GIT Structure and Function Flashcards
Describe the small intestine and compare it to the large intestine
What does each part of the small intestine do
It is larger than the large intestine but its diameter is smaller
It is broken into 3 parts
1. Duodenum (small)
2. Jejunum (main abs section)
3. Ilium (cleans and pans a lot of things)
Which structure connects the liver and gull bladder and is involved with the secretion of the pancreatic duct
(Duodenum, Jejunum, Ilium)
Duodenum
What are the 7 GIT jobs
- Motility
- Secretion
- Digestion
- Absorption
- Communication
- Immune system
- Detoxification and modification by metabolism
What substances get secreted into the GIT
- electrolytes
- water
- digestive enzymes
- bile salts
- acids and bases
What is the main reason why foods are broken down into simpler chemical compounds
So that they can cross the epithelial layer
What happens in ABS in the GIT
What does this include
It transfers nutrients to circulation (brings it into blood)
This includes réabsorption of endogenous secretion
What systems are involved in GIT communication
- the nervous system
- the endocrine system
The git system linked to every system in the body
What does GALT stand for what is its purpose
Gut associated lymphoid tissue
What does immune system tolerance mean
It is when the gut tolerates good bacteria
True or false: microbes can toxify and detoxify things
True
What are the parts of the GI tract
- forestomach
- stomachs
- mouth
- pharynx
- esophagus
Forestomach
- omasum
- rumen
- reticulum
Stomachs
- abomasum
- small intestine
1. Duodenum
2. Jejunum
3. Ileum
Cecum and large intestine
Do humans have a cecum
No not really
It is really small
List the accessory organs of the GI tract
- teeth
- tongue
- salivary glands
- liver
- gall bladder
- pancreas
What causes appendicitis
It happens when the appendix bursts and releases a large amount of microbes into the body
What things influence the structure of GI tracts
- Diet
- Size of the animal
What is the intestinal arrangement of the esophagus
How is this related to its function
Has a stratified layer of cells
Don’t want to abs things here
What is the intestinal arrangement of the stomach
How is this related to its function
Has deep crypts and also has shallow crypts that secrete acid
Minimal abs mostly just breaking things down
Where does most absorption happen
Most absorption happens in the small intestine
Describe the intestinal arrangement of the small intestine
How does this related to its function
Has microvilli to increase surface area for better absorption
Most absorption happens in the small intestine
What is the intestinal arrangement of the large intestine
How does this related to its function
It has a single layer of cells that act as a barrier to the environment
(Mainly absorbs short chain fatty acids)
What are the crypts found in the small intestine called
The crypts of lieberkuhn
What are the layers of the intestinal wall (4)
- Mucosa
- Sub mucosa
- Muscular is external
- Serosa
What is found in the mucosa
- Lamina propria
—) capillaries, nerve fibers, smooth muscle (muscularis mucosa) and immune cells - Epithelium
What are found in the submucosa
- Nerves
- Contains glands (if present)
What does the muscularis external contain
Where is it found (what is its path)
- Nerves and muscles
Found: inside and goes around outside (goes up and down)
What is found in the serosa, what is its purpose
Connective tissue
To allow the gut to slide around in your abdominal cavity and keep it separated
What kind of cell makes up most of the epithelium in the GIT
Columnar epithelial cells
What is the name of the mucus producing cells found in the GIT where their only job is to secrete mucus
Goblet cells
What are the five types of epithelial cells in the GIT what do they do
- Columnar absorptive cells (absorption)
- Mucous (goblet) cells (secrete mucus)
- Paneth cells (defend intestinal stem cells)
—) important in supporting crypts
—) stay at crypt base
—) secrete antimicrobial molecules to provide host defence against gut microbes - Endocrine cells (release hormones into blood to communicate locally and systemically)
- Intestinal stem cells (differentiate into different cell types)
—) found at bottom of crypts
If intestinal stem cells migrate up what can they become
They can become either mucus cells or endocrine or columnar cells
If intestinal stem cells migrate down what can they become
They become paneth cells
True or False: immune cells are not found in GIT tissue
False immune cells are found in GIT tissue
What kind of cells sample antigens and educate the immune system
M cells
What does the peyer’s patch do in the GIT
What are they
What are they involved with
It monsters for antigens and microbes in the intestinal lumen
They are secondary lymphoid organs
Involved with immune response
What kind of cells educate the immune system
Paneth cells
What are dendritic cells found in the GIT lining similar to?
They are kind of like a macrophage
What is a mini gut culture system used for
It is used to study how cells work or function
How often are cells replace, why are they replaced
Every 3-5 days usually (depends on rate of cell damage)
They are replaced to take the place of dead cells (due to cell death)
What can influence the rate of cell death in the GIT
It depends on signals from microbes (the microbial environment)
What is the purpose of tight junctions in the GIT
They are there to keep harmful agents out of the GIT
True or False: pathogens can disrupt the intestinal surface
True
