the digestive system ch 38-40 Flashcards
layers of the GI tract (sup to deep)
serosa/adventitia
muscularis
submucosa
mucosa
deglutition
swallowing
accessory organs include: (6)
teeth
tongue
salivary glands
liver
gallbladder
pancreas
how long is the GI tract or alimentary canal?
9m or 30ft
catabolism
larger molecules are broken into smaller molecules (mouth, stomach, & duodenum)
anabolism
smaller molecules used for building blocks for larger molecules (liver)
mastication
chewing
peristalsis
CN 10 - Vagus
involuntary movement of muscles in the GI tract that facilitates movement of food
5 major peritoneal folds
greater omentum
falciform ligament
lesser omentum
mesentery
mesocolon
grater omentum
largest peritoneal fold.
“fatty apron”
too much fat can expand “beer bellies”
falciform ligament
attaches the liver to the anterior abdominal wall & diaphragm
lesser omentum
suspends to the stomach and duodenum
forms pathway for blood vessels & has the bile duct
mesentery (small intestine) & mesocolon (large intestine)
work together to hold the intestines loosely in place as muscular contractions mix & move contents along the tract
3 phases of digestion
cephalic phase
gastric phase
intestinal phase
cephalic phase
nerves only
sight, smell, thought, and hearing of food stimulates secretion of gastric juice
gastric phase
nervous & hormonal
bolus in stomach secrete gastric juice
intestinal phase
mostly hormones
begins when food enters small intestine
cheeks, hard/soft palate & tongue form?
the oral or buccal cavity
salivary regulation of parasympathetic stimulation …
promote secretion, as well as touch, smell, taste, and psychological factors
salivary regulation of the sympathetic stimulation…
decreases saliva secretion
oropharynx & laryngopharynx have digestive and ___ functions
respiratory
3 stages of deglutition:
voluntary - tongue forces bolus back
pharyngeal - bolus passes into the oropharynx, epiglottis moves to close the glottis
esophageal - bolus enters the esophagus
propulsion
only digestive function occurring in the esophagus to move food into stomach
this regulates the movement of food from the esophagus into the stomach
lower esophageal sphincters
4 region of the stomach
cardia
fungus
body
pylorus
rugae
large folds in the mucosa of an empty stomach
beginning of the small intestine
the duodenum
gastric glands (4)?
mucous neck cell - produces mucus
chief cell - secrete protease pepsinogen & gastric lipase
parietal cell - produce intrinsic factor & HCI
endocrine cell - secrete gastrin hormones into the blood steam
gentle, rippling, peristaltic movements that pass over the stomach every 15-25 seconds
mixing waves. the waves macerate food, mix it w secretions of gastric glands & reduce it to a soupy liquid called chyme
3 regions of the small intestine
duodenum - 10 in
jejunum - 8ft
ileum - 12 ft
main site for absorption
small intestines, mechanical digestion is a localized mixing contraction called SEGMENTATION
multicellular structures barely seen by the naked eye
villi
microscopic folds in villi
microvilli, allow for max reabsorptions of nutrients
the passage of digested nutrients into the blood or lymph 90% of intestinal absorption occur in the small intesteine
intestinal absorption
how long is the large intestine
5 ft
4 regions of large intestine
cecum - 2.5 cm
colon
- ascending, transverse, descending + sigmoid
rectum - last 8 in
anal canal
termination of the rectum
anal canal
opening of the anal canal to the exterior
anus
about 9 l of fluid enter the small intestine each day
true
- 9.2 are reabsorbed
- o.1 are excreted in feces
defecation reflex
activated by stretch receptors of the rectum
- diaphragm, intercostals, & abdominal muscles contract to increase intraabdominal pressure
pancreas
secretes enzymes, which digest food in small intestine & hormones (glucagon, insulin & somatostatin & pancreatic polypeptide)
- pancreatic lipase, major triglyceride digesting enzyme in adults
liver
largest gland in body
2nd largest organ
2 lobes; R is bigger than L
divided by falciform ligament
repeating functional unites that make up the liver
liver lobules
major functional cells of liver
hepatocytes; synthesis, transformation, & storage of proteins, carbs, & fats
bile salts
emulsification & absorption of lipids, or else most fat would go undigested & we poop it out
major function of the gallbladder
secrete bile salt to breakdown fats
common bile duct merges with the ____ ___ to form the ____ ___
pancreatic duct, hepatopancreatic ampulla @ the 2nd part of the duodenum
which step of deglutition is under voluntary control?
oral stage
which controls the opening of the stomach into the small intestine
pyloric sphincter
the movement of lower colon & rectum contents at a rate slower than normal bc?
constipation
Each villus in the intestine contains a lymphatic vessel, or _____, that absorbs lipid or fat materials from the chyme.
lacteal
the longest portion of the small intestine is the
ileum
microvilli can be found in the
small intestine
surgical removal of the gallbladder is referred to as
cholecystectomy
enzyme pepsin begins the digestion of
protein
principle enzyme of saliva is
amylase
villi are important modifications of the ___ layer of the small intestine
mucosal
hormone to stimulate the gallbladder to release bile is
cholecystokinin
Which hormone decreases peristalsis and slows the passage of food from the stomach to the duodenum?
gastric inhibitory peptide (GIP)
which is not a function of the liver?
secretion of insulin
the terminal inch of the rectum is called the
anal canal
