Share interesting facts about human body systems.

Organs on the Left Side of the Body

We claim to know our body well, but how well do we really know it? Spare a thought. We live with it, but I dare say, we don't know all about it! This article, equipped with illustrations, concentrates on citing and explicating the organs that completely belong to the left side of the body, feature in pairs -- so a twin lies on the left, and the organs that flex to the left.
Batul Nafisa Baxamusa
Last Updated: Mar 19, 2018
Did you know...
0.01% of the world's population is born with a congenital condition, called Situs inversus, wherein their visceral organs are found on the opposite side of the body.
It has perpetually been a matter of instinctual fascination, to keep learning and exploring the facets of the human body; a living factory that never takes a break! There are innumerable chemical reactions taking place in the human body with the help of organic catalysts, known as enzymes.

Moreover, we live because we breath in oxygen, and this is made possible by a pair of vital organs of the body, called the lungs. Besides, the blood is able to transfer the essential molecule of life, oxygen to various organs of the body, courtesy of the continual pumping action of the heart to purify it.

However, our current fascination lies with studying the organs situated on the left side of the body. Certain organs like the heart, spleen, stomach, and pancreas are situated on the left side of the body. Then again, we cannot leave out the paired organs like the lungs, kidneys, ovaries, testicles, eye, ear, etc. Let's find out more about these organs.
Left Side Organs
Left Side Organs
Left Labelled Heart
The heart is located posterior to and marginally toward the left of the breastbone. The function of the heart is to purify and pump blood to all the parts of the body. A healthy human heart, beats 100,000 times per day, on an average and pumps an estimated 2,000 gallons of blood. The heart, for its optimum functioning, follows a cycle. There is a left and right side of the heart which is separated by a thick wall called the septal wall. Both sides have two chambers each, the upper chambers are called atria and the lower, ventricles. The atria are smaller as compared to the ventricles and hold the blood till it travels to the ventricles. The function of the right ventricle is to pump the blood into the lungs while ... the left ventricle pumps blood to all the parts of the body. The left atrium and ventricle is thicker than the right side of the heart as the left supplies blood to all the parts of the body.
The sac-like structure dedicated to facilitating digestion is located on the left side of the upper abdomen. The stomach plays an important role in the process of digestion. Its function is to secrete enzymes that help digest food. Located at the rear end of the stomach, is the pyloric sphincter that acts as the passageway for food to travel to the small intestine.
The organ where lymphocytes are created for destroying and recycling old blood cells is known as the spleen. This 4-inch long organ is located on the upper-left side of the abdomen. Besides, it also filters blood and helps fight bacteria that may prove to be the prime causes of conditions, such as pneumonia and meningitis. The spleen also assists in water redistribution; i.e., it rids the areas of the body that have a higher concentration of fluid to successively lubricate the areas that need moisture; the joints, for instance. Problems, like water retention in a specific part of the body may occur if the working of the spleen endures any form of disruption.

Know that the spleen finds it comforting to digest warm beverages and food items; to facilitate food breakdown, the digestive juices require warmth, which is absorbed by warm foods and drinks. Consuming drinks that are too cold may disrupt the optimum functioning ability of the spleen.
The pancreas is located behind the stomach across the abdomen. The 6-inch long organ has its head on the right side of the abdomen, and the narrow end called the tail extends to the left side of body. Its function is to absorb and process essential nutrients, such as proteins, carbs, fats facilitated by digestive and intestinal juices.
Paired/Section Organs
Left Hemisphere of the Brain
Left Hemisphere Brain
The left hemisphere of the brain is known to be the rational, practical, and logical side. It responds to verbal instructions, solves problems logically, assimilates different parts sequentially, differentiates between two or more objects, and possesses an adroitness in planning and structuring. This side gives preference to talking, fine-tunes writing skills, displays alacrity in multiple-choice tests, and masters emotions. It is thoroughly oriented to detail and formulating strategies. It concentrates on the past and present, and does not reside in the fantasy world, thus being concretely based in reality. The left hemisphere of the brain is known to play safe, barring the risk-taking flair showcased by the right brain.

A concretely baked research pronounces that the left side of the face is considered more expressive and aesthetically appealing than the right side of the face. This is courtesy of the fact that the left hemisphere of the brain controls the right side of the face and the body; the right hemisphere is dedicated to controlling the left side of the face and the body. Literally speaking, the left hand, sure doesn't know what the right hand is doing, but the left brain, indeed does! Also, further probe states that more than 80% of the populace the world over are right-handed. The element of robustness, when found dominant in one hand, decides what is called handedness. Ambidexterity is rarely found. Lateral dominance also exists where lower limbs are concerned. Research states that individuals rely more on their left leg to ensure stability; the right leg, in most cases, specializes in fine-tuning the coordination of movements.
Your Brain Is Working Now ... and How ....
  • You can read and comprehend the text on this page, is courtesy of your left frontal lobe.
  • If you can differentiate between a "=" and "∞", it's thanks to the left hemisphere of your parietal lobe.
  • Did you just sneeze? Well, registering and processing the 'achoo' sound is your left temporal lobe at work.
  • You 'see' the words on this page on your computer screen; it's your highly active left occipital lobe.
  • You just blinked -- the little brain, anatomically phrased the cerebellum, is responsible here. Maintaining balance and facilitating coordination are functions of the left cerebellum as well. 
Left Eye
Our eyes are one of the most delicate structures of the body. The eye captures and focuses light onto the sensory receptors at the posterior section, for the light energy must be converted to neural signs that are transferred to the brain. The neural signals are what help us comprehend the various images. Regarded as windows to the soul, eyes help us envision the world and are responsible for absorbing, processing, and sending out 4/5th of the information to our brain. The function of the eye may be likened to that of a camera. Both are known to "capture" images; such is the complexity of our visual faculty. It is one of the dominant senses that living beings rely on. It, indeed, is interesting to know how the many parts of the eye work in concert to deliver clear frames of vision.

Analogous to the right- and left-brain dominance is a tendency centripetal to the eye. Ocular dominance, indeed, runs lateral to the study of cognitive or hemispheric dominance. Research spells that approximately 30% of the population is left-eye dominant; ... however, the dominance may not remain constant as it depends on the line-of-path or the direction in which the individual may behold the target, due to which there are changes in the field-of-view on the retina.
Left Ear
The ears help translate the innumerable sounds around us. Besides hearing sounds and converting them into meaningful messages, the ear carries the onus of maintaining the body's equilibrium, too. If this does not happen, one may suffer from conditions, such as vertigo, where the individual may feel the surroundings are in a perpetual state of whirlpool. The anatomical structure of the ear consists of the auricle, external auditory meatus, tympanic membrane, middle ear, ossicles, malleus, incus, stapes, round window, inner ear, semi-circular canals, cochlea, Eustachian tube and cochlear nerve. It is when these parts coordinate that we are able to hear sounds with lucidity.

It, by and large, is believed that there is no difference between the functioning of the left and the right ear. We sure may be termed left- or right-brained individuals; however, there could be nothing like "right- or left-eared," right? Wrong. Auditory laterality is another concept paralleled with brain hemispheric dominance. Studies conducted by Tommasi et al have revealed the true nature of your ears and the domain of sound they are profound at grasping. According to the study, phonemic sounds are better heard with the right. The left ear, on the other hand, has the ability to outperform the right ear in siphoning the "non-phonemic aspects" of speech. Another research on auditive dominance doles out a very interesting aspect. People would be receptive to your requests and, more often than not, do you a favor; well, the condition: the request must be received, not in the left, but in the right ear! Although there is no connection found between the 'type' of request and the ear hearing the request.
Left Anterior Naris (Section Organ)
The sweet smell of roses and the pungent aroma of garlic are realized with the help of the nose. The nose is a complex structure having a smooth bony constriction in the front that is smaller in diameter than that of a finger. We breath with the help of our nose, making it one specialized and exclusive breathing apparatus. The nose is divided by a septal wall into right nostril and left nostril also known as the anterior or external nares -- openings that allow air to pass into the nasal cavity. Individually, each opening is called the anterior naris. The air that we breathe passes through the nostrils leading toward the nasal passage. The process continues with the air moving through the pharynx down to the trachea and to the lungs.

The sense of smell plays a vital role in recognizing and appreciating the flavors and juices elicited by food as well. When you process a morsel of food, the olfactory system is activated, courtesy of the chemicals released by the food. It is no wonder that when you suffer from cold, your sense of taste, too, is hampered. Due to the occlusion endured by the nose, the chemical release of the food may not be received by the olfactory system. Thus, the food has not lost out on the taste; it's just the aroma that suffers a beating!
Left Lung
The lungs facilitate the function of respiration. They are a pair of sponge-like organs located on either side of the thorax. The air passes through the trachea into the lungs through branch-like structures called the bronchi. The left lung is smaller ... than the right lung as it needs to accommodate the heart that is located slightly toward the left side of the chest cavity. The left lung ... is divided into two lobes, ... namely, the superior and the inferior lobe, and the right lung, into three lobes -- superior, middle, and inferior. Besides, the left lung ... is narrower than the right lung; ... the right is wider due to the compressive strength applied by the liver located under it.
Left Breast
Breasts are a pair of organs, located at the anterior section of the chest wall. The breasts in females are far developed than in males. The reason for this is their primary lactational function in order to provide nutrition to infants. A nerve-rich spot, estrogen and progesterone are the major hormones that promote growth of the breasts. There are a number of changes in relation to the size and appearance of the breasts, especially during pregnancy. The breast size increases as a sign of preparing the mammary glands to produce milk. Changes also occur in the size and color of the areola, with it dilating and becoming darker during the third trimester.

What must be known is that, in most cases, the left and right breasts are asymmetrical. The exact cause of why this happens needs further probe. Few women have symmetrical breast shape and size, so breast asymmetry is far common than you think. Nevertheless, there are surgical options that may be adopted to either reduce or augment the size of your breast. The decision depends on your preference and, of course, the surgeon's advice. It is normally during puberty or specifically the thelarche that breast asymmetry is noticed, where the left breast is found to be marginally larger in size than its right-sided twin.
Left Kidney and Left Adrenal Gland
There are two small organs that serve as the filtration machines of the body; they filter urea, mineral salts, toxins, and other waste products from the blood. One of the two kidneys is located on the left side of body. The left kidney is located slightly higher than the right ... as the liver compresses the right in a downward direction. The pair resembles kidney beans and is approximately the size of your fist. As the body has taken what it requires from the food ingested, the remaining matter must be extricated by the kidneys. Thus, the functioning of the kidneys is vital; if they do not work toward the removal of wastes, the waste matter would remain in the body and corrupt the system.

Sitting atop each kidney is the adrenal or suprarenal gland. The right adrenal gland varies in size and shape as compared to the left adrenal gland. Where the right is pyramidal in shape, the left resembles a crescent. The adrenal glands function as managers of hormone production.
Left Ureter
The urine flows out from the kidney to the bladder through two tube-like structures called the ureters. The ureters are compressed by the urinary bladder; thus when there is pressure build up in the bladder while urination, there is no back flow of urine. If there is malfunction, the kidney maybe susceptible to infection. As mentioned above the ureters originate from the sinus of the kidneys, there is but, a slight difference in the left and the right ureter. In terms of location, ... the left ureter is marginally lateral to the inferior mesenteric nerve, whereas the right ureter is slightly lateral to the inferior vena cava.
Left Fallopian Tube
The uterus is a pear-shaped organ located behind the urinary bladder. It is responsible in order to nurture the fetus before it matures or until birth. The lining of the uterus (the endometrium) is the location where the fertilized ovum is implanted. The pelvic bones, bowels, and the bladder rely on the uterus, for it provides the anatomical integrity required to keep these organs in place. The two sides of the uterus has a Fallopian tube each that extends toward the ovaries located on the corresponding side of the uterus.

The Fallopian tubes are responsible to capture the egg that is released from the ovaries and draw it in. This occurs every month during the stage of ovulation. Besides, the Fallopian tubes must maintain the released egg's health as it sits there waiting for fertilization to occur. If fertilization occurs, the tube contracts to shift the egg to the uterus where it is implanted in the endometrium.
Left Ovary
The ovaries are a pair of almond-shaped organs that secrete female sex hormones -- estrogen and progesterone. It is also responsible for producing a mature egg, which may be fertilized by the male sperm if sexual intercourse takes place. The left and the right ovary take turns to release an egg every month. There are greater chances of the woman conceiving if the intercourse takes place during the most fertile days of her menstrual cycle. Besides, the function of the ovaries also involves the secretion of inhibin, which controls the production of the follicle-stimulating hormone (FSH).
Left Testis
The testes are located outside the male body. They stay protected in a sac called the scrotum, which is located between the base of the penis and the anus. A man has a pair of testes consisting of testosterone, Sertoli or nurse cells, and Leydig cells. It is possible that the testes may hang at different levels. For most men, the testes hang equidistantly at the same level; however, some, the left testis may be positioned higher than the right testis. Besides, the left testis in most cases is smaller in size due to the large number of veins that run above it as compared to the right testis. The extra veins above the left testis encourages an increased amount of heat due to which the left testis may remain smaller.

The testes are further divided into seminiferous tubules (ST), which play an important role in the production of sperms. They also produce anti-Müllerian hormone (AMH) -- a protein hormone secreted during the preliminary stages of embryogenesis of a fetal male, and inhibin and activins -- hormones secreted post puberty that essay a substantive role in regulating the follicle-stimulating hormone.
Left Appendicular Portion/Skeleton
There are 206 bones in the human body. Medically regarded as the appendicular portion of the body, the bones that lie on the left shoulder girdles which include the scapulae and the clavicle are lateral to the sagittal plane of the body. The left brachial (upper arm) and antebrachial (forearm) regions consist of ... the left humerus, left radius and ulna, left wrist composed of the carpal bones, the left hand, left metacarpals, left finger phalanges. The pelvic girdle includes the ilium, ischium and pubis; they are known as the coxal bones. The left femoral (thigh) region and left crural (leg) region constitute ... the latter portion of the appendicular skeletal section. They constitute the femur, tibia, fibula, patella, tarsals (the ankle region), metatarsals proximal phalanges, middle phalanges, and distal phalanges (the pedal region).
Flexural Organs
Curvatures of the Esophagus
The esophagus may be defined as a canal, which is musculomembranous in nature, is about 9'' in length (25 to 30 cm), extending from the pharynx and passing through the diaphragm to the abdomen. Know that the esophagus has two curvatures that incline to the left. ... The first one is observed under the corona or the starting point of the esophagus. This curve deviates toward the left and sustains the inclination till it reaches the fifth plane of the thoracic vertebra. The second curve, also inclines to the left, noted just before it makes way through the diaphragm. The upper esophageal sphincter (UES) muscles are at the anterior portion of the esophagus responsible to regulate breathing, eating, and regurgitation. The lower esophageal sphincter (LES) is a cluster of muscles that lies in the posterior section of the esophagus. These muscles control the stomach acids and prevent the ingested food contents from regurgitating.
Large Intestine (Descending colon, Sigmoid colon, Rectosigmoid colon, and the Rectum)
The large intestines are located at the base of the abdominal cavity, joined to the rear end of the small intestine. It is divided into cecum, colon, and rectum. The cecum arises from the lower right side. It ascends then transverses and descends into parts of the colon (sigmoid and rectosigmoid) that enter the lower left side of rectum. Thus, the descending colon, sigmoid colon, rectosigmoid colon, and the rectum lie on the left side of body.
To say the least, the human body system is a marvel of science and the greatest invention credited to divinity. It is stupendous how the minute units of the human body, like the cells are self-sufficient to carry out replication, and release energy, without us even realizing the diversity of the processes that occur.