Digestive System Flashcards
what are the macronutrients in the digestive system?
carbohydrates/ sugars
fats/lipids
proteins
what are the key functions of the digestive system?
ingestion
digestion
absorption
elimination
what is included in the gastrointestinal tract of the digestive system?
mouth
oral cavity
oropharynx
oesophagus
stomach
small intestine
large intestine
rectum
anus
what are the accessory componenets of the digestive system?
teeth
tongue
salivary glands
liver
gall bladder
pancreas
what is the arrangement of the cross-section ofn the GI tract?
lumen
mucosa
submucosa
circular muscle layer
longitudinal muscle layer
serosa
what is the lumen?
epithelial tissue, food move from mouth to anus
what is the mucosa?
thin layers of epithelium, lamina propria (connective
tissue) and muscularis mucosa (smooth muscle).
Secretes mucus, digestive enzymes, and hormones.
what is the submucosa?
Thick layer of loose connective tissue.
Contains blood vessels, lymphatic vessels, and nerves.
Glands may be embedded in this layer. enables peristalsis
what is circular muscle layer?
smooth muscle layers, blood vessels and plexus and innervation
what is longitudinal muscle layer?
peristalsis- involuntary contraction and relaxation- movement of food
what is serosa?
thin sheet of connective tissue that contains blood and
lymphatic vessels, and is covered by the peritoneum, Secretes serous
fluid to allow lubricated sliding movements between opposing surfaces
what do peristaltic waves do?
Moves the bolus forward movement/Propulsive
Coordinated involuntary contraction and relaxation of circular and longitudinal muscles
Adjacent segments alternatively contract and relax
Sphincters prevents the back flow
what is segmentation?
Moves the bolus first forward and then backword
Primarily mixing, some propulsive movement as well
Blending of bolus with digestive enzymes and secretions
Non-adjacent segments alternatively contract and relax
what is mastication?
chopping and grinding of food in the mouth
teeth and tongue aid the physical breakdown of food
salivary glands in the mouth secrete amylase enzyme
water in salivary glands heps make to food moist and bolus for easy swallowing and passage into oropharynx
what is the structure of the stomach form the top to bottom?
cardiac sphincter
funder
body
antrum
pylorus
chyme
(Rugae is inside the stomach)
what is the cardiac sphincter?
A thin ring-like muscle helps to prevent
stomach contents from going back up into the oesophagus.
Also, vents air out (burping)
what are the three regions of the stomach?
fundus, body, antrum
-mixing of food bolus with acid & enzyme
- largely digestion but some absorption (like alcohol,
aspirin, some lipid-soluble’s)
what is rugae?
Series of ridges by folding of the stomach
walls; contains secretory pits (acid and others);
provides large surface area and expansion to full capacity
what is the pylorus sphincter?
A valve/sphincter that connects the
stomach to the small intestine.
Prevents the backflow of contents from the small intestine to the stomach
what is the structure of the small intestine?
duodenum
jejunum
ileum
what is the duodenum?
mixing of chyme and secretions (digestive acids and enzymes) from gall bladder & pancreas ducts (Oddi-tonically controlled sphincter).
Absorption of minerals, vitamins and other micronutrients begins here
what is the jejunum?
further (segmentation) mixing of chyme and secretions
(digestive acids and enzymes).
Absorption of minerals, vitamins and other micronutrients, digested
carbs, fats and proteins.
what is the ileum?
last part (largest part) of the small intestine,
several folds-thin walls; mixing of digested, non-digested (segmentation) and secretions (digestive acids and enzymes). Absorption of leftover digested carbs, fats and proteins from the jejunum
what is the structire of the large intestine?
caecum
ascending
ytransverse
descending
sigmoid
rectum
anal sphincter
what is the caecum?
water and electrolyte absorption starts and the mixing of mucus to lubricate the faces
what is the anal sphincter?
a group of mucles at the end of the rectum that surrounds the anus and controls the release of stool
what is the liver responsible for?
- Glucose and fat metabolism
- Protein synthesis
- Hormone synthesis
- Urea production
- Detoxification
- Storage
what is the gall bladder?
The gallbladder is a small pouch-like organ found underneath the liver, for the storage and concentrate bile (help digest fats) and it is passed from the liver into the gallbladder through a series of channels known as bile
ducts.
what is the pancreas responsible for?
Exocrine glands: ~95 percent of the pancreas is exocrine tissue. It produces pancreatic enzymes to aid digestion.
Endocrine glands: ~ 5 percent comprises hundreds of thousands of endocrine cells known as islets of Langerhans. (glucose control by insulin and glucagon)
what soes acid in the stoach lumen cause?
-release and activation of pepsin, an enzyme that digests proteins.
-somatostatin release from D cells.
-denatures proteins (more accessible pepsin)-
-kill bacteria and other ingested microorganisms.
-inactivates salivary amylase, stopping carbohydrate digestion that began in the mouth
what are the upper GI tract diseases?
GORD
peptic ulcers
gastritis
gastroparesis
gallstones
what are the lower GI tract diseases?
celiac disease
diverrticular disease
inflammatory bowel disease
irratable bowel syndrome
what is GORD?
Gastro-oesophageal reflux disease (GORD) is a common condition, where acid from the
stomach leaks up into the oesophagus
what are the symptoms of GORD?
*heartburn (an uncomfortable burning sensation in the chest that often occurs after eating)
*acid reflux (where stomach acid comes back up into your mouth and causes an unpleasant,
sour taste)
*oesophagitis (a sore, inflamed oesophagus)
*bad breath
*bloating and belching
*pain when swallowing
what are the possible complications of GORD?
*ulcers (sores) on the oesophagus – these may bleed and make swallowing
painful
*the oesophagus becoming scarred and narrowed – surgery may be required
*changes in the cells lining the oesophagus (Barrett’s oesophagus) – very
occasionally, oesophageal cancer can develop from these cells
what are epetic ulcers?
Stomach ulcers, also known as gastric ulcers, are sores that develop on the lining of the
stomach
what are the symptoms of peptic ulcers?
*heartburn (an uncomfortable burning sensation in the chest that often occurs after eating)
*acid reflux (where stomach acid comes back up into your mouth and causes an unpleasant,
sour taste)
*indigestion
what are the progressive complications of peptic ulcers?
*bleeding at the site of the ulcer
*the stomach lining at the site of the ulcer splitting open
(perforation)
*the ulcer blocking the movement of food through the
digestive system (gastric obstruction)
what is gastroparesis?
Gastroparesis is a long-term (chronic) condition where the stomach cannot empty in the
normal way. Food passes through the stomach slower than usual (due to issues with
nerves and muscles involved in motility)
what are the symproms of gastroparesis?
feeling full very quickly when eating
feeling sick (nausea) and vomiting
loss of appetite, weight loss
Bloating, tummy (abdominal) pain or discomfort, heartburn
what are the progressive complications of gastroparesis?
*dehydration from repeated vomiting
*gastro-oesophageal reflux disease (GORD)
*malnutrition
*unpredictable blood sugar levels
what is gastritis?
Gastritis occurs when the lining of the stomach becomes inflamed after it’s been
damaged
what are the symptoms of gastritis?
feeling full very quickly when eating
feeling sick (nausea) and vomiting
tummy (abdominal) pain or discomfort,
heartburn
what are the progressive compilactions of gastritis?
*dehydration from repeated vomiting
*gastro-oesophageal reflux disease (GORD)
*malnutrition
*unpredictable blood sugar levels
what are gallstones?
the level of cholectrol in bile become too high and the excess cholectrol forms into stones
what are the 2 types of inflammatory bowel disease?
ulcerative colitis
crohns disease
what is ulcerative colitis?
inflammation in the colon and rectum
what are the symptoms of ulcertive colitis?
recurring diarrgoea
abdominal pains
needing to empty your bowels frequently
what is crohns disease?
inflammation in any part of the digestive system from the mouth to the bottom
what are the symptoms of crohns disease?
siarrhoea
stomach aches and cramps
blood instool
tiredness
weight loss
what are the progressive complications of inflammatory bowel disease?
primary sclerosing cholangitis
risk of developing bowel cancer
poor growth and development in children and young people
what is celiac disease?
gluten intolerance
what are the symptoms of celiac disease?
diarrhoea
abdominal pain
bloating
what is diverticular disease?
diverticular disease and diverticulitis are related digestive conditions that affect the large intestine
diverticula are small bulges or pockets that can develop in the lining of the intestine with ageing
what are the symptoms od diverticular disease?
stomach pain
constipation, diarrhoea
blood in stool
how does the aciic environment in the stomach help protein digestion?
denatures the protein
what molecular bonds are broken during the digestion of carbohydrates into monosacharides?
glycosidic bonds
