Intro to GIT Flashcards
State what components form the ‘headgut’ (3)
- mouth
- salivary glands
- pharynx
State what components form the ‘foregut’ (2)
- oesophagus
- stomach
State what components form the ‘midgut’ (2)
- duodenum
- small intestine
State what components form the ‘hindgut’ (a.k.a large intestine) (3)
- caecum
- colon
- rectum
State the function of the headgut in the GIT (2)
- prehension of food
- mastication
State the function of the foregut in the GIT
digestion
State the function of the midgut in the GIT (2)
- absorption
- initial storage of nutrients
State the function of the hindgut in the GIT
expulsion of unabsorbed portions of food
List the structures of the GIT (7)
- oral cavity/mouth
- pharynx
- oesophagus
- stomach
- small intestine
- large “ “
- anal canal/anus
State the structure of the oral cavity/mouth (4)
- lips
- tongue
- teeth
- salivary glands
State the structure(s) of the pharynx
epiglottis
State the function of the oesophagus
connects pharynx & stomach
Name the divisions of the small intestine (3)
duodenum
- jejunum
- ileum
Name the associated organs which are located next to the small intestine (3)
- liver
- gall bladder
- pancreas
The morphology of what GIT structure allows us to differentiate species on being monogastric/ruminants?
stomach
Define ‘prehension’
the act of getting food into the mouth
Define ‘mastication’
the mechanical breakdown of food & mixing w/ saliva
Define ‘deglutition’
the act of swallowing
State the type of control in the diff. phases of deglutition (swallowing) (2)
- initial phase = voluntary
- remaining phases = involuntary
State the function of the salivary glands & saliva (4)
- moisturize & lubricate food
- aids bolus formation
- aids enzymatic digestion
- aids swallowing
Name the enzyme present in the saliva & its function
amylase –> breaks down carbohydrates
List the main salivary glands & type of secretion they produce if known (4)
- parotid gland –> serous
- mandibular gland –> mixed serous & mucous
- sublingual gland –> mucous
- zygomatic gland
State the 2 types of salivary glands
- serous
- mucous salivary
The basic secretary unit of salivary glands are clusters of cells called ________.
acini
State the 2 basic types of acinar epithelial cells
- serous cells
- mucous cells
State what these cells secrete
serous cells
- watery fluid, essentially devoid of mucous
mucous cells
- mucous-rich secretion
Name the divisions of the oesophagus (3)
- cervical part
- thoracic part
- abdominal part
State the type of epithelium that is on the mucosa of the oesophagus
stratified squamous epithelium
Describe the submucosa layer in the oesophagus (3)
- consists of elastic & collagen fibres
- dense & irregular connective tissue
- contains glands, blood, & lymphatic vessels
Describe the tunica muscularis in the oesophagus (3)
- contain longitudinal & circular muscles
- longitudinal = superficial
- circular = located deeper
Describe the tissue of the serosa in the oesophagus
loose connective tissue
State the function of the stomach (2)
- temporarily store food b/f it is passed onto the intestines
- enzymatic breakdown of food
Name the diff. areas of the stomach (4)
- cardia –> entrance of stomach
- fundus –> upper area
- body –> central & largest area
- antrum (/ pylorus) –> lower area
Name the structure in the stomach that increases surface area of the organ
rugae (folds)
_____ _____ secrete _______ in the stomach
- gastric pits
- enzymes
State the pH of the stomach
3
Name the 2 sphincters in the stomach & their function
- cardiac sphincter –> control food passing from oesophagus to stomach
- pyloric sphincter –> control food passing from stomach into duodenum & small intestine
State the 3 layers of the stomach
- mucosa –> inner layer
- submucosa
- muscularis externa
Describe the mucosa in the stomach
- contains gastric glands & pits –> breaks down food chemically
- contains layer of smooth muscle (muscularis mucosa)
Describe the muscularis mucosa in the stomach
the contraction of this muscle helps to expel the contents of the gastric glands produced in the mucosa
Describe the submucosa in the stomach (2)
contains:
- blood vessels
- lymphatic vessels
Name the 3 layers of muscle in the mucularis externa in the stomach
- inner oblique layer
- middle circular
- external longitudinal layer
State the function of the muscularis externa in the stomach
the contraction of the muscle layers help to break up the food mechanically
Compare the anatomy of the stomach in diff. species (3)
- carnivores & hindgut fermenters (e.g pigs, horses) –> monogastric; one simple stomach
- ruminants (e.g sheep, goat, cow) –> complex 4 chambered stomach
- pseudoruminants (e.g camels, hippos) –> 3 chambered stomach
Name the diff. chambers in ruminants & pseudoruminants
4 chambered stomach:
- rumen
- reticulum
- omasum
- abomasum
3 chambered stomach:
- rumen
- reticulum
- omasum & abomasum combined into one
State the function of diff. parts of the small intestine (5)
duodenum:
- lining secretes mucous & fluids
- interacts w/ juices from bile duct & pancreatic duct
jejunum & ileum:
- secretes fluids
- chemical digestion
- nutrient absorption
State the functional unit of the liver (cells)
hepatocytes
State the function of liver cells (4)
- synthesis of bile
- biotransformation of substances in body
- storage
- synthesis of blood components
The liver is supplied by the ______ artery
hepatic
Blood is drained from the liver by the _____ _____ & the _____ _____ _____
- portal vein
- caudal vena cava
Describe the lobule & associated structures (3)
- hexagonal shape
- portal triads –> at the vertices
- central vein –> middle
Sheets of ______ _______ divide the liver into lobules
connective tissue
Name the 3 main structures the portal triad contains
- bile duct
- hepatic arteriole
- portal venule
State the blood supply of the pancreas
branches from the splenic artery
State in what way the structure of the pancreas is similar to that of the liver
the pancreas is divided into lobules by connective tissue (septae)
State the 3 diff. regions of the pancreas
- head
- body
- tail
Explain why the pancreas is a ‘compound gland’ (2)
bc it contains:
- a cluster of exocrine cells –> acini
- endocrine cells –> pancreatic islets of Langerhans
State the 2 main types of cells in the islet of Langerhans
- alpha cells
- beta cells
State their functions
- alpha cells –> produce & secrete glucagon
- beta cells –> produce & secrete insulin
State the function of pancreatic acini
produce pancreatic juice containing digestive enzymes –> will be released into the pancreatic duct to the duodenum
State the endocrine & exocrine products of the pancreas
endocrine:
- hormones-: glucagon & insulin)
exocrine:
- digestive enzymes
Name the 6 divisions of the large intestine
1) caecum
2) ascending colon
3) transverse colon
4) descending colon
5) rectum
6) anus
State the function of caecum
digestion of cellulose via microflora
State where the digestion of cellulose via microflora occurs in the large intestine in hindgut fermenters (2)
- caecum
- colon
State the functions of the colon (2)
- absorption of water & ions
- compaction of undigested material & microflora
State the function of the rectum & anus
expulsion of faeces that were undigested
State what is the ‘ileocaecal junction’
the union b/n the ileum & caecum
Describe the caecum in dogs (5)
- on right side of abdomen
- no direct connection to the ileum
- short
- held by the ileocaecal fold
- little microbial fermentation
Describe the caecum in ruminants (3)
- on right side of abdomen
- in the supraomental recess
- some microbial fermentation
Describe the caecum in horses (3)
- formed by haustra & tenia
- significant amount of fermentation
- points cranially
Describe the caecum in pigs (2)
- on left side of abdomen
- apex points caudoventrally
State at which point the descending colon is renamed ‘rectum’
once it enters the pelvic cavity
State how many layers the colon has
4
Describe the tunica muscularis
contracts the colon to facilitate the movement of food through the colon
____________ is the process that involves the mechanical breakdown of food and allows mixing with saliva.
mastication
Which salivary gland produces mixed (serous and mucous) secretion?
mandibular
Which layer surrounds the oesophagus external surface?
serosa (/ adventitia)
“The main role of the colon is to promote fermentation through cellulose breakdown by microflora” True/False?
FALSE
Name 2 animals that are considered to be hindgut fermenters
- horse
- rabbit
In the __________ is when there is most absorption of water and ions together with compaction of undigested material.
colon
