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