Did you know that the human body’s made up over 100 trillion cells has 206 bones 320 pairs of muscles and 5 vital organs.

It is a remarkable biological machine with so many systems working together to allow for life movement cognitive function, growth, repair, reproduction and so much more. These systems include the central nervous system the circulatory system, the respiratory system, the digestive system, the immune system, the reproductive system, the skeletal structure and musculature. The human body is made up of a head, neck, torso, two arms and two legs the average height of an adult human is about five to six feet the human bodies made to stand erect to walk on two feet to use the arms to carry and lift and has opposable thumbs.



The Human brain is the central command system for the whole body. It’s a mass of about one hundred and eighty billion neurons neurons have multiple synapses that create a network of over 100 trillion connections tiny electrical currents and chemical messengers send information around the brain at 268 miles per hour. There’s enough electrical current in your brain to power an LED light bulb about 12 to 25 watts. An adult brain weighs about three pounds and if you hold your fists together with your thumbs touching that’s about the size of your brain the folds in the brain increase its area of size. A baby’s brain is nearly smooth while an adult brain looks a lot like a walnut with lots of little folds. Brain tissue needs both oxygen and glucose to function it uses 20% of the bloods oxygen and glucose and brain cells begin to die after around 5 minutes of no oxygen. Different parts of the brain have different functions. The main structure in the brain are the frontal lobe, the parietal lobe, the occipital lobe, the cerebellum, the temporal lobe and the brainstem. The brain connects to the rest of the body through the spinal cord which branches out into similar and smaller nerves throughout the body. The nervous system is the body’s wiring system it transmits messages to and from the brain that are both a voluntary and involuntary. The involuntary messages are things we can’t control like a heartbeat, feeling pain and reflexes.V oluntary messages are things we are aware of like reaching for a pen or speaking. The pins and needles sensation happens when a nerve is compressed and the signal is disrupted. Injury to nerves can cause permanent paralysis and numbness.  Doctors can perform an MRI a CT or an EEG scan the healthy brain and nervous system needs a varied and healthy diet and lots of vitamin B1, B9, zinc ,calcium, magnesium and vitamin C in particular because the brain is over 70% water it’s very important to drink a lot of water. The study of the brain is called Neurology.



The Heart and the Circulatory system

The Heart is one big pump which is made of muscle fibers. It’s job is to circulate blood around the body so that oxygen nutrients can be delivered to the cells, carbon dioxide can be removed and infections fought. A healthy adult heart beats around 60 to 80 beats per minute. Children’s heart beats are faster around 100 to 120 bpm. The heart has four chambers to pump blood. The oxygenated blood enters the right atrium then into the right ventricle where it goes to the lungs. Once oxygenated it enters the left atrium down into the left ventricle and a big squeeze of the left ventricle pushes blood into various arteries. Blood is transported around the body through blood vessels that are split into two functions carrying oxygenated blood away from the heart and carrying deoxygenated blood towards the heart blood vessels carrying oxygenated blood in order of large to small are called the arteries.Arterioles and capillaries vessels carrying deoxygenated blood in order of large to small  veins and capillaries.There are so many blood vessels in the human body that if you laid them out end to end they would span 60,000 miles. Red blood cells carry oxygen around the body. They’re so small that 2.5 million can fit on the head of a pen. An average adult has about five quarts of blood and the heart pumps 83 gallons an hour or 2000 gallons every single day. It takes around 60 seconds blood to leave the heart circulate around the body and then return back to the heart. The Heart is protected by the ribcage and the sternum and because the heart is a muscle physical exercise helps to keep it healthy and working well so you can live longer. Heart disease is one of the biggest killers in America every single year eating too much fat and animal products can cause cholesterol to build up in the blood vessels and when a blockage occurs it can cause a heart attack. Smoking in excess, alcohol, too much salt, drug abuse, stress and high blood pressure can all lead to heart disease.

Heart attack and stroke

Common signs of a heart attack will include difficulty breathing, a pain in the left arm, a heaviness on the chest, flu-like symptoms sudden pain in the chest or turning blue. Both anxiety and acid reflux can sometimes feel like a heart attack but you should always call emergency services if someone thinks they’re having a heart attack the study of the heart is called cardiology the lungs and respiratory system.


The function of the Lungs is to exchange oxygen from the air to the Bloodstream.  Humans have two lungs side by side but they’re not the same size the left lung is slightly smaller to make room for your heart. Each lung is divided into lobes. The right lung has three lobes and the left lung two .When breathing air enters the respiratory system through the nose or mouth paired in the nose and mucus in the sinuses trap dust and germs and as air travels down the trachea is warmed and moistened. The trachea branches into left and right bronchi.Each bronchus branches into smaller and smaller bronchi, bronchioles and finally into Alveoli. Pair of lungs weighs 2.9 pounds. They have a spongy structure for a lot of surface area for gas exchange. When laid out flat that cover an entire tennis court. The lungs can’t expand and contract on their own. This movement is controlled by the diaphragm under the ribcage and the muscles between the Ribs. The Lung capacity will depend on a personal size fitness and even the altitude where they are on the earth. An average adult male has a 1.5 gallon lung capacity. Most adults breathe 12 to 20 times per minute which amounts to thousand nine hundred gallons of air per day. An average person could hold their breath for about two minutes. The epiglottis is a flap that protects the lungs from food and liquid when we swallow. Coughing and Sneezing is the respiratory systems mechanism for getting rid of irritants like dust and pollen. Asthma is a respiratory condition where the Airways constrict as a result of an irritant and breathing can become very difficult. A person is still able to live with only one lung but their ability to do physical exercise is limited because the lungs are the only organs that exchange oxygen and carbon dioxide.

It is very important to keep them healthy and clean. Smoking and air pollution damages lung tissue and leads to lung diseases like cancer and emphysema the study of lungs is called Pulmonology.



The digestive system

The purpose of the digestive system is to break down food into components. The body can use glucose for energy, protein for building and repairing cells and extracting vitamins, minerals and amino acids a cell function.

The digestive system begins with the mouth where teeth mash food, the tongue moves it around and saliva lubricates there and begins digestion upon swallowing. Food travels down the esophagus and into the stomach where acid kills bacteria and breaks down food further. The liquid food then enters a small intestine where the acid is neutralized and enzymes break down fat, protein and carbohydrates for absorption by tiny hairs called villi. After traveling through 20 feet of small intestine through passes into the large intestine or colon where water is absorbed in bacteria very extract and manufacture important vitamins. A colon is around 5 feet long. The final stop is directon where in the adjustable food matter and gas are passed through the anus as feces and flatulence. The study of the digestive system is called Gastroenterology.

The stomach

The Stomach is a muscular sac with hydrochloric acid to protect yourself from the acid. It has a mucous lining an adult stomach can hold not 0.5 gallons of food and liquid. There are nerves in the stomach that tell your brain when it’s empty or when it’s full vomiting is the body’s way of rejecting food and liquid that is bad for the stomach. The small intestine after leaving the stomach partially digested food called chyme enters the small intestine. The small intestine is 16 to 20 feet long in an adult human being. It’s called small because it is narrow about the thickness of your thumb. In the small intestine the gallbladder secretes gall to break down fats and the pancreas secretes insulin to manage blood sugar levels. Inside the small intestine millions of tiny hairs called villi increase the surface area so that nutrients can be absorbed into the bloodstream. Food moves along the intestine through like contractions called Peristalsis.  The main job of the colon is to reabsorb most of this fluid so things move slowly. They can take 18 to 24 hours for food to leave your digestive system. The large intestine hosts billions of beneficial bacteria called gut flora or the microbiome. They manufacture and extract certain vitamins in fermentation by the gut. Bacteria creates gas. Fiber is very important for a healthy gut.

Diseases and Disorders of the colon include Irritable bowel syndrome and Colon cancer.

The immune system the human immune system is the military of the body it’s comprised of white blood cells and antibodies. These seek out and destroy foreign bodies including viruses, bacteria, parasites, fungi and abnormal cells. White blood cells are created in bone marrow and carried in the blood and lymphatic system.  A single drop of blood can have 25,000 white blood cells. When white blood cells attack they envelope the pathogen and destroy it. The remains are carried away into the lymph system. The immune system is able to remember infections and fight them off better through antibodies. Vaccines work by stimulating the immune system to create antibodies for specific disease by polio or measles without actually getting it the person is then protected against that disease. It’s important to get vaccines even if the disease is no longer common because of the herd Immunity effect which is a form of immunity that occurs when the vaccination of a significant portion of a population or herd provides a measure of protection for individuals who have not developed immunity. Stress, smoking, lack of sleep, poor diet and diseases like HIV and AIDS can weaken the immune system making you vulnerable to infection, allergies and allergic reactions are false alarm and the result of an overactive immune system. Allergic reactions can cause anaphylactic shock and swelling where a person can’t breathe. Autoimmune diseases like lupus mean that the immune system attacks his own body and not just the germs.

Being too clean isn’t always a good thing without germs to develop antibodies the immune system doesn’t develop or learn what’s harmful and what’s not. The study of the immune system is called immunology.


The Reproductive system

The reproductive systems function is to create new life so that genes can be passed along to future generations.

A woman’s reproductive organs include a pair of ovaries that form eggs and the uterus where baby States until it’s ready to be born.

A man’s reproductive system includes the testes where sperm is formed and a penis for delivering sperm into the uterus. When an egg and sperm cell fused as a result of sexual intercourse conception occurs and the baby begins to grow. The gestation period for a human baby is 40 weeks or nine months and during which it grows from a few cells into a fully formed baby. Humans can reach reproductive age at around 13 years old with good nutrition. Puberty is arriving sooner with every generation. A woman produces one egg every 28 days. If it’s not fertilized menstruation sheds the uterine lining. A man’s ejaculate can have as many as 300 million sperm cells.

Sexually transmitted diseases include HIV/AIDS, chlamydia syphilis and HPV which can cause cervical cancer. The most common cancers of the reproductive organs include ovarian and cervical cancer and women and testicular and prostate cancer in men. The study of women’s reproductive organs is called Gynecology and the study of men’s reproductive organs is called Andrology.

The skeleton humans are vertebrates means they have a backbone or a spinal column. An adult skeleton has 206 bones. A baby has 300 bones of and some fuse together as they grow. Half of these bones are in your hands and feet. The largest and strongest bone in the body is the femur and the smallest bones are in the middle ear where bones meet is a cushion of cartilage bones are held together by tough ligaments. Bones consists of hard bone which gives structure spongy bone which is still hard but has more air pockets and bone marrow where blood and stem cells are produced. A healthy human bone come with stands three times your body weight in force arm and leg fractures and breaks are more common in growing children because the growth plates there are vulnerable when a bone fractures or breaks is able to repair itself special bone cells will surround the injury former callous breakdown the injured bone and replace their even healthy bones are continually maintained by the body. Bone is made mostly of calcium for strength and collagen for flexibility which is why it’s important to eat lots of green leafy vegetables. An adult reaches their full height in their 20s and maximum bone density in their 30s. We can view the bones of a human body by using an x-ray. Diseases of the bone include Osteoporosis and Arthritis and the study of bones is called Osteology.



The human body is incredibly flexible and able to move in thousands of ways. All thanks to 320 pairs of skeletal muscles. Muscles are made where muscle proteins form strands of muscle fiber. These then form bundles which make up largest skeletal muscles. Skeletal muscles occur in pairs. When one muscle group contracts the opposing pair relaxes for example to raise your forearm your bicep contracts and your tricep relaxes. Bones can’t move by themselves that’s the work of your muscles where ligaments connect bones to each other tendons connect muscle to burn electrical signals which are carried by nerves to and from the brain will instruct your muscles on how to contract or relax the muscles are responsible for creating body heat. They twitch so slightly you don’t even feel it.

This generates enough heat for metabolism. Your muscles are built and repaired when tiny tears in the muscle fiber are filled in with new muscle cells and the muscle needs oxygen and glucose to function and protein to repair and regenerate. The body has three kinds of muscle skeletal for movement cardiac for the heart and smooth for the digestive system. Around 40 percent of a person’s weight is comprised of their muscle mass is also denser than fat which is why two people at the same size can have different weights. The largest muscle in the body is the gluteus maximus and your jaw muscles are the strongest they can exert 200 pounds of force the study of muscles is called Myology.

we hope you enjoy these interesting facts about the human body