Swallowing - Tongue, Palate and Pharynx Quiz

Answer: Palatoglossus

All of the extrinsic muscles, as their names suggest, arise from structures outside of the tongue, and insert on the tongue itself. All of the intrinsic muscles and the extrinsic muscles (excluding palatoglossus) are supplied by the hypoglossal (XII) nerve, while palatoglossus is supplied by the pharyngeal plexus of the vagus (X) nerve.

The integrity of the hypoglossal nerve can be tested in the living by asking the subject to stick out their tongue; deviation to one side means that the nerve is damaged on that side as the tongue on that side is not coming out of the mouth.

Answer: Genioglossus

Genioglossus arises from the mandible and attaches to the hyoid bone, forming most of the body of the tongue. The muscle has various different levels of fibers with different actions: its superior fibers move the tip of the tongue, the middle fibers depress the tongue, and the inferior fibers are primarily involved in protruding the tongue out of the mouth.

Hyoglossus arises from the hyoid bone, and pulls the sides of the tongue down toward the hyoid. Styloglossus arises from the styloid process of the temporal bone in the skull, and is involved in retracting the tongue back after it has been stuck out. Palatoglossus, arising from the soft palate, mainly pulls the soft palate down to the tongue, but is also involved in retracting the tongue.

Answer: Soft

The hard palate contains bone and cannot move. The soft palate, however, has no bone and consists of muscle fibers. The levator of the soft palate elevates it, and is innervated by the pharyngeal plexus of the vagus (X) nerve. The tensor muscle contracts to make the soft palate stiff, and is innervated by the mandibular branch of the trigeminal nerve (V3).

Answer: Pharyngeal raphe

The constrictors form most of the wall of the pharynx, which is approximately 6 inches long in a human. It lies behind the nose and mouth, and is separated into three parts; nasopharynx, oropharynx, and laryngopharynx. The fibers of each constrictor arise from different places, but all converge on the pharyngeal raphe, a fibrous line of tissue running down the posterior center of the pharynx.

Answer: Cricopharyngeus

Cricopharyngeus is not in fact a separate muscle, but, as the question states, is formed from the lower fibers of the inferior constrictor. The upper oesophageal sphincter opens in swallowing to allow the bolus of food to pass through; it also serves to prevent a backflow of contents from the oesophagus or the stomach into the pharynx.

Answer: Elevating the pharynx

Stylopharyngeus travels from the styloid process along the superior constrictor, and moving underneath the middle constrictor at the overlap point between the two constrictors. It is supplied by the glossopharyngeal nerve (IX), and as well as elevating the pharynx during swallowing (which shortens it), it elevates the larynx and pulls the epiglottis up during swallowing and speaking.

Answer: Soft palate moving downward

The soft palate actually moves upward when swallowing, engaging with the ridge at the back of the pharynx. Stylopharyngeus acts in concert with the suprahyoid muscles to elevate the pharynx; effectively this causes the pharynx to jump up and "grab" the food bolus. Of course, if the food is sitting at the back of the mouth with nothing underneath it, gravity will cause it to fall downward.

The uvula helps to close off the nose so that food does not enter it.

Answer: Geniohyoid

As the name suggests, the infrahyoid muscles attach to the inferior (lower) border of the hyoid bone in the neck. They are sometimes called the "strap muscles" due to their long thin shape. When the hyoid bone is fixed, the infrahyoid muscles can work to elevate the larynx. There are four of them on each side of the neck: sternohyoid (between the sternum and hyoid), thyrohyoid (between the thyroid cartilage and hyoid), omohyoid (which has two bodies joined by an intermediate tendon and runs from the scapula to the hyoid), and finally the sternothyroid, which as its name suggests runs between the sternum and the thyroid cartilage without actually inserting on the hyoid bone itself. Omohyoid and sternohyoid are more superficial while the sternothyroid and thyrohyoid are situated deeper in the neck.

Geniohyoid is one of the four suprahyoid muscles that attach to the superior (upper) border of the hyoid bone. It runs between the chin and the hyoid. The others are: mylohyoid (which forms the floor of the mouth), stylohyoid (between the styloid process of the temporal bone and the hyoid), and digastric, which, like omohyoid, has two bellies joined by an intermediate tendon. The digastric tendon attaches to the hyoid while the two bellies arise from the mandible and the mastoid process of the temporal bone respectively.

Answer: Eustachian tube

Salpingopharyngeus arises from the Eustachian tube in the nose and its fibers blend into the palatopharyngeus in the pharynx. It helps stylopharyngeus in raising the pharynx during swallowing. It is important in equalizing air pressure in the middle ear, which is why swallowing a lot on airplanes helps "pop" your ears.

Answer: False

While we mainly think of swallowing as the process that occurs at the back of the mouth, there are actually a lot more things going on after that that are still part of the swallowing process. The oral stage is primarily voluntary, i.e. a person can choose to initiate swallowing whether there is food in the mouth or not.

The autonomic nervous system plays a bigger role in the pharyngeal and oesophageal phases, including closure of the larynx, opening of the Eustachian tube, and contraction (peristalsis) of the oesophageal smooth muscle to transmit the bolus of food to the stomach. Damage to the autonomic nervous system, for example due to Alzheimer's disease or stroke, can disrupt the swallowing process, causing dysphagia (difficulty or pain in swallowing).