Ears

As you can see in the human ear diagram, it is designed in such a way that it captures the maximum auditory stimuli from the atmosphere and transfers them to the brain for translating into hearing response. Three major parts of a human ear are the outer, middle and inner respectively, each having its own functions, anatomy and ear diseases as well.

The external ear anatomy is the study of the parts of the outer ear. There are two major parts of the external ear, i.e. the pinna and the external acoustic meatus. Pinna or the auricle lies externally and its main job is to capture the sound waves and transmit them to the external acoustic meatus. Most of the framework of the auricle is cartilaginous in nature. Here lobule is the only structure which does not have the support of cartilage.

The external acoustic meatus, on the other hand, is a tube like structure that extends from the middle hollow depression or concha of the auricle. At the other end, it reaches the tympanic membrane. It has a cartilaginous structure and gets the bony support from the temporal bone. The branches of vagus and mandibular nerves provide sensory innervation to this particular part of your external ear.

Do you know if the external acoustic meatus travel in the straight path? Well, this is not the case. In fact, it has got an S-shaped path.

⇛ Link between Cold and Dumbness: Do you know about one of the amazing ear facts that there is a connection between the middle ear and the throat? This connection develops through a tube, i.e. the Eustachian tube. This is the very reason behind your going dumb every time you catch cold. The main function of the tube is to equalize the pressure between the atmosphere and the body.

⇛ Disturbance in Equilibrium: At higher pressures, and on mountain tops, it is common for people to go dumb. Meanwhile, they experience a disturbing feeling in their ears. It is because the Eustachian tube is unable to maintain equilibrium in body pressure.

⇛ Strength of Temporal Bone: According to the opinion of many people, femur is the hardest, longest and strongest bone in human body. But it does mean that the temporal bone is less in strength, i.e. it is equally hard and strong.

⇛ Remove Wax & Damage The Ear: Ear produces its own wax to protect itself from friction and dust. So, if you make frequent attempt to remove this wax, it may damage the tympanic membrane in the ears causing deafness.

Do you know exactly how the ear works? The sound waves that strike at the ear drum set it on vibration. This vibration then travels to the three small bones of the middle ear, (the malleus, stapes and incus). The bones of the middle ear, on the other hand, make specific movements and hit at the oval window.

Different parts of the ear and their functions are very important for hearing. The vestibular window separates the middle ear from the inner ear. The inner ear is also termed as cochlea, which is a dual membrane delicate structure, with fluids filled between the membranes and lined with hair cells. The movement of the hair cells that line cochlea, in response to the sound waves, is like that of grasses in the meadows. It serves to sends electrical impulses to the brain, i.e. the master organ, that accurately identifies the sounds we hear.

Rectum

The straight part of the colon is the dilated pouch like structure that is preceded by sigmoid colon and followed by anal canal. Before you defecate, the feces is temporarily stored in this gastrointestinal structure which becomes dilated on the arrival of waste material and induces the urge for its elimination through anal verge. The word "rectum" has been derived from a Latin phrase "Rectum Intestinum" which means "straight intestine". As the rectum facts suggest, this organ is about 12 cm in length, and begins at the third sacral vertebrae and is joined with the preceding section of large bowel at rectosigmoid junction. Based on the structure and function of the distal end of large gut, you can divide rectum parts

The primary rectum function is the temporary storage of stool so that you may have some time to reach the place where it can be defecated. As the waste and indigestible materials get entry into it, the canal becomes dilated, thus stretching the muscles lining the rectal region. Stretch receptors are located in the wall of rectum which sense the dilation of the gut and send signal to the nervous system (brain) where these are processed and a response is generated that induces the need for the elimination of waste materials passing through anal canal and getting out through anal verge. However, if you do not go for defecation for a prolonged duration, the stool gets back into the colon for further absorption of fluids which may also result in hardening of stool and constipation.

Small Intestine

Small Intestine Function

Functionally, you will find small gut very important part of gastrointestinal tract as it not only digests major part of the dietary contents but is also meant for absorbing finally broken down food particles. Meanwhile, you cannot underestimate the importance of large intestine and anus function. It’s the place where almost all of the absorption takes place including nutrients, bile salts, vitamins, and so on. Some of the major small intestine function can be listed as under:

Neutralization

The partly digested food that is coming from stomach through pyloric opening is highly acidic in its medium, but the enzymes present in duodenum and other parts of the canal cannot perform their activity as biological catalysts. So as the first and foremost function of the gut, this medium is neutralized and the enzymes are made to act in the most efficient way.

Digestion

After the medium has been made feasible for the enzymatic actions, the digestion of the remaining contents of chyme is accomplished here. As a part of overall small intestine function, different secretions are poured into canal, like bile and pancreatic juice that facilitate the process of breakdown to a greater extent, until the finally digested food particles are ready to be absorbed.

Absorption

Here it is surprising to know that among all the segments of gut, this is the only portion where almost all of the absorption and assimilation of digested food, vitamins and salts, takes place. For the intake of nutrients into the bloodstream, there are specialized cells (e.g. enterocytes) that facilitate the process of absorption. After entering the bloodstream, the food particles are delivered to all the living cells in the body where, by means of metabolic reactions, energy is extracted to accomplish all the vital activities.

Parts of Small Intestine

To enjoy an ideal health and counter the diseases, you must have sound knowledge of different parts of the body with facts. Small bowel is further divided into three structurally and somewhat functionally distinguishable smaller segments, viz. duodenum, jejunum and ileum. In various segments, the three layers of its wall are similar throughout its length, but there do exist certain structural differences among them.

Duodenum
The foremost and shortest part, it is functionally very important as major portion of the chemical digestion takes place here. Varying in length from 10 to 15 centimeter, it is, on the anterior end, connected with stomach, while the posterior end touches jejunum.

Jejunum
Constituting the second part of your small bowel, located between duodenum and ileum, it has the average length of about 8.4 feet or two and a half meter in adult humans. The pH of the medium inside this part of gut may vary between neutral to slightly alkaline, i.e. 7 to 9. The enterocytes are the specialized cells present in the lining of the canal that are actively involved in the absorption of small particles of food that were digested by enzymes in duodenum.

Ileum
This final section of small gut, on one hand, continues with jejunum, while on the other, it makes a connection with colon through ileocecal valve. In adult humans, it may vary from 7 to 14 feet in length, and the pH of the medium is same as that of jejunum which is neutral to a bit alkaline. Its major function is to absorb any nutrients that were not absorbed in the preceding sections of the gut. However, it is particularly involved in the absorption of bile salts and vitamins

Pancreas

Pancreas is one of the extrinsic glands of the digestive system. It has mixed endocrine and exocrine functions, and is present outside the wall of the digestive tract. In order to fully understand, "What is pancreas?" you must know its location, functions and diseases. The exocrine part secrets pancreatic juice into the duodenum; the juice contains a number of digestive enzymes and pro enzymes that help digest the food. The endocrine part produces hormones such as insulin that play significant role in the absorption, metabolism and storage of nutrients such as glucose. Dysfunction in the endocrine part of the pancreas leads to diabetes mellitus.

 A normal pancreas is about 12 to 15 cm long and weighs about 110 gm. Pancreas location is behind the stomach and it lies more or less transversely in the posterior wall of the abdomen; it has duodenum on its right and spleen on its left. It has a head that lies within the curvature of the duodenum, a neck that connects the head to the body and a body that blunts into its tail to touch the spleen. Cancer of the pancreas usually involves the head and accounts for most of the cases of extrahepatic biliary obstruction.

About 1500 ml of pancreatic juice is secreted everyday which contains many digestive enzymes, water and various ions such as bicarbonate, sodium, potassium.

pH of the pancreatic juice is alkaline in nature which helps neutralize the gastric content entering the duodenum from the stomach.

Pancreatic enzymes and pro-enzymes (zymogens) are essential for the digestion of protein, carbohydrate and fat constituents of food that we eat every day.

Endocrine part of pancreas secrets two important hormones - insulin and glucagon - both of which are secreted reciprocally from pancreas and also act reciprocally in most circumstances. In a nutshell, insulin increases storage of glucose, fatty acids and amino acids. On the other hand glucagon is a catabolic hormone so it mobilizes glucose, fatty acids and amino acids from stores into the bloodstream.

Secretion of the pancreatic juice is primarily regulated by two hormones -

Secretin

Cholecystokinin (CCK)

Both of these hormones are produced by specialized cells of the duodenum. They are secreted in response to gastric acid entering the duodenum from the stomach and in response to products of protein and fat digestion (e.g. small peptides, amino acids and fatty acids). Both hormones act synergistically in response to a meal and cause a large volume of alkaline pancreatic juice rich in digestive enzymes to be released.

Lungs

Lungs are the major organ of our respiratory system. They help you obtain oxygen and get rid of carbon dioxide. The gaseous exchange takes place in the tiny air sacs which have just one-cell thick walls. Blood absorbs oxygen and delivers it to every individual cell in the body.

A cylindrical tube, called trachea, is the main link between the human lungs and the nose and mouth. When we breathe in, air travels through the trachea to the main respiratory organs. As the trachea moves down the chest, it splits into two branches, i.e. bronchi, one for each lung.

Each bronchus then further subdivides into several smaller tubes, namely, bronchioles. Thus, each lung contains many bronchioles. They spread all over its structure in order to ensure an even distribution of oxygen. You can view the details in the lungs diagram.

For oxygen to be able to reach all the parts of our body, it dissolves into the blood. The blood stream then distributes oxygen to the entire body. Therefore, there has to be a supply of blood vessels in the lungs. These blood vessels are present on minute, sac-like structures, the alveoli.

The alveolar sacs are present at the end of bronchioles. There are numerous alveoli in each lung. This is to provide the maximum surface area for the exchange of oxygen as well as carbon dioxide with the blood stream.

Do you know the expanse combined surface area of all the tiny alveolar sacs in the lungs? Quite unbelievably, it is equal to the area of an entire tennis court.

It is possible for a person to survive with just one lung. However, he would be weaker than normal individuals who have a pair of these organs.

On average, the volume of air that the respiratory system takes in every day is approximately 9,000 liters!

The pulmonary structures of newly born babies breathe at a faster rate in comparison with those of adults.

Your pulmonary organs play an important role in respiration system of the body. Oxygen moves in when you inhale air. The air travels from the external air passages (mouth and nose) down the trachea and finally into the alveoli through the bronchus and bronchioles.

This oxygen dissolves into the layer of moisture around each alveoli and finally moves into blood capillaries. In this way, a lung plays a vital role in providing oxygen to all the body organs.

It is important for your body to get rid of carbon dioxide which is a waste product of respiration. Once again, these are the pulmonary organs which help in the elimination of this toxic waste product. The path of carbon dioxide from the blood to the external environment is the reverse of the path that the oxygen takes to enter the blood stream.

Kidneys

Location of kidneys is of particular importance in your body. There are two bean shaped kidneys in the human body. A normal kidney is about 2.5 cm thick, 10 cm long and 5 cm wide. They are reddish-brown in color. Each weighs around 130 gm in adults. Both kidneys receive blood from the renal artery. In a resting adult nearly 1.2 to 1.4 liters of blood flows through both kidneys in one minute. It means every 4 to 5 minutes all the circulating blood in the body passes through the kidneys. Kidneys help remove excess salt, water and waste products from the bloodstream.

Like other endocrine organs, kidneys also secrete important hormones such as rennin and erythropoietin into the circulation. These hormones play a significant role in the production of blood cells. In addition, they also assist in the regulation of blood pressure.

It won’t be wrong to call kidney as the natural filter in your body. Its job is to purify blood and make it free from all the waste substances that it has collected from every individual cell. but how is such an important kidneys function executed? For this purpose, you need to study the kidney anatomy.

Location Of KidneysYou can better understand the anatomy of kidneys from the labelled diagrams. One of these is shown here. In the kidney images, you can see that a nephron serves as the basic structural and functional unit. There are a large number of nephrons in each of these organs. They make a direct connection with a complex network of blood vessels.

From the kidneys pictures, you can easily distinguish among different parts, such as medulla, cortex and the renal pelvis. On the side of the renal hilum, you will come across renal artery and the renal vein. From the renal pelvis, there emerges a ureter which descends downward to reach bladder. It also indicates that the location of kidneys is directly above the bladder.

The function of kidneys is to produce urine by filtering large quantities of fluid from the blood plasma. Urine consists of approximately 95% water. Urine also contains urea, creatinine, phenols, phosphate, potassium and sulfates. There are also nitrates and a large amount of uric acid.

Urea, uric acid and creatinine are all nitrogenous waste products. Nitrogen containing compounds are among the most toxic metabolic waste substances. Your body produces them as a result of various metabolic processes.

You can express the level of nitrogenous waste products in our blood as BUN (blood urea nitrogen). In healthy adults, normal BUN level ranges from 8 mg/dL to 25 mg/dL. A high level of BUN indicates renal insufficiency, i.e. one of the kidney problems.

The volume and composition of urine that the kidneys produce and excrete every day depend crucially on various factors. These factors include fluid intake, diet, renal functions, climate, metabolic activities of cells. Meanwhile, the presence or absence of systemic diseases also has a role to play in this regard.

Gall Bladder

What is gallbladder? The gallbladder facts reveal that it has to play an important role in the breakdown of food items and, consequently, their absorption into the blood. Before learning gallbladder definition, you should know about the extent of digestive system. The digestive system is perhaps the largest system in the human body. It has many accessory organs and glands to perform its overall digestive function
According to gallbladder definition, it is a small gland at the base of liver. Its main job is to assist in the emulsification, digestion and absorption of fats in food. The liver secretes the bile and transfers it to gall bladder for temporary storage.

Another gallbladder function is to concentrate the alkaline fluid that contains salts, pigments, fats and about 85% watery component.

Recent gallbladder information suggests that this structure in an adult human would measure about 8 x 4 cm or a bid more. It secretes bile juice to facilitate digestive processes of oily diet. The organ has divisions into three parts, which are neck, body and fundus. The neck of gall bladder establishes a connection with liver through common bile duct and transcends its secretions through it. Fundus appears at the opposite end of this pear-shaped organ, while body lies in its proximity away from the neck.
Bile Juice Secretion & Storage: The liver secretes the bile juice and pours it into gallbladder. The gallbladder then stores the bile juice for some time.

As the need arises, the bile juice enters into the duodenum of small intestine. This commonly happens after taking food that is rich in cholesterol or other lipids.

Breakdown and Digestion: Do you know the bile from the gall bladder emulsifies fat molecules? As a result, the fat digesting enzymes, like lipase, can carry out their breakdown and digestion effectively.

Bile Concentration: Here is another of the interesting facts about the gallbladder in the digestive system. That is, the biliary vesicle achieves about 10 times concentration of bile.

Formation of Gallstones: Frequent and prolonged intake of fatty foods, would result in excessive concentration and hardening of bile juice. It will, in turn, result in the formation of gallbladder stones.

Gallbladder Removal: Removing gallbladder does not interfere much with fat metabolism and there direct secretion of bile into the intestine.

Inflammatory disorder: Inflammatory disorder of the gallbladder is also common among people who have been suffering from chronic infection of typhoid.

The gallstone are usually small, hardened deposits that measure not more than a few millimeters. That is why, in most of the cases, they do not cause any severe symptoms and go without detection for years. At the later stage, however, they lead to pain, infection and inflammation of the organ.

The gallstones can be of two major types, i.e. pigment stones and cholesterol stones. The pigment stones result from the accumulation of calcium bilirubinate – a chemical produced after the breakdown of red blood cells. In the latter case, accumulation of cholesterol is the sole cause for the formation of such stones.

There are usually very rare cases of this type of cancer. However, there are chances for its spreading to other parts of the body. In that case, the disease becomes fatal. If there is timely discovery of the gallbladder cancer, it is easily treatable. But, unfortunately, it is one of the gallbladder facts that in most of the cases, the cancer is diagnosed at a very later stage. The primary reason behind delay in the diagnosis is that such type of cancer does not cause any obvious signs or symptoms soon after its onset.

Bronchi

Do you have any brief idea about “What is bronchi?”. Well, it is a plural form of bronchus. Here it becomes pertinent to define bronchus. A bronchus, on the other hand, can be defined as either of the two branches of trachea which lead directly to the lungs. So, the appendix definition makes it clear that a bronchus is actually a sub-division of the windpipe. The trachea or windpipe serves as a passage for airflow between mouth or larynx and the lungs.

Structurally composed of cartilaginous material, the air passages show a significant amount of flexibility. This flexibility, in turn, substantially contributes to their functioning efficiency. Any abnormal condition in the structure gives rise to great disturbance and severe symptoms of the respiratory system. But a number of remedial strategies are available for almost all of such disorders.

                          
Though their walls do not let the respiratory gases pass across them, the bronchial canals are the main channels for the passage of airstream towards the major respiratory organs. They also make significant contribution to the protection of lungs against germs and dirt particles. The germs and dirt particles are trapped in the mucous lining of the lumen.

Afterwards, there is upward expelling and removal of such unwanted things out of the windpipe with the help of ciliated cells. The hyaline cartilaginous material that forms the D-shaped incomplete rings of the bronchial walls prevents the tubes from collapsing and obstructing the flow of air.

However, with the passage of time as you grow older, this soft flexible material becomes a hard and rigid bony substance. Consequently, it reduces the overall efficiency of the structure. The alveolar sacs (or alveoli) form as a result of many subdivisions of the mainstem bronchi. And these are the places where the exchange of respiratory gases takes place.

There are a number of respiratory disorders that affect the subdivisions of windpipe at different levels, i.e. bronchi, bronchioles and alveoli or respiratory sacs. For example, bronchitis – as the very name suggests – is the inflammatory disorder of bronchi. It may occur in either of the two major forms, viz. chronic and acute one.

Chronic bronchitis results from the prolonged exposure to the irritants and smoking habits. While acute form is the result of the bacterial and viral infections. As a response to the allergens (antigens producing abnormally vigorous immune response), hyperactivity occurs in the bronchial canals. People call this condition as asthma.

Because of its vertical position, the right main bronchus is more vulnerable to the disorders. It is because the germs and dust particles present in the atmospheric air get entry into the right lung quite easily. Over there, they cause mild or severe medical conditions.

Appendix

Before turning to interesting appendix facts, let’s have basic information about this vestigial organ of the body. What is appendix definition? Literally speaking, an appendix is something added on to something else as an appendage. Are you really confused? Have you seen the appendix in the books? The appendix of a book is a collection of specific pages, containing additional information, in the end of the book. In this case, the appendix is added to the regular pages.

According to biological appendix definition, it is a finger like growth at the junction between small and large intestine. It has a blind end which means anything entering into it cannot come back. This organ is of no particular use to humans. However, appendix is still functional in the grazing animals.

It is located at the junction where small and large intestines join each other, i.e. in the right lower abdominal quadrant. Find it somewhere between the top section of the pelvic bone and the navel area. Normally, we cannot determine the exact location of the appendix and even in the scanned image.

However, it is not clearly visible. You can locate this body organ in the specified abdominal chamber,

when the visceral organs in human body are at their normal positions. Physicians refer to such a condition as situs solitus. There is a congenital condition (i.e. situs oppositus) in which there is delocalization or reversing of the internal organs. So, in the rare cases of situs inversus, this vestigial

organ appears on the opposite side of the body.

In human body, the vestigial structure of appendix develops a collection with the cecum of colon. Do you know what side is your appendix on? You can find this tube-shaped pouch in lower right side of your abdomen. It is very small in size and looks like a worm. That is why, you may also call it "Vermiform Appendix" or simply "Vermix" which comes from Latin meaning "worm-shaped"

Resembling a small, hollow, finger-like tube, vermix is blind at one end while the other end opens into cecum of large bowel (or colon). On average, the length is about 11 centimeters, but it varies greatly from person to person, and can enlarge up to 20 cm.

As the free end has no opening, anything entering into it will remain there with no way to come out of it. The stagnation of food will cause inflammation of the organ along with severe pain. Physicians can relieve the symptoms only with its immediate surgical removal, or else the victim may die. 

A well-known disease of appendix is appendicitis. Do you know the appendix causes? In this case, some food particles, passing through gastrointestinal canal, get an accidental entry into this hollow structure with blind end. But there is no way for the food to come out of it.

Thus, the stagnation of organic material produces pus and toxic substances. Consequently, it leads to severe inflammation. If you do not address the condition timely, the swollen tube bursts open. It releases its harmful contents to the sensitive internal organs, and may even cause the death of the victim.

Tongue

Did you ever think that, without the tongue, you would have been unable to taste all the deliciousness of the natural world? Can the scientists create and install such a tool in your body which would make you taste things in the absence of tongue? Maybe the invention of such an instrument is possible, it can never work as perfectly as your natural human tongue.Taking into account the value of human tongue, this small muscular organ in your mouth cavity is a wonderful blessing of nature. In addition to providing a taste of the food, the tongue helps in manipulation of food for mastication. Its third important function is to help in the swallowing of meal.

 As you can observe in the tongue pictures, the human tongue has got a rough texture. It is the presence of tiny bumps, called papillae, all over the dorsal surface of the tongue that make it look so rough. The surfaces of the papillae, on the other hand, contain thousands of taste buds. The taste buds are actually a collection of the nerve-like cells. Nerves develop a connection between taste buds and the brain.

The upper most layer of tissue on the human tongue is that of mucosa. The mucosa keeps it moist. It also makes the tongue a bit slippery to touch.

The ability of tongue to taste food is because of the presence of taste buds on its surface. Meanwhile, different parts of the tongue sense only a specific taste. Different types of receptor cells help to distinguish between various sorts of differently tasting substances, such as sweet, sour, bitter, spicy and salty. On the tip, you will find taste buds for sensing sweet. Bind the apex and along the sides, there are receptors for tasting bitter, sour and salt.

Dorsum – the upper surface of the tongue – contains lots of lingual papillae. The papillae house the taste buds and the taste receptors. These receptors assist in the sensation of taste of different types of dietary components which come into contact with them. They are basically of two types, that is, sweet taste receptors and bitter taste receptors.

In addition to enabling you sense the deliciousness of the food, the human tongue also performs a number of other important functions. For example, the additional tongue function involves the mastication of food and the act of swallowing it. Do you know any other interesting tongue function? The list of the some of the additional functionalities of the tongue is given below:

Nose Definition

There are lots of amazing human nose facts which you may not be aware of. Also the human nose has got incredible importance in the life of an individual. For example, according to the nose definition, it serves as a passage for the entry of fresh air into your body. In other words, function of nasal passage is to assist in the process of respiration.

Human life will cease to exist in earthly atmosphere without fresh air. You get oxygen from the fresh air through nose. Here, you can call oxygen as the elixir of life. Across civilizations, man has been in search of good air.

In other words, healthy air is a primitive physiological need for humans. They base their existence on it on earth. But they failed to realize the importance of nose in human body. In addition to useful information, you will also come across various nose facts in this article.

The function of nose in respiratory system is very important. It is responsible for choosing, filtering and inhaling the atmospheric oxygen. The incoming oxygen is in sufficient amount to meet body needs. This article also throws some light on the basic parts of the nose and their functions.

Contributing to Facial Beauty:

Regarding it function, here are some interesting nose facts. Nose is the most prominent and perhaps the first attractive feature of the face. It occupies the central position along the geometrical division of the face. The organ has two chambers which divide in proportion by a septum.

These are the two nose parts. The human nose structure and function is of special interest for the biology students. It truly contributes to the overall beauty of humans.

After its purification, the air enters the middle nose for humidification. Meanwhile, the nasal cavity also warms the air to match body's internal temperature. Here is one of the wonderful nose facts. Before you accuse someone for not trimming his nasal hairs, remember they are inhaling better air than the rest of us.

⇛ A nasal septum separates the nasal cavity to form two equally dividing nostrils.

⇛ The fine hair or cilia in the nose collectively behave like a mechanical filter.

⇛ The atmospheric air is pre-treated to match body's temperature during inhalation.

⇛ The nose and the eyes are made of ethmoid bone. The ethmoid bone is present now
here else in the body other than the eye orbits.

⇛ One of the little interesting nose facts is the presence of Little's area at its interior aspect. This area may cause serious bleeding of no specific reason with constant picking of the nose.

⇛ Depending on their race, the individuals may lose their sense of small with age.

⇛ Which is the oldest sense in your body? Well, it is smell!

⇛ It may be one of the strange nose facts that women have a better sense of smell than that of men.

⇛ If someone has a long nose, they will show a good sense of business and respond positively to your leadership.

Liver Definition

Do you know the secrets about the human liver anatomy? Let’s learn it here. Skin is the largest organ. Whereas, liver is the largest internal organ and the largest gland in the human body. You may wonder "What is liver?" and what a purpose it serves. Precisely, it is one of the most fantastic organs of your body.

Being a glandular structure, it is a group of cells or tissues that secrete or excrete certain substances. However, these secretions have to do their job elsewhere in the body. The largest gland, liver also enjoys the distinction of being the h
ottest organ in your body.


The answer to “What does the liver do?” contains some interesting information. The human liver is, actually, a gland. There is broad classification of glands into two major groups i.e. endocrine and exocrine glands. Interestingly, liver belongs to both of these categories.

That is, it serves as both an endocrine gland as well as an exocrine gland. A normal liver weighs about 1.2 to 1.5 kg and performs both endocrine and exocrine functions. Studying the human liver anatomy, you will also come to know about its size.

Keep on reading this article about the human liver anatomy. Here, you will get useful and interesting information about the liver size, location, function, diseases and risk factors for liver disease.

The human liver size varies across gender. That is, it is bigger in size in male as compared with the one in females. The size of this gland is around 10.5 centimeters for men and about 7 centimeters for women. In the similar way, the weight of this organ is also different in different genders.

The largest internal organ, liver appears in the right upper quadrant of the abdomen. It lies just beneath the right side of the diaphragm and under the right lower rib cage. Concerning human liver anatomy, there are eight functional segments in it.

Within a minute, approximately 1500 ml of blood flows through the liver. This is so to ensure its efficient working. Partly due to its ample blood supply, liver is the prime site for metastatic spread of cancer.

Eye Definition

What do you know about the eye definition biology? Just learn about human eye facts and you will get precious information about it. You can define the eye as an organ of vision which makes you visualize the world around you. The eyes are two in number and each is placed inside specialized compartments in the skull.

The human eye is the organ which enables you to see. The human eye does not only let you view the scenes and phenomenon in your surroundings, but also enables you to differentiate between colors. Sometimes, there is a minor defect in the eye function and the individual cannot make difference between the red and green color. What is the name for such a condition? Well, you call it ‘color blindness

Eye function renders you the sense of sight. They convert light into electrical signals. Afterwards, the brain deciphers these electrical signals into images. Properly working healthy eyes are able to perform the following functions.

It is one of the important human eye facts that they help us view our surroundings.

Our eyes enable us to see colors. Certain organisms, such as dogs, cannot see colors and, so, their world is black and white.

Eyes help us see near as well as distant objects.

When we see an object, light is reflected off it into our eyes.

The light rays entering our eyes first pass through the pupil. These are the muscles of iris that control the size of the pupil.

After passing through the pupil, light passes through the transparent lens of the eye. There occurs the refraction and focusing of the light rays on the retina.

Light sensitive cells, rods and cones, present in the retina covert the light rays into electrical impulses. Isn’t it one of the most amazing facts about eyes of human beings.

The optic nerve transfers these electrical impulses from the retina to the brain which then processes these signals and translates them in the form of an image.

Thyroid

   

 Thyroid gland is the largest endocrine gland in adult human. Endocrine glands are those that secrete their products directly into the bloodstream. In contrast, most exocrine glands release their secretions through a duct onto an epithelial surface such as skin or mucosa. Thyroid gland is made up of two lateral lobes joined together across midline by a narrow bridge of tissue called isthmus. It is relatively larger in women and children than in men.

Thyroid gland lies in the anterior part of our neck, immediately below the larynx and overlying the trachea (windpipe). A normal thyroid gland weighs between 25 and 40 gm. This butterfly shaped gland is highly vascular so it receives one of the highest rates of blood flow per gram of tissue. Thyroid gland moves with the larynx in swallowing and speaking - this feature helps a healthcare professional to differentiate swellings in the glands from those in the adjacent structures.

Thyroid gland lies in the anterior part of our neck, immediately below the larynx and overlying the trachea (windpipe). A normal thyroid gland weighs between 25 and 40 gm. This butterfly shaped gland is highly vascular so it receives one of the highest rates of blood flow per gram of tissue. Thyroid gland moves with the larynx in swallowing and speaking - this feature helps a healthcare professional to differentiate swellings in the glands from those in the adjacent structures.


Iodine is essential for thyroid hormone synthesis. Dietary intake of about 150 microgram per day mainly in the form of iodide is typical to maintain normal thyroid hormone secretion. In many countries common table salt is iodized to prevent iodine deficiency. Iodine deficiency is the most common cause of goiter which is considered as one of the thyroid diseases.

⇛ Thyroid hormones are essential for normal growth and maturation. They play crucial role in the development of central nervous system (CNS). The most serious effect of thyroid hormone deficiency during childhood is permanent brain damage and dwarfism.

⇛ Thyroid hormones accelerate cholesterol clearance from the plasma.

⇛ Thyroid hormones are required for conversion of carotene to vitamin A; patients with hypothyroidism may suffer from night blindness.

⇛ Thyroid gland also releases a minor hormone called calcitonin which is involved in calcium and phosphate metabolism. Calcitonin stimulates cartilage growth and causes increased deposition of calcium in the bones therefore promoting bone formation and reducing calcium concentration from the blood.

Spleen

Spleen is the largest lymphatic organ in the human body. Lymphatic or lymphoid organs are the major parts of the immune system of our body. Function of the immune system is to protect the host from the invasion of foreign organisms. Immune system helps the body to distinguish its own tissues from external substances such as bacteria, viruses and toxins. Thus dysfunction or deficiency of components of the immune system can lead to various diseases ranging from arthritis, HIV and cancer.

                               

Spleen weighs about 150 gm in adults and lies under the diaphragm in the left upper part of the abdomen at the level between 9th and 11th ribs. Anterior to the spleen lies stomach and medially lies the superior part of the left kidney. Spleen resembles the size and shape of a clenched fist.

⇛ Spleen participates in the primary immune response to invading bacteria, viruses, parasites or foreign particles. Spleen is a strong defense against blood-borne pathogens. Removal of spleen increases the risk of infection.

⇛ Spleen acts like a filter for the blood; it removes cellular residues, particulate matter, senescent RBCs and other abnormal cells from the bloodstream.

It is the abnormal enlargement of spleen. When the spleen is diseased it can be 10 times larger than its normal size. Causes include:

⇛ parasitic infection such as malaria, kala azar
⇛ chronic tuberculosis
⇛ typhoid, septic shock, infective endocarditis
⇛ rheumatoid arthritis, systemic lupus erythematosus
⇛ portal hypertension, liver diseases
⇛ lymphomas, anemia, leukemia

Pituitary Gland

Hormones are chemical mediators that control and regulate the entire mechanism of the body throughout an individual's lifespan. These hormones are secreted by specific ductless glands spread across various organs of the body. The pituitary gland or hypophysis regulates the hormonal secretions and controls the growth,

development, secretions and functioning of other endocrine glands, for example, adrenal glands. This small endocrine gland has got a pea-sized body and is found at the base of brain in the skull cavity lying below the controlling organ, called hypothalamus. Owing to its large impact on the body, pituitary is also known as the “master gland”.

⇏ Measuring about the size of a pea, this pink-colored hormone secreting organ measures 5 grams in weight, and is located in the folds of brain.

⇏ The height, shape and size of an individual is greatly influenced by the activity of pituitary gland. The excessive secretion of growth hormone leads to increased height and its decreased secretion results in dwarfism.

⇏ Pituitary gland is called the king of all glands (or master gland) as it controls them all and is in-turn controlled by the Hypothalamus.

⇏ It is pituitary that serves as the center of sexuality and reproduction in your body. In other words, the secretions of the posterior lobe of the pituitary are responsible for child birth and sexual life of an individual.

⇏ Though many other parts of the body are actively involved in sexual processes, this gland enjoys a prominent position because it initiates all such processes.

⇏ Do you know around 30 to 40% percent of population suffers from sexual dysfunction at some time in life? It is because of the malfunctioning of the pituitary gland.

⇏ A connection is built between endocrine and nervous systems through hypophysis (an alternative term to denote hypothalamus).

⇏ The gland hangs from a part of the brain called the hypothalamus and is connected with the same through a small stalk called the infundibulum.

⇏ The hypophysis generates and releases nine hormones, in total, into the blood stream which mainly serve to maintain homeostasis in the body.

⇏ Having its origin in the pituitary gland, the Cushing’s disease is a deadly condition that is very difficult to diagnose and treat.

⇏ Cortisol or ACTH is a life hormone that is regulated by the pituitary. We would soon die in the absence of this hormone!

Mouth Definition

A precise answer to what is mouth is that it is the anterior most part of the gastrointestinal tract. According to mouth definition, this organ is also known as the oral cavity. This cavity contains several different other organs. Organs in the oral cavity include uvula, palate, teeth, tongue, and so on.

In the pictures about what is mouth, you can distinguish the palate into soft palate and hard palate. Each type has got its own role to play in the mouth. On the other hand, different structures of the human mouth perform a number of important functions. They include sound production, breathing, tasting, and grinding and masticating food, etc. Below is further detail about what is mouth.

 Secretion of saliva is also a mouth function. Meanwhile, there are several articulatory and static organs in the oral chamber. They significantly contribute to the production and modification of sounds. Initially, the sounds start from the vibration of vocal cords in the laryngeal cavity.

Another name for the laryngeal cavity is the voice box. A number of mild and critical mouth diseases have been affecting one of the most important organs of your body. Some of these conditions do not even require formal treatment.

In other words, you can easily cure them by proper modifications in the behavior. However, other diseases need urgent, prolonged and very expensive treatment measures. Such measures include medications and surgical therapy.

Study of mouth parts is pertinent to the topic what is mouth. Moving in sequence from anterior to the posterior, you will come across different mouth parts. These are: lips, teeth, tongue, alveolar ridge, soft and hard palate, uvula and throat. The teeth ridge or gum ridge are alternative names for the alveolar ridge.

However, if you look at the human mouth externally, many structures of the front part of head may be included in it. They collectively form the facial organs, namely, lips, nose, chin, cheeks, eyes, eyebrows and forehead.

Lips are the soft, movable and flexible muscular structures. They are under the voluntary control of an individual. Therefore, you can open, close, or round them at will. In digestive system, their function is to serves as a passage for dietary and fluid intake.

Larynx Definition

Larynx Definition

What is larynx? Talking about the larynx definition, it is structure lying just at the top of trachea. It plays a significant role in the production of vocal sounds. The larynx is also responsible for the protection of windpipe against the entry of food particles.

Owing to its great contribution to phonation, it is also known as voice box or sound apparatus. The voice box contains vocal cords.

In human adults, it lies at the level of third to sixth vertebrae of the cervical region. But in newborn babies, it is at a higher position. That is, here you will find it at the point of second to third vertebrae. As you can see in the larynx pictures,

Larynx covers the tracheal opening through a flexible flap, i.e. epiglottis. The epiglottis sits on the aperture like a lid. To learn more about larynx definition and function, just go through the rest of the article.

Parts of Larynx

After learning the larynx definition, you need to proceed to its parts. The larynx cartilage makes up the structure of the sound apparatus. There are nine laryngeal cartilages in the skeleton of this body part. Out of nine cartilages, six appear in the form of pairs. While the other three remain single. The unpaired cartilages are cricoids, thyroid and epiglottis.

On the other hand, the cuneiform, corniculate and arytenoids are three paired ones. However, talking of the interior of sound apparatus, you can distinguish it into three divisions, viz. subglottis, glottis and supraglottis.

Meanwhile, there are also a number of intrinsic and extrinsic muscles that are present in the region. These muscular structures facilitate the functioning of the organ in various ways. For example, the intrinsic cricothyroid muscles help in the stretching and elongation of the vocal folds.

Different types of sensory and motor nerves innervate various muscular structures of larynx. They include vagus, superior laryngeal and recurrent laryngeal nerves. The vocal folds of voice box are of two types, i.e. false and true.

Here the former do not contain muscle and have nothing to do with the production of sound. But they play their role in the resonance. The true mucosal folds, on the other hand, do have skeletal muscle and play an active role in phonation.

Heart Definition

Heart Definition – What Is Heart?

A simple answer to "What is heart and the heart functions" is that it is the main organ of your body's circulatory system, pumping blood throughout the body. According to the heart definition, you can call it a muscular pump which contracts at regular intervals in order to squeeze the blood through it into the blood vessels.

As you can see in the human heart diagram, there are four chambers in this tireless pumping organ. All the chambers work in coordination for the successful execution of different heart functions. The right chambers contain unclean or the deoxygenated blood. On the other hand, the left chambers contain clean or the oxygenated blood. Just look at the different parts of heart to get a better understanding of the heart functions.

How Heart Works?

In order to understand how the heart works, it is important to know about its main parts. There are four chambers in the heart; the top chambers are atria while the chambers below them are ventricles. As many as four valves control the flow of blood into and out of the heart.

A double-walled membrane, the pericardium, separates the right and left chambers, preventing oxygen-rich blood from mixing up with the one without oxygen. So, the heart functions go smoothly.

Deoxygenated blood enters the right atrium. The valve present between the right atrium and the right ventricle is the tricuspid valve. It opens to let the blood flow into the right ventricle. The valve then closes to prevent the backward flow of blood.

This deoxygenated blood enters the pulmonary artery and moves to the lungs to replenish its oxygen content. This oxygen-rich blood them comes back to the heart through the pulmonary vein. The right atrium receives this oxygenated blood.

The mitral valve between the right atrium and the right ventricle opens to let the blood flow into the right ventricle. It then closes to prevent the backward flow of blood. Finally, there is pumping of the blood into the aorta from where it is distributed to the rest of the body through the arteries. So, you can say that main function of the heart is to supply all the body cells with oxygen and nutrients through the circulation of blood.