Lips

Lips are lower or upper fleshy structure surrounding the opening of the mouth. It serves as an opening for the intake of food and also helps with the articulation of our voice. Lips have sensory nerve which could become sensitive when kissing another person in a sexual manner. The skin of the lips and its fewer melanocytes (responsible for the production of skin color pigments) is what gives our lips a thinner and contrasting color compare to the facial skin surrounding it. Therefore the blood vessels appear on the lips which gives it's red color. It is also worth mentioning that lips do not have sweat gland or sebaceous glands, therefore it gets drier faster that other areas of human body.

Nail

Nails are made of Keratin which is hard protein. It is an elastic structure at the end of a finger or a toe. Each nail is divided into three parts. The root of the nail fastens the nail to the finger or toe by fitting into the dermis of the skin. There are vascular ridges underneath the nail body and on the nail plate which lies under the nail body. The part of the nail bed that the behind the nail root is responsible for the production of new nail cells. Nails are similar to claws and hoofs as well.

Eustachian tube

The Eustachian tube is a tube that connects the nasopharynx with the middle ear cavity. The tube is normally closed but opens when a person is yawning, chewing or swallowing to create a balance of air pressure in the middle ear in comparison to the air pressure outside. It is approximately 3.5 centimeters long. The Eustachian tube drains the mucous from the middle ear to the pharynx but may not drain properly if it is infected which could cause a swelling of the tube.

Tongue

Tongue is a muscular organ of the digestive system that is responsible for the sense of taste. It is located on the floor of the mouth with papillae located on it's surface. Taste buds contain taste receptors and are able to recognize salty, sweet, sour, bitter and umami (savour) tastes. An average human tongue contains about 8000 taste buds. The human tongue includes eight muscles which aid with chewing food. These muscles allow the tongue to move in different directions. The human tongue is approximately 4 inches long. The human tongue is attached to the floor of the mouth by the frenulum and hyoid bone in the throat. Tongue's primary function is mastication (chewing) and its secondary function is speech, kissing, etc.

Auditory Processing Disorder

Auditory processing disorder affects a person's ability to hear and/or comprehend sound. It is related to how the auditory section of the brain processes the sound. A person with this disorder can have normal hearing ability since this particular disorder does not mean inner ear impairment which is responsible for hearing sounds only. People who are affected by this condition cannot comprehend verbal words clearly and have  a difficult time distinguishing between different sounds. Some signs of this condition are: more time to process what is said, difficulty listening, having trouble paying attention to details, need the speaker to speak slowly. An Auditory Trainer can be used to help a person with this disorder.

Human Faeces

Feces are the waste product of human digestive tract. The faecal matter is formed in the large intestine where it solidifies. The faeces contain food residue, water, bacterias, and secretions from the small intestine and the liver such as bile, etc. The food that is eaten is absorbed through the small intestine and then the unabsorbed parts of the food accumulates, moves and stores in the large intestine. In large intestine the water and ions are absorbed through it's muscular walls, therefore the materials turn solid. The solid materials move out of the body through anus, by means of the muscles in large intestine and rectum contracting and moving the solid wastes forward. when blood cells die their colour change to brown/yellow and the bile coming from the liver causes the faeces to have a brownish colour. The smell of the faeces is the result of bacterias in the faeces, therefore giving it a bad smell.

Angioplasty

Angioplasty is the reconstruction of blood vessels that were damaged by cholesterol deposit, disease or injury. In this technique, a ballon catheter is inserted to the narrowed blood vessel and then inflated. The inflation causes the fatty deposits to disappear. After the ballon successfully widened the vessel, it is deflated and withdrawn. Another method to widen the blocked blood vessels is to use a stent. In this procedure a stent is placed around a balloon and inserted inside the vessel with a catheter. After the balloon is positioned properly, the balloon inflates and stent is left around the vessel's wall. The stent remain in the blood vessel permanently in this procedure. Radioactive colours are used to determine the site of damaged blood vessels before Angioplasty is done.

Tinnitus

Tinnitus is a subjective ringing/buzzing noise sensation in one or both ears that does not have an external source. Tinnitus is considered to be a symptom of an underlying condition such as otosclerosis or accumulation of ear wax. Listening to loud music with a headphone could cause the ringing sound in one or both ears. Tinnitus can last for a few minutes to many years and it can have negative effects a person's ability to sleep. Some of the treatments available for tinnitus are: cleaning the ear canal (if the condition is caused by ear wax accumulation) and cochlea implant (auditory part of the ear responsible to transfer vibrations to never fibbers) . Cochlea implant is surgically inserted inside the ear and allows the person to hear external voices.

How Do We Hear?

Sound waves first enter through the flap of the ear. The ear drum vibrates and causes three small bones (malleus, incus and stapes) to vibrate also afterwards.  As the stapes (one of the small bones) moves, it touches the oval window which separates inner and middle ear. At this stage, the oval window fluctuations causes the sound waves to be transferred to what is called the cochlea. There are two auditory liquids inside cochlea, perilymph and endolymph. In the organ of corti (auditory receptor area) small hair  cells receive vibrations from the auditory liquids and then the sound waves are sent to auditory nerve fibres where the sounds are heard.

Testosterone & It's Function In The Body

Testosterone is a male hormone (androgen) that is responsible for men's secondary sexual characteristics such as beard, deep voice and muscle mass. Testosterone is secreted from testes and adrenal glands(glands located on top of the kidneys that produce hormones and release them to the body) in males. Females body produces small amounts of testosterone in the adrenal glands which is necessary for healthy sexual drive and also prevents bone loss. According to a study the male body produces ten times more the amount of testosterone produced in females. It should also be mentioned that as the result of this, females are more sensitive to testosterone molecule. Some effects of testosterone on the body are: sperm production, causes enlargement of body organs such as brain, heart and liver, attention, spatial ability.