GIT Anatomy Revision Flashcards
What are the 3 salivary glands in the oral cavity?
1 - sublinguinal glands
2 - submandibular glands
3 - parotid glands
What are the 3 salivary glands in the oral cavity?
1 - sublinguinal glands
2 - submandibular glands
3 - parotid glands
What % of salive do the the 3 salivary glands in the oral cavity contribute towards total saliva?
1 - sublinguinal glands - 5%
2 - submandibular glands - 70%
3 - parotid glands - 25%
Of the 3 salivary glands, sublinguinal glands, submandibular glands and parotid glands, which nerve innervates the parotid glands?
- glossopharyngeal nerve
Of the 3 salivary glands, sublinguinal glands, submandibular glands and parotid glands, which nerve innervates the sublinguinal and submandibular glands?
- facial nerves
What are the 3 phases of swallowing?
1 - oral phase
2 - pharyngeal phase
3 - oesophageal phase
Of the 3 phases of swallowing oral, pharyngeal and oesophageal phase, which is the only voluntary phase?
- swallowing phase
What is the anatomical landmark used to determine the upper from lower aspects of the GIT?
- suspensory muscle of the duodenum
- also known as the ligament of Treitz
The suspensory muscle of the duodenum, also known as the ligament of Treitz is the anatomical landmark used to determine the upper from lower aspects of the GIT. Where does this attach and what is the importance of this muscle/ligament?
- attaches at the duodenojejunal flexure and celiac artery
- contracts and increases area for chyme movement helping motility
- marks transition from foregut to the midgut
What are the 4 layers of the GIT?
1 - mucosa
2 - submucosa
3 - muscularis propria
4 - serous
The mucosa is the first layer of the GIT. What 3 makes up the mucosa?
1 - epithelium
2 - lamina propria
3 - muscularis mucosae
What are the 2 plexi of the GIT wall?
1 - submucosa plexus (secretions and blood flow)
2 - myenteric plexus (peristalsis)
What is the role of the sub muscularis?
- contract and make mucosa fold
- increases surface area of GIT
What is intrinsic and extrinsic regulation of motility in the GIT?
- intrinsic = enteric nervous system
- extrinsic = autonomic control
There are 2 types of motility in the small intestines, segmentation and peristalsis. Which is responsible for mixing and which is responsible for chyme motility?
- segmentation = mixing
- peristalsis = motility
In the GIT what does bi-directional flux refer to?
- fluid and secretions being released into the GIT
- then reabsorbed by the GIT (aprox 99%)
Which exocrine cells in the gastric pits of the stomach are responsible for secretion of HCl and intrinsic factor (B12 binding)?
- parietal cells
Which exocrine cells in the gastric pits of the stomach are responsible for secretion of gastric enzymes pepsinogen and gastric lipase?
- chief cells
Which endocrine cells in the gastric pits of the stomach are responsible for secretion of gastrin?
- G cells
- G for Gastrin
Which endocrine cells in the gastric pits of the stomach are responsible for secretion of somatostatin?
- D cells
Which endocrine cells in the gastric pits of the stomach are responsible for secretion of histamine?
- enterochrommafin like cells
In the small intestines which cells secrete mucus?
- goblet cells
In one cell in the small intestines is able to secrete cholecystakinin, secretin and glucose dependent insulinotropic peptide?
- enteroendocrine cells
In the small intestines which cell differentiates from daughter cells and then migrates downwards below the stem cells? These cells also secrete antimicrobial lysosomes.
- paneth cells
- migrate down to protect the stem cells
In the small intestines there is a specific cell that is only found in the small intestines, what is responsible for secreting HCO3- and mucus, what is this cell called?
- brunners gland
What are the 3 ways in which pareital cells can be stimulated to secrete HCl?
1 - gastrin
2 - histamine (stimulated by gastrin)
3 - ACh (stimulated by vagal nerve)
What secretion in the stomach is able to in hibit secretion of HCl by D cells?
- somatostatin
The pancrease contains endocrine and exocrine clusters, what is the majority of the pancreas made of?
- exocrine clusters
Where are the endocrine cells of the pancreas located within the pancreas?
- in the islets of langerhans
Somatostatin can be released from D cells in the islets of langerhans. They act as inhibitors, what are the 2 things they they inhibit in the GIT?
- HCl secretion in the stomach by parietal cells
- inhibition of both glucagon and insulin
- somatostain appears to inhib all secretions
- remember STOP secretions for somatostatin
What is the main nerve that stimulates pancreatic secretions?
- vagal nerve
A hormone is secreted in response to fat, carbohydrates and proteins being present in the duodenum. What is this hormone and what does it increase the secretion of from the pancreas?
- cholocystekinin (CCK)
- increases pancreatic enzyme rich secretions to digestion nutrients
A hormone is secreted in response to high level of H+ and a low pH being present in the duodenum. What is this hormone and what does it increase the secretion of from the pancreas?
- secretin
- increases HCO3- rich pancreatic secretions to neutrilise acidic chyme
There are 3 phases of pancreatic secretions, what are they and what % of the toal secretions does each one contribute?
1 - cephalic = 20% of secretions
2 - gastric = 10% of secretions
3 - intestinal = 70% of secretions
Which part of the stomach does the stretching signal gastric secretions
- fundus
What are the 3 broad types of transport in enterocytes?
1 - passive (down electrochemical gradients)
2 - solvent drag (parracellular)
3 - active (Na+ / K+ ATPase, needs energy)
What is solvent drag?
- H2O moves due to osmosis and balance concentrations
- solutes are able to follow or be dragged (Na+. K+, Cl-)
Solvent drag is where H2O moves due to osmosis and balance concentrations. Solutes are able to follow or be dragged (Na+. K+, Cl-), but this only occurs paracelluarly between cells and tight junctions. Where in the small intestines does the majority of this occur?
- proximally, so mainly in the duodenum
If enzymes from the pancrease were secreted in their active form they would digest the pancreas, such as proteases. How does the pancreas and small intestines get around this?
- secretes inactive protein digesting enzymes called zymogens
To ensure enzymes from the pancrease do not digest the pancreas, such as proteases, the pancrease secretes inactive protein digesting enzymes called zymogens. How do these enzymes then become active?
- enterokinase in the brush border
- trypsinogen becomes trypsina and can they activate other enzymes
H2O is able to diffuse in a number of ways through osmosis to maintain equilibrium of ion concentrations (isotonic). H2O can be absorbed in 2 main ways in the GIT, what are they?
- enterocytes contain aquaporins allow H2O to diffuse and maintain equilibrium
- H2O can move paracelluarly via solvent drag and move electrolytes with it to maintain equilibrium
From the options belowe, which is not a risk factor for malnutrition?
- Being 95 years old
- Being a nursing home resident
- Being male
- Chronic Kidney Disease
- Moderate dementia
- being male
Which of the following information would be needed to calculate a patients MUST score?
- MUAC score (Mid-humeral circumference)
- His total body fat percentage
- His ulnar length
- Total weight lost unintentionally in the last 3-6 months.
- Whether Colin is acutely unwell at this time OR unlikely to have any nutritional intake for 5 or more days
- Total weight lost unintentionally in the last 3-6 months
To calculate a MUST score for malnutrition, what 3 thinsg are required, and what score determines if someone is malnourished?
- score of _>_4
- patients BMI
- % weight lost unintentionally in last 3-6 months
- if patient is acutely unwell and low nutritional intake for >5 days
What are some of the most common risk factors for colorectal cancer?
- age (median age 71 years old)
- genetics (family history)
- smoking
- processed meats and low fibre
- long standing UC with PSC
Is smoking associated with crohns or UC?
- Crohns disease