Home > Uncategorized > Diagram of Human Mouth and Throat (Cut View)

Diagram of Human Mouth and Throat (Cut View)

Bagan mulut dan rongga mulut

Epiglottis

The epiglottis is the flap of cartilage lying behind the tongue and in front of the entrance to the larynx (voice box). At rest, the epiglottis is upright and allows air to pass through the larynx and into the rest of the respiratory system. During swallowing, it folds back to cover the entrance to the larynx, preventing food and drink from entering the windpipe. The throat contains both an air passage (the wind pipe) and a food passage (the esophagus). If these passages were both open when a person swallowed, air could enter the stomach and food could enter the lungs. Part of the safety hatch that seals off the windpipe is the “epiglottis,” a little valvelike cartilage, which works with the larynx to act as a lid every time we swallow. The larynx draws upward and forward to close the windpipe. This keeps solid food and liquid out of the respiratory tract. At the end of each swallow, the epiglottis moves up again, the larynx returns to rest, and the flow of air into the windpipe continues. The uvula (Latin for “little grape”) is a fleshy piece of muscle, tissue and mucous membrane that hangs down from the palate. It is the part that moves upward when we say, “Ah!” It flips up and helps close off the nasal passages when we swallow. Contrary to the depictions seen in cartoons, the uvula does not vibrate during singing and shouting and, in fact, has nothing to do with the voice.

Esophageal Muscle

Just above the point where the esophagus joins the stomach, some of the circular muscle fibers in its wall are thickened. These fibers are usually contracted, and function to close the entrance to the stomach. In this way, they help prevent regurgitation of the stomach contents into the esophagus. When peristaltic waves reach the stomach, the muscle fibers that guard its entrance relax and allow the food to enter.

Esophagus

The esophagus is a muscular tube which carries food and liquids from the throat to the stomach for digestion after it has been chewed and chemically softened in the mouth. Food is forced downward to the stomach (or upwards, if one is standing on his head) by powerful waves of muscle contractions passing through the walls of the esophagus. Because these contractions are so strong in the throat and the esophagus, we can swallow in any position — even upside-down! If the food is bad, poison, or more than we can “stomach,” it may travel back by the same force to be thrown out through the mouth, which is called vomiting. The esophagus has a ring of muscle at the top and at the bottom. These rings close or contract after the food passes through and enters the stomach, where there is an abundance of churning acid waiting to digest the food. If the bottom muscle weakens, stomach contents, along with the stomach acid, may return to the esophagus and cause an uncomfortable, burning sensation known as “heartburn”, although it is not connected with the heart at all, but be careful next time you are forced to swallow your pride.

Genioglossus Muscle

The genioglossus muscle is a flat, fan-shaped muscle that runs from the front of the lower jaw into the tongue from tip to base. Contraction of these muscles (on either side) makes the tongue stick out as its whole foundation is pulled forward.

Genihyoid Muscle

The geniohyoid muscle is a flat, straplike muscle, which passes from the side of the tongue down to one arm of the wishbone-shaped hyoid bone in the throat. Movement of these muscles pulls the sides of the tongue downward.

Palate

The palate forms the roof of the mouth and is made up of a hard surface in the front and a soft surface in the back. The “hard palate” is formed by the maxillary bones in the front and the horizontal portions of the palatine bones in the back. The “soft palate” forms a muscular arch that extends back and down as a cone-shaped projection called the “uvula.” During swallowing, muscles draw the soft palate and the uvula upward. This action closes the opening between the nasal cavity and the pharynx, preventing food from entering the nasal cavity.

Hyoid Bone

Just under the mandible is a U-shaped bone called the hyoid. The hyoid is closely associated with the skull but is not strictly a part of it. It anchors muscles, especially those of the tongue, and is the only bone in the body which is not linked to another. The blood vessels into and out of the hyoid bone are small branches of the external carotid artery, and are called “superior thyroid arteries” and “superior thyroid veins.”

Lingual Tonsil

The lingual tonsil is the group of lymphnoid follicles which can be located at the base of the tongue. It is just anterior of the epiglottis.

Lips

The lips are highly mobile structures that surround the mouth opening. They contain skeletal muscles and a variety of sensory nerves that are useful in judging the temperature and texture of foods. Their normal reddish color is due to an abundance of blood vessels near their surfaces. The external borders of the lips mark the boundaries between the skin of the face and the mucous membrane that lines the alimentary canal.

Mandible

The mandible (lower jawbone) consists of a horizontal horseshoe-like body with a flat “ramus” projecting upward at each end. The rami are divided into two processes: the “mandibular condyle” and a front “coronoid process.” The mandibular condyles unite with the mandibular tissues of the temporal bones, while the coronoid processes serve as attachments for muscles used in chewing. Other large chewing muscles are attached on the side surfaces of the rami.

Maxillary Bones

The maxillary bones form the upper jaw; together they are the keystone of the face, for all other immovable facial bones are connected to them. Portions of these bones make up the front of the roof of the mouth (hard palate), the floors of the orbits, and the sides and floor of the nasal cavity. They also contain the sockets of the upper teeth. Inside the maxillae, on the sides the nasal cavity, are the “maxillary sinuses” (antrum of Highmore). These air-filled spaces are the largest of the sinuses, and they extend from the floor of the orbits to the roots of the upper teeth. During development, portions of the maxillary bones called “palatine processes” grow together and fuse along the middle to form the front section of the hard palate.

Palatine Glands

In the back of the mouth, on either side of the tongue and closely associated with the palate, are masses of lymphatic tissue called “palatine tonsils,” or sometimes just tonsils. These structures lie beneath the lining of the mouth and, like other lymphatic tissues, they help to protect the body against infections. These are common sites of infection, and when they become inflamed, the condition is called “tonsillitis.”

Palate

The palate forms the roof of the mouth and is made up of a hard surface in the front and a soft surface in the back. The “hard palate” is formed by the maxillary bones in the front and the horizontal portions of the palatine bones in the back. The “soft palate” forms a muscular arch that extends back and down as a cone-shaped projection called the “uvula.” During swallowing, muscles draw the soft palate and the uvula upward. This action closes the opening between the nasal cavity and the pharynx, preventing food from entering the nasal cavity.

Thyroid Cartilage

The larynx (voice box) is composed primarily of muscles and cartilages that are bound together by elastic tissues. The thyroid cartilage was named for the thyroid gland that covers its lower part. This cartilage is the shieldlike structure that protrudes in the front of the neck and is sometimes called the “Adam’s apple.” The protrusion is usually more prominent in males than in females because of the effect of male sex hormones on the development of the larynx.

Thyroid and Parathyroid Glands

The thyroid gland is shaped like a butterfly and usually weighs less than one ounce. The thyroid cartilage covers the larynx and produces the prominence on the neck known as the “Adam’s Apple”. The thyroid gland controls the rate at which the body produces energy from nutrients. If the body does not get enough iodine, the thyroid gland cannot produce a proper amount of hormones for this conversion process. The result can be a goiter, an enlargement of the thyroid gland. In some parts of the world, iodine is so scarce that most of the population have goiters. The parathyroid glands are four small oval bodies located on either side of and on the dorsal aspect of the thyroid gland. These glands control the level of calcium in the blood. The thyroid gland secretes hormones which regulate energy, and emotional balance may rely upon its normal functioning. When the rate of production is excessive, the results can be weight loss, nervousness, or even emotional disturbances. If the rate of production is excessively low, a slowing of bodily functions may result. The parathyroid glands, located behind the thyroid, control the blood-calcium level. Calcium is important, not only for bones and teeth, but also for nerve functioning, muscle contractions, blood clotting and glandular secretion. If we don’t have enough calcium for these functions, the body will take it from the bones, causing them to easily fracture. It may also cause twitching, spasms, convulsions and even death. Too much calcium may cause a weakening of muscle tone and kidney stones.

Tongue

Anchored to the floor of the mouth and slung at the rear from muscles attached to a spiky outgrowth at the base of the skull, the tongue is a strong muscle that is covered by the lingual membrane, which has special areas which detect the flavor of food. The tongue is made up of muscles covered by mucous membranes. These muscles are attached to the lower jaw and to the hyoid bone (a small, U-shaped bone, which lies deep in the muscles at the back of the tongue) above the larynx. There are very small nodules, called papillae, from the top surface of the tongue, which give it its rough texture. Between the papillae at the sides and base of the tongue are small, bulblike structures that are sensory organs, called “taste buds,” which enable us to enjoy the sensations of flavor and warn us when food is unfit to eat. The muscle fibers are heavily supplied with nerves, so it can manipulate food in the mouth and place it between the teeth for chewing – without being bitten in the process. Babies have many more taste buds than an adult, and they have these almost everywhere in the mouth, including the cheeks. Nevertheless, adults enjoy more flavors than babies, who dislike bitter tastes and prefer bland food. The tongue also aids in the formation of sounds of speech and coordinates its movements to aid in swallowing. It is especially helpful when we are forced to “eat our words.” Enjoy!

The Tooth

A tooth is a hard structure, set in the upper or lower jaw, that is used for chewing food. Teeth also give shape to the face and aid in the process of speaking clearly. The enamel that covers the crown (the part above the gum) in each tooth can be broken down by acids produced by the mouth for digestive purposes. This process is called “decay”. To prevent decay, good oral hygiene, consisting of daily brushing and flossing, is necessary. The hardest substance in the human body is one of the four kinds of tissue which make up the tooth. It is enamel and covers the crown (area above the gum line) of the tooth. A bony material called “cementum” covers the root, which fits into the jaw socket and is joined to it with membranes. “Dentin” is found under the enamel and the cementum, and this material forms the largest part of the tooth. At the heart of each tooth is living “pulp,” which contains nerves, connective tissues, blood vessels and lymphatics. When a person gets a toothache, the pulp is what hurts.

Trachea

The trachea begins immediately below the larynx (voicebox) and runs down the center of the front part of the neck ends behind the upper part of the sternum. Here it divides to form two branches which enter the lung cavities. The trachea (windpipe) forms the trunk of an upside-down tree and is flexible, like a vacuum tube, so that the head and neck may twist and bend during the process of breathing. The trachea, or windpipe, is made up of fibrous and elastic tissues and smooth muscle with about twenty rings of cartilage, which help keep the trachea open during extreme movement of the neck. The lining includes cells that secrete mucus along with other cells that bear very small hairlike fringes. This mucus traps tiny particles of debris, and the beating of the fringes moves the mucus up and out of the respiratory tract, keeping the lungs and air passages free. In Russian folk medicine, there is the thought that rubbing the chest with pork fat will cure a cold. Mustard plasters and boiled snails in barley water were thought to be effective by others, and nobody knows what the ingredients were for early “cure-all tonics” and “snake oil” kits. It is now believed that the best medicine is to rest, keep warm, drink plenty of fluids, and eat good, digestible meals. Sounds good to me…and certainly better smelling.

Spine, Vertebra and Disk

The spine is a column of bone and cartilage that extends from the base of the skull to the pelvis. It encloses and protects the spinal cord and supports the trunk of the body and the head. The spine is made up of approximately thirty-three bones called “vertebrae.” Each pair of vertebrae is connected by a joint which stabilizes the vertebral column and allows it to move. Between each pair of vertebrae is a disk-shaped pad of fibrous cartilage with a jelly-like core, which is called the “intervertebral” disk – or usually just the “disk”. These disks cushion the vertebrae during movement. The entire spine encloses and protects the spinal cord, which is a column of nerve tracts running from every area of the body to the brain. The vertebrae are bound together by two long, thick ligaments running the entire length of the spine and by smaller ligaments between each pair of vertebrae. The anterior longitudinal ligament consists of strong, dense fibers, located inside the bodies of the vertebrae. They span nearly the whole length of the spine, beginning with the second vertebrae (or “axis”), and extending to the sacrum. The ligament is thicker in the middle (or “thoracic” region). Some of the shorter fibers are separated by circular openings, which allow for the passage of blood vessels. Several groups of muscles are also attached to the vertebrae, and these control movements of the spine as well as to support it. Quasimodo, the central character of Victor Hugo’s novel, “The Hunchback of Notre Dame,” is probably the most famous of all real or fictional sufferers of “kyphosis,” an abnormal, backward curvature of the spine.

Vocal Chord

The vocal cords are two fibrous sheets of tissue that are stretched in the inner surface of the Adams apple, which are responsible for voice production. (part of larynx)

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