Class 9: Digestive System Flashcards
most absorption takes place in the
SI
name the two anatomical subdivisions of the digestive system
- digestive tract (alimentary canal)
- accessory organs
GI tract is lined with
lumen
within the lumen, the lining is made up of …
stratified squamous epithelium
middle layer of GI tract is composed of…
smooth muscle
nervous system for the GI tract…
enteric nervous system-controlled by medulla oblongata
serosa is…
the tough fibrous wrapping around the GI tract
smooth muscle (muscularis externa) is responsible for…
peristalsis
which plexuses go to the enteric nervous system?
- submucosal
- mysenteric
Auerbach plexus is…
the nerves innervating the esophogus, stomach, and intestine
auerbach plexus is connected to which part of the brain?
medulla oblongata
the enteric nervous system functions completely dependently/independently of the cns
independently
Autonomic nervous system exerts a significant influence on the…
enteric nervous system
motility and secretion of the digestive tract are controlled by
neural, hormonal, and paracrine mechanisms
neural control- 2 types of reflexes
short, long
hormones of digestive tracts
gastrin and secretin
chemical messengers are secreted into the bloodstream and stimulate distant parts of the
digestive tract
paracrine secretions are…
prostaglandins with a local effect
components of saliva
salivary amylase, lingual lipase, mucus, lysozyme, immunoglobulin A, elecrolytes
salivary amylase function
breaks down starches in the mouth
lingual lipase function…
enzyme that is activated by stomach acid and digests fat after the food is swallowed
mucus function
binds and lubricates the mass of food and aids in swallowing
lysozyme function
enzyme that kills bacteria
immunoglobulin A function
an antibody that inhibits bacterial growth
average pH of saliva
6.8-7.0
salivary gland in front of ear is called
parotid gland
what squirts saliva into the cheek?
parotid duct
pharynx is a…
muscular funnel that connects the oral cavity to the esophagus
the pharynx allows the entrance of air from the
nasal cavity to the larynx
esophogus is a…
straight muscular tube 25-30 cm long
esophagus begins level with
C6 and the cricoid cartilage
esophagus extends from the
pharynx to the cardiac orifice of the stomach
esophagus passes through the
esophogeal hiatus
the lower esophogeal sphincter causes food to…
pause at this point
the stomach function
- mechanically breaks up food particles
- liquifies the food
- begins the chemical digestion of protein and fat
chyme is
soupy or pasty mixture of semi-digested food in the stomach
most digestion occurs after the chyme
passes on to the small intestine
primary function of the stomach is for food…
storage
four regions of the stomach
1-cardiac region
2- fundic region
3-body
4-pyloric region
cardiac region of the stomach is located
small region within 3 cm of the cardiac orifice
the fundic region of the stomach is the
dome-shaped portion of the stomach
the body of the stomach makes up the…
greatest part of the stomach
the pyloric region of the stomach is located
at the narrower pouch at the inferior end of the stomach
vasovagal reflex is the collection of…
parasympathetic fibers from vagus and sympathetic fibers from celiac ganglia
all blood that’s drained from the stomach and intestines enters the
hepatic portal circulation
blood from st and intest. is filtered through the …. before returning to the …
liver, heart
4 cells in gastric pit
1) mucous cells
2) parietal cells
3) chief cells
4) enteroendocrine cells
mucous cells secrete… predominate in…
mucus, cardiac and pyloric glands
parietal cells secrete
hydrochloric acid and intrinsic factor
chief cells secrete (most numerous)
lipase and pepsinogen
enteroendocrine cells are concentrated in the
lower end of the gland
hydrochloric acid converts… to …, which breaks down… to …..
pepsinogen, pepsin, proteins, peptides
intrinsic factor is a…
glycoprotein secreted by parietal cells
intrinsic factor is essential to…
absorption of vitamin b12 by the SI
vitamin B12 is needed to synthesize…
hemoglobin. Prevents pernicious anemia
the only indispensable function of the stomach is
secretion of intrinsic factor
meal emptied from stomach takes about
4 hours
most ulcers are caused by what bacteria?
helicobacter pylori
gastritis is…. that can lead to a
inflammation of the stomach, peptic ulcer
functions of liver
-absorb glucose, amino acids, etc. from blood
-remove and degrade hormones, toxins, etc
-secrete into the blood stuff
-
between meals the liver
breaks down stored glycogen and releases glucose into the blood
gallbladder function
stores and concentrates bile
bile definition
a yellow-green fluid containing minerals, cholesterol, neutral fats, etc.
gallstones are hard masses in either the… or..
gallbladder or bile ducts
the pancreas is both a…
endocrine and exocrine gland
endocrine portion of pancreas secretes
insulin and glucagon
the exocrine portion of the pancreas
secretes pancreatic juice
sodium bicarbonate raises
pH of acidic chyme in duodenum
pancreatic amylase digests
starch
pancreatic lipase digests
fat
pancreatic protease digests
proteins
acetylcholine comes from the
vagus and enteric nerves
cholecystokinin is secreted by…. in response to the arrival of…
mucosa of duodenum, fats in SI
secretin is released from…. in response to…
duodenum, acidic chyme arriving from the stomach
3 parts of the stomach
duodenum, jejunum, ileum
duodenum function
receives stomach contents, pancreatic juice, bile
neutralize stomach acid
jejunum function
most digestion happens here
ileum forms the last…
60% of the post-duodenal SI
ileocecal valve is a sphincter formed by
the thickened muscle of the ileum
the ileocecal valve protrudes into the
cecum
function of ileocecal valve is to
regulate the passage of food residue into the large intestine
lipids are absorbed by
lymphatic capillaries called lacteals
sigmoid colon is the…
s-shaped portion leading down into the pelvis
rectum is the portion…
ending at the anal canal
the anal canal is the final…
3 cm of the LI
