SCI-228 Week 1 Discussion: The Digestive System | Already Graded A+

SCI-228 Week 1 Discussion: The Digestive System Week 1 discussion Class -Please define the following and identify their location along the digestive tract! Esophageal sphincter Gastroesophageal sphincter (sometimes referred to as the lower esophageal sphincter) Pyloric sphincter Ileo-cecal valve Why are these important along the route of the digestive tract? Esophageal sphincter- In upper esophageal sphincter. A sphincter that keeps the opening between the pharynx and the proximal esophagus closed, except during swallowing. It is maintained by the cricopharyngeal muscle. Gastroesophageal sphincter- a ring of smooth muscle fibers connecting the esophageal and stomach. Also called lower esophageal sphincter. Pyloric sphincter- The pyloric sphincter is a band of smooth muscle at the junction between the pylorus of the stomach and the duodenum of the small intestine. It plays an important role in digestion, where it acts as a valve to controls the flow of partially digested food from the stomach to the small intestine ileocecal valve - the valve formed by two folds of mucous membrane at the opening of the ileum into the large intestine—called also Bauhin's valve, ileocolic valve, valvula coli. • Imagine yourself eating a ham and a sandwich which steps take place with regard to digest the sandwich? a) Make sure that the students can distinguish between mechanical and chemical digestion. I would say that while eating sandwich all system of body is involved in preparing and eating process except reproductive system. I believe that the journey of a sandwich and a ham (or any piece of food) takes as it makes its way through the digestive tract. I will say that first; it all starts in our head. For example, in front of my is a turkey and a cheese sandwich with lettuce, onion, red bell, pepper, mustard and mayonnaise on multi-grain bread. If I really want that sandwich, I must have to notice that i am salivating. The hungrier I am and the more I will salivate. That’s because digestion actually begins in the brain. This is the cephalic phase of digestion, which is stimulated by the parasympathetic nervous system. When I see and smell food and even start thinking about eating, the brain readies the digestive tract for nourishment. This anticipation stimulates the secretion of saliva in the mouth and gastric juices in the stomach. a) Digestion in the mouth and distinguish between mechanical and chemical digestion. Once if I take a bite of sandwich I have initiated mechanical digestion. This chewing reduces the size of the food particles and mixes them with saliva for easier swallowing. Before my food passes from the mouth and down to esophagus, salivary amylase, an enzyme in saliva, begins to digest the starch in my bread. That is the start of chemical digestion. The mass of chewed sandwich is called a bolus. I voluntarily swallow it, but the rest of the digestion-absorption process is involuntary. The passage of the bolus through the esophagus to the stomach occurs by peristalsis, a series of wave-like muscle contractions. Reference Food and our Digestive Tract.(n.d.). Retrieved from,