L9 - Swallowing Flashcards
What 2 tissue types is the tongue composed of?
1) Intrinsic Skeletal Muscle
2) Adipose Tissue
How is skeletal muscle arranged in the tongue?
Organized into bundles of fibres
What lines the adipose tissue on tongues?
Epithelium and Taste Buds
Which muscles are responsible for moving the tongue?
Extrinsic muscles
Which muscles anchor the tongue to the hyoid bones?
Extrinsic Muscles
What is the term used to describe movement of the tongue forward? “Push forward”
Protraction
What is the term used to describe movement of the tongue backwards?
Retraction
Which cranial nerve innervates the extrinsic muscles of the tongue?
Hypoglossal Nerve (XII)
What type of innervation comes from the Hypoglossal Nerve?
Motor
What are Brachyodont teeth?
Short-crowned teeth
What are hypsodont teeth?
Long-crowned teeth
What are the three tissues that comprise the tooth in all species?
Enamel
Dentine
Cement
What is the hardest substance in the body?
Enamel
Which species are brachyodont teeth common?
Carnivores
Which species are hypsodont teeth common?
Horses
What is the name of the structure that anchors the tongue to the floor of the mouth?
Lingual Frenulum
What is the difference between intrinsic muscles of the tongue and extrinsic muscles of the tongue?
Intrinsic muscle of the tongue are the ones within the tongue itself
Extrinsic muscles of the tongue are muscles that originate from another location and terminate on the tongue.
What effect will be had on the tongue if the hypoglossal nerve is damaged?
Will be unable to move the tongue because it has motor supply.
What anchors the tooth?
Root
What is the visible portion of the tooth called?
Crown
What is premolar 1 in horses?
Wolf Tooth
Why does the area within the gum line where the root is present get smaller in size with age in horses?
The teeth in horses are used for grinding. Overtime, the surface gets ground down, the root pushes out to maintain size of the tooth.
What 3 structures does the hypoid apparatus articulate with?
1) Skull
2) Tongue
3) Larynx
How does the hyoid apparatus facilitate swallowing?
Gets jerked rostrally during swallowing.
List the muscles associated with the hyoid apparatus.
Styloglossus Genioglossus Geniohyoid Hyoglossus Sternohyoid
Which muscle runs from the front of the mandible and articulates with the basihyoid bone in the hyoid apparatus?
Geniohyoid
Which muscle associated with the hyoid apparatus contracts to move the apparatus rostrally and causes swallowing?
Geniohyoid Muscle
Which muscle associated with the hyoid apparatus contracts to move the hyoid apparatus back into position after swallowing?
Sternohyoid
Which part of the hyoid apparatus does the styloglossus muscle articulate with?
Stylohyoid Bone
What is another term for swallowing?
Deglutition
Which pharyngeal muscle is the only one that dilates the pharynx?
Stylopharyngeus
How does a bolus of food get moved caudally into the oropharynx during the first step of swallowing?
The tongue squeezes the bolus caudally by applying pressure against the hard palate.
How does the tongue and soft palate move in the second step of swallowing?
The tongue moves caudally, causing the bolus to be pushed towards the esophagus. The soft palate moves dorsally to open the up the glottic cleft.
What is the difference between the larynx and pharynx?
The larynx is the upper part of the trachea.
The pharynx extends from the nasal cavity and mouth to the larynx. (Both food and air pass through here)
What is the glottis?
The opening between the vocal folds of the larynx.
What happens in the last step of swallowing?
The laryngopharynx squeezes the bolus towards the esophageal sphincter and the soft palate returns to its position ventrally.
List the cranial nerves that are associated with swallowing.
Trigeminal (V) Facial (VII) Hypoglossal (XII) Glossopharyngeal (IX) Vagus (X)
What structures involved in swallowing are innervated by cranial nerve XII (Hypoglossal)?
Tongue
Extrinsic Muscles of the Tongue
Geniohyoid Muscle
Which structures involved in swallowing are innervated by cranial nerve X (Vagus)?
Pharynx
Larynx
Glottis (closure of glottis)
Soft Palate Muscles
Which two cranial nerves that are associated with swallowing form a plexus?
IX and X (Glossopharyngeal and Vagus)
Which two cranial nerves are involved in the closure of the lips and sensation?
V and VII (Trigeminal and Facial)
Problems with which cranial nerves can cause issues in swallowing?
IX and X
What are the major differences in the facial anatomy of brachycephalic dog breeds?
Shortened Nasal Bone
Narrow Nostrils
Long and thickened soft palate
What is the clinical implication of the long and thickened soft palate in brachycephalic breeds?
Narrows the airway
Causes a constant need for increased respiration
What are the three regions that make up the ear?
1) External Ear
2) Middle Ear
3) Inner Ear
What is another word for the structure that composes the middle ear?
Tympanic bulla
What is the function of the external ear?
To receive sound waves
What is the auricle/pinna?
The flared portion of the external ear that is covered by skin and supported by cartilage.
Which three bones are contained within the middle ear (tympanic bulla) in order from out to in?
Malleus
Incus
Stapes
What is the function of the bones of the middle ear?
To transmit vibrations of the tympanic membrane to the oval window of the inner ear.
What is the tympanic membrane?
Ear Drum
What is the inner ear composed of?
Semi-circular ducts and Cochlea
Which portion of the ear is a common location of bacterial and yeast infections?
The middle ear.
Which salivary gland is present ventral to the ear?
Parotid salivary gland.
What is the name for the cartilage that is located rostromedially to the base of the auricle (pinna) on the surface of the temporal muscle?
Scutiform Cartilage
What is the function of the inner ear?
Converts sound to nerve impulse and maintains body balance.
Which structure in the inner ear detects sound?
Cochlear Ducts
What is the air filled cavity in the middle ear that can cause head-tilt, involuntary eye movement and vertigo when inflamed?
Tympanic cavity
What is a another term that can be used to refer to the bones of the middle ear (malleus, incus, stapes)?
Ossicles
