system. These relationships are complex, and researchers are still determining what constitutes a healthy microbiome for an individual. Digestive symptoms should not automatically be blamed on “bad bacteria,” and microbiome test results do not always reveal the cause of a person’s symptoms.
How can a healthcare professional evaluate digestive problems?
An evaluation usually begins with your symptoms, medical and family history, medications, eating patterns and a physical examination. Depending on the problem, testing may include blood work, stool testing, breath testing or imaging. An upper endoscopy can examine the esophagus, stomach and first part of the small intestine, while a colonoscopy examines the rectum and colon. Tissue samples may be collected during these procedures when necessary.
No single test evaluates the entire digestive tract, and the appropriate tests depend on the symptoms and suspected condition. Seek timely medical attention for blood in the stool, black or tarry stool, persistent vomiting, difficulty swallowing, unexplained weight loss, severe or continuing abdominal pain, jaundice or a lasting change in bowel habits.
SKIN
The skin is the body’s largest organ and its primary barrier against the outside environment. It helps protect you from injury, infection, ultraviolet radiation and excessive water loss. The skin also supports temperature regulation, sensation, immune activity and vitamin D production. Changes in its color, texture, temperature or ability to heal may reflect a condition within the skin itself or provide clues about circulation, nutrition, hormones, medications and overall health.
What does your skin do besides cover your body?
Your skin forms a protective barrier between your body and the outside environment. It helps keep harmful organisms and substances out while limiting the loss of water from within. Skin also contains immune cells that help detect and respond to potential threats.
Blood vessels and sweat glands in the skin help regulate body temperature. Sensory nerves allow you to detect touch, pressure, pain, heat and cold. When sunlight reaches the skin, it also begins the process the body uses to produce vitamin D. These functions make the skin an active organ rather than simply an outer covering.
How does skin change with age?
As skin ages, it generally becomes thinner, drier and less elastic. It may bruise more easily and take longer to heal. Years of sun exposure can add changes such as wrinkles, uneven pigmentation, rough areas and a higher risk of skin cancer. Smoking, dry environments, certain medications and medical conditions may also affect the skin.
Some changes are common with aging, but a new or changing growth should not automatically be dismissed as an age spot. Regularly examining your skin can help you notice a spot that changes in size, shape, color or texture, or one that begins itching, bleeding or failing to heal.
What can changes in your skin reveal about your overall health?
Changes in the skin sometimes provide clues about conditions elsewhere in the body. Persistent color changes, unusual dryness, widespread itching, easy bruising, swelling or slow wound healing may be associated with circulation, blood sugar, nutrition, medications, immune activity or the function of internal organs. However, the appearance of the skin alone usually cannot identify the cause.
Many skin findings are harmless or result from a local irritation. A healthcare professional considers where the change appears, how long it has been present, whether it is spreading and whether other symptoms are occurring. A persistent or unexplained change deserves evaluation, particularly when it is accompanied by fever, pain, joint symptoms, fatigue or a wound that is not healing.
How can a healthcare professional assess a skin problem?What happens when histamine balance shifts?
Evaluation usually begins with a close examination of the affected skin and a review of your symptoms, medical history, medications, allergies, sun exposure and family history. A healthcare professional may examine the skin with magnification, check other areas of the body or take photographs so that a spot can be compared over time.
Depending on the concern, testing may include a skin scraping, culture, blood test, allergy testing or a biopsy in which a small tissue sample is examined. Seek prompt care for a rapidly spreading or painful rash, blistering, signs of infection, a wound that is worsening or not healing, or swelling of the lips or eyes. Difficulty breathing or swallowing with a rash requires emergency medical attention.
OTHER ORGANS
The gallbladder, spleen, bladder and reproductive organs perform specialized functions that support the body’s larger systems. The gallbladder assists digestion, the spleen helps filter blood and support immune activity, and the bladder stores urine until it is eliminated. Reproductive organs produce hormones and support sexual and reproductive health. Although these organs have different roles, changes in one may affect digestion, immunity, hormone balance, elimination or overall well-being.
What does the gallbladder do?
The liver continuously produces bile, a fluid that helps the body digest and absorb fats. The gallbladder stores and concentrates bile between meals. When food containing fat enters the small intestine, the gallbladder contracts and releases bile through the bile ducts.
Gallstones may form without causing symptoms. Problems occur when a stone or another obstruction blocks the flow of bile, potentially causing pain in the upper-right abdomen, nausea, inflammation or infection. The gallbladder is helpful but not essential. If it is removed, bile flows directly from the liver into the small intestine instead of being stored between meals.
What role does the spleen play in blood and immune health?
The spleen is located in the upper-left abdomen and is part of both the blood-filtering and immune systems. It removes aging or damaged red blood cells and helps recover materials the body can reuse. It also monitors the blood for certain microorganisms and supports immune responses against infection.
A person can live without a spleen because other organs can perform some of its functions. However, people without a functioning spleen have a greater risk of serious infection and may require particular vaccinations and other medical precautions. An enlarged or injured spleen may not always produce obvious symptoms, but pain or tenderness in the upper-left abdomen, especially after an injury, requires medical attention.
What does the urinary bladder do?
The kidneys continuously remove waste and excess water from the blood to produce urine. Urine travels through the ureters to the urinary bladder, where it is stored until you urinate. Urine travels through the ureters to the bladder, where it is stored. As the bladder fills, nerves send signals to the brain. When it is appropriate to urinate, the bladder muscle contracts while the urinary sphincters and pelvic-floor muscles relax, allowing urine to leave through the urethra.
Problems can develop when these muscles and nerves do not coordinate properly or when infection, obstruction, medication or another condition affects the urinary tract. Warning signs include pain or burning during urination, blood in the urine, loss of bladder control, a sudden major change in frequency or urgency, or an inability to empty the bladder. Evaluation may include a urine test, examination, imaging or tests that measure how well the bladder stores and releases urine.
How do reproductive organs affect health beyond reproduction?
The reproductive organs include the ovaries, uterus and related structures in females, and the testes, prostate and related structures in males. In addition to producing eggs or sperm, the ovaries and testes produce hormones that influence sexual function, bone health, muscle, body composition and other processes throughout the body.
Reproductive function is coordinated with hormone-producing glands in the brain, so a change in one part of this system may have effects elsewhere. Symptoms such as unexplained pelvic pain, abnormal bleeding, a new lump, persistent urinary or sexual changes, or unexpected changes in reproductive function should be medically evaluated. The appropriate assessment depends on the person’s anatomy, age, symptoms and health history.
