Digestive System GIT - Canine Flashcards
In the digestive system, what are the organs grouped as?
grouped as alimentary canal and accessory organs
what is the alimentary canal?
it is a tube from lips to anus
what is the digestive system composed of?
mouth, pharynx, oesophagus, stomach, small and large intestine
what is the general structure of tubular organs?
have 4 layers
what are the four layers of the tubular organs of the digestive system?
tunica mucosa
tunica submucosa
tunica muscularis
tunica serosa/adventitia
what is the tunica mucosa?
it is the layer closest to the lumen (next to the lumen) and is protected by a layer of mucus
how many layers is the tunica mucosa divided into?
3
what is the tunica submucosa?
the layer found below the the tunica mucosa, it is dense connective tissue that may have glands, blood, lymph vessels and Meissner’s plexus (ANS)
What is the tunica muscularis?
smooth or skeletal muscle. contains the nerve plexus: myenteric (Auerbach’s) plexus (ANS)
What is the tunica serosa/adventitia?
loose connective tissue
What three layers is the tunica mucosa divided into?
the laminae epithelialis mucosa
lamina propria
lamina muscularis mucosae
What is the laminae epithelialis mucosa?
surface epithelium - for absorption and secretion, the type of epithelial cells depends on the function (where we are in the digestive system)
The cells are resting on a very thin basal membrane so that they are not floating around
what is the lamina propria?
layer of connective tissue (collagen, elastic and reticular fibres). Has mucosal glands, blood vessels and lymphoid structures and gut-associated lymphoid tissue
What is the lamina muscularis mucosae?
thin layers of smooth muscle
one layer of the three layers that make up the tunica mucosa is not always present, which layer is this?
the lamina muscularis mucosae
gut -associated lymphoid tissue?
lymphoid tissue that is specific to the gut
Describe the oesophagus:
it is relatively wide and dilatable
why can you sometimes not find the oesophagus in practicals?
because it has collapsed as there is no food in there
where is there constriction along the oesophagus?
at the origin
in all species the oesophagus is split into three parts, how many parts are there?
3
What are the parts of the oesophagus called?
cervical, thoracic and then abdominal
cervical part of the oesophagus?
follows the trachea down the neck and sits dorsally to the trachea (sits on top)
in which direction does the oesophagus incline before regaining a median position again?
left at first
what does the diaphragm separate?
The abdominal cavity and the thoracic cavity
after regaining a median, where does the oesophagus go?
has a continuous direction beyond trachea bifurcation (past the heart) and penetrates the diaphragm
where does the oesophagus join the stomach?
it joins the stomach ventral to the 11/12th thoracic verterbrae
what structure does the stomach have?
it is a C-shaped organ which has a tubular structure
what two sphincters are found in the stomach?
the cardiac sphincter and the pyloric sphincter
point of the muscles in the stomach?
protecting the stomach and the oesophagus e.g. no stomach acid gets sent in the wrong direction
where is the stomach found?
between the oesophagus and the small intestine
what side of the abdomen is the stomach found on?
left side
point of the sphincter muscles?
controls emptying the stomach
what are the several segments that the stomach is divided into? (from oral to aboral)
cardia, fundus, body and pylorus
what is the pylorus divided into?
the canal and the antrum
describe what the antrum and the canal are:
antrum is an entrance and the canal is what links the small intestine to the antrum (the canal gets smaller than the antrum)
what is the cardia segment of the stomach?
opening of the oesophagus
what is the fundus?
it is the blind expanded portion of the stomach
what is the middle segment of the stomach?
the body
what is distal to the body of the stomach?
the pylorus
what is the simple stomach primarily composed of?
glands
what part of the stomach do the glands mainly occupy and what type are these glands?
they are gastric glands and they occupy most of lamina propria
what do glands produce?
gastric juices
the fold in the stomach are called?
the rugae - created byntunica mucosa
what causes the ‘butterflies’ we get in our stomach?
the nerve plexus in the tunica submucosa
The nerve plexus is Meissner’s plexus
where are the folds present in the stomach?
in the mucosa of the stomach - in the tunica mucosa layer
What does the tunica muscularis consist of?
consists of three layers of smooth muscle between layers of the myenteric or Auerbacch’s plexus
What does the tunica submucosa contain?
Meissner’s plexuses
Name all of the gastric glands:
cardiac gland
fundic gland
pyloric gland
Where is the cardiac gland found in the stomach?
found in the cardiac region which occupies a very small area - this area contains mucous secreting glands and is closest to the oesophagus
Where is the fundic gland found in the stomach?
in the fundus region, which includes the space between the cardiac gland and pyloric gland regions