digestive system Flashcards
ingestion
the first stage of digestion
- the process of taking in food/drink through the mouth
propulsion
movement of food through the digestive tract through both voluntary and involuntary processes
through:
- deglutition (swallowing)
- peristalsis
- gastric emptying
mechanical digestion
the physical breakdown of food into smaller pieces (with no alteration of its chemical composition)
increases surface area of food, making it easier for enzymes to chemically digest it
chemical digestion
breaking down food into simpler molecules using enzymes and digestive secretions
changes the chemical structure of food molecules so it can be absorbed by the body
areas:
- mouth (salivary amylase breaks down carbohydrates from starch -> maltose)
- stomach (pepsin (activated by stomach acid) breaks downs proteins -> peptides)
- small intestine (pancreatic amylase (continues carb digestion), trypsin chymotripsin and peptidase (breaks into amino acids), lipase (with bile from liver, breaks down fats -> fatty acids and glycerol)
absorption
digested food passing into the bloodstream or lymph to be transported to the body
* maybe add more
defecation
final stage of digestive process, where the body eliminates undigested food, waste products, and toxins from the digestive tract through feces
extracellular digestion
process of breaking down food outside the cells
intracellular digestion
food particles being taken by phagocytosis
peristalsis
involuntary wave like contractions that moves food, liquids, and other substances down the digestive tract:
- the GI tract has 2 layers of muscle (stomach has 3)
- circular muscles contact, squeezing the tube
- at the same time in the section inferior to the circular muscles, longitudinal muscles contract, widening tube and shortening it
deglutition
the process of swallowing, moving food from mouth to stomach
has 3 phases:
1. oral phase (voluntary) - the tongue pushes the food (bolus) towards the back of the mouth
2. pharyngeal phase (involuntary) - the bolus moves through the pharynx, the epiglottis closes over the trachea to prevent choking
3. esophageal phase (involuntary) - the bolus is pushed down by the esophagus by peristalsis into the stomach
chyme
when bolus is mixed with gastric juices in the stomach that moves into the small intestine
understand and label:
- organs in digestive system
- stomach
- intestines
- liver & gallbladder
roles it plays in food related functions in the buccal cavity:
- lips
the entrance to the mouth, with very vascular thin layer of keratin
- regulates what comes and goes in the mouth
roles it plays in food related functions in the buccal cavity:
- cheeks
confines food between teeth
- allows food to be chewed evenly during mastication
roles it plays in food related functions in the buccal cavity:
- hard palate
the bony structure that forms the roof of the mouth and separates the oral from the nasal cavity
- plays roles in digestion, speech, and breathing:
1. aids in chewing - lets the tongue have a space to press down on food
2. facilitates swallowing - helps push food toward the pharynx during swallowing
3. separates cavities - prevents food/liquids from entering the nasal passages
roles it plays in food related functions in the buccal cavity:
- soft palate
the flexible, muscular part at the back of the roof of the mouth
- plays a crucial role in swallowing, breathing, and speech
1. closes off the nasal cavity when swallowing- moves upwards to block the nasopharynx
2. prevents choking - works with the epiglottis to direct food down the esophagus and away from the airway
roles it plays in food related functions in the buccal cavity:
-uvula
the small dangly thang at the back of the back of ya throat (love u cardi)
1. aids in swallowing - helps close off the nasal cavity during swallowing
2. triggers gag reflex - acts as a protective mechanism to prevent choking by inducing a reflex when touched by large/foreign objects
3. assists in lubrication - produces saliva to keep throat most
roles it plays in food related functions in the buccal cavity:
- teeth
organs similar to bones that tears, grinds, and mechanically breaks down food
roles it plays in food related functions in the buccal cavity:
- tongue
a WORKHORSE????
1. facilitates ingestion
2. aids in mastication (chewing) - positions food between teeth for proper grinding
3. assists in swallowing (deglutition) - moves food towards the pharynx, initiating swallowing process
4. has taste buds to detect flavours
5. cleanses mouth - moves food particles away and helps stimulate saliva production for oral hygine
6. chemical digestion (lingual lipase for fat digestion)
muscles of the tongue perform 3 digestive functions in the mouth:
1. position food for optimal chewing
2. gather food into a bolus (rounded mass)
3. position food so it can be swallowed
roles it plays in food related functions in the buccal cavity:
- salivary glands
housed within mucous membranes of the mouth and tongue
- these minor exocrine glands constantly secrete saliva, directly into oral cavity of indirectly through ductws
- secretions increases when eating, because saliva is essential to moisten food and initiate the chemical breakdown of carbs
- small amts of saliva is also secreted by the labial glands in the lips
roles it plays in food related functions in the buccal cavity:
- lingual glands
located on the top and sides of the tongue, secretes a mucus and watery serous fluid that contains the enzyme lingual lipase, that plays a minor role in breaking down triglycerides (fats)
salivary amylase
produced by: salivary glands
function: breaks down polysaccharides (starch, glycogen) -> maltose
sucrase
produced by: small intestine
function: sucrose -> glucose + fructose
maltase
produced by: small intestine
function: maltose -> glucose