Digestive System Flashcards
Organs of digestive system
alimentary canal and accessory digestive organs
alimentary canal
continuous muscular digestive system
organs of alimentary canal
mouth, pharynx, esophagus, stomach, small/large intestine, and anus
accessory digestive organs
teeth, tongue, gallbladder, digestive glands. salivary glands, liver, pancreas
Digestive process
ingestion, propulsion, digestion
ingestion
taking food into digestive tract
propulsion
swallowing and peristalsis
mechanical digestion
chewing, churning food in stomach, segmentation, mixes food with digestive jucies
segmentation
rhythmic local constrictions of intestine
chemical digestion
food molecules are broken down by enzymes secreted by various glands
where does chemical digestion begin an end
begin in mouth, end in SI
absorption
passage of digested products into blood or lymph, small intestines
defecation
elimination of indigestiable substances from the body
membranes of organs in abdominopelvic organs
visceral peritoneum and parietal
visceral peritoneum
covers external surface of digestive organs is continuous with the parietal peritoneum
parietal peritoneum
lines abdminopelvic cavity
peritoneal cavity
contains serous fluid
messentery
a double layer of peritoneum, provides route for bv, lymph, nerves, holds organs in place
largest mesentery
greater omentum
retroperitoneal organs
SAD PUCKER
suprarenal gland
aorta/ivs
dudoenum
pancreas
ureters
colon
kidney
esophagus
rectum
peritonitis
inflammation of peritoneum
peritonitis comes from
wound piercing abdomen, from perforating ulcer, burst appendix
4 layers of alimentary canal
mucosa, submucosa, muscularis externa, serosa
mucosa
inntermost layer, lines lumen
functions of mucosa
secretion of mucus, enzmes, hormones, absorption, protection against infection
3 sublayers of mucosa
epithelial, lamina propria, muscularis mucosae
epithelial lining
mucus secreting
lamina propria
loose CT, collagen, elastin, thick, MALT
muscularis mucosae
thin layer of smooth muscle cells, twitches to dislodge food
submucosa
dense CT with blood and lymph vessels, rich supply of elastic fibers and collagen, provides vascular network
muscularis externa
inner cirrcular layer of smooth muscle, outer layer of longitudinal muscle, peristalisis and segmentation
sphincter
when smooth muscle circular thickens
serosa
outermost protectice layer-visceral
what is serosa replaced by in esophagus
adventita
nerve suppy
submucosal nerve plexus, myenteric nerve plexus
submucosal nerve plexus
submucosa, controls activity of glands and smooth muscle in mucosa
myenteric nerve plexus
b/w circular and longitudinal smooth msucles, controls GI tract mobility
how are nerve plexus linked
afferent visceral nerves, efferent sym and para ANS
parasympathetic nerves control what in the digestive system
peristalsis and segmentation
Mouth
oral cavity, lined with stratified squamous, tongue and salivary glands
tongue
grips food, mixes it with salivia, compacts food into bolus, pushes it into pharynx, held in place by lingual frenulum
salivary glands
secrete saliva, extrinsic and intrinsic glands
extrinsic salivary glands
produce a majority of saliva, parotid, submandibular, sublingual, located outside oral cavity
intrinsic salivary glands
scattered throughout mucosa
salivary gland cells
serous, mucous, partoid gland, submandibular, intrinsic, sublingual
serous gland cells
watery fluid full of enzymes
mucous gland cells
stringy viscous fluid
parotid gland cells
serous
submandibular gland cess
serous and mucus
intrinsic gland cells
serous and mucus
sublingual cells
mucous
Saliva
mostly water, slightly acidic, produce 1 liter a day
parts of saliva
ions, amylase, proteins, lysozymes, IgA, metabolic wastes
what is saliva controlled by
ANS
Pharynx
stratified squamous epithelium, mucus producing glands, constrictor muscles propels food into esophagus
esophagus
normally collapsed
esophagus hiatus
esophagus pierces diaphragm here
cardiac orifice
where esophagus joins stomach
cardiac sphincter
gastroesophageal sphincter
stages of food going down esophagus
- Buccal Phase
- Pharyngeal-esophageal phase begins
- Pharyngeal phase 2
- Pharyngeal phase 3
- Pharyngeal phase 4
Buccal Phase
upper esophageal sphincter is contracted, tongue presses against the hard palate, forcing food bolus into the oropharynx
pharyngeal-esophageal phase begins
tongue blocks mouth, soft palate and uvula rise, epiglotitis blocks trachea, upper sphincter relaxes
pharyngeal-esophageal phase 2
constricter muscles of pharynx contract forcing food into the esophagus inferiorly, upper esophageal sphincter contracts after food enters
pharyngeal-esophageal phase 3
peristalsis moves food through esophagus to the stomach
pharyngeal-esophageal phase 4
spincter opens, food enters stomach, then closes again
stomach
temporary storage tank
food in stomach
creamy paste, chyme
stomach empty
holds 50 mls, mucosa and submucosa fold forming rugae
stomach at maximum
hold 4L or one gallon
pyloric sphincter
connects stomach to duodenum, controls stomach opening
lesser omentum
a mesentery connection of liver to lesser curvature
greater omentum
a mesentery running from greater curvature to coils of SI
oblique layer of stomach
allows churning and mixing of food
chemical digestion of proteins
by pepsin, only intiated in the stomach
renin in children
secreted by glands, breakdown milk protein casein
Gastric secretions
mucosa makes 3L of gastirc juice a day
increase of gland activity
vagus, parasympatheitc
decrease gastric gland activity
sympathetic nervous system
stomach lining
simple columnar epithelium-goblet cells and gastric puts
goblet cells of stomach
produce productive alkaline mucus
gastric pits
lead to glands, produce gastric juice, goblet cells
gastric glands
in cardiac and pylorus, secrete mucus
gastic glands in pyloric antrum
secrete mucus and the hormone gastrin
gastric glands in fundus and body secrete
mucus, HCL, enzymes, gastrin
cells of gastric glands
mucous neck cells, parietal cells, cheif cells, enteroendocrine cells
mucous neck cells
produce acidic mucus, towards bottom of upper duct
parietal cells
secrete HCL and intrinsic factor, responsible for extreme acidity of stomach
What do parietal cells do?
activates pepsin, denatures protein, breaks down wall of plant foods, kills many bacteria
chief cells
secrete pepsinogen