Upper GI Tract Structures and Function Flashcards
What is chewing’s main physiological purpose?
To defend against respiratory failure
Which nerves control voluntary chewing?
Somatic nerves
What 3 pairs of glands secrete saliva?
Parotid
Submandibular
Sublingual
What are the 5 main constituents of saliva?
Water Mucins - lubricant a-Amylase - cattalyses breakdown of polysaccharides Electrolytes - regulates pH Lysozyme - bacteriocidal
Which 2 nervous systems control salivary secretion?
Sympathetic and Parasympathetic
What is the effect of parasympathetic stimulation on salivary secretion?
Produces profuse watery salivary secretion
What is the effect of sympathetic stimulation on salivary secretion?
Produces small viscous salivary secretion
Is the 4th layer in the esophagus; serosa or adventitia?
Adventitia
What type of epithelium lines the mucosa in the esophagus?
Stratifies squamous epithelium
Does the esophagus contain mucous glands in the submucosa?
Yes
What occurs in the oral phase of swallowing?
The bolus (food) is pushed to the back of the mouth by the tongue
What effect does the presence of a bolus have on the pharynx?
It causes a sequence of reflex contractions of pharyngeal muscles?
Where are the contractions of pharyngeal muscles co-ordinated from?
Medulla
What is the name of the structure that relaxes allowing food to pass into the esophagus?
Upper esophageal sphincter
What does the upper esophageal sphincter do after the bolus has entered the esophagus and why?
Contracts to prevent food reflux
What is the name of the process that propels the bolus from the esophagus to the stomach?
Peristalsis
Which sphincter relaxes to allow the bolus to enter the stomach?
Lower esophageal sphincter
What process occurs immediately after the bolus has entered the stomach?
Relaxation of the stomach
Which nerves innervate the relaxation of the elastic smooth muscle of the gastric fundus and body of the stomach?
Vagal nerves
What are the 5 basic functions of the stomach?
Temporary storage Dissolve and begin to digest food Control delivery to small intestine Sterilise ingested materials Produce intrinsic factor
What sphincter allows entering of food to the duodenum?
Pyloric sphincter
What is the name of the submucosal and mucosal folds in the stomach?
Mucosae
Is the outer layer of the stomach; serosa or adventitia?
Serosa
