Digestion and Metabolism: Meal Response Phases & Stomach to Mouth Functions Flashcards
What is the autonomic nervous system responsible for?
Involuntary control of cardiovascular, respiratory, urinary, digestive, and reproductive functions.
Adjusts internal water, electrolyte, nutrient, and dissolved gas concentraions in body fluids
Where are signals of the brain sent to?
Gangli and then to peripheral target organs
What are the two autonomic systems?
Sympathetic and parasympathetic
What is autonomic tone?
A background level of activity maintained by autonomic motor neurons to regulate our bodies/
How is heart rate maintained?
With autonomic tone and the continuous release of acetylcholine and norepinephrine.
What ANS dominates our resting state
Parasympathetic
What is the digestive tract?
A long twisty tube that starts from mouth and ends at anus
Why are accessory organs called accessory organs?
They help the GI tract by secreting substances but do not actually take food iinto them.
What are the three phases of digestion?
Cephalic,
Gastric,
and Intestinal
What is the cephalic phase?
The first phase of digestion; it starts with the anticipation of ingestion and ends when the last mouthful is swallowed.
What is the gastric phase?
Time during which food is in the stomach
What is the intestinal phase
Begins when chyme enters into duodenum; controls that rate of gastric emptying and coordinates the activities of the intestinal tract, pancreas, liver, and gall bladder
What ANS mediates our response to food-based stimuli
PANS
How does COVID19 impact the cephalic phase?
Impact feeding behavior as smell and taste are lost, there is a lower drive to eat
What is the function of saliva?
Helps us form and swallow a bolus of food and breaks down food while we eat for taste perception.
What digestive enzymes are in the saliva?
Amylase and Lipase
What does Amylase act on?
Starches and turns them into simple sugars
What does Lipase act on
Triglycerides and turns them into fatty acids and glycerol
What does Lysozyme do in the saliva?
Lyses bacteria and creates an antibacterial affect
How does sleep affect salivary flow?
Suppresses the rate
What is dental plaque?
sticky, colorless biofilm that forms when bactera in the mouth mix with sugary or starchy food
How does dental plaque affect teeth?
Bacteria break down caught sugars more which bathes our teeth in acid and releases calcium causing tooth decay.
What are the major causes of dental caries?
high intake of sugars, lack of toothbrushing, and inadequate exposure to fluoride
What is mastication
chewing to break down food; increases surface area of food for saliva to work on
How does swallowing work?
retraction of the tongue forces the bolus into the oropharynx and elevates the soft palate which blocks the nasopharynx,
the epiglottis then closes to block the airway and the pharyngeal muscles contract and force the bolus into the esophagus
Where do peristaltic waves begin
In the esophagus
What is peristalsis?
Involuntary contractions and relaxations of the digestive tract muscles that create wave like movements to push contents forward.
How does the bolus enter the stomach?
As it approaches the lower esophageal sphincter, the sphincter opens allowing it to empty into the stomach.
What is Aschalasia?
Failure of the Lower esophageal sphincter to open when swallowing; it is related to damaged nerves either in esophagus or LES.
What is GERD
Gastroesophageal Reflux Disease; When LES doesn’t close properly, it allows juices from the stomach to enter the esophagus (acid reflux) occurs more than 2x a week.
Treated by antacids, H2 receptor blockers, and proton pump inhibitors.
How does sword swallowing work?
Hyperextension of the neck to align the mouth with the esophagus and straightens the pharynx.
