1. Oral Cavity, Pharynx and Oesophagus Flashcards
Name the muscles of mastication
Temporalis; Masseter; Lateral pterygoid, Medial Pterygoid
Name the Action of the temporalis
Elevation of mandible (jaw) ; opens/closes.
Retracts mandible - moving it backwards
Name the actions of the masseter
Elevates the jaw and protracts (moves jaw anteriorly)
Name the action of the lateral pterygoid
Protracts and adducts and abducts mandible
Name the actions of the medial pterygoid
Protracts, adducts and abducts
What are the muscles of mastication innervated by?
Innervated by the mandibular division of the trigeminal nerve - CNV3 (the mandibular division is the 3rd of 3 divisions of the trigeminal nerve, which is cranial nerve 5. )
Name the muscles of facial expression (also involved in speech)
Orbicularis Oris:: The sphincter of the lips is called the orbicularis oris, because it ‘orbits’ the mouth
Buccinator muscle- cheeck muscle: positioning a bolus of food between the molar teeth for grinding (but the movements at the TMJare caused by muscles of mastication
What are the muscles of facial expression innervated by?
CN7- Facial nerve
How many teeth do we have? what are they called?
Permanent: 4 quadrants x 8 teeth/quadrant
2 incisors
1 canine/cuspid
2 premolars/bicuspids
3 molars
32 teeth
PRIMARY (deciduous) 4 quadrants x 5 teeth: 2 incisors 1 canine 2 molars = 20 teeth
Explain the motor innervation of the tongue
MOTOR:
The muscles of the tongue (intrinsic and intrinsic) are innervated by the HYPOGLOSSAL NERVE (CN12)
EXCEPT the palatoglossus, which is innervated by the VAGUS NERVE (CNX). This muscle is also a muscle of the palate and most palate muscles are innervated by the vagus nerve
Explain sensory innervation of the tongue
Sensory innervation of the tongue includes general sensation (touch, pain, temperature) and hthe special sensation of taste.
Anterior 2/3 of the tongue:
- General sensation: MANDIBULAR DIVISION OF TRIGEMINAL NERVE (CNV3)
- Taste: FACIAL NERVE (CN7)
Posterior 1/3 of tongue
General Sensation: Glossopharyngeal Nerve (CN9)
Taste: Glossopharyngeal nerve again!
What are the intrinsic tongue muscles?
These are within the tongue:
Longitudinal, transverse, vertical= and change the shape of the tongue
Name the extrinsic tongue muscles
BONE TO TONGUE
- Genioglossus; Depress and protrudes the tongue
- Hyoglossus: depress and retract the tongue
- Styloglossus: Elevate and retract the tongue
- Palatoglossus- Elevates posterior tongue, closes oropharyngeal isthmus and aids in initiation of swallowing.
What are the salivary glands in the oral cavity?
Parotid, submandibular, sublingual, many small intrinsic.
Produce 1-1.5 l of saliva!!
How do we stimulate salivary gland secretions?
The thought, sight, smell, presence of food stimulates the PARASYMPATHETIC NERVOUS SYSTEM (or the craniosacral division of the autonomic nervous system) to stimulate saliva production and secretion.
What stimulates the Parotid Salivary gland?
CN9 (glossopharyngeal).
preganglionic nucleus is in the medulla
Ganglion: Otic
What stimulates the submandibular and sublingual salivary glands?
CN7 (facial nerve)
Preganglionic nucleus: in the pons
Ganglion: submandibular
What are the functions of the pharynx and oesopahgus?
Swallowing, propulsion of food to stomach
Pharynx also a part of the upper respiratory tract for breathing
Secretions (mucous) protect the mucosa
Upper and lower oesophageal sphincters - prevent air from entering the oesophagus and reflux of stomach contents
What are the three parts of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
What level does the pharynx run?
from BASE OF SKULL to C6/7 vertebrae
What is the sensory innervation of the pharynx?
CN9- GLOSSOPHARYNGEAL
CNX- VAGUS
What are the muscles of the pharynx? and what are they innervated by?
Superior, middle, inferior pharyngeal constrictors
Inferior constrictor include cricopharyngeus (upper oesophageal sphincter UOS or UES)
Palatopharyngeus
All innervated by CNX except
Stylopharyngeus - innervated by CN9
What are the muscles of the soft palate?
What is their innervation
LEVATOR VELI PALATINE
TENSOR VELI PALATINE- elevate palate during swallowing to prevent food moving into the nasopharynx.
PALATOGLOSSUS, PALATOPHARYNGEUS- depress palate and narrow opening to the oropharynx- enable you to chew and breathe at the same time.
All innervated by CNX (vagus)
Except tensor veli palatine (innervated by mandibular division of trigeminal nerve CNV3)
The Oesophagus
Skeletal, mixed and smooth muscle, innervated by CNX (Vagus nerve)
Mucus from glands protect the mucosa
Constrictions of the oesophagus at the origin (UOS), arch of aorta, diaphragm, LOS - pathology is more likely at these areas
Describe the anatomical relationship of the pharynx
In the posterior mediastinum: it is anterior to the descending aorta.
In the abdominal cavity it is posterior to the left lober of the liver.
Explain the stages of sWhat are the stages of swallowing?
VOLUNTARY (oral/buccal) phase
Pharyngeal phase
Explain the voluntary phase of swallowing
Tongue moves bolus of food into the oropharynx
Explain the pharyngeal phase of swallowing
Soft palate is elevated to close off the nasopharynx
Larynx: Elevated, moves anterior (suprahyoid muscles)- this opens the laryngopharynx
Elevation of the pharynx by the stylopharyngeus, palatopharyngeus.
The larynx is protected by contraction of the muscles around the laryngeal inlet to narrow the inlet, epiglottis pulled posteriorly- by the aryepiglottic and thyroepiglottic muscles
Vocal and vestibular folds are ADDUCTED by the lateral and transverse cricoarytenoids
The UOS RELAXES to allow bolus into the oesophagus
Waves of relaxation and contraction of the pharyngeal constrictors from superior to inferior moves bolus inferiorly.
CONTROL- Bolus contracting soft palate and oropharynx initiating swallowing reflex
The swallowing centre in the medulla coordinates motor neurons in pons, medulla, and upper cervical cord.
Explain the oesophageal phase of swallowing
Waves of peristalsis (contraction, relaxation) propels bolus from superior to inferior to stomach.
Controlled via swallowing centre and locally via the enteric nervous system.
UOS, LOS tonically contracted, relax to let bolus pass.
What are the pressures of the UES and LOS??
UOS: 60mmHg
LOS: 20-40mmHg
What are some oesophageal Disorders?
Oesophageal Reflux and Complications
Achalasia- poor relaxation of LOS, loss of peristalsis, simultaneous contraction of full length of oesophagus
Scleroderma causes fibrosis of the oesophagus
Tumours
What are the parts of the teeth?
CROWN, NECK, ROOT
The teeth are secured by gomphoses (fibrous joints of the ‘peg in socket’ variety) to the superior alveolar process of the maxilla and the inferior alveolar process of the mandible.
The teeth are living structures, with a rich neurovascular supply. The SUPERIOR ALVEOLAR nerves, branches of the maxillar division of the trigeminal nerve (CNV2) innervate the MAXILLARY teeth.
The INFERIOR alveolar nerve, a brance of the mandivular division (CNV3) of the trigeminal nerve, innervates the MANIDBULAR TEETH
