W9 Digestive System Flashcards
what is the GI tract
- Gastrointestinal tract
- Muscular tube that runs from mouth to anus
describe the GI tract from proximal to distal
- Mouth to Oesophagus
- Stomach to small intestines
- Large intestines to Rectum to Anus
what is the portal triad
1) hepatic portal
2) hepatic artery proper
3) common bile duct
Why do rabbits have big caecums
fermentation of high fibre low nutrient grass
How long is the small intestine
6m
What are nutrients in small intestines called
chyme
what are the 3 sections of the small intestine
- duodenum
- ileum
- jejunum
whats the function of the small intestine
- digest food from the stomach
- absorbs nutrients and water
which side is the stomach on
left
what are the layers of the GI tract
- mucosa
- submucosa
- muscularis externa
- serosa
what is the duodenum
- c shaped structure that wraps the head and neck of pancreas
how does bile enter the duodenum
major pancreatic duct joins the the major duodenal papilla
whats the function of duodenum
- site for the secretion of fluid by accessory organs
- iron absorption in mammals
how long is the duodenum
10 to 15 inches
what are the 4 parts of the duodenum
- superior
- descending
- transverse
- ascending
what is villous mucosa
joins directly to duodenum
what is brunners gland and its function
- gland which lines the duodenum
- secretes mucus and bicarbonate
what is the jejunum and its function
- absorption enterocytes
- 2nd part of the small intestine
where is the jejunum located
between duodenum and ileum at the start of duodenojejunal flexure
how long aprox is the jejunum
2.5m
whats the ileum and its function
- 3rd part of the small intestine
- absorbs vitamin B12 + bile salts
main diff between jejunum and ileum
- ileum has a smaller lumen and thinner walls
- ileum has smaller folds and absent at terminal end
which section of small intestine has high amount’s of peyer patches
ileum
what are the 5 sections of the large intestine
- caecum
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
what are the main 3 functions of the large intestine
- absorb water snd electrolytes
- produce + absorb vitamins
- propelling faeces
what is the caecum and its function
- enlarged pouch within peritoneum at start of large
- most proximal point of large intestine
- receives chyme from ileum
where is the caecum located
- right side of the body
- on the same side of appendix
what is ICV
- ileocaecal value
- sphincter muscle that separate small and large intestine
what is the function of ICV
- limit reflux of colonic content
- regulate flow of semi-liquid from ileum
what is appendicitis
inflammation of the vermiform appendix
what is the taeniae coli
3 longitudinal bands of smooth muscle
what are epiploic appendices
fat deposits on external surface of large intestine
what is the rectum
terminal end of the digestive system that connects colon to anus
whats the role of the anus
an opening for the release of stool
where are rectal varices
proximal in rectum derived from portsl syste,
where are haemorrhoids
distal in rectum and derive from systemic circulation
what are the muscles of mastication innervated by
mandibular branch of trigeminal nerve
what does the temporalis muscle control
adduction and retraction of jaw
what does the masseter control
adduction and protrusion of jaw
what are the 4 muscles of mastication
temporalis
masseter
lateral and medial pterygoid
what supplies the motor nerve to tongue
hypoglossal nerve (12)
what are the 2 skeletal muscles of the tongue
intrinsic and extrinsic muscles
what are the 3 salivary glands
Parotid gland
Submandibular gland
Sublingual gland
how does the parotid gland drain
parotid duct
where does the parotid gland enter from
2nd upper molar
which glands do the facial glands control in the mouth
sublingual gland
submandibular gland
where is the pharynx found
between oral cavity and oesophagus
which muscle controls the Upper Oesophageal sphincter (UoS)
cricopharyngeus
how does the oesophagus enter the stomach
at an acute angle
what is the oesophagus lined
with stratified squamous epithelium
where does the foregut start
T12
what are the 5 regions of the stomach
fundus
cardia
body
antrum
pyloric canal
where is most of the stomach in situ
left side of abdomen
what increases the SA of the stomach
gastric rugae
what does the stomach connect directly to
oesophagus
how is food broken down in the stomach
gastric muscle layers and peristaltic contractions in fundus
what are the digestion accessory organs
liver
gall bladder
pancreas
where is the liver in situ
under the right dome of the diaphragm
what are liver cells called
hepatocytes
how does the liver supply and drain blood
supply hepatic portal vein
drain from HPV to IVC
what is the main function of the liver
detox of alcohol
fibrinogen for blood clots
what is produced and stored in the gall bladder
bile
how does bile enter the duodenum
out of major pancreatic duct to duodenal papilla
where does the pancreas lie
posterior to stomach
what are all the parts of the pancreas
uncinate
head
neck
body
tail
whats the function of the pancreas
release exocrines
what are the main exocrines
digestive enzymes
what are endocrine cells
alpha cells that secrete glucagon
beta cells that secrete insulin
how does the G1 tract drain
through the portal system
into the inferior vena cava via the hepatic veins
what is the portal system
all veins which carry blood from abdomen to spleen, pancreas, gall bladder
how much of the total liver flow does the portal vein carry
75%
what are portacaval anastomoses
circulatory anastomosis between veins of portal system and vena cava
what is found in the retroperitoneal
Duodenal
pancreatic
right and left colic veins
what vein is found in the rectum
superior/inferior rectal vein
which vein is found in the oesophagus
left gastric vein
what is variceal bleeding
cirrhosis where rupture in oesophagus happens
