Flashcards in Anatomy- how do we taste, chew and swallow? Deck (91):
What are the four muscles of mastication?
Specify which of these are jaw opening and jaw closing muscles.
Jaw closing: masseter, temporalis, medial pterygoid
Jaw opening: lateral pterygoid
What is the origin and insertion of the masseter?
The angle of the mandible and the zygomatic arch/zygoma.
What is the origin and insertion of the temporalis?
The coronoid process of the mandible and the lateral aspect of the neurocranium
What is the origin and insertion of the medial pterygoid?
The Medial side of the angle of the mandible
The pterygoid plates of the sphenoid bone
What is the origin and insertion of the lateral pterygoid?
The condyle of the mandible
The pterygoid plates of the sphenoid bone
What supplies the muscles of mastication?
The mandibular division of the trigeminal nerve (CNV3)
What are the muscles of facial expression?
A group of skeletal muscles, attaching between bones of the face and the superficial fascia just deep to the skin of the face.
What supplies the muscles of facial expression?
Cranial nerve VII (facial nerve)
What is the name of the circular muscle which encircles the lips?
What does it do?
Orbicularis oris. It creates a seal that prevents dribbling during chewing and swallowing.
What type of epithelium lines the oral cavity? Which parts of the epithelium are keratinised?
Stratified squamous epithelium
The epithelium lining the gingivae and the hard palate are keratinised for their protection during swallowing.
Why does the mucosa in the oral cavity appear pinker than skin?
Because it is very vascular.
How is the mucosa in the oral cavity named?
Name all the different parts.
It is named according to the area of the oral cavity it covers.
I.e. palatal mucosa, lingual mucosa, mucosa of the floor of the mouth, buccal mucosa and labial mucosa.
What are the parts of the oral cavity from which the teeth protrude named?
The upper and lower dental arches
Why is the mouth the most sensitive body area?
There is a large number of sensory receptors in the oral mucosa and there is a large area of brain dedicated to interpreting sensory signals from the mouth area.
What are the general sensations felt by the mouth?
Which nerve is responsible for these?
Pain, temperature, touch and proprioception.
Cranial Nerve V (trigeminal)
What is the special sensation sensed by the mouth?
Which nerves transmits these impulses?
Taste is the special sensation of the mouth.
Cranial nerves VII and IX (facial and glossopharyngeal)
What is the tongue made of?
Which nerve supplies it?
It is made of skeletal muscle and is supplied by CN XII (hypoglossal nerve)
What structures cover the tongue?
What are their functions?
Some papillae give surface texture which helps the tongue manipulate food.
Some papillae have the function of taste.
Which part of the tongue is in the oral cavity?
The anterior 2/3, which is the horizontal part of the tongue.
Where is the posterior 1/3 of the tongue located?
In the oropharynx
Which papillae have taste buds?
Which cranial nerves are they supplied by?
The foliate papillae, the valate papillae and the fungiform papillae.
They are supplied by cranial nerves VII and IX (facial nerve and glossopharyngeal nerves)
Which papillae do not have taste buds and just have general sensations?
Which cranial nerve are they supplied by?
CN V (trigeminal)
How is the tongue suspended in position?
By four pairs of skeletal muscles called the extrinsic muscles of the tongue. These muscles attach at one end to structures outwith the tongue and insert at the other end into the tongue.
How is the shape of the tongue modified?
By four pairs of skeletal intrinsic muscles of the tongue.
What muscle in the cheek is closely related to the orbicularis oris?
What nerve supplies this muscle?
What is the function of this muscle?
It is supplied by cranial nerve VII.
With the help of the tongue, it acts to position the food bolus between the occlusal surfaces of the premolar and molar teeth for mastication.
Where do the external muscles of the tongue originate from?
The styloid process of the temporal bone, the hard palate, the hyoid bone and the mandible.
How many teeth does an adult have?
How are they arranged?
32. They are in 4 quadrants (upper and lower right and left).
The teeth in each quadrant is number 1-8.
1-2 = incisors
4-5 = premolars
6-8 = molars ( 8 are the wisdom teeth).
What are the salivary glands classified as?
Accessory organs of the upper GI tract
What does saliva contain?
Water (99%)- solute to allow tasting to occur
Mucin- a lubricant to aid speech and swallowing and for keeping the mucosa moist
Buffer- for plaque acids
Amylase to begin CHO digestion
What are the major salivary glands?
There are 3 pairs:
These produce 90% of our saliva
What are the minor salivary glands?
There are 1000s in the oral mucosa. These carry out basal secretion which is background and continuous to keep the mucosa moist.
Where is the parotid duct?
It crosses superficial to the masseter muscle and and pierces the buccinator muscle to reach the buccal mucosa.
Where are the ducts of the sublingual gland?
There are multiple, which open out into the mucosa of the floor of the mouth
Where is the submandibular duct?
In the floor of the mouth
What kind of epithelium lines the pharynx?
Non-keratinised stratified squamous epithelium
What does the pharynx connect with?
Superiorly it connects anteriorly with the nasal cavities
Then it connects anteriorly with the oral cavity
Inferiorly it connects anteriorly with the larynx
What type of muscle is in the pharynx?
Where are the tonsils?
In the mucosa of the nasopharynx and oropharynx
What type of tissues are the tonsils and what do they do?
They are lymphoid tissues
They produce white blood cells
What is the ring of tonsils called?
Waldeyer's ring of tonsils
What is the opening to the larynx called?
The laryngeal inlet
Which bone is at the posterior aspect of the nasal septum?
How many layers of pharyngeal muscles are there?
Describe the inner layer of pharyngeal muscles.
A vertically arranged layer of longitudinal muscles.
These attach inferiorly to the larynx.
They contract during swallowing to shorten the pharynx (to reduce bolus transit time) and raise the larynx. Raising the larynx towards the epiglottis closes the laryngeal inlet.
Describe the outer layer of pharyngeal muscles.
A circularly arranged layer of constrictor muscles.
These are called the superior, middle and inferior pharyngeal constrictors.
They sequentially contract from superior to inferior to push the bolus inferiorly into the oesophagus.
What are the three groups of tonsils, and where are they found?
1. The adenoids/pharyngeal tonsils: found in the mucosa of the rood and the posterior wall of the nasopharynx
2. The tonsils/palatine tonsils: found in the mucosa of the lateral walls of the laryngopharnyx
3. The lingual tonsils: found in the mucosa of the posterior 1/3 of the tongue.
What supplies the inner longitudinal layer of muscles of the pharynx?
Cranial nerves IX and X.
What supplies the outer circular layer of pharyngeal constrictor muscles?
Cranial nerve X.
What is the name for the sphincter at the junction between the pharynx and the oesophagus?
What is its function?
The cricopharyngeal sphincter
It is made from a complete circle of skeletal muscle called the cricopharyngeus.
It helps to prevent regurgitation.
What is the area of common ground between the upper respiratory tract and upper GI tract?
The oropharynx and the laryngopharynx
Where does the oesophagus lie in relation to the trachea?
It is posterior to the trachea.
What kind of epithelium lines the oesophagus?
Non-keratinised stratified squamous epithelium
What kind of muscle is in the oesophagus?
It gradually transitions from skeletal muscle to smooth muscle
What is aspiration?
What can cause it?
The inhalation of liquid or solid matter into the lungs.
It can be caused by:
1. abnormal swallowing, which can be accidental or pathological, e.g. due to a stroke which affected the nerve supply to the pharyngeal muscles (mainly CN X)
2. breathing in
3. Abnormal coughing
What is CNV3?
The mandibular division of the trigeminal nerve
Where does CNV3 enter/exit the CNS?
At the pons
Where does CNV3 exit the cranial cavity?
Through the formaen ovale
Which nerve supplies the posterior 1/3 of the tongue with the Special sensation of taste and general sensation?
Which nerve supplies the anterior 2/3 of the tongue with the special sensation of taste?
Where in the mouth does CNV3 supply, and what does it supply?
It supplies general senstion
To the anterior 2/3 of the tongue
The gingivae of the inferior half of the oral cavity
The floor of the mouth
What supplies general sensation over the gingiva of the superior half of the oral cavity, and the palate?
What is CN V2?
The maxillary division of the trigeminal nerve
Where does CN V2 enter/exit the CNS?
At the pons
How does CN V2 enter/exit the cranial cavity?
Through the foramen rotundum
Where does CN VII exit/enter the cranial cavity?
The internal acoustic meatus
The stylomastoid foramen
What does the chorda tympani branch of CN VII supply?
special sense of taste to anterior 2/3rds tongue
parasympathetic secretomotor to submandibular & sublingual salivary glands
Where does CN VII enter/exit the CNS?
The junction of the pons and the medulla
Name the extrinsic muscles of the tongue
palatoglossus, styloglossus, hyoglossus and genioglossus
Which nerve supplies all but one muscles of the tongue?
Where does CN XII exit the CNS?
At the medulla
Where does CN XII exit the cranial cavity?
The hypoglossal canal
What innervates the posterior wall of the oropharynx?
Somatic sensory nerve fibres within CN IX
Which nerve fibres carry out the sensory part of the gag reflex?
Nerve fibres within CN IX
What nerve fibres carry out the motor part of the gag reflex?
Nerve fibres within CN IX and CN X
Where does CN IX exit the CNS?
Where does CN IX exit the cranial cavity?
The jugular foramen
What type of muscles are all of the muscles of swallowing?
What types of nerves innervate them?
Where do the parotid ducts enter the oral cavity?
Opposite the upper 2nd molar
Where do the submandibular ducts enter the oral cavity?
At the base of the lingual frenulum
Where do the sublingual ducts enter the oral cavity?
Into the floor of the mouth
What is the site of the upper oesophageal sphincter?
The cricopharyngeus muscle
What is the enteric nervous system?
an extensive network of nerves found only within the walls of the GI tract which can act independently of other parts of the nervous system but can also be influenced by
autonomic motor nerves
Is the oesophagus anterior or posterior to the heart in the chest?
Where does the oesophagus begin?
at the inferior edge of the cricopharyngeus muscle (approx. level C6)
What sphincters does the oesophagus have?
an anatomical upper oesophageal sphincter
(cricopharyngeus muscle) and a physiological lower
What is the name of the plexus which supplies the oesophagus?
Where does it run?
What does it contain and what does it do?
The oesophageal plexus
It runs on the surface of the oesophagus
It contains vagal trunks and sympathetic nerve fibres
These fibres influence the nerves of the enteric nervous system to speed up (P) or slow down (S) peristalsis
What causes the constrictions in the oesophagus?
How many does it have?
constrictions are caused by adjacent structures forming
an impression on its external wall
It has 3
Name the 3 constrictions of the oesophagus and describe what causes them.
1. The cervical constriction, as a result of the cricopharyngeus muscle, i.e. the UOS
2. The thoracic constriction(s), as a result of the arch of the aorta and the left main bronchus
3. The diaphragmatic constriction = the lower oesophageal sphincter,as a result of passing through the diaphragm.
Is the lower oesophageal sphincter an anatomical or a physiological sphincter?
What causes it?
The sphincter effect is a result of various
• the contraction of the diaphragmatic
muscle around the oesophagus
• the intrabdominal pressure being slightly
higher than the intragastric pressure
• the oblique angle at which the
diaphragm enters the cardia of the
What is the line that marks the change from oesophageal mucosa to gastric mucosa?
The Z line