Lecture 19: Gustation Flashcards
Where are gustatory receptors housed?
In specialized taste buds on the surface of the tongue
What are the 4 types of papillae on the tongue?
- filiform
- fungiform
- vallate
- foliate
Where are filiform papillae found on the tongue? Do these house taste buds?
On the anterior 2/3rds of the tongue
Do not house taste buds and have no sensory role in gustation
Where are fungiform papillae found on the tongue and do these contain taste buds?
On the tip and sides of the tongue. Contain only a few taste buds each
What is characteristic of the vallate (circumvallate) papillae of the tongue?
Least numerous but the largest. Arranged in an inverted V shape on the posterior dorsal surface of tongue. Each is surrounded by a deep narrow depression. Most of our taste buds are housed within the walls of these.
What is characteristic of the foliate papillae?
Not well developed on the human tongue. Extend as ridges on the posterior lateral sides. House only a few taste buds during infancy and early childhood.
What are the 5 basic taste sensation?
- salty
- sweet
- sour
- bitter
- umami
What is the function of olfactory supporting cells?
Sandwich the olfactory nerves and sustain and maintain the receptors
What is the function of basal cells in olfaction?
Stem cells that replace olfactory epithelium components
How many primary odors can the olfactory system recognize and how many chemical stimuli can it recognize?
- 50-60 different primary odors
- thousands of other chemical stimuli
What is the oral cavity the initial site of?
Mechanical digestion and chemical digestion
What is the superior boundary of the oral cavity formed by?
The hard and soft palates
What does the inferior surface of the oral cavity contain?
The tongue as well as the mylohyoid muscle covered with mucosa
What is the vestibule of the oral cavity?
Space between the cheeks or lips and the gums
What is muscle of the cheeks?
Buccinator muscle
What is another name for the gums?
Gingivae
What is characteristic of the anterior 2/3rds of the palate and what about the posterior 1/3rd?
Anterior 2/3=hard and bony (hard palate)
Posterior 1/3=soft and muscular (primarily skeletal muscle)
During swallowing, what elevates to close off the opening of the nasopharynx?
The soft palate and uvula
What is the fauces? What are these bound by?
The opening between the oral cavity and the oropharynx
Paired muscular folds
-glossopalatine arch (anterior fold)
-pharyngopalatine arch (posterior fold)
What is housed between the glossopalatine arch and the pharyngopalatine arch?
The palatine tonsils
What is the lingual frenulum?
A thin vertical mucous membrane that attaches the inferior surface of the tongue to the floor of the oral cavity
What does the posterior surface of the tongue contain?
Lingual tonsils
About how much saliva is secreted daily?
Between 1 and 1.5 L
What makes up 99% of the volume of saliva?
Water
What are the 3 maintain salivary glands?
- parotid glands
- submandibular glands
- sublingual glands
What stimulates parotid salivary gland secretions?
Parasympathetic axons in CN IX
What stimulates submandibular and sublingual salivary glands?
Parasympathetic axons in CN VII
What stimulates mucus secretion in salivary glands?
Sympathetic stimulation from cervical ganglia
What are the largest salivary glands?
Parotid
Where are parotid glands located?
Anterior and inferior to the ear partially overlying the masseter muscle
About what percent of the saliva is produced in the parotid glands?
25-30%
Where does the parotid duct open into in the oral cavity?
Into the vestibule next to the second upper molar
Where are submandibular glands located?
Inferior to the body of the mandible
About what percent of the saliva do the submandibular glands produce?
About 60-70%
Where does the duct of the submandibular gland open into?
Through the papilla in the floor of the mouth on the lateral sides of the lingual frenulum
Where are the sublingual glands located?
Inferior to the tongue and internal to the oral cavity mucosa
What is characteristic of the ducts of the sublingual glands and where do these open into?
Each gland extends multiple tiny sublingual ducts that open onto the inferior surface of the oral cavity, posterior to the submandibular duct papilla
What percent of the saliva is produced by the sublingual glands?
3-5%
What type of secretions come from the parotid gland?
Only serous
What type of secretions come from the submandibular gland?
Both mucous and serous
What type of secretions come from the sublingual gland?
Both mucous and serous
What are the functions of saliva?
- moistens ingested food and helps turn it into a semisolid bolus that is more easily swallowed
- moistens and cleanses the oral cavity structures
- inhibits bacterial growth in oral cavity
- watery medium into which food molecules are dissolved so taste receptors can be stimulated
What all parts does a tooth have?
An exposed crown
A constricted neck
One or more roots that anchor it to the jaw
What are dental alveoli?
Sockets within the alveolar processes of both the maxillae and the mandible in which the roots of the teeth fit tightly into
How many teeth does an infant gain and when do these appear?
20 deciduous teeth that erupt between 6 month and 30 months after birth
How many permanent teeth replace the baby teeth?
32
What are the 3 phases of swallowing?
Voluntary
Pharyngeal phase
Esophageal phase
What happens during the voluntary phase of swallowing?
Bonus of food is pushed by tongue against hard palate and then moves toward oropharynx
What happens during the pharyngeal phase of swallowing?
As bogus moves into the oropharynx, the soft palate closes off the nasopharynx, the epiglottis closes over laryngeal opening
What happens during the esophageal phase of swallowing?
Esophageal muscle contractions push bonus toward stomach; soft palate and epiglottis return to their pre-swallowing positions
