Lecture 46- Digestive System Part 1 Flashcards
What is the gastrointestinal tract (GI Tract)?
Long twisting tube that starts at the mouth and ends at the anus
What are examples of the accessory organs?
Salivary glands, liver, pancreas, and the gall bladder
What do the accessory organs do?
Food does not move through them but they secrete substances into the GI tract
What are the three phases of digestion?
Cephalic, gastric, and intestinal phase
Where does the cephalic phase start?
When does it end?
The head (anticipation of ingestions)
Ends when the last mouthful is swallowed
What does the gastric phase represent?
The time that food is present in the stomach
What does the intestinal phase begin with?
What is its role?
Begins when chyme enters the duodenum
Controls the rate of gastric emptying and coordinates activities of organs
What phase has a parasympathetic response to food-based stimuli?
Cephalic phase
What two responses does the cephalic phase have? What do they mean?
- Secretory- secreting digestive juices by enzymes/glands
- Non-secretory- mixing, chewing, smooth muscle contraction/relaxation
What is the primary function of the cephalic phase?
Improve/optimize the efficiency of digestion, absorption, and use of nutrients contained in ingested foods
What phase does Covid-19 impact the most?
Cephalic phase- affects taste and smell/wanting to eat foods
What two factors make up saliva?
Water and glycoprotein
What two digestive enzymes can be found in saliva?
What do they do for conversion?
- Amylase- converts starches into simple sugars
- Lipase- converts triglycerides into fatty acids and glycerol
What is saliva super important for?
Taste perception
True or false:
Sleep suppresses rate of salivary flow
True
What is dental plaque and how does it form?
Sticky colorless film that forms when bacteria in the mouth mixes with sugary/starchy foods
Bathes tooth in acid, calcium released causing tooth decay
What are the 3 major causes of dental caries (tooth decay)?
- High intake of free sugars
- Lack of removal of plaque by brushing
- Inadequate exposure to fluoride
What is mastication?
Involves alternated symmetrical/rhymthic/coordinated movement between the 2 sides of the dental arches (chewing food)
What does chewing increase which enhances the ability of the salivary enzymes to digest food?
surface AREA/VOLUME
What is bolus the mixture of?
Chewed food and saliva
What does swallowing begin with?
Compression of the bolus against the hard plate
What happens after the bolus is compressed against the hard plate?
Retraction of the tongue forces the bolus into the oropharynx and assists in elevating the soft palate which seals off the nasopharynx
Once the bolus enters, the oropharynx reflex responses begin and the bolus is moved toward the _____
Stomach
The folding of ____ directs the bolus away from the trachea
Epiglottis
What are the 6 steps of swallowing by name?
- Hard palate
- Soft palate
- Bolus
- Oropharynx
- Epiglottis
- Trachea
What type of muscle contraction forces the bolus through the entrance to the esophogus?
Pharyngeal muscle contraction
What type of wave pushes the bolus from the esophagus to the stomach?
Peristaltic wave
What is peristalsis?
Involuntary constriction/relaxation of the muscles in digestive tract that creates wave like movements to push the contents of the canal forward/push food through
What is acid relfux?
Occurs when Lower esophageal sphincter (LES) does not close properly which allows digestive juices from stomach to rise to esophagus
What is GERD?
Gastroesophageal reflux Disease- if acid reflux happens more than two times a week
Which type of fiber would be most helpful and why in reducing the risk of diabetes?
Soluble fiber because it entraps sugars
