HUBS192 Lecture 20 - Gastrointestinal System I: The Basic Structure of the GI System Flashcards
what is the primary function of GI system?
bring nutrients (from the external environment e.g food) into the internal environment so that they can be transported to all body cells to be utilised for growth and energy
what are the 4 things the GI system needs to be specialised for to perform its primary function?
1) motility
2) secretion
3) digestion
4) absorption
what is the function of motility in the GI system?
movement of things through the tract at an appropriate rate
what is the function of secretion in the GI system?
can be related to the:
- secretion of enzymes
- secretion of acid for digestion
- secretion of mucous for protection
- secretion of serous fluid for lubrication
what is the function of digestion in the GI system?
refers to the process of breaking things down into smaller particles
- mechanical digestion
- chemical digestion
what is mechanical digestion?
physically breaking things down into smaller parts to increase surface area
what is chemical digestion?
process that involves breaking down by enzymes
what is the function of absorption in the GI system?
absorb the smaller particles across the intestinal epithelium and into the blood for transport the cells
what are the 6 major organs of the digestive tract?
1) oral cavity (mouth)
2) pharynx
3) oesophagus
4) stomach
5) small intestine
6) large intestine
what are the 6 accessory structures of the digestive system?
1) teeth
2) tongue
3) salivary glands
4) liver
5) gallbladder
6) pancreas
what is the GI system in simple terms?
a long tube with outgrowths lined with epithelium that is closed off at both ends
-the accessory organs into the system via a duct system
what are sphincters?
bands of smooth muscle that regulate the passage of lumen content from one region to another and parties the GI tract into different functional compartments
what is the process of ingesting food material in terms of the structures it passes down?
- ingested into the oral cavity (mouth)
- then moves down to the pharynx when we swallow
- firstly into the oropharynx and then down into the laryngopharynx
- then moves down into the oesophagus
- then to the finally into the stomach (where it can be stored for up to 2 hours)
- moves down to the small intestine (nutrient absorption)
- moves down to the large intestine and then is excreted through the rectum
what is the start and end of the GI tract?
from the oral cavity to the anus
what is the type of epithelium in the mouth/oral cavity and the oesophagus? and what is the function of this epithelium?
- stratified squamous epithelium
- protects from abrasion
what is the type of epithelium in the stomach, small intestine, and large intestine? and what is the function of this epithelium?
- simple columnar epithelium
- secretion and absorption
what is the type of epithelium in the anal canal? and what is the function of this epithelium?
- stratified squamous epithelium
- protects from abrasion
what is the simplest form of a gland?
unicellular gland
what is the only unicellular gland in the body?
goblet cell
what are the 4 features that make up a goblet cell?
- columnar epithelium
- goblet shape
- apical mucous granules
- basal nucleus
what are multicellular glands?
epithelium that has invaginated to form glands
what are the 2 types of multicellular glands and what are they?
1) simple: gland with a single duct (e.g stomach an small intestine)
2) compound: gland with 2 or more ducts (e.g salivary glands)
- increased SA
what are the 4 layers of the gut tube?
1) mucosa (deep)
2) submucosa
3) muscularis (externa/proper)
4) adventitia (superficial)