GI tract - The upper GI tract

Flashcards made using the lecture by Dr Emily Hunter - The upper GI tract. Also using https://teachmeanatomy.info/encyclopaedia/m/mylohyoid/ by Max Bidewell. Video by Sam Webster https://www.youtube.com/watch?v=gdq8mjsWRkk.

What are the main structures of the upper GI tract?

Oesophagus, stomach, duodenum, liver, pancreas and gallbladder.

What makes up the roof of the mouth?

The hard and soft palate.

What makes up the floor of the mouth?

The mylohyoid muscle.

What makes up the lateral walls of the mouth?

The cheeks.

What makes up the posterior of the mouth?

The palatoglossal fold.

What makes up the anterior of the mouth?

The lips.

What is meant by the mylohyoid bone being one of the suprahyoid muscles?

It means that it is one of the four muscles that is found superior to the hyoid bone.

What is the action of the mylohyoid muscle?

It raises the hyoid bone and the floor of the mouth.

Where does the mylohyoid bone originate from?

It begins at the mylohyoid line of the mandible.

What is the attachment of the mylohyoid muscle?

It attaches to the hyoid bone.

What is the innervation of the mylohyoid muscle?

Innervation from the inferior alveolar nerve which is a branch of the mandibular nerve which is itself a branch of the trigeminal

What is the blood supply of the mylohyoid muscle?

Blood supply comes from the inferior alveolar artery which is a branch of the maxillary artery.

What is the vestibule of the mouth?

It is the space between the lips and the teeth.

What is the oral cavity?

It is the space behind the teeth.

What is the common name of the gingiva?

The gums.

Are salivary glands endocrine or exocrine glands?

Exocrine glands.

What are the three salivary glands located in the mouth?

The sublingual, submandibular and parotid.

What is the secretion of saliva from the salivary glands controlled by?

The autonomic nervous system - the sympathetic and parasympathetic nervous system.

What does the serous secretion from salivary glands contain?

Alpha amylase.

Where is the parotid gland located?

Next to the ear.

What muscle of mastication does the duct from the parotid gland run over?

The masseter.

What muscle of the cheek does the duct from the parotid gland pierce through?

The buccinator muscle of the cheek.

Where do the ducts of the submandibular gland open into?

The floor of the oral cavity, underneath the tongue.

What is the main branch of the nervous system that supplies the teeth?

The trigeminal nerve.

What branch of the trigeminal nerve supplies the maxillary teeth?

The maxillary branch of the trigeminal nerve which then branches into the superior alveolar nerve that supplies the maxillary teeth.

What branch of the trigeminal nerve supplies the mandibular teeth?

The mandibular nerve which then branches into the inferior alveolar nerve.

What is the origin artery for the blood supply of the teeth?

The external carotid artery.

What branches of the external carotid artery supply the teeth?

The maxillary artery branches off of the external carotid artery which supplies both the maxillary and mandibular teeth. The inferior maxillary artery supplies the mandibular teeth and the anterior and posterior superior maxillary artery supplies the maxillary teeth.

What kind of joint is the temporomandibular joint?

A synovial joint.

What is the innervation of the muscles of mastication?

The mandibular branch of the trigeminal nerve.

What is the blood supply of the muscles of mastication?

The maxillary artery and the superficial temporal. Venous drainage is the corresponding vessels to the arterial supply.

What are the other muscles of mastication other than the masseter and the temporalis?

The medial and the lateral pterygoid muscles.

Which muscles of mastication are responsible for opening the jaw?

The lateral pterygoid muscle. Gravity also has a role.

What muscles of mastication are responsible for closing the jaw?

The masseter, the temporalis and the medial pterygoid muscle.

Is the genioglossus muscle an intrinsic or an extrinsic muscle?

It is an extrinsic muscle.

What is the origin of the genioglossus muscle?

The mental spines of the mandible.

Which extrinsic muscle of the tongue helps in tongue protrusion?

The genioglossus muscle.

What is the origin of the hyoglossus muscle of the tongue?

The hyoid bone.

What is the role of the hyoglossus muscle?

It depresses the tongue during contraction.

What is the origin of the styloglossus muscle?

The styloid process.

What is the origin of the palatoglossus muscle?

The palate.

What does the palatoglossus muscle form?

The palatoglossus fold.

What is the role of the palatoglossus muscle?

Keep the saliva in the mouth to prevent it leaking into the oropharynx unintentionally. It is also responsible for moving the bolus of food to the back of the mouth and into the oropharynx.

What is the innervation of the tongue?

Primarily through the hypoglossal nerve.

The majority of the tongue receives innervation from the hypoglossal nerve what is the exception?

The palatoglossus which is supplied by the vagus nerve.

What is the blood supply of the tongue?

Mainly the lingual artery and vein but also by the tonsillar branch of the facial artery and the ascending pharyngeal artery.

Describe the innervation for general sensation of the tongue.

Posterior 1/3rd supplied by the glossopharyngeal nerve, anterior 2/3rds supplied by the lingual nerve which is a branch of the mandibular nerve from the trigeminal nerve.

Describe the innervation of the tongue for special sensation.

Posterior 1/3rd is supplied by the glossopharyngeal and the anterior 2/3rds is the facial nerve.

Where does the pharynx extend to?

C6.

What muscle is responsible for closing off the nasopharynx during the swallowing reflex?

The levator veli palatini which lifts the palate up. The musculus uvulae also has a role in closing the nasopharynx off.

What is responsible for preventing the passage of food accidentally into the larynx?

The epiglottis.

What is the innervation of the pharynx?

The pharyngeal plexus formed from the pharyngeal branches of the glossopharyngeal and the vagus nerve.

What happens to the larynx during swallowing?

It lifts up and causes the epiglottis to close it off.

What happens to the vocal folds during swallowing?

They close.

Where does the oesophagus extend to and from?

From C6 to T10.

What is the oesophageal hiatus?

It is where the oesophagus passes through the diaphragm.

What type of muscle makes up the upper oesophageal sphincter?

Skeletal muscle.

What are the muscles that make up the upper oesophageal sphincter?

The cricopharyngeus and the inferior constrictor muscles of the pharynx.

What type of muscle is the lower oesophageal sphincter made up of?

Smooth muscle.

What does the lower oesophageal sphincter prevent?

Gastro-oesophageal reflux.

What are the three anatomical constrictions of the oesophagus?

The pharyngo-oesophageal junction, the bifurcation of the trachea and the gastroesophageal junction.

What is the histology of the mouth, oropharynx, laryngopharynx and the oesophagus?

Non-keratinised stratified squamous epithelium.

What is the histology of the stomach?

Simple columnar epithelium.

What is Barrett’s oesophagus?

It is the migration of the simple columnar epithelium of the stomach up the oesophagus. It can be a precursor of oesophageal cancer.

What is the arterial supply of the stomach?

Arterial supply comes from the coeliac trunk.

What are the names of the lymph nodes that are responsible for lymph drainage of the stomach?

Coeliac nodes.

What are the five branches of the coeliac trunk that supply the stomach?

Left gastric artery, right gastric artery, left gastroepiploic artery, right gastroepiploic artery and short gastric artery.

What provides parasympathetic innervation to the stomach?

The vagus nerve.

What are parasympathetic functions of the stomach?

Secretory functions and peristalsis.

What are the roles of sympathetic innervation of the stomach?

Pain and also supplies the vasculature.

What is the feature of the stomach that allows it to stretch when ingesting food?

Rugae.

What is the name of the sphincter between the stomach and the duodenum? Where is it found?

Pyloric sphincter. It is found at the transpyloric plane.

What are the four parts of the duodenum?

Superior, descending, horizontal and ascending.

Is the superior part of the duodenum peritoneal or retroperitoneal?

Peritoneal.

What two important features are posterior to the superior part of the duodenum?

The common bile duct and the gastroduodenal artery.

Is the descending part of the duodenum peritoneal or retroperitoneal?

Retroperitoneal.

What two ducts enter into the descending part of the duodenum?

The pancreatic duct and the common bile duct.

What is the point called where the common bile duct and the pancreatic duct meet?

The hepatopancreatic ampulla (ampulla of Vater).

What is the major duodenal papilla?

It is where the hepatopancreatic ampulla empties into the duodenum.

Is the horizontal part of the duodenum peritoneal or retroperitoneal?

Peritoneal.

What vessel is anterior to the horizontal aspect of the duodenum?

The superior mesenteric artery.

What vessels are posterior to the horizontal aspect of the duodenum?

The inferior vena cava and the aorta.

What is the duodenojejunal flexure?

It is part of the ascending part of the duodenum which joins the duodenum to the jejunum.

What is the ligament of Treitz?

It joins the duodenojejunal flexure to the right crus of the diaphragm.