-
What is it called to take in food into the digestive tract?
ingestion
-
What is the movement of food through the digestive tract?
propulsion
-
What are 3 processes of mechanical digestion?
chewing, churning, segementation
-
What process of digestion occurs in the mouth?
chewing
-
What process of digestion occurs ibn the stomach?
churning
-
Where does segementation occur?
small intestine
-
What are the 2 processes of propulsion?
-
What 4 organs does peristalsis occur?
- esophagus
- stomach
- small intestine
- large intestine
-
Where does swallowing occur?
oropharynx
-
What are the 6 processes of digestive system overall?
- ingestion
- mechanical digestion
- propulsion
- chemical digestion
- absorption
- defecation
-
What is the catabolic breakdown of food?
chemical digestion
-
What do the 4 ingredients we ingest break down to during chemical digestion?
- carbohydrates = simple sugars
- proteins = amino acids
- lipids = fatty acids
- nucleic acids = nucleotides
-
Where does chemical digestion begin?
in the mouth
-
What is the difference between perastalsis and segmentation?
- peristalsis adjacent segements of GI tract moves food distally down
- segmentation nonadjacent segments of GI tract move food forward and backward
-
What is absorption?
movement of nutrients from GI tract to blood or lymph
-
What is the major absorption site?
small intestine
-
What is the elimination of indigestable solid wastes?
defecation
-
Where does defecation occur?
anus
-
What are 2 waste scenarios that would provide defecation?
- indigestable food (fiber)
- food that didn't get a chance to be absorbed
-
What are 2 things that control the GI tract?
mechano receprots and chemoreceptors
-
What meaqsures the stretchability of the GI tract?
mechanoreceptors
-
What measures the pH and osmolarity of the GI tract?
chemoreceptors
-
What mix GI tract's lumen contents and move them along?
mechanoreceptors and chemoreceptors
-
What 2 factors control the regulation of digestion?
intrinsic and extrinsic
-
What is the gut brain?
intrinsic nerves
-
What kind of factors are the central nervous system and autonmic nervous system (symp/parasymp) that act on the GI tract?
extrinsic factors
-
Which has shorter reflexes, intrinsic or extrinsic factors?
intrinsic
-
What 2 responses do the instrinsic and extrinsic factors have on the GI tract?
change in contractions or change in secretions
-
What are the 4 layers of tissue in the intestinal wall?
- mucosa
- submucosa
- musculariz externa
- serosa / adventitia
-
What layer of the intestinal wall lines the lumen of the alimentary canal?
mucosa
-
What are 3 major functions of the mucosa?
- secrete mucus
- absorb
- protect against infections
-
What are the 3 layers of the mucosa?
- epithelial
- lamina propia
- muscularis mucosae
-
What is the connective tissue that anchors epithelium?
lamina propia
-
What does mucus protect the GI tract from?
mucus protects from the enzymes within the GI tract from digesting the organs when theyre digesting food
-
What are 2 functions of mucus in the GI tract?
- protect from digestive enzymes harming organs
- ease food along the tract
-
What type of tissue is the epithelial lining of the mucosa?
simple columnar epithelium
-
What secrete mucus in the GI tract?
goblet cells
-
What 2 things do the stomach and small intestine mucosa layer secrete?
enzymes and hormones
-
What is the connective tissue that nourishes and absorbs nutrients of the epithelium?
lamina propia
-
What does lamina propia contain that protects the GI tract from nfection?
MALT
-
What kind of cells is the muscularis mucosa of the intestinal wall made of?
-
What is the difference between loose and dense connective tissue?
loose connective tissue has less fibers than dense
-
What type of tissue is the submucosa layer of the intestinal wall made of?
dense connective tissue
-
What 4 things does connective tissue contain?
- glands
- blood
- lymphatic vessels
- nerve plexus
-
What 2 types opf smooth muscle make up the muscularis externa layer of the intestinal wall?
- inner circular smooth muscle
- outer longitudinal smooth muscle
-
What layer of the intestinal wall is responsible for peristalsis?
muscularis externa
-
What happens if the muscularis externa layer of the intestinal wall thickens?
may form sphincters
-
What regulates how much food goes into each organ in order to prevent overfilling of that organs?
sphincters
-
What layer of the intestinal wall is the protective visceral peritoneum?
serosa
-
What is the serosa replaces by in the esophagus?
fibrous adventitia
-
What layers of the intestinal wall do retroperational organs have?
- mucosa
- submucosa
- muscularis externa
- serosa AND adventitia
-
What layer of the intestinal wall anchors and supports the organs of the digestive tract?
serosa
-
What tissue is the oral cavity lines with?
stratified squamous epithelium
-
What are 2 other names for the mouth?
-
What are 5 muscles of the lips and cheeks (oral cavity)?
- buccinator
- masseater
- zygomaticus
- temporalis
- orbicularis oris
-
What 2 bones make up the hard palate?
- palatine bone
- palatine process of the maxilla
-
What are 3 functions of the tongue?
- grips/positions food
- mixes food with saliva/ form bolus
- initiates swallowing
-
What are the 3 salivary glands?
- sublingual
- submandibular
- parotoid
-
What 4 functions does saliva have?
- cleanse mouth
- moisten food
- form bolus
- enzymes that break down starch
-
What are the 4 functions of the mouth in the digestive system?
- ingestion
- mechanical digestion
- chemical digestion
- propulsion initiated
-
What is one way mechanical digestion occurs in the mouth?
mastication (chewing)
-
What type of chemical digestion occurs in the mouth?
salivary amylase breaks down starch
-
What action in the mouth initiates propulsion?
deglutition (swallowing)
-
What are 4 types of teeth the mouth has?
- incisors
- canines
- premolars / bicuspids
- molars
-
What are 2 parts of the pharynx?
oropharynx and laryngopharynx
-
What type of epithelium is the pharynx lined with?
stratified squamous
-
What 3 things are sllowed to pass through the pharynx?
food, fluid, air
-
What is the layer of the pharynx that has two skeletal muscle layers present?
muscularis externa
-
What is type of muscle the esophagus made of?
1/3 skeletal, 2/3 smooth
-
Where in the brain do we initiate swallowing?
motor cortex in frontal lobe
-
What type of epithelium is the esophagus lined with?
stratified squamous
-
What do the glands in the pharynx do?
secrete mucous
-
Where does the esophagus go through to become the stomach?
pierces diaphragm, hole is called "hiatus"
-
What are the 2 phases of deglutition?
- buccal phase
- pharyngeal-esophageal phase
-
What happens during the buccal phase of deglutition?
bolus forced into oropharynx
-
What controls the pharyngea-esophageal phase?
medulla and lower pons
-
What phase of deglutition closes of respiratory passages?
pharyngeal-esophageal phase
-
What is the surface epithelium layer of the intestinal wall?
mucosa
-
What kind of special cells is the mucosa composed of?
goblet cells
-
What produces a coat of alkaline mucus for the mucosa layer?
goblet cells
-
What tissue is the mucosa?
simple columnar epithelium
-
What type of glands do gastric pits have?
gastric glands
-
What 3 things gastric glands secrete?
secrete gastric juices, mucus, and gastrin
-
What are 4 types of special cells in the stomach's mucosa?
- mucous neck cells
- parietal cells
- chief cells
- enteroendocrine cells
-
Which special cell of the mucosa layer secretes acidic mucus?
mucous neck cells
-
What type of special cell in the stomach's mucosa releases HCl?
parietal cells
-
What does HCl activate?
pepsinogen
-
What are parietal cells used for in the small intestine?
to absorb vitamin B12 for RBC production
-
What type of special cell in the stomach's mucosa produces pepsinogen?
chief cells
-
What secretion by the enteroendocrine cells stimulates contraction of the stomach and more gastric secretions?
gastrin
-
What are the 3 layers of the stomach's muscularis externa?
- longitudinal
- circular
- oblique
-
What 3 functions do the layers of the stomach's muscularis externa have?
- propulsion
- mechanical digestion
- chyme formation
-
What 2 chemical digestion acts occur in the stomach?
- pepsin breaks down proteins
- chyme formed
-
What 3 things are absorbed in the stomach?
water, alcohol, aspirin
-
What does the alkaline mucus secreted by goblet cells in the stomach do?
prevents digestive enzymes from digesting organs
-
What kind of mucous coat does the stomach have?
bicarbonate rich
-
What junctions of epithelium is the stomach?
tight junctions
-
How often is stomach epithelium replaced?
3-6 days
-
What are erosions of the stomach wall known as?
gastric ulcers
-
What causes gastric ulcers?
high acidity
-
What are Helicobacter pylori bacteria involved with?
cause of gastric ulcers
-
How are gastric ulcers treated?
antibiotics, acid reducers
-
What are the 3 phases of gastric secretion?
- cephalic
- gastric
- intestinal
-
What gastric secretion phase stimulates gastric secretion by pathway that includes hypothalamus, medulla, and parasympathetic NS?
cephalic phase
-
What 4 senses trigger gastric secretion?
- see
- taste
- smell
- thought of food
-
What phase of gastric secretion last up to 4 hours?
gastric phase
-
What 3 things is the gastric phase of gastric secretion stimulated by?
- distension
- peptides
- low acidity
-
Which phase of gastric secretion involves neural AND hormonal stimuli?
gastric phase
-
Which phase of gastric secretion stimulates the stomach?
gastric phase
-
What part of the intestine is in charge of the intestinal phase of gastric secretion?
duodenum
-
What type of reflex inhibits the stomach from entering chyme into intestine?
enterogastric reflexes
-
What 2 hormones are released from duodenum?
-
What hormone released from the duodenum stimulates enzyme-pancreatic juice and gallbladder contraction?
CCK
-
What 2 hormones from the duodenum inhibits the stomach?
-
What 2 things does secretin stimulate?
- bicarbonate-pancreatic juice
- liver's bile production
-
What 2 things could happen to chyme?
- delivered from stomach to duodenum
- forced back into stomach for further mixing
-
Where do peristaltic waves move toward? How fast?
- toward pylorus
- 3 per minute
-
What are the 3 peristaltic waves in the stomach?
- propulsion
- grinding
- retropulsion
-
How many hours does it take for the stomach to empty?
4
-
Which moves quicker from stomach to duodenum, carbohydrate chyme or fat chyme?
carbohydrate chyme
-
What two sphincters begin and end the small intestine?
- pyloric sphincter
- ileocecal valve
-
What is the longest section of the small intestine?
ileum
-
What are plicae circulares?
- deep circular folds
- small intestine
- mucosa and submucosa
-
What are the finger like extensions of the mucosa in the small intestine?
villi
-
What type of epithelium are primarily in small intestine?
absorptive columnar
-
What 2 places do nutrients from small intestine absorb into?
blood and lymph
-
What is the largest gland in the body?
liver
-
What shape of lobules is the liver made of?
hexagonal
-
What are the 4 hepatocyte (liver) functions?
- produce bile
- process nutrients to blood
- store fat vitamins
- detox
-
What is the yellow green alkaline solution from the liver?
bile
-
What are the bile pigments?
bilirubin
-
What are the 5 components of bile?
- bilirubin
- cholesterol
- triglycerides
- ions
- bile salts
-
What do bile salts do?
- emulsify fat
- aid fat+cholesterol absorption
-
What organ is bile stored in?
gallbladder
-
What cells are involved in the pancrease exocrine functions?
acini
-
What cells are involved in the pacrease endocrine functions?
beta cells
-
What do acini secrete?
pancreatic juice
-
What 3 things are in pancreatic juice
-
How does pancreatic juice neutralize acidic chyme?
pH = 8
-
What 2 forms do we find enzymes in pancreatic juice?
-
What is 1 inactive enzyme in pancreatic juice?
trypsinogen
-
What are 3 active enzymes in pancreatic juice?
- amylase -pancreatic
- lipase
- nuclease
-
Where is the main site of chemical digestion?
-
Does fat digestion take place in the duodenum?
no
-
How long does digestion in the duodenum take?
up to 5 hrs
-
What 2 movements occur in the small intestine?
-
What are 2 unique features of the large intestine??
-
What are the three bands of longitudinal smooth muscle in the large intestine's muscularis?
tenaie coli
-
What are the pocket like sacs caused by the tone of tenaie coli of the large intestine?
haustra
-
What are 2 functions of the large intestine?
- propulsion of feces to anus
- reclaimation of vitamins, water, electrolytes
-
What are the three big movements when the stomach is digesting called?
mass perastalsis forces
-
What intiates peristalsis?
presence of food in the stomach
-
What do bacteria do in the large intestine for digestion?
- chemical digestion
- ferment indigestables
- synthesize vitamins (K+B)
|
|