1.1 introduction to GIT Flashcards
function of the GIT
- prehension of food
- mastication
- digestion
- absorption
- expulsion unabsorbed portions of food
what does headgut consists of
oral cavity:
lips, tongue, teeth, salivary glands
pharynx:
epiglottis
what does foregut consists of
oesophagus
stomach
what does midgut consists of
small intestines
- duodenum
- jejunum
- ileum
liver
pancreas
gall bladder
what does the hindgut consists of
large intestines
- caecum
colon
rectum
anal canal and anus
function of salivary glands and saliva
- moisturize food and lubricate it
- amylase - breakdown of starch
- aids with mastication, bolus formation, digestion, and swallowing
what is the basic secretory unit of salivary glands
acini
3 major pair of salivary glands
- parotid glands
- submaxillary glands (aka mandibular glands)
- sublingual glands
where are the locations of the 3 major salivary glands
look at the graph
what do each pair of the 3 major salivary glands produce
parotid glands:
- produce a serous secretion
mandibular glands:
- produce a mixed serous and mucous secretion
sublingual glands:
- produces a mucous secretion
which 3 parts is the oesophagus divided into
cervical
thoracic
abdominal
give the 4 layers of the oesophagus
mucosa
submucosa
tunica muscularis
serosa/ adventitia
what are the characteristics of the 4 layers of oesophagus
- Mucosa
○ Nonkeratinized stratified squamous epithelium that covers the lumen
- Submucosa
○ Consists of elastic and collagen fibres that forms a dense, irregular connective tissue
○ This layer consists of blood and lymphatic vessels
- Tunica muscularis
○ Longitudinal and circular muscles forms a tube
§ Longitudinal muscle fibres are located superficially § Circular muscle fibres are located deeply
- Serosa/adventitia
○ This layer surrounds most of the oesophagus
It consists of loose connective tissues
what type of epithelium is the mucosa
non-keratinized stratified squamous epithelium
function of the stomach
- Temporary food container before it is passed into the intestines
- Enzymatic breakdown of food
adaptation of the stomach of the muscular wall
- Muscular wall with rugae (folds)
- Enable increase area, hence churning (mixing of food) is optimized
what are the two sphincters of the stomach
lower oesophageal sphincter (LSE)
pyloric sphincter
what are the 3 layers of the stomach
- mucosa
- submucosa
- muscularis externa
what is special about the mucosa in the stomach
it has a layer of smooth muscle called muscularis mucosa
what are the 3 layers of muscle in muscularis externa
inner oblique
middle circular
external longitudinal
what is the use of the muscles in the mucosa
helps with excretion of the glands
what is the use of the muscularis externa
contraction to help with breaking down food (churning)
differences between monogastric and ruminants and pseudoruminants
ruminants: 4 stomach chambers
pseudoruminants: 3 stomach chambers
monogastric: 1 stomach chamber
what are the four chambers of stomach in a ruminant
rumen, reticulum, omasum, abomasum
what are the 3 parts of the small intestines
duodenum, jejunum, ileum
what is the functional unit of the liver
hepatocytes
histology of the liver
- Sheets of connective tissues divide liver into many lobules
- A lobule is roughly hexagonal in shape
- Each lobule has portal triads at the vertices and a central vein in the middle
- Portal triads
○ Bile duct
○ Hepatic arteriole
○ Portal venule
what is the artery that supply blood to the pancreas
splenic artery
celiac artery
the 2 compound glands in the pancreas
pancreatic acini
islets of langerhans
