Intro to GI tract Flashcards
What is the primary function of the GI tract
Absorption of nutrients
What is the blood supply to the gut
3 major arteries:
- Coeliac artery
- Superior mesenteric artery
- Inferior mesenteric artery
Where does the coeliac artery supply to
Liver, pancreas and gut
Where does the superior mesenteric artery supply to
Small intestine and most of large intestine
Where does inferior mesenteric artery supply to
Terminal portions of large intestine and rectum
What is the blood flow regulated by
- ANS
- Hormonal control
- Local control
What does the mucosa consist of
Epithelium, lamina propria and muscularis mucosa
What does submucosa consist of
Blood vessels and nerve bundles that form the submucosal plexus
What does the muscularis externa consist of
2 smooth muscle layers - circular muscle and longitudinal muscle
What lies between the circular muscle and longitudinal muscle
The mysenteric plexus
What does serosa consist of
Connective tissue and squamous epithelial cells
What PNS nerves affect GI tract
Vagus and pelvic nerves
What is the effect of PNS on GI tract
It stimulates GI secretions and motility facilitating digestion and absorption of nutrients (rest and digest)
What innervates the upper GI tract
Nerves that synapse in superior cervical ganglion
What is the effect of SNS on GI tract
It decreases GI secretions and motility (fight of flight)
What does the ENS consist of
Submucosal plexus and myenteric plexus
What does the submucosal plexus do
It regulates intestinal secretions and area specific absorption. It also interacts with blood vessels, circular and longitudinal muscle and muscularis mucosa
What does the myenteric plexus do
It regulates intestinal smooth muscle that helps generate tonic and rhythmic contractions
What are the 3 digestive phases
- Cephalic phase
- Gastric phase
- Intestinal phase
What is in the upper GI tract
Mouth, oesophagus and stomach
What is the function of the upper GI tract
It transports and prepares food to be absorbed
How many teeth do I have
32 teeth
What are the 3 salivary glands
- Parotid - in cheeks beside ear, watery secretion
- Submandibular - under jaw, watery secretion
- Sublingual - floor of mouth, mucous secretion
What are the stomach’s 3 primary motility functions
- Accommodation of food via receptive relaxation
- Mixing via slow wave-initiated contractions and retropulsion
- Gastric emptying
