Digestive Flashcards
Label a tooth
enamel - dentin - pulp - cementum - peridontal ligament - root canal - alveolar bone - blood supply
What are the three major types of papillae?
filiform, fungiform, vallate/circumvallate
describe filiform papillae
- no taste buds
- jagged/saw-tooth/pointy looking
describe fungiform papillae
- few tatse buds
- look like budding mushrooms
describe vallate/circumvallate papillae
- location of majority of taste buds
- dome shaped deep “moat” surrounding its circumference
State the properties of the serous cells of salivary glands
- watery
- enzyme rich
- lysozome
- amylase
- parotid gland
State the properties of the mucous cells of the salivary glands
- visocus
- mucus-rich
- lubrication
What gross convolutions of the gut tube enchance surface area and thus absorption?
- coiled nature of small intestines
- ascending, trasnverse and descending colon
What evaginations of the gut tube enchance surface area and thus absorption?
intestinal villi
What invaginations of the gut tube enchance surface area and thus absorption?
- intestinal galnds (aka crypts of Lieberkuhn)
- gastric glands
What luminal folds of the gut tube enchance surface area and thus absorption?
- plicae circularis
- gastric rugae
indicate the 4 layers of thre GI tract
Serosa, muscularis externa, submucosa, mucosa
What layer of the mucosa porduces local movment independent of peristalsis?
muscularis mucosae
What is the name of the nerve plexus that innervates the muscularis mucosae?
submucosal nerve plexus
How is the muscularis externa arranged for most of the alimentary tract?
inner circular layer, outer longtitudinal layer
The visceral peritoneum of the intestines is also known as the?
serosa
Digestion begins at?
- mouth
- mechanical and chemical digestion (chewing, enzymes)
The epithelium in the oesophagus is unique because ?
It is stratified to protect against abrasion
- When abrasive food passes through the oesophagus the stratified layers can slough off and be digested along with the food
The primary function of the stomach is ?
- storage
- can be eaten at a much faster rate than it can be digested or absorbed, so the stomach acts as a storage site for food before it is transported through the pyloric sphincter and into the duodenum.
What is stored in the liver?
glycogen
What two endocrine secretions does the pancreas release?
insulin and glucagon
What is different between thoracic and abdominal oesophagus?
thoracic - adventitia
abdominal - serosa
Name another region besides the oesophagus in the alimentary tract that is lined with startifies squamous epithelium
oropharynx - protect passageway from friction caused by the passage of food
Label the wall of the digestive tract CCA2
- epithelium being sloughed off
- epithelial germ cells
- structures that supply the mucose with nutrients
- muscularis extera (inner ciruclar)
- muscularis externa (outer longitudinal)
- Myenteric plexus
What would be the consequence if the surface mucous cells failed to perform their function?
- destruction of the stomach lining by digestive juices
- (Their secretions help protect the stomach lumen from acid and pepsin.)
What do parietal cells do?
- secrete HCl which kills microbes and living cells
- secreted intrinsic factor
What do enteroendocrine cells do?
- release gastrin (which enters the blood as a hormone)
1. stimulates secretion of acid and pepsinogen
2. increases muscular contractions of stomach
3. relaxes pyloric sphyncter
What do chief cells do?
- release pepsinogen and gastric lipase
- pepsinogen is converted into the protein-splitting enzyme pepsin by acid in the lumen of the gland
Why is it important that the parietal cells and chief cells release their products in their inactive/precursor forms?
To prevent auto-digestion
It is important that the products from these cells are released in either inactive or precursor forms to prevent damage to the cells which release them (autodigestion)
Why is it important that the parietal cells and chief cells release their products in their inactive/precursor forms?
To prevent auto-digestion
It is important that the products from these cells are released in either inactive or precursor forms to prevent damage to the cells which release them (autodigestion)
Bile is a secretory product of the liver which is stored and concentrated in the gall bladder, before being released via a common duct with the pancreas into the duodenum. Which substance does bile play an important part in the digestion of?
lipids
Where does the blood traveling in the larger branch of the hepatic protal vein come from immediately upstream of the liver?
intestinal wall/gut
- carries nutrient-rich but deoxygenated blood from the intestinal wall. The proteins, carbohydrates and lipids carried in this blood supply are metabolised in the liver and either released into the blood stream or stored as necessary. The hepatocytes also require oxygenated blood provided by the arterial side of the systemic circuit (via the hepatic artery) in order to get oxygen to provide energy to carry out the metabolic processes that occur within the cell. Therefore, the liver has a dual blood supply.
What makes up the portal triad?
bile duct, hepatic artery, hepatic portal vein
