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.