Palate and its function
Dr Prithvi Raj K
Sarjapur main road, Bengaluru Feb 9, 2017
The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate.
The palate has two main functions. The first is to act as a mechanical barrier between the mouth and the nose so that what we eat and drink doesn’t leak back out through the nose. The second is to act as a valve at the back of the throat to block the flow of air into the nose. This second function is extremely important and is necessary for feeding as an infant and for speech.
When we talk, air comes out of our lungs, travels up through the vocal cords and arrives at the back of the throat. In order to form speech sounds from that air, it then has to go to the right place – we make some speech sounds in our nose and others in our mouth. The soft palate directs the flow of air into the right place for the right sound. Most of the sounds in speech are made in our mouths, so if the soft palate has a cleft, or if it doesn’t work well, then most of the sounds that we use in speech can’t be made. See the speech section for more information.
Types of palate:
The hard palate is a thin horizontal bony plate of the skull, located in the roof of the mouth. It is formed by the palatine process of the maxilla and horizontal plate of palatine bone, and spans the arch formed by the upper teeth.
The hard palate is formed by the palatine process of the maxilla and horizontal plate of palatine bone. It forms a partition between the nasal passages and the mouth. On the anterior portion of the roof of the hard palate are the plicae, irregular ridges in the mucous membrane that help facilitate the movement of food backwards towards the larynx. This partition is continued deeper into the mouth by a fleshy extension called the soft palate.
The hard palate is important for feeding and speech. Mammals with a defective hard palate may die shortly after birth due to inability to suckle (see Cleft palate below). It is also involved in mastication in many species. The interaction between the tongue and the hard palate is essential in the formation of certain speech sounds, notably palatal consonants
The soft palate (also known as the velum or muscular palate) is, in mammals, the soft tissue constituting the back of the roof of the mouth. The soft palate is distinguished from the hard palate at the front of the mouth in that it does not contain bone.
Muscles: Dissection of the muscles of the palate from behind.
The five muscles of the soft palate, play important roles in swallowing and breathing. The muscles are:
Tensor veli palatine, which is involved in swallowing
Palatoglossus, involved in swallowing
Palatopharyngeus, involved in breathing
Levator veli palatini, involved in swallowing
Musculus uvulae, which moves the uvula
These muscles are innervated by the pharyngeal plexus via the vagus nerve, with the exception of the tensor veli palatini. The tensor veli palatini is innervated by cranial nerve 5 branch V3 (which is the mandibular division of the trigeminal cranial nerve).
The soft palate is moveable, consisting of muscle fibers sheathed in mucous membrane. It is responsible for closing off the nasal passages during the act of swallowing, and also for closing off the airway. During sneezing, it protects the nasal passage by diverting a portion of the excreted substance to the mouth.
In humans, the uvula hangs from the end of the soft palate. Research shows that the uvula is not actually involved in the snoring processes. This has been shown through inconsistent results from uvula removal surgery. Snoring is more closely associated with fat deposition in the pharynx, enlarged tonsils of Waldeyer's ring, or deviated septum problems. Touching the uvula or the end of the soft palate evokes a strong gag reflex in most people.