Alimentary - Introduction Flashcards
What does the headgut consist of ?
Oral cavity incl lips, tongue, teeth and salivary glands
Pharynx incl epiglottis
What does the foregut consist of?
Oesophagus
Stomach
What does the midgut consist of?
Small intestines (duodenum, jejunum and ileum)
Liver, gall bladder and pancreas
What does the hindgut consist of?
Large intestines (caecum, colon and rectum)
Anal canal
What is the function of saliva?
-Moisture and lubricate food
-Mastication
-Bolus formation
-Enzymatic digestion (alpha amylase)
-Swallowing
(Ruminants) - Buffering microflora
What produces saliva?
Glands are made of acini (small sacs)
White foamy - mucosal
Pink - watery/serous
What type of glands are there?
Parotid glands
Submaxillary/mandibular glands
Sublingual glands
Zygomatic glands (only in carnivores)
Minor glands (labial/buccal)
What type of saliva does the parotid gland produce?
Ruminants - serious
Dogs - mixed
What type of saliva does submaxillary/mandibular glands produce?
Mixture
What type of saliva does the sublingual glands produce?
Mucosal
What type of saliva does the zygomatic gland produce?
Mucosal
What type of saliva does the minor glands produce?
Mucousal
What is the anatomy of the oesophagus?
Long tube from pharynx to stomach. 1-2’ wide.
-Mucosa
-Submucosa
-Tunica Muscularis
-Serosa/Adventitia
What is the mucosal lining made of in the oesophagus?
Non-keratinised stratified squamous epithelium
What is the submucosa made of in the oesophagus?
Elastic and collagen fibres forming a dense and irregular connective tissue. Blood and lymph vessels
What is the tunica muscularis made of in the oesophagus?
Longitudinal muscle (superficial)
Circular muscle (deep)
Skeletal and smooth muscle, with mostly smooth descending
What is the basic function of the stomach?
Acts as flexible temporary food container filled with rugae, which have gastric pits.
What are the regions of the stomach?
Cardiac region - incl cardiac sphincter
Fundus region - secretes hormones responsible for feeling of hunger and dilates when stomach is stretched stimulating vagus nerve. Additional gastric glands
Body - gastric glands
Pyloric region - incl. pyloric sphinter and pyloric spine
What are the histological layers of the stomach?
-Mucosa
-Mucosa muscularis - helps push the gland cell contents
-Submucosa
-Tunica Muscularis - 3 layers
-Serosa/Adventitia
What makes up the small intestine?
Duodenum
Jejunum
Ileum
What is the duodenum?
The first part of the small intestine which chyme sprays into. Buffered to help with HCl that escapes through, secreted from Brunners gland (mucous).
Has different ducts (papillae) connecting to pancreas and liver
What is the jejunum?
Second and longest part of SI. Long and thin for slow time
Most nutrient absorption occurs
What is the ileum?
Final and smallest part
Lots of lymphatic cells and nodes
How does the small intestine move?
Peristalsis
Enteric nervous system
Movement is back and forth
What does the liver do?
Synthesis of bile (stored in gall bladder)
Storage of glucagon and fat
Biotransformation of toxins
Synthesis of blood components
Defence system e.g. Kupfer cells
What is the circulation of the liver?
Receives nutrient rich deoxygenated blood from gut via portal vein and oxygenated blood from circulation via hepatic artery.
Anamatose to supply hepatocytes, via sinusoid.
Through central vein to caudal vena cava
What does the histology of the liver look like?
Sheets of connective tissues with lobules, which are hexagonal with portal triads at vertices and central vein in middle.
Whats a portal triad?
Formed of:
Hepatic artery - thicker wall
Portal vein wider and thinner
Bile duct - columnar epithelium
Heads towards the central vein and all joins
What is the gall bladder?
Stores bile
Stimulated by CKK
Made up of columnar epithelium
What does the pancreas do?
Produced digestive enzymes and hormones which drain into duodenal epithelium.
What is the anatomy of the pancreas?
Found on the right side of abdomen, adjacent to duodenum.
Supplied by splenic artery divided into lobules by septae
Cuboidal epithelium
What are the two types of cells in the pancreas?
Exocrine cells - Made up of acini
Endocrine cells - Pancreatic Islets of Langerhans
What do the exocrine cells produce?
Acini produce digestive enzymes such as lipases
Stains purple
What do the endocrine cells produce?
alpha -glucagon
beta -insulin
gamma - pancreatic polypeptide
Stains pink - less frequent
What is the caecum?
A small blind sac responsible for the microbiome secretion, breaking down fibre and cellulose.
Dogs/humans - caecum?
Non-functional, part of the appendix
Ruminants - caecum?
Found on the right in the supraomental recess, with a little fermentation occuring here.
Porcine - caecum?
Found on left, apex pointing caudally and moderate in size.
Equine - caecum?
Signifiant amount of fermentation occurs here. Formed by haustra and taenia, large and sits dorsally and ventrally (against xiphoid process)
What is the colon?
Shorter and wider than the SI
Has ascending, transverse and descending
What are the layers of the colon?
Mucosa, submucosa, muscularis and adventia
