By: Chantea Braddock
HS130 Section # 9
Unit 9 Assignment
Once again my mini sub and I will be miniaturized making us 8 microns long and witnessing another Fantastic Voyage in a human body. This time I will be swallowed by a 55 year old man, while he is eating his meal consisting of a hamburger, French fries, and a root beer. I will be piloting my sub through his gastrointestinal tract to monitor the digestion of his meal, I will be describing all major structures I go through.
Digestion begins in the mouth. A brain reflex triggers the flow of saliva when we see or even think of food. Saliva moistens the food while the teeth chew it up and make it easier to swallow. Amylase, which is the digestive enzyme, found in saliva, starts to break down starch into simpler sugars before the food even leave the mouth. The nervous pathway involved in salivary excretion requires stimulation of receptors in the mouth, sensory impulses to the brain stem and parasympathetic impulses to salivary glands. Swallowing his food happens when the muscles in his tongue and mouth move the food into his pharynx. The pharynx, which is the passage way for food and air, a small flap of skin called the epiglottis closes over the pharynx to prevent food from entering the trachea and causing choking. For swallowing to happen correctly a combination of 25 muscles must all work together at the same time. After being chewed and swallowed the food enters the esophagus or gullet is the muscular tube in vertebrates through which ingested food passes from the throat to the stomach. It connects the pharynx, which is the body cavity that is common to both the digestive and respiratory systems behind the mouth, with the stomach, where the second stage of digestion is initiated. The esophagus is a long tube that runs from the mouth to the stomach. It uses rhythmic wave like muscle movements called peristalsis to force food from the throat into the...