Chapter 25 Flashcards
Accessory digestive organs
Teeth, tongue, gallbladder, liver, pancreas, salivary glands
digestive glands
Salivary glands
Liver
Pancreas
6 digestive processes
ingestion propulsion mechanical digestion chemical digestion absorption defecation
Ingestion
eating or drinking nutrients.
Propulsion
movement of the ingested material from the mouth through the GI tract to the anus
Mechanical digestion
breaking down the food by physical means, such as chewing
Chemical digestion
breaking down the nutrients in basic units that can be absorbed
Absorption
moving nutrients across the basement membrane of the mucous membrane into the blood of lymph by active or passive transport processes.
Defecation
excretion of food content that cannot be broken down and absorbed in the GI tract
what controls the digestive system?
ANS
the 2 groups of organs in the digestive system
- Alimentary canal (gastrointestinal or GI tract)
- Accessory Digestive Organs
organs of alimentary canal
Mouth, pharynx, esophagus, stomach, small intestine, and large intestine
what do mechanoreceptors and chemoreceptors respond to?
stretch, change in osmolarity and presence of substrate and end products of digestion
the serous membrane that lines the peritoneal cavity
peritoneum
function of the peritoneum
to hold organs in place and store fat
4 layers of the alimentary canal
- Mucosa
- Submucosa
- Muscularis External
- Serous
functions of the mouth
- Ingestion
- Propulsion (into pharynx)
- Mechanical digestion
- Chemical digestion (amylase)
function of hard palate
helps with chewing and formation of bolus
what does the soft palate do during swallowing?
closes off the nasopharynx
function of the tongue
Repositions and mixes food during chewing
where is the tongue attached to?
the lingual frenulum
term for dry mouth
xerostomia
how many baby teeth do we have
20
how many permanent teeth do we have?
32
word for baby teeth
deciduous teeth
which teeth do grinding?
molars
which teeth do tearing?
canines
which teeth do cutting?
incisors
where does the esophagus run from?
laryngopharynx to stomach
what regulates gastric secretion?
neural and hormonal mechanisms
inflammation of the mucosa of the stomach
grastritis
erosion of the stomach wall
ulcer
most common cause of ulcers
Helicobacter pylori bacteria
where does the small intestine run from?
from pyloric sphincter to ileocecal valve
where does 90% of absorbtion occur?
in the small intestine
where are enterocytes found?
small intestine
location of peyer’s patches
small intestine
function of Brunner’s glands
secrete alkaline mucus to neutralize the low pH of chyme
organ that produces and releases bile
liver
function of gallbadder
Stores and concentrates bile by absorbing its water and ions
major function of the large intestine
propulsion of feces toward the anus
regions of the large intestine
- Cecum (pouch with attached vermiform appendix)
- Colon
- Rectum
- Anal canal
Organs of the Alimentary Canal
Mouth, pharynx, esophagus, stomach, small intestine, and large intestine
another term for Alimentary Canal
gastrointestinal or GI tract
location of the parietal peritoneum
lines the inner wall of the peritoneal cavity
location of the visceral peritoneum
outer surface of most digestive organs
organs within the peritoneal cavity
intraperitoneal or peritoneal organs
organs located posterior to the peritoneum
retroperitoneal organs
structure of the peritoneum - R
double layered structure called the mesentary
what drains the venous blood from the digestive organs?
Hepatic portal circulation
where does the Hepatic portal circulation deliver blood to?
to the liver for processing
innermost layer of the GI tract
mucosa
outermost layer of the GI tract
serosa
layer of the GI tract Made of dense connective tissue with blood and lymphatic vessels
Submucosa
layer of the GI tract which is responsible for segmentation and peristalsis
Muscularis External
what regulates the GI tract motility
myenteric nerve plexuses
structure of the muscularis externa
2 sub-layers made of smooth muscle > inner circular and outer longitudinal
4 types of papillae
Filiform
Fungiform
Circumvallate
Foliate
which glands produce secretions when chemoreceptors and mechanoreceptors get stimulated?
Extrinsic salivary glands
3 extrinsic salivary glands
parotid
submandibular
sublingual
what does saliva contain?
electrolytes, enzymes, metabolic wastes and defensive compounds
term for swallowing
deglutition
major stomach regions
Cardiac region or cardia
Fundus
Body
Pyloric region
what does the pyloric region consist of?
antrum, pyloric canal, and pylorus
what is the pylorus continuous of?
the duodenum through the pyloric valve
Dome-shaped region beneath the diaphragm
Fundus
phases of gastric secretion regulation
Cephalic phase
Gastric phase
Intestinal phase
phase that includes the sight, thoughts, smell and taste of food
cephalic phase
phase when partially digested food inter the duodenum
intestinal phase
phase when food or fluid enters the stomach
Gastric Phase
which chemical messengers can stimulate Parietal Cells Releasing HCI?
Acetylcholine (Ach)
Histamine
Gastrin
how long does fatty chyme remain in the duodenum?
6 hours or more
subdivisions of the small intestine
Duodenum
jejunum
ileum
how long is the small intestine
7-14ft
what are Peyers Patches part of?
Mucosa-Associated Lymphatic Tissue (MALT)
another word for Duodenal glands
Brunner glands
structural and function units of the liver that process nutrient rich blood
Hexagonal Liver Lobules
word for liver cells
hepatocytes
leaky capillaries that surround the plates of hepatocytes in the liver _R
sinusoids
fixed macrophages in sinusoids
Kupffer cells
where do sinusoids empty into?
the central vein > hepatic vein > IVC
Cholesteral derivatives that function in fat emulsification and absorption - R
bile salts
pigment formed from heme during hemoglobin breakdown
Bilirubin
where does the liver receive bile from?
cystic duct
structure of the gallbladder
Thin-walled muscular sac on the ventral surface of the liver
hormone that stimulates the contraction of the gallbladder
cholecystokinin (CCK)
production site of gastrin
G cells of gastric glands
GI tract reflexes
pain reflexes vagovagal reflexes enterogastric reflex gastroileal reflex intestino-intestinal reflex gastrocolic reflex duodenocolic reflex defacation reflex
reflex that enhances the force of segmentation in the ileum
Gastroileal reflex
what moves chyme into the esophagus?
peristalic waves
what breaksdown proteins in the stomach
pepsin
what does the terminal sulcus mark?
the boarder between the body of the tongue and
3 unique feature of the large intestine
Teniae coli
Haustra
Epiploic appendages
Fat-filled pouches of visceral peritoneum
Epiploic appendages
Pocketlike sacs caused by the tone of the teniae coli
Haustra
Three bands of longitudinal smooth muscle in the muscularis
Teniae coli
what stops feces from being passed with gas?
3 rectal valves
regions of the colon
Asending Colon
Transverse Colon
Descending Colon
Sigmoid Colon
what relaxes to allow chyme into the large intestine
the ileocecal sphinter
hormone that increases motility of the ileum
gastrin
hormone that starts peristaltic waves that move meal remnants, bacteria, and debris into large intestine
motilin
what prevents blackflow into the small intestine?
ileocecal valve
structure in the small intestine that forces chyme to slowly spiral through the lumen
circular folds
the brain of the small intestine
duodenum
absorptive cells in the epithelium of the small intestine
enterocytes
what is the brush boarder
enterocytes (absorptive cells) with microvilli
part of the small intestine that produces a slightly alkaline intestinal juice
crypt epithelium
finger-like extensions in the small intestine
villi
what is at each corner of the liver lobule?
portal triad
what does the portal triad consist of?
bile duct
portal arteriole
hepatic venule
where does the bile duct receive bile from?
the bile canaliculi
what does the peritoneal cavity contain?
lubricating fluid to allow the mobile parts to move against each other without friction
3 layers of the mucosa
epithelium
lamina propia
muscularus mucosae
function of the mesentery
provides routes for blood vessels, lymphatics, and nerves
where do digestive organs in the abdominal cavity receive blood from?
branches of the aorta:
hepatic, splenic, left gastric, inferior mesenteric, and superior mesenteric
layer of the GI tract that contains lymphoid follicules, lacteals, and peyers patches
submucosa
basic mechanisms of mechanoreceptors and chemoreceptors reflexes
activate or inhibit digestive glands
stimulate smooth muscle
what regulates the glands and smooth muscle in the mucosa
submucosal nerve plexuses
which system inhibits activity of the GI tract?
sympathetic
which system stimulates activity of the GI tract?
parasympathetic
the only papillae that aids in mechanical digestion
filiform
what innervates the anterior 2/3 portion of the tongue?
the facial nerve
function of the intrinsic salivary glands
keep mouth moist continuously
function of extrinsic salivary glands
produces secretions when ingested food stimulates chemoreceptors and mechanoreceptors in the mouth
extrinsic muscles of the tongue
genioglossus, hypoglossus, and styloglossus
which accessory organ produces a fluid to soften food?
salivary glands
portion of the peritoneum largely responsible for carrying blood and lymph vessels to the intestines
mesentery
which cells secrete gastric acid?
parietal cells
this hormone is stimulates by high levels of dietary fat in the small intestine
cholecystokinin
which hormone stimulates the pancreas contraction to release bicarbonate-rich fluis?
secretin
what breaks down starch?
amylase
largest gland in the body
liver
function of intrinsic pacemaker cells
initiate smooth muscle contraction that mix and move contents towards the ileocecal valve
where is motilin used?
duodenum
which organs is secretin used on?
stomach
pancreas
liver
which organs is CCK found in?
stomach
pancreas
gallbladder
hepatopancreatic sphincter
what does bile contain?
bile salts
bilirubin
cholesterol, neural fats, phospholipids, and electrolytes
where is intrinsic factor produced?
the stomach
what does the lack of intrinsic factor lead to?
pernicious anemia
another name for esophagus
gullet