ORGANS AND FUNCTIONS

DIFFERENT ORGANS AND FUNCTIONS 

Learning outcomes

Here are four potential learning outcomes related to organs and their functions:

1. Identify and describe the structure and function of major organs: Students can identify and describe the location, structure, and function of major organs in the human body.

2. Explain the relationships between organs and systems: Students can explain how organs work together in systems to maintain overall health and function.

3. Understand the impact of organ dysfunction or disease: Students can understand the consequences of organ dysfunction or disease on overall health and well-being.

4. Apply knowledge of organ function to real-world scenarios: Students can apply their knowledge of organ function to real-world scenarios, such as understanding the impact of lifestyle choices on organ health or explaining the effects of medical conditions on organ function.

Organs and functions

Here are the main organs of the human body and their functions:

Circulatory System

1. Heart: Pumps blood throughout the body.

2. Blood vessels: Arteries, veins, and capillaries transport blood.

Respiratory System

1. Lungs: Exchange oxygen and carbon dioxide through breathing.

2. Trachea: Airways that lead to the lungs.

Digestive System

1. Mouth: Food enters the body and is broken down.

2. Esophagus: Food passes through to the stomach.

3. Stomach: Digests food with enzymes and acids.

4. Small intestine: Absorbs nutrients.

5. Large intestine: Absorbs water and eliminates waste.

Nervous System

1. Brain: Controls thoughts, movements, and functions.

2. Spinal cord: Transmits messages between brain and body.

3. Nerves: Carry signals throughout the body.

Other Vital Organs

1. Kidneys: Filter waste and excess fluids from blood.

2. Liver: Detoxifies, metabolizes, and produces vital proteins.

3. Pancreas: Produces hormones (insulin, glucagon) and digestive enzymes.

These organs work together to maintain overall health and function.

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Review questions

What is the function of heart

In which system include brain

Mention organs in digestion

What are the functions of brain

FUNCTIONS OF LIVER

 LIVER

LEARNING OUTCOMES

To Understand structure of liver

To Understand function of liver

To get idea of liver diseases

Liver

The liver is a large organ in the abdomen that performs many important bodily functions, including blood filtering. It is also considered a gland because it makes chemicals the body needs. Certain diseases and lifestyles can damage the liver, but there are many ways to protect this vital organ.

Your liver is the biggest organ in your body and it performs hundreds of functions every day.

What is the liver?

The human liver is an organ and gland in the human body. It’s spongy, wedge-shaped, reddish-brown in color and about the size of a football. The size varies based on how tall you are and how much you weigh.

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The liver is an essential organ, performing hundreds of functions necessary to sustain life. It's also a gland because it makes proteins and hormones that other parts of the body need.

Weighing, on average, about three pounds in an adult, the liver is the largest internal organ. Under normal conditions, the liver is located on the right side of the body, under the ribs. In a condition called situs inversus, the liver is located on the left side.

Issues related to the liver are called hepatic conditions. A medical professional who specializes in the liver is a hepatologist.

What does the liver do?

The liver has hundreds of jobs. Some of the most vital are:

Cleans toxins (harmful substances) out of the blood.

Gets rid of old red blood cells.

Makes bile, a fluid that helps the body digest (break down) food.

Metabolizes proteins, carbohydrates and fats so your body can use them.

Produces substances to help blood clot.

Regulates the amount of blood in the body.

Stores glycogen (an energy source) and vitamins to be used by the body later.

What are the parts of the liver?

The liver has two main parts: the larger right lobe and the smaller left lobe.

The lobes contain many blood vessels. Blood travels through the liver. The liver filters (cleans) the blood, removing toxins and waste that eventually leave the body through urine and feces.

The lobes also contain thousands of lobules (small lobes). These lobules connect with many bile ducts, tubes that transport bile from the liver to the small intestine.

What conditions and disorders affect the liver?

Many conditions can affect the liver. Among the most common are:

Diseases that occur when a person consumes too many toxins, such alcohol-related liver disease and fatty liver disease (extra fat).

Inherited diseases like hemochromatosis (iron overload) and Wilson disease (too much copper in the body).

Liver cancer, when abnormal cells grow too quickly.

Problems when the immune system attacks the liver, such as autoimmune hepatitis, primary sclerosing cholangitis and primary biliary cholangitis.

Viral infections, such as hepatitis A, hepatitis B and hepatitis C.

Many of these conditions can lead to cirrhosis (scarring) of the liver.

Sometimes, damaged liver tissue can regenerate, or grow back. Other times, liver disease can cause serious symptoms and even be life-threatening.

What are the symptoms of liver problems?

When a person has a liver problem, one of the most common symptoms is jaundice.

With jaundice, the skin and whites of the eyes turn yellow because of too much bilirubin in the blood. Bilirubin is a yellow waste product the liver gets rid of when it breaks down red blood cells. Higher levels of bilirubin indicate a possible problem in the liver.

Other symptoms of liver problems may include:

Build-up of fluid in the belly area (ascites).

Easy bruising.

Itchy skin.

Low blood pressure.

Pain in the abdomen.

Swelling in the legs or ankles.

Tremors (shaking).

Weakness, loss of balance or constant fatigue.

Confusion or loss of orientation

How can I keep my liver healthy?

To keep your liver healthy and functioning well, try to follow these tips:

Avoid toxins, such as chemicals, smoking and illegal drugs.

Don’t share needles, razors, toothbrushes or any other personal items, which can spread viruses.

Drink alcohol only in moderation.

Follow healthcare professionals’ instructions about medications, especially warnings against mixing medications and alcohol.

Maintain a healthy weight, including eating a nutritious diet and exercising regularly.

Practice safe sex to avoid hepatitis infection.

Talk to your healthcare provider about vaccinations against hepatitis.

Wash your hands frequently.

When should I seek medical attention?

If you have any symptoms of liver problems, especially jaundice or belly pain, talk to a healthcare provider. Anytime you have severe pain in your abdomen, get immediate medical care.

How do I know if I’m at risk for liver problems?

You may be at risk for liver problems if you:

Are exposed to chemicals regularly.

Have overweight/obesity.

Drink a lot of alcohol.

Have relatives who’ve had liver disease.

Practice poor personal hygiene, such as having unprotected sex, sharing personal items and not washing your hands often.

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The liver is both an organ and a gland that performs hundreds of functions vital to human life. Many common conditions and diseases can damage the liver, but you can take steps to protect it. Talk to a healthcare professional if you have any symptoms, especially jaundice or pain in your belly.

Review Questions

What is the main function of liver

Name largest gland in human body

How liver helps in digestion 

FUNCTIONS OF KIDNEY

Learning outcomes

To understand the function of kidney

To understand structure of kidney

To get knowledge about kidney diseases

Kidney

Most people have two kidneys, organs that sit in the back of your abdomen. Your kidneys’ primary function is to filter your blood. They also remove waste and balance your body’s fluids. Common kidney conditions include kidney disease, kidney infections and kidney cysts. 

Overview

Function

Anatomy

Conditions and Disorders

Care

Additional Common Questions

Overview

Your kidneys filter through all your blood once an hour — keeping what you need and getting rid of the rest.

What are the kidneys?

The kidneys are two bean-shaped organs that filter your blood. Your kidneys are part of your urinary system.

Your kidneys filter about 200 quarts of fluid every day — enough to fill a large bathtub. During this process, your kidneys remove waste, which leaves your body as urine (pee). Most people pee about two quarts daily. Your body re-uses the other 198 quarts of fluid.

Your kidneys also help balance your body’s fluids (mostly water) and electrolytes. Electrolytes are essential minerals that include sodium and potassium.

Who is at the greatest risk of kidney problems?

People with diabetes or high blood pressure have the highest risk of kidney problems. Accidents or trauma can also harm your kidneys, such as car accidents or sports injuries.

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Function

What do the kidneys do?

Your kidneys have many important functions. They clean toxins and waste out of your blood. Common waste products include nitrogen waste (urea), muscle waste (creatinine) and acids. They help your body remove these substances. Your kidneys filter about half a cup of blood every minute.

In the process:

Blood flows into your kidneys through a large blood vessel called the renal artery.

Tiny blood vessels in your kidney filter the blood.

The filtered blood returns to your bloodstream through a large blood vessel called the renal vein.

Pee travels through tubes of muscle called ureters (yer-it-ter) to your bladder.

Your bladder stores pee until you release it through urination (peeing).

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The kidneys also:

Control the acid-base balance (pH balance) of your blood.

Make sugar (glucose) if your blood doesn’t have enough sugar.

Make a protein called renin that increases blood pressure.

Produce the hormones calcitriol and erythropoietin. Calcitriol is a form of vitamin D that helps your body absorb calcium. Erythropoietin helps your body make red blood cells.

An adrenal gland sits on top of each kidney. It produces hormones, including cortisol, which helps your body respond to stress.

Cortisol also plays a role in:

Controlling metabolism

Reducing inflammation

Regulating blood pressure

Increasing blood sugar levels

How do my kidneys filter blood?

Each kidney contains more than a million filtering units called nephrons. Each nephron consists of:

Glomeruli. Glomeruli are groups of tiny blood vessels that perform the first stage of filtering your blood. They then pass filtered substances to the renal tubules. The name for this process is glomerular filtration.

Renal tubules. These tiny tubes reabsorb and return water, nutrients and minerals your body needs (including sodium and potassium). The tubules remove waste, including excess acid and fluids through a process called diffusion. Your body sends the remaining waste through your kidneys’ collecting chambers. Eventually, it leaves your body as pee.

Can you live without a kidney?

You can live with just one kidney. Healthcare providers may remove one of your kidneys in a radical nephrectomy.

Someone may have only one kidney if they:

Had a kidney removed due to cancer or injury

Made a kidney donation to someone else for a kidney transplant

Were born with only one kidney (renal agenesis)

Were born with two kidneys but only one kidney works (kidney dysplasia)

Anatomy

Kidney anatomy, including their location in the body and details of the parts that make up your kidneys

Kidney anatomy.

Where are your kidneys located?

Your kidneys sit just below your ribcage and behind your belly. Typically, one kidney sits on either side of your spine. Your kidneys reside between your intestines and diaphragm. A ureter connects each kidney to your bladder.

What are the parts of the kidney?

Your kidneys are highly complex organs with many parts. The main parts of your kidney anatomy include:

Kidney capsule (renal capsule)

The renal capsule consists of three layers of connective tissue or fat that cover your kidneys. It protects your kidneys from injury, increases their stability and connects your kidneys to surrounding tissues.

Renal artery

The renal artery is a large blood vessel that controls blood flow into your kidneys. For most people at rest, the renal kidneys pump a little over 5 cups (1.2 liters) of blood to your kidneys each minute.

Renal cortex

The outer layer of your kidney, where the nephrons (blood-filtering units) begin. The renal cortex also creates the hormone erythropoietin (EPO), which helps make red blood cells in your bone marrow.

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Renal medulla

The renal medulla is the inner part of your kidney. It contains most of the nephrons with their glomeruli and renal tubules. The renal tubules carry urine to the renal pelvis.

Renal papilla

These pyramid-shaped structures transfer urine to the ureters. Dehydration and certain medications — especially nonsteroidal anti-inflammatory drugs (NSAIDs) — may damage your renal papilla.

Renal pelvis

This funnel-shaped structure collects urine and passes it down two ureters. Urine travels from the ureters to the bladder, where it’s stored.

Renal vein

This vein is the main blood vessel that carries filtered blood out of your kidneys and back to your heart. Each of your kidneys has a renal vein.

What color are the kidneys?

Your kidneys are reddish-brown.

How big is a kidney?

Each kidney is about 4 or 5 inches long, around the size of a fist.

How much do my kidneys weigh?

The weight of your kidneys varies. Variances may include your height, weight, age, body mass index (BMI) and location.

If you’re male, your right kidney may range from 1/5 to about 1/2 lbs. (79 grams to 223 grams). Your left kidney may range from a little less than 1/5 to a little more than 1/2 lbs. (74 grams to 235 grams). Your kidneys may weigh between the weight of one tennis ball and four tennis balls.

If you’re female, your right kidney may range from a little more than 1/10 to 3/5 lbs. (55 grams to 274 grams). Your left kidney may range from 3/20 to a little less than 3/5 lbs. (67 grams to 261 grams). Your kidneys may weigh between the weight of one tennis ball or five tennis balls.

Conditions and Disorders

What causes kidney damage?

Your kidneys perform several important functions within your body. Many different disorders can affect them. Common conditions that impact your kidneys include:

Chronic kidney disease. Chronic kidney disease (CKD) may lessen your kidney function. Diabetes or high blood pressure usually causes CKD.

Kidney cancer. Renal cell carcinoma is the most common type of kidney cancer.

Kidney failure (renal failure). Kidney failure may be acute (worsen suddenly) or chronic (a permanent lessening of how well your kidneys work). End-stage renal disease is a complete loss of kidney function. It requires dialysis (treatment to filter your blood in place of your kidneys).

Kidney infection (pyelonephritis). A kidney infection can occur if bacteria enter your kidneys by traveling up your ureters. These infections cause sudden symptoms. Healthcare providers treat them with antibiotics.

Kidney stones. Kidney stones cause crystals to form in your urine and may block urine flow. Sometimes these stones pass on their own. In other cases, healthcare providers can offer treatment to break them up or remove them.

Kidney (renal) cysts. Fluid-filled sacs called kidney cysts grow on your kidneys. These cysts can cause kidney damage. Healthcare providers can remove them.

Polycystic kidney disease. Polycystic kidney disease (PKD) causes cysts to form on your kidneys. PKD is a genetic condition. It may lead to high blood pressure and kidney failure. People with PKD need regular medical monitoring.

Countless other disorders can affect your kidneys. Some of these conditions include:

Acidosis. Excess acid accumulates in your kidneys, which may cause many health problems. It can be life-threatening.

Acute or interstitial nephritis. Your kidneys become inflamed, sometimes after exposure to certain antibiotics, which may lead to kidney failure.

Azotemia. Nitrogen waste builds up in your kidneys. Without treatment, azotemia may be fatal.

Caliectasis. Excess fluid causes your calyces (where urine collection begins) to swell. Without treatment, caliectasis may result in kidney failure.

Diabetes-related nephropathy or hypertensive nephropathy. Unmanaged diabetes or chronically high blood pressure causes kidney damage.

Glomerular diseases. Glomerular diseases cause inflammation or damage to your glomeruli. Glomerular diseases may cause kidney failure.

Minimal change disease and nephrotic syndrome. Minimal change disease and nephrotic syndrome cause your kidneys to release the excess protein in your pee.

Papillary necrosis. Chunks of kidney tissue die in the medulla and papilla. The tissue can break off and clog your kidneys, leading to kidney failure.

Proteinuria. Proteinuria means you have high levels of protein in your kidneys. It can be a sign of kidney damage.

Pyelonephritis. This sudden kidney infection causes edema (swelling) in your kidneys. It can be life-threatening.

Uremia. Toxins that normally leave your body through your pee end up in your bloodstream. Without treatment, uremia can be fatal.

What are the first signs of kidney problems?

Most kidney problems don’t have signs in their early stages. As kidney damage progresses, you may notice:

Cramping muscles. Electrolyte imbalances cause your muscles to stiffen.

Dark urine or urine with blood in it. Damage to your kidneys’ filters lets blood cells leak into your urine.

Foamy urine. Bubbles in your pee can signal excess protein.

Itchy, dry skin. An imbalance of minerals and nutrients in your blood leads to itchy skin.

More frequent urination. Problems filtering waste cause you to pee more often.

Puffy eyes or swollen ankles and feet. Reduced kidney function can cause your body to hold onto protein and sodium, resulting in swelling.

Sleep problems, fatigue and lack of appetite. If toxins build up in your blood, your sleep, appetite and energy levels may be off.

What are common tests to check the health of my kidneys?

Healthcare providers use several tests to measure kidney function and diagnose kidney problems. Your provider may recommend:

Advanced imaging. An X-ray, CT scan, MRI, ultrasound or nuclear medicine image can show kidney abnormalities or obstructions (blockages).

Blood tests. Blood tests show how well your glomeruli filter your blood.

Kidney biopsy. During a kidney biopsy, your healthcare provider removes a small amount of your kidney tissue to examine it under a microscope.

Ureteroscopy. Your healthcare provider passes a tube (endoscope) through your urethra into your bladder and ureters to look for abnormalities.

Urinalysis. A urinalysis analyzes your pee. It measures specific substances, such as protein or blood.

Care

How can I keep my kidneys healthy?

It’s important to have regular checkups and blood and urine tests to measure your kidneys’ health. You can reduce your risk of developing a kidney problem by:

Avoiding or quitting smoking and using tobacco products (your provider can help you find ways to quit)

Cutting out excess salt, which can affect the balance of minerals in your blood

Drinking water

Increasing daily exercise, which can reduce high blood pressure

Limiting your use of NSAIDs, which can cause kidney damage if you take them too much

Maintaining a healthy weight

Monitoring your blood pressure levels

Watching your blood sugar levels if you have diabetes

Is drinking a lot of water good for my kidneys?

Drinking an appropriate amount of water is good for your kidneys. Water helps your kidneys get rid of toxins and wastes through your pee. It also helps keep your blood vessels healthy, making it easier for blood to deliver necessary nutrients to your kidneys.

It’s also a good idea to drink an appropriate amount of water to help prevent kidney stones and urinary tract infections (UTIs). Kidney stones are less likely to form when you have enough water in your kidneys. You’re less likely to get a UTI when you drink a lot of water because you’ll pee more. Peeing helps flush out the bacteria that cause UTIs.

In general, the color of your pee can reveal if you’re drinking enough water. Your pee should be light yellow or clear if you’re drinking enough water. If you’re dehydrated, your pee will be dark yellow.

How much water should I drink to keep my kidneys healthy?

On average, males should drink about 13 cups (3 liters) of water each day. On average, females should drink about 9 cups (a little over 2 liters) of water each day.

Is it possible to drink too much water?

Yes, it’s possible to drink too much water. Drinking too much water may cause water intoxication or hyponatremia (primary polydipsia). These conditions may cause seizures, coma, mental status changes and death without treatment.

Is it kidney pain or back pain?

Kidney pain and back pain are similar, and people often confuse them.

Back pain usually occurs in your lower back.

Kidney pain is deeper in your body and higher up your back. You’ll likely feel pain in your sides or your middle- to upper-back area (most often under your ribs, to the right or left of your spine). The pain may progress to other areas, including your abdomen or groin.

Kidney pain results from swelling or blockage of your kidneys or urinary tract. Symptoms include fever, nausea, vomiting or pain when you pee.

Additional Common Questions

When should I call my healthcare provider about my kidneys?

Kidney conditions can cause different symptoms in different people. If your kidneys aren’t working correctly, you may notice one or more of the following signs:

Changes in your urine or urination habits (like more frequent bathroom trips)

Confusion or trouble concentrating

Dry or itchy skin

Fatigue (extreme tiredness)

High blood pressure (hypertension)

Muscle cramps

Poor appetite or metallic taste of food

Stomach pain or vomiting

Swelling, especially around your hands or ankles

You should have your kidney function regularly tested if you have:

A family history of kidney disease

Diabetes

Heart disease

High blood pressure

Obesity or overweight

Regular use of certain medications, such as blood pressure medicine

A note from Cleveland Clinic

Your kidneys filter your blood and remove waste from your body. Your kidneys also help balance your body’s fluids and electrolytes. Many different conditions may affect your kidneys, so it’s essential to take steps to keep your kidneys healthy. Regular testing is a good idea if you have a high risk for kidney problems.

 

Review questions

Role of kidney in homeostasis

Mention kidney diseases

Mention two parts of kidney

FUNCTIONS OF LUNGS

  LEARNING OUTCOMES

To get knowledge about lungs

To understand importance of lungs

To know how lungs works 

Lungs

Your two lungs make oxygen available to your body and remove gases like carbon dioxide. There are many conditions that can affect your lungs. Not smoking may help you prevent some illnesses.

A step-by-step explanation of how your lungs work.

What are your lungs?

Your lungs make up a large part of your respiratory system, which is the network of organs and tissues that allow you to breath

You have two lungs, one on each side of your chest, which is also called the thorax. Your thorax is the area of your body between your neck and your abdomen.

Right lung

The lung on your right side is divided into three lobes: the superior, the middle and the inferior. It’s shorter than your left lung, but also wider than your left lung. Both of your lungs are covered with a protective covering called pleural tissue.

Left lung

Your left lung has two lobes: the superior and the interior. Your left lung is smaller than the right because your heart is where the middle lobe on your left lung would be. Your left lung has two parts that your right lung doesn’t have: the cardiac notch (where your heart fits) and the lingula, an extension of the superior lobe.

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Function

What do lungs do?

Your lungs make oxygen available to your body and remove other gases, such as carbon dioxide, from your body. This process takes place 12 to 20 times per minute.

When you inhale through your nose or mouth, air travels down your pharynx (back of your throat), passes through your larynx (voice box) and into your trachea (windpipe).

Your trachea is divided into two air passages called bronchial tubes. One bronchial tube leads to your left lung, the other to your right lung. For your lungs to perform their best, your airways need to be open when you inhale and when you exhale. They also need to be free from inflammation (swelling) and abnormal amounts of mucus.

Your bronchial tubes lead to smaller air passages called bronchi, and then into bronchioles. The bronchioles end in tiny air sacs called alveoli, where oxygen is transferred from the inhaled air to your blood. Alveoli look like clusters of small round fruits.

After absorbing oxygen, the blood leaves your lungs and is carried to your heart. From there, it’s pumped through your body to provide oxygen to the cells of your tissues and organs.

When cells use oxygen, they produce carbon dioxide and transfer it to your blood. Your bloodstream carries the carbon dioxide back to your lungs. When you exhale, you remove the carbon dioxide.

Your respiratory system prevents harmful substances from entering your lungs by using:

Small hairs in your nose that act as an air-cleaning system and help filter out large particles.

Mucus produced in your trachea and bronchial tubes to keep air passages moist and help catch dust, bacteria and other substances.

The sweeping motion of cilia (small hairs in your respiratory tract) to keep air passages clean. One of the reasons that cigarette smoke is dangerous is that it stops cilia from working properly.

Interesting facts about your lungs

You can have lobes of your lung removed and live. You can even live with only one lung.

Lungs are the only organs in your body that will float.

Exercise can help you increase your lung capacity.

A typical adult has 300 million to 500 million alveoli.

Anatomy

Where are your lungs located?

Your lungs are located in your chest (your thorax). Your thoracic cavity is the name of the space that contains your lungs and other organs. Your lungs rest on a muscle called your diaphragm.

What do lungs look like?

Healthy lungs are pinkish-gray in color. You’ve probably seen photographs that compare the lungs of people who smoke to the lungs of people who don’t. Damaged lungs are darker gray and can have black spots in them.

Your triangularly shaped right and left lungs look a little bit like the ears of an elephant.

A typical lung in a human adult lung weighs about 2.2 pounds and is a little longer than 9 inches when you’re breathing normally, and about 10.5 inches when your lungs are completely expanded.

Conditions and Disorders

What are the common conditions and disorders that affect your lungs?

There are many different lung conditions. Some are minor and temporary, while others are chronic and more severe.

Asbestosis: Inhaling asbestos fibers causes scars on your lungs and pleural tissue.

Asthma: Airway tightening makes breathing difficult.

Bronchiectasis: Inflamed bronchi cause you to cough up mucus and have trouble breathing.

Bronchitis: The main characteristic of this condition is coughing. Bronchitis can be acute or chronic.

Chronic obstructive pulmonary disease (COPD): This is a progressive breathing disorder that can’t be reversed.

COVID-19: This infection can cause mild or severe respiratory illness.

Croup: This respiratory infection happens in children under the age of 5.

Cystic fibrosis: This inherited condition causes sticky mucus to build up in your lungs and other organs.

Influenza: This lung disease, known as the flu, is caused by a virus.

Lung cancer: A major risk factor for developing lung cancer is smoking cigarettes.

Mesothelioma: This type of cancer is mainly caused by breathing in asbestos fibers.

Pneumonia: This lung infection causes fluid in your lungs and can lead to hospitalization.

Pulmonary fibrosis: Scarring of your lungs causes breathing difficulty. It isn’t curable.

Pulmonary nodules: These growths in your lungs are mainly benign (noncancerous).

Respiratory syncytial virus (RSV): This respiratory infection can happen in children and adults.

Tuberculosis: This infection affects your lungs, but can also affect other body parts.

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What are some common signs or symptoms of lung conditions?

Common signs and symptoms of lung conditions include:

Shortness of breath (dyspnea).

Chest pain.

Cough, especially chronic cough or coughing up blood or mucus.

Fatigue.

Wheezing.

Swelling in your ankles and feet.

What are some common tests to check the health of your lungs?

Your healthcare provider can tell certain things during a physical examination. They can:

Listen for sounds in your lungs, including those that indicate a problem, including crackles (also called rales), wheezing and stridor (a high-pitched noise).

Count the number of breaths you take (your respirations).

Hear a change in your voice while they’re listening to your lungs.

Use a device called a pulse oximeter to measure the oxygen levels in your blood.

In addition to a physical examination, your provider may order different kinds of tests, including:

Imaging tests show your provider what your lungs look like

Chest X-ray.

Computed tomography (CT) scan.

Ultrasound.

Magnetic resonance imaging (MRI) scan.

Lung function tests (also called pulmonary function tests) tell your provider how well your lungs are working

Body plethysmography.

Diffusion testing.

Exhaled nitric oxide test.

Lung volume test.

Methacholine inhalation test.

Six-minute walk test.

Spirometry.

Procedures that may require sedatives or anesthesia

Bronchoscopy or endobronchial ultrasound bronchoscopy (EBUS).

Lung biopsy.

Thoractomy. Your surgeon makes a cut in between your ribs so they can diagnose or treat body parts located in your chest.

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What are common treatments for lung conditions?

If you have a lung condition, your treatment will depend on your actual condition, as well as your health status. Types of treatments may include medications, exercises, devices and surgeries.

Medications may be offered as inhalers, nebulizer solutions, oral products or injections (shots)

Steroids to reduce inflammation (swelling) in airways.

Antibiotics to treat infections.

Bronchodilators to open up airways. These come in long-acting and short-acting versions.

Mucolytics to make mucus thinner so it’s easier to cough up and out.

Oxygen therapy to improve your oxygen levels.

Chemotherapy and/or radiation to treat cancers.

Vaccines to help prevent infections.

Exercises and devices

Pursed lip breathing.

Diaphragmatic breathing.

Airway clearance devices, including vest therapy. These products help to clear your airways of mucus.

Surgeries

Lobectomy, the removal of one lobe of the lung.

Bilobectomy, the removal of two lobes of the lung.

Removal of sections of lungs.

Thoracentesis, a procedure to drain fluid from your lungs.

Thoracotomy.

Pneumonectomy, the removal of one lung.

Lung transplant.

Care

What can I do to keep my lungs healthy?

There are many things you can do to keep your lungs healthy or to help manage lung conditions.

The first thing you can do is to stop smoking and vaping.

Try to reach and maintain a healthy weight. People with obesity have less space for lung expansion.

Exercise regularly. Check with your provider before you start exercising.

Eat healthy foods in moderation.

Stay hydrated, unless your provider gives you a limit on how much liquid you can drink.

Get the vaccines that your provider suggests.

Wash your hands well to avoid infections.

Limit your exposure to people who are sick.

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Review questions

How Lungs helps in gaseous exchange 

What are the functions of lungs

Mention two lung diseases

FUNCTIONS OF BRAIN

LEARNING OUTCOMES

To understand functions of brain

To understand major parts of brain

To get idea about brain diseases

Brain

Your brain is a major organ that regulates everything you do and who you are. This includes your movement, memory, emotions, thoughts, body temperature, breathing, hunger and more. There are a lot of complex parts of your brain that work together to help you function. Since your brain is always working, conditions are common.

Contents

Overview

Function

Anatomy

Conditions and Disorders

Overview

The layers, lobes and main parts of the human brain

The main parts of the human brain, including the layers and lobes.

What is the brain?

Your brain is a complex organ that regulates everything you do, like your senses, emotions, thoughts, memories, movement and behavior. It even controls body processes you don’t have to think about, like your breathing, body temperature and your heart rate. Everything that makes you uniquely individual comes from your bra

Your brain is made up of many different parts, each with its own job. But they all work very closely together. This system works by sending and receiving information between nerve cells (neurons) that make up your brain. It then translates this information into a language that your body can understand, so you can function as expected.

Your brain connects to your spinal cord. They make up your central nervous system (CNS).

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Function

What is the brain’s function?

Your brain is responsible for the following functions:

Automatic behaviors like breathing, heart rate, sleep and temperature control

Fight-or-flight response (stress response)

Keeping your organs working as expected

Memories and emotions

Movements (motor function), balance and coordination

Sensory processing (vision, hearing, smell, touch and taste)

Speech and language

Thoughts and decision-making

Your brain’s job is to send, receive and process signals sent through your central nervous system. These signals are messages that carry information from your five senses (sight, smell, sound, touch and taste). Your brain also identifies signals from inside of your body, like pain, temperature or how fast your heart is beating. It interprets or translates this information so you can understand and associate meaning with what goes on around you.

When does the brain stop developing?

The majority of your brain development happens between birth and your teenage years. But your brain needs time to mature. It’ll continue this process through your mid to late 20s. One of the last parts of your brain to develop and mature is the prefrontal cortex. This part of your brain helps you make decisions, prioritize tasks and regulate your emotions.

Anatomy

What are the main parts of the brain?

Your brain has three main parts:

Cerebrum. Your cerebrum interprets your five senses. It regulates conscious actions that require thinking, like your speech, memory, behavior, personality, movement, reasoning and judgment. It’s the largest part of your brain, divided into two halves: the left and right hemispheres. The two halves connect by nerve fiber bundles (white matter) called the corpus callosum.

Cerebellum. Your cerebellum maintains your balance, posture, coordination and fine motor skills. It’s a small, half-circle shape that’s located in the back of your brain around your brainstem.

Brainstem. Your brainstem regulates many automatic body functions. You don’t consciously control these functions, like your heart rate, breathing, sleep and wake cycles, and swallowing. Your brainstem is in the lower part of your brain. It connects the rest of your brain to your spinal cord.

A bony structure called your cranium surrounds your brain. Your cranium is part of your skull. Your brain floats in a liquid called cerebrospinal fluid (CSF). All the bones of your skull and CSF protect your brain from injury.

Between your brain and skull, you have three layers of tissue called the meninges:

Dura mater. The outermost layer lines your cranial vault.

Arachnoid membrane. The middle layer has a thin layer of tissue that covers your entire brain.

Pia mater. The innermost layer contains blood vessels that run into your brain’s surface.

Your brain has 12 cranial nerves. Nerves carry messages by sending electrical impulses back and forth between your brain, organs and muscles. Information from your body passes through your nerves to your brain and from your brain to the rest of your body.

Other important parts of your brain include:

Amygdala. Part of your limbic system and located in your temporal lobes, it helps you regulate your emotions, especially fear.

Basal ganglia. Deep within your cerebrum, these structures regulate your movement.

Hippocampus. This small structure in your temporal lobes is responsible for your memory and learning.

Thalamus. Sitting above your brainstem, this is the switchboard to your central nervous system. It relays sensory information to your cerebral cortex from the rest of your body.

Hypothalamus. Just below your thalamus, the hypothalamus regulates hormones and autonomic functions like hunger and thirst.

Pituitary gland. Below the hypothalamus, the pituitary gland regulates hormone activity.

Pineal gland. In the back of your corpus callosum, this gland regulates your sleep and wake cycle

What are the lobes that make up your brain?

Your cerebrum is split into hemispheres (sides). On each side, there are four lobes (sections) with different functions:

Frontal lobes. Located in the front part of your brain, behind your forehead, this is the largest lobe. It controls voluntary movements, social understanding, thinking and learning, and more.

Occipital lobes. Located in the back of your brain, this lobe allows you to process and interpret visual information from your eyes.

Parietal lobes. Near the upper back of your brain, this lobe receives and interprets signals from other parts of your brain so you can understand your environment and the state of your body.

Temporal lobes. On the side of your head near your ears, this lobe helps you retrieve memories and understand language and emotions.

What is the gray and white matter in the brain?

There are two tissues in your brain known as gray and white matter. They differ based on their color and function:

Gray matter is the darker, outside section (the cerebral cortex) that helps you with your day-to-day functioning., like muscle control, using your senses, remembering something, experiencing emotions and speech.

White matter is the lighter section below the gray matter that sends signals to different parts of your central nervous system to help you function.

You can compare gray matter to a computer. White matter is the cables for the computer.

How many brain cells does a human have?

There are close to 86 billion nerve cells (neurons) in the human brain and an equal amount of non-neuronal glial cells:

Neurons send and receive electric and chemical signals.

Glial cells help maintain your brain, form myelin (a fatty, protective substance found in white matter) and provide nutrition to your brain.

How much does the human brain weigh?

An adult human brain weighs, on average, about 3 pounds. When you’re born, it weighs about 1 pound and grows to about 2 pounds through childhood. The weight of your brain varies based on your sex and body size.

Conditions and Disorders

What conditions can affect the brain?

Since your brain is responsible for almost everything you do, brain conditions are common. There are many types of brain disorders and conditions that vary in severity. Some of the most common include:

Alzheimer’s disease and dementia

Amyotrophic lateral sclerosis (ALS)

Autism spectrum disorder (ASD)

Brain bleed

Brain tumor

Concussion

Depression

Epilepsy

Multiple sclerosis

Parkinson’s disease

Stroke

Traumatic brain injury

Depending on the type of condition, you may be born with it or acquire it. Signs and symptoms vary and could affect your mental health, movement, memory, thinking and speech, among other important functions.

A note from Cleveland Clinic

Your brain has a really important job, and it often goes unnoticed. Right now, you’re using your brain to read this text. At the same time, your brain is running your body’s motor to keep you breathing, make sure your eyes are blinking and remind you that it’s time for a snack.

Since your brain is constantly working to keep your entire body functioning, it’s important that you take steps to keep it healthy. You can do this by meeting up with friends and socializing, completing puzzles or meditating to reduce stress. The usual habits like eating nutritious meals and getting regular exercise and enough sleep are helpful, too.

Review questions

Mention functions of brain

What are the severity of brain

FUNCTIONS OF HEART

LEARNING OUTCOM

To understand structure of Heart

To understand Function of Heart

Understood the parts of heart

The functions of the heart are to pump blood and oxygen around the body and deliver waste products (carbon dioxide) back to the lungs to be removed.

The heart consists of four chambers, each separated by valves which direct the flow of blood.

Conditions affecting the heart include coronary heart disease, angina, heart attack, heart failure, heart valve diseases, abnormal heart rhythms including atrial fibrillation, heart inflammation, congenital heart disease (present from birth) and rheumatic heart disease.

On this page

The four chambers of the heart

The heartbeat

Blood vessels of the heart

Common heart conditions

Symptoms of heart disease

Where to get help

Your heart is a vital organ. It is a muscle that pumps blood to all parts of your body. The blood pumped by your heart provides your body with the oxygen and nutrients it needs to function.

Your heart is about the size of a clenched fist, and weighs between 300 and 450 g. It lies in the middle of your chest, behind and slightly to the left of your breastbone.

If you are of average body weight and size, your body contains about five litres of blood, all of which passes through your heart every minute or so. When necessary, such as during exercise, your heart can pump up to four times that amount per minute.

The four chambers of the heart

Your heart has a right and left side separated by a wall called the septum. On each side of the wall, there is a small collecting chamber called an ‘atrium’, which leads into a large pumping chamber called a ‘ventricle’. There are four chambers: the left atrium and right atrium (upper chambers), and the left ventricle and right ventricle (lower chambers).

The right side of your heart collects blood on its return from the rest of your body. The blood entering the right side of your heart is low in oxygen. Your heart pumps the blood from the right side of your heart to your lungs so it can receive more oxygen.

Once it has received oxygen, the blood returns directly to the left side of your heart, which then pumps it out again to all parts of your body through an artery called the aorta.

Blood pressure refers to the amount of force the pumping blood exerts on arterial walls.

The heartbeat

Each atrium is connected to its ventricle by a one-way valve. The valve on the right side of the heart is called the tricuspid valve, while the valve on the left side is called the mitral valve.

The familiar 'lub-dub' sound of the heartbeat is caused by the rhythmic closing of the heart valves as blood is pumped in and out of the chambers.

The heart rate is regulated by a special cluster of cells in the right atrium, called the sinus node. The sinus node prompts the upper chambers to contract first. Then, an electrical impulse is sent to a second cluster of cells (the atrioventricular node), which is found between the upper and lower chambers of the heart. The electrical impulse causes the lower chambers to contract. At rest, your heart beats approximately 60 to 100 times a minute.

Blood vessels of the heart

The blood vessels of the heart include:

coronary arteries – like any other organ or tissue, the heart needs oxygen. The coronary arteries sit on the surface of the heart and supply the heart muscle with blood and oxygen

aorta – this is the largest artery in the body. Oxygen-rich blood is pumped into the aorta from the left ventricle. The aorta divides into various branches that deliver blood all around the body

pulmonary arteries – blood low in oxygen is pumped by the right ventricle into the pulmonary arteries that link to the lungs

pulmonary veins – the pulmonary veins return oxygen-rich blood from the lungs to the left atrium of the heart

venae cavae –blood low in oxygen is delivered to the right atrium by two veins. One (superior vena cava) carries blood from the head and upper torso, while the other (inferior vena cava) carries blood from the lower body

Common heart conditions

There are many different types of heart conditions. Some common heart conditions include:

coronary heart disease – coronary heart disease happens when the coronary arteries supplying blood to the heart muscle become blocked or narrowed by a build-up of fatty deposits (plaque). Coronary heart disease can cause angina and heart attacks.

angina – a type of chest pain caused by a build-up of plaque in the coronary arteries. Part of the heart muscle may not receive enough blood and oxygen. This causes chest tightness, discomfort or pain.. Pain or discomfort may also be felt in the arms, neck, jaw, shoulders or back

heart attack – happens when something, usually a blood clot, cuts off the flow of blood to the heart. Without oxygen and nutrients, the heart muscle begins to die. A heart attack may not be fatal, especially if you receive immediate medical treatment, but it can still cause lasting damage to the heart.

heart failure – a condition where the heart is not able to pump blood and oxygen around the body as well as it should

abnormal heart rhythms (arrhythmias) - a range of conditions where there is a fault in the heart’s electrical system, which affects your heart’s pumping rhythm. Atrial fibrillation is the most common type of abnormal heart rhythm, where the heart beats irregularly and often fast

heart valve disease – when the heart valve or valves don’t open or close properly. Damage to the heart valves can make it harder for the heart to pump blood around the body

congenital heart disease – problems with the heart or blood vessels that you are born with. Problems include the blockage of blood flow inside the heart or blood vessels, abnormal flow of blood within the heart, or the heart may not have developed properly.

heart inflammation – includes pericarditis (inflammation of the outer lining of the heart) andand myocarditis (inflammation of the heart muscle)

rheumatic heart disease - damage to the valves in the heart that develops after acute rheumatic fever. Rheumatic heart disease affects more Aboriginal and/or Torres Strait Islander Peoples, Maori and Pacific Islander Peoples, and those who have migrated to Australia from low to middle income countries where this disease remains common.

Symptoms of heart disease

‘Heart disease’ is a broad term for different conditions affecting the heart.

Different heart conditions can have different symptoms.

It’s important to be aware of the following symptoms, which can be a warning sign of a medical emergency, including a heart attack:

Chest discomfort or pain. This can feel like uncomfortable pressure, aching, numbness, squeezing, fullness or pain in your chest. This discomfort can spread to your arms, neck, jaw, shoulders or back. It can last for several minutes or come and go.

Shortness of breath or difficulty breathing (with or without chest discomfort)

Racing heart or a feeling of your heart pounding or fluttering in your chest (palpitations)

Light headedness, dizziness, feeling faint

Feeling anxious

Nausea, indigestion, vomiting

Sweating or a cold sweat.

If your symptoms last more than 10 minutes, are severe or getting worse, call triple zero (000) immediately for an ambulance.

Where to get help

In an emergency, call triple zero (000) for an ambulance. Don’t drive yourself to hospital.

Your GP (doctor).

Cardiologist.

References

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Acute rheumatic fever (ARF) and rheumatic heart disease (RHD)

Stopping episodes of recurrent ARF can prevent rheumatic heart disease (RHD).

Amyloidosis

A person with amyloidosis produces aggregates of insoluble protein that cannot be eliminated from the body.

Anaemia

When a person is anaemic, the red blood cells have to work harder to get oxygen around the body.

Aneurysm

An aneurysm may have no symptoms until it is either very large or it ruptures.

Aortic stenosis

Aortic stenosis may be congenital (present from before birth), but is often diagnosed during teenage years.

Review questions

What is the function of heart

How heart pump blood

Mention two heart diseases