Anatomist 2009Anatomist 2009 Yearbook

One of the most incredible and effective systems in the human body is barely noticed by most people. It is the immune system and what it does is truly incredible.

Our bodies are under constant attack and we barely notice. Everyday millions germs and other harmful organizations attack our bodies and the immune system successfully fights them off. Indeed the immune system probably keeps us alive.

How the Immune System Works

The immune system provides what military strategists would call a layered defense. Just as a fortress might have several defenses including walls, landmines, barbed wire, machine gun nets and armed sentries, the immune system has several defenses.

Indeed anatomists say that the body has two different immune systems the innate immune system and the adaptive immune system. The innate immune system is composed of simple barriers that work like the walls of a fortress. They keep out attackers but not much more.

Innate Immune Sytem

Components of the innate immune system include inflammation which includes increases the flow of blood to infected areas. The innate immune system reacts to any sort of infection and the presence of foreign substances. Most allergies are caused by overreactions of the immune system to foreign substances.

The body’s next line of defense is the white blood cells or leukocytes. These cells act like soldiers they identify, track down and destroy invaders. The leukocytes automatically attack any intruder so they function much like an attack dog. A class of leukocytes called phagocytes actually patrols the body looking for intruders.

Adaptive Immune System

Humans like other mammals have what is called an adaptive immune system. This immune system creates defenses against harmful organisms and remembers them. This way it can activate a particular defense whenever a germ or virus is detected.

The adaptive immune system is the key to vaccination. In a vaccine, doctors inject a small less potent amount of a virus into the body. The hope is that the body will remember the virus and develop a defense against it. Then trigger this defense whenever a person is exposed to the virus.

Already this tinkering with the immune system has led to the elimination or near elimination of many deadly diseases including small pox and polio. In the future it might be possible to use this effect to protect the body from most infections and many kinds of cancer.

Except for birds, people probably have the best vision because of their highly developed eyes. Even though the eye can discern complex images it is basically just a light sensor. In primitive animals all the eye does is sense light while in mammals and birds it can send images to the brain.

This is why people have such a hard time seeing in the dark, all vision is based upon light. Take away the light and you will take away the vision.

The human eye actually functions much like a camera does. Just as in a camera light passes through a lens and gets focused upon the optic nerve where it is converted into data that is sent to the brain. This makes the eye the original digital camera.

The lens is located inside the pupil of the eye and covered by the cornea. The pupil functions like a hole which allows light to enter the eye.

Like a modern digital camera the eye can adjust itself to light conditions. It can also focus like a camera does to help long distance vision.

The peripheral retina is the part of the eye responsible for focusing vision. When there is something wrong the retina sight can be limited and even damaged.

Just like a camera the eye can actually wear out as people get older the lens gets less pliable. This makes it harder for a person to focus on objects close to them. That condition explains why many older people have to use reading glasses.

The eye actually contains photoreceptors that can detect light and respond to reactions. These can protect the eye from bright lights and other problems.

Your tears actually perform a very function they lubricate the eye and help it function properly. The eye also contains tiny blood vessels that provide it with nutrients and keep it functioning.

The eye could be one of our most important organs because without it human civilization would be impossible. Without eyes people wouldn’t be able to read, design and construct buildings and machines, drive, fly plant crops or navigate the oceans. After our minds the eyes could be our most important asset.

The center of the digestive system is the stomach which is also one of the most important organs in the body. The stomach is crucial to your survival because it is where food digestion begins.

A popular misconception is that food is digested in the stomach. In reality digestion begins in the stomach and is completed in the intestines. The stomach contains acids that break down food and enzymes that digest proteins.

Instead the stomach’s major purpose is to store food until the intestines have the room to digest it. This means the stomach is more of a storage sack than a digestion center.

Food or bolus reaches the stomach from the esophagus. The bolus stays in the stomach until it is transformed into chime or partially digested food which can be digested in the intestine. The process of making chime can take anywhere from forty minutes to a few hours.

When the chime has been properly broken down it is moved through the pyloric sphincter and into the small intestine where the process of extracting nutrients from food is completed.

In an adult human being the stomach can normally hold up to three liters of chime. The stomach contains hydrochloric acid which is powerful enough to dissolve human flesh. This acid is used to kill harmful bacteria and germs that maybe consumed with the food.

The four parts of the stomach are the cardia which is where food enters the stomach, the fundus or upper portion of the stomach, the body or corpus the largest area of the stomach and the pylorus which is where the chime leaves for the intestines.

The stomach is actually composed of muscles that move food in and chime out. There are also several glands in the stomach which manufacture and secrete hormones, acids and other chemicals needed in the digestion of food.

The stomach also acts as a nutrition sensor by using glutamate receptors to test the nutritional value of food. This information is passed onto the brain which uses it to determine which foods should be eaten and which shouldn’t.

Despite the presence of acids the stomach can become infected. Peptic ulcers, gastritis and even stomach cancer are caused by infections in the stomach.

After the brain, the human heart is the most important organ in the human body. The heart keeps a person alive by circulating blood throughout the human body.

The heart’s importance has long been recognized, the Ancient Romans thought that the heart was a furnace that powered the human body. We now know that the heart is actually a pump that moves about ten liters of blood through the body every minute in the average person.

A healthy heart should beat or pump about 72 times a minute. The number of heart beats will determine how much blood the heart is circulating. In a very healthy person such as an athlete or a commando the heart can actually up to 20 liters of blood a minute.

The heart actually has two pumping chambers or ventricles. Each ventricle normally pumps about five liters of blood a minute. The right ventricle performs the important task of pumping blood to the lungs to be oxygenated. The left ventricle pumps oxygenated blood throughout the body.

Every cell in the body depends upon the heart. In very healthy people the blood carries a lot of oxygen to all the cells. In addition to carrying oxygen to cells the blood brings them nutrients and takes away waste products.

Despite its power the heart is actually quite small it is about the size of a fist and it normally weights between seven and 15 pounds. Even though it is small the heart is able to pump about 7,571 liters or 2,000 gallons of blood everyday.

The way the heart works is quite simple it contracts and expands every time it gets an electrical impulse from the conduction system. This is the heart beat and it is what keeps you alive. When you see paramedics or doctors using electric shock on a patient they are trying to mimic this process and get the heart going again.

Heart disease and heart attacks are now among the leading cause of death. Cardiac or heart surgery is now among the most important specialties performed at many hospitals.

Doctors can already perform a wide variety of procedures on the heart including heart transplants. In the future, it could be possible for doctors to grow new hearts and heart valves outside the body to replace defective ones. This could extend our lives and make us much healthier.

The human body is one of the most complex structures and to date, numerous studies have been conducted to better understand the magic-like functioning of the body and how it came about. Human Anatomy is the science and study of various human organs, their functions and their inter-connectivity. One branch of human anatomy is that of the Digestive System.

The Digestive System in a human being is the process of food conversion into smaller particles that can easily be absorbed and used up by the human body. The reason for this is that the food that we consume in our daily life is not in a readily usable form by our body. The digestive system is basically made up of a track of long and twisting tube that connects various organs. It starts with the mouth, followed by the esophagus, the stomach, small intestine, large intestine- which is also called the colon-, rectum and finally the anus. In the process of digestion, food is broken down into smaller particles, mixed with various digestive juices and is then used up, along with the waste product out of it being discarded from the body.

The first step is the mouth. When we eat and chew food, the first type of digestive juice which is the saliva, mixes with our food in order to lubricate it, to convert the starch into sugar and to finally pass it into the esophagus. The esophagus is an elongated pipe like organ that connects the mouth to the stomach. The stomach performs 3 basic functions which include storing food, processing it and transferring it into the small intestine. Once the food reaches the stomach, it is mixed with various gastric juices including water, Mucin (which lubricates the food) and Hydrochloric acid (which dissolves acidic salt). These juices contain enzymes which are responsible for speeding up chemical reactions in a human being. After this process in the stomach, the food turns into a semi-digestible form called the Chyme. The Chyme is a thick, semi-fluid mass of food.

The semi-digested food is then transferred into the small intestine. This is where the final digestion of the food takes place. In this, the Chyme is further broken down to even smaller molecules. It is mixed with bile (which is secreted from the liver), pancreatic juices (which are secreted from the pancreas) and other intestinal juices. From the addition of these, the food finally turns into a usable form by the body. Thus, food is absorbed by the body in the Ileum which is the final part of the small intestine.

The food that we eat is not absorbed and used in its entirety. Some part of it, after the digestion process, is found to be waste. That unabsorbed part is pushed forward into the large intestine from the small intestine. This passes into the rectum and finally the waste product passes out through the process of secretion from the rectum.

The above is a very simplified version of the whole digestive system. If one goes into the depth of it, each different digestive juice performs a different function and is also composed of varying types of enzymes. In addition to this, different types of food take different amounts of time to get digested. Carbohydrates, being the simplest of forms, take the shortest time to digest. On the other hand, fats take the longest time to break down. This is how the food we eat actually turns into energy for our body.

We are very amazing creatures. We often forget about that when we look at other animals in the natural word because we only see the odd things that they do or have. If you were an average man and six foot tall and weighed 200 pounds how would you fit in?

Think for a moment if you were a dung beetle. You would be a little stronger. In fact, you would be able to lift 170,000 pounds by yourself. That is a lot but the down side is what you have to eat. You could be a frog. You would be able to leap over 50 feet but what are you going to do with an 18 foot tongue? If you could fly like a bat you had better be good because you are going to need to catch and eat over 80 Big Mac’s a night to keep up your weight. We can do none of those things but we are amazing in are own way.

Our bodies are vast chemical reactors that also serve as mining machines. Mining machines, you ask?

Yes, we eat plant matter because it has leached valuable chemicals we need out of the soil. Even when we eat meat we eat meat that ate plants. We need all those elements that have come from the ground even when they are in small amounts. Take magnesium, for example. Our bodies have to have it to work. It does not take much but is necessary in over 230 biochemical reactions that happen in us every day.

Next, think about how our bodies try to conserve energy when it thinks it needs to. When your body burns more calories than it takes in it starts to convert fat into energy. Only as a last resort will it burn muscle. Long before that the body will notice what is going on and a biochemical reaction occurs that lowers your metabolism rate to make that fat last as long as it can.

Then you have temperature. If you are sick you get a fever. This is the bodies way of trying to kill off the virus by becoming an unpleasant place to live. When you get cold, however, your body starts to shiver. It is trying to produce heat to keep the core of the body warm. If it gets even colder the blood stops flowing to fingers and toes to save heat and sacrificing a few digits. The colder you get the more circulation will get cut off to keep the heart going. The body tries to save itself.

What are bodies do every day in an effort to keep us alive is amazing. It works with how we are built and how we are designed. Man can not make a machine as complex as we are.

The cycle of respirations contains two major processes; External breathing and Internal (cellular) respiration. In the process of internal respiration, energy (carbon dioxide) is produced by the oxidation of glucose and similar other molecules. The process of getting oxygen from air and then returning carbon dioxide is call external respiration.

Nose and mouth together are called the respiratory tract as external respiration starts from it. The windpipe is called trachea. It starts from the neck goes to thorax and then divides in to two right and left branches called bronchi. Each bronchi then enters right and left lungs respectiThe Anatomy of Respirationvely. They further break up into smaller branches called bronchi and bronchioles. These small branches then ends in small air sacs called alveoli. Alveoli are the place where gaseous exchange actually takes place. Further division of lungs in to right and left takes place. Left one is smaller in size and is responsible for the accommodation of the heart. Further division is into lobes. Left side has two lobes and right has three. The supply of deoxygenated blood and removal of oxygenated blood is the collective responsibility of pulmonary arteries, bronchi and veins. Supplying lungs the oxygenated blood is the responsibilities of veins and bronchial arteries. However, all pulmonary arteries, bronchi, bronchial arteries, veins and lymphatic use hilum (lung’s root) for entry and exit of lung for these activities. In heavy smokers, lung substance and lymph nodes are found to blacken by soot particle and in case of non-smokers by the pollution around. The lobes in the lung are further divided into pyramid shaped bronchopulmonary segments.

What’s the breathing mechanics? When the air is taken in, the ribcage moves up and out. This is due to the contraction of intercostals muscles. Within the thorax, the simultaneous downward movement of the diaphragm creates negative pressure. As a result the pleural membrane in the thoracic walls hold lung. This negative pressure lets air rush in through upper and lower air tracts. This shows that the lung’s natural elasticity is basis for actual respiration cycle.

Now, let’s talk about the physiology of gas exchange. As discussed above, the actual gaseous exchange takes place in alveoli. Each lung has millions of them. The deoxygenated blood is carried away from pulmonary artery with the help of huge capillaries network with which each alveolus is meticulously attached. Thin walls of alveolar and capillary lets the “passive diffusion along concentration gradient” which allows gaseous exchange to take place rapidly. The lower concentration in alveolus lets the CO2 to move in. furthermore, oxygen and the continuous blood flow in capillaries prevent blood saturation allowing maximum absorption in membrane.

Human Anatomy is a complicated subject, as it involves all the organs of the human body. Most of the students of science, especially those studying medical, find the subject of Anatomy very tough to learn and memorize, and hence most of them end up getting bad grades in the subject. But there are simple ways that medical students can adopt, which will make learning of Anatomy comparatively easy for them.

In terms of learning aids, there are a lot of varieties available including books, journals, and online sources, etc. These do help in learning other subjects but when it comes to human anatomy, these cannot be termed as the best source to learn. The question now is what is the best way of learning human anatomy? Human Anatomy being the tough subject that it is, the easiest way to learn it is through a technique referred to as Anatomy Mnemonics.

Mnemonics may be defined as a system of memorization techniques or memory aids. By the use of this method, commands that can be easily understood by the human memory processing system are made. Human processes any data available to them in three stages namely:

Encoding – In this stage the memory receives and interprets data,

Storage – It is the second stage where some part of the data received is stored in the memory

Retrieval -The third and the final stage is retrieval that is remembering the data when required.

Our mind is more receptive to simpler words or things that aren’t very complicated in nature. Mnemonics is designed in a way that helps in finding easier ways to retain stuff in our memory. If one gets in the habit of using mnemonics to memorize stuff, it is surely going to benefit them.

So for all the students out there, start practicing mnemonics and it will actually help you so much so that you won’t have to look through the bundles of notes and stack of books just to revise a few basic concepts. Anatomy mnemonics are even a very good option for professional doctors who wish to brush up their memories. It may work well even for those who want to continue independent studies in the field of anatomy. So if we cut the long story short, Anatomy mnemonics are just the best way for anyone who wants to learn Anatomy and excel in it.

Ever thought about the great flexibility in movements and the mobility that the human body has? Thanks to the muscular system that extracts nutrients from the food we intake and converts them into energy that could be utilized by the muscles to facilitate the movements of the different parts of the human body.

The body muscles could be divided into three different types, namely; cardiac, smooth and skeletal muscles. Each set of muscles has its own tasks and functionalities and takes care of different regions of the body. The cardiac muscles are only found in the heart. These muscles don’t work independently and are controlled by the nervous system. These tissues are the building blocks of the walls of the heart. These muscles control the spontaneous reflexes of the body. Can you imagine what would happen if your heart forgets to beat and you have to remind it every time? Scary thought right? The heart beats even when you are sound asleep. These are all the wonders of these muscles.

The smooth muscles work independently like cardiac muscles and are found in the stomach, throat and intestine, and even the digestive tracts are made up of these muscles. They are controlled by the nervous system as well.

The muscles that make up to 40% of the overall body weight are the skeletal muscles. These are voluntary muscles and can be controlled by human themselves. Though some of the contractions of these muscles are automatic, we still can control a part of it. These muscles are responsible for the overall external movement of the body. They are large in size, as can cover up to some feet.

There are more than 630 skeleton muscles in the human body that are divided into a large number of motor units. The working, control and balance of these motors are guided by the cerebellum region of the brain. Skeletal muscles in the face control the facial movements. The muscles in the neck allow the movement of the head. Shoulder muscles also play a vital role. All the movements like picking up things, throwing a ball and stretches are all guided by the group of muscles present in this part of the body. If you want that huge bulky look of a body builder, your focus should be the arm muscles. These are the ones most affected by exercising and weight lifting. The muscles in the abdomen help to move your waist, bend down, lie down and move your body in different directions.

The wonders of muscular anatomy cannot be neglected. The effortless moves that we make and the spontaneous actions of our body parts are all the marvels of this bunch of muscles.

Human Anatomy revolves around all the organs and their functions in our body. Each organ has a specified function and deviation from the routine functions results in making the person ill. People through their previous experiences have certain myths about human anatomy, specifically related to our digestive system. We will talk about some facts related to our digestive system in order to burst some myths that prevail in our minds.

Most of us considers digestive system as an organ that has a comparatively simpler function as compared to heart and brain. In our understanding, digestive system simply digests the food that we take in every day and lets it out in the form of excretory waste from our body. Obviously, some of us would know a bit more about the digestive system, but we will be discussing some interesting facts about the digestive system that most of us won’t be very familiar with, which will surely enhance our understanding of the digestive system. These facts include the following:

• Interesting Fact -1: In our body the food and the liquids we take are mixed together with digestive juices until they are tiny enough to be absorbed by our body. Every single day digestive system produces around 11.5 liter of such juices and it’s very interesting to know that our body consumes most of it and only 100mls approx of the entire amounts is sent out as waste material through our bowels.

• Interesting Fact -2: Liver is the food inspector of our body and it monitors which nutrients should go to our blood stream. It basically detoxifies food, and this detoxifying liquid is provided by the digestive system to the liver. Hence, in order for the liver to function properly, it is very necessary for the digestive system to be super fit.

• Interesting Fact- 3: This is the most interesting of all of the ones listed above. One can stand on their head and the food will still get digested. Reason being that our esophagus is around 25 cm long and the muscles will contract in order to push the food down the esophagus; however, we would highly recommend that you don’t try this.

Now you all know that the digestive system is as important as other organs in our body. In fact, proper functioning of the digestive system is absolutely necessary for the proper functioning of other organs, like liver.