Year 2; Gi Block; Pbl 1

Front 1

Back 1

Front 2

What is the name of the muscles in the cheeks and what is their function?

Back 2

- buccinator muscles

- hold cheeks to teeth and assist in chewing

Front 3

What is the name of the muscles in the lips and what is their function?

Back 3

- orbicularis oris

- controls movement of mouth and lips

Front 4

What connects the middle of the gum to the lip?

Back 4

- labial frenulum

Front 5

Name and describe the 2 cavities in the mouth

Back 5

- oral vestibule: between the teeth cheeks

- oral cavity proper: between teeth and fauces

Front 6

What is the name of the 2 palates in the mouth and where is their location to one another

Back 6

- hard and soft palate

- hard palate anterior; soft palate posterior

Front 7

What forms the hard palate?

The soft palates separates the ------ and ---------

Back 7

- maxillae and palatine bones

- oropharynx and nasopharynx

Front 8

How is food prevented from entering the nasal cavity during swallowing?

Back 8

- the uvula and soft palate move upwards and block the nasal cavity

Front 9

Name three small salivary glands

Name the three major salivary glands

Back 9

- labial, buccal and palatal

- parotid, submandibular and sublingual

Front 10

Describe the difference in function between the extrinsic and intrinsic muscles of the tongue

Back 10

- extrinsic muscles are located outside of the tongue. They are involved in the movement of food during chewing.

- intrinsic muscles are located inside the tongue. They alter the size and shape of the tongue and are more involved in speech and swallowing.

Front 11

Where are papillae located in the mouth?

What cell type covers them?

What is their function?

Back 11

- upper and lateral surface of the tongue

- stratified sqaumous epithelium

- function as taste buds (sense receptor) and provide friction during mastication and swallowing

Front 12

What is the name of the glands found on the tongue and what is their function?

Back 12

- lingual glands

- secrete mucous and lingual lipase

Front 13

Back 13

Front 14

Back 14

Front 15

Does the pharynx have a mucous membrane?

What type of muscle does it contain?

Back 15

- yes

- skeletal

Front 16

What are the associated functions of the nasopharynx, oropharynx and laryngopharynx, respectively

Back 16

- nasopharynx functions only in respiration

- oropharynx and laryngopharynx are involved in respiration and digestion

Front 17

What is the name of the opening in the diaphragm which the oesophagus passes through?

Back 17

- eosophageal hiatus

Front 18

Back 18

Front 19

Back 19

Front 20

Which anatomical feature allows distension of the stomach during filling?

Back 20

- rugae: large folds of the mucosa

Front 21

Which feature of the cardia allows separation between the eosophagus and cardia?

What else would you find in the cardia?

Back 21

- cardia sphincter

- also contains mucous secreting glands: cardia glands

Front 22

Describe the fundus and its functions

Back 22

-distensible “pouch” at the top which expands as food fills thestomach

-stores gases produced as a by-product of digestion and food as needed

Front 23

What are the three regions of the pyloric part?

Back 23

- pyloric antrum, pyloric canal and the pylorus

Front 24

What anatomical feature would you find in the pylorus?

What is its function?

Back 24

- pyloric sphincter

- regulates passage of gastric contents into the duodenum and prevents backlflow

Front 25

What are the three regions of the small intestine?

Back 25

- duodenum, jejunum and ileum

Front 26

What are the four layers found in the majority of the GI tract?

Back 26

- mucosa, submucosa, muscularis and serosa

Front 27

In the stomach, name the 3 layers of mucosa

Back 27

- epithelial, lamina propria and muscularis mucosae

Front 28

What cell type covers the epithelial layer of the mucosa in the stomach and small intestine?

What is the cell type in the rest of the GI tract e.g. mouth, pharynx, oesophagus and anal canal?

Back 28

- simple columnar epithelial cells - called surface mucous cells

- non-keratinised stratified sqaumous epithelium

Front 29

List 4 features of the lamina propria i.e. what is found in this layer?

Back 29

- composed of areolar connective tissue

- blood vessels

- lymphatic vessels

- mucosa-associated lymphatic tissue (immune responses)

Front 30

What is the main tissue type in the muscularis mucosae of the stomach and small intestine?

What is its main function?

Back 30

- smooth muscle

- produces folds and waves to make sure the stomach contents come into contact with absorptive cells

Front 31

Back 31

Front 32

Gastricglands have three types of exocrine gland cells which secrete intothe stomach lumen. What are they called, what is their function, and what do their products collectively form?

Back 32

- mucous neck cells: secrete mucous

- chief cells:secrete pepsinogen and gastric lipase

- parietal cells: secrete HCl and intrinsic factor B for B 12 absorption

- collectively form gastric juice

Front 33

What is the name of the enteroendocrine cell found in gastric glands and what is its function?

Back 33

- G cells

- secretes gastrin

Front 34

Which layers of the GI tract are associated with neuronal regulation and what is its collective names?

Back 34

- submucosa and musclaris

- submucosal and myenteric plexus

Front 35

Describe the muscle layers found in the muscularis of the stomach

Back 35

- composed of three layers of smooth muscle - rather than 2)

- contains; an outer longitudinal layer, middle circular layer and inner oblique layer

Front 36

What cell type is found in the serosa of the stomach?

Back 36

- simple sqaumous epithelium

Front 37

What is the dominant cell type in the mucosa of the eosophagus?

Back 37

- non-keratinised sqaumous epithelium

Front 38

What cell type would you find as you approach the inferior portion of the eosopahgus?

Back 38

- mucous cells

Front 39

List 5 regions of the GI tract where the mucosa contains stratified sqaumous epithelium?

Back 39

- lips, mouth, eosophagus, tongue, oropharynx and laryngopharynx

Front 40

Describe how the muscle tissue in the eosophagus changes as you move inferiorly

Back 40

- top third: skeletal muscle

- middle: skeletal and smooth

- lower third: smooth muscle

Front 41

Name the 2 sphincters in the oesophagus and describe their difference in muscle composition

Back 41

- upper and lower eosophageal sphincters (UES/LES)

- UES contains skeletal muscle; LES contains smooth muscle.

Front 42

Describe the general functions of the UES and LES

Back 42

- UES: regulates passage of food between the pharynx and eosophagus

- LES: regulates passage of food between the eosophagus and stomach

Front 43

Back 43

Front 44

What gastric process occurs as food enters the stomach and how often

Back 44

- peristalsis; every 15-25 seconds

Front 45

In the stomach, where is peristalsis weakest/strongest

Back 45

- weakest in the fundus and intesifies as it approaches the pylorus

Front 46

Roughly how much chyme enters the duodenum during gastric emptying per contraction?

Back 46

- 3ml

Front 47

What are the 2 arms of the enteric nervous system?

Back 47

- submucosal and myenteric plexus

Front 48

Broadly, what are the differences in function between the submucosal and myenteric plexuses?

Back 48

- submucosal: involved more in regulation of secretions

- myenteric: involved more in motility

Front 49

What are the three types of neuron found in the submucosal and myenteric plexuses?

Back 49

- afferent (sensory)

- efferent (motor)

- interneurons (connect the two)

Front 50

What do motor neurons in the submucosal and myenteric plexuses - respectively - supply?

Back 50

- submucosal plexus: secretory cells in the epithelium

- myenteric plexus: smooth muscle

Front 51

What do sensory neurons in the submucosal and myenteric plexuses - respectively - supply?

Back 51

- both supply the mucosal epithelium

- act as either chemoreceptors or stretch receptors

Front 52

What is the function of interneurons?

Back 52

- allow communication between the 2 plexuses

Front 53

Which arm of the autonomic nervous system exerts the biggest influence on the enteric nervous system?

Back 53

- parasympathetic

Front 54

What cranial nerve innervates most of the GI tract?

Which nerves innervate the second half of the large intestine?

Back 54

- vagus (X)

- plevic splanchnic nerves from the sacral region

Front 55

What is the general outcome of an increase in parasympathetic nerve stimulation?

Back 55

- an increase in enteric nervous system activity

- leads to an increase in motility and secretion

- the opposite is true sympathetic stimulation

Front 56

What is the product of parietal cells and where is their product released?

Back 56

- H+ and Cl- (forming HCl)

- released into the stomach lumen

Front 57

Which enzyme is responsible for secreting H+ into the stomach lumen?

Generally, what happens?

Back 57

- H+/K+ ATPases

H+ moves into the lumen and is exchanged with K+

Front 58

How does Cl- enter the stomach lumen?

Back 58

Diffusion through the apical membrane

Front 59

Describe how HCl is produced, recycled and secreted - including all used enzymes

Back 59

- proton pumps transport H+ through the apical membrane of parietal cells in the stomach lumen in exchange for K+, using H+/K+ ATPases

- K+ and Cl- are able to diffuse freely back into the stomach lumen through Cl- and K + channels

- the enzyme, carbonic anyhydrase, uses H20 and CO2 to produce carbonic acid (H2CO3). The carbonic acid then dissociates to provide a readily available supply of H+ and bicarbonate ions (HCO3-). The H+ is then agian pumped into the stomach lumen using the H+/K+ ATPases

- As HCO3- builds up, it is exchanged for Cl- minus across the basolateral membrane. The Cl-, as before, enters the stomach lumen through the apical membrane. The HCO3- enters the blood stream, producing the alkaline tide that occurs after a meal.

- HCl secretion is stimulated by Ach from parasympathetic neurons, gastrin from G cells, and histamine released from mast cells in the lamina propria

Front 60

Which three chemical factors stimulate the release of HCl from parietal cells, and where are they released from?

Back 60

- acetylcholine from parasympathetic neurons

- gastrin from G- cells

- histamine (acts as a catalyst to acetylcholine and gasstrin)

Front 61

What are the functions of gastric secretions (3)?

Back 61

- kill microbes

- denature proteins

- promote production of certain hormones involved in regulating bile and pancreatic juices

Front 62

Inwhat area of the stomach would you find D cells?

What is the function of D cells?

How do they do it?

Back 62

-next to G cells in the pyloric region

- make gastric juice more alkaline (raise the pH)

- D cells release somatostatin in response to low pH. Somatostatinacts on G cells, causing them to stop releasing gastrin

Front 63

Which cells produce pepsin?

Where are these found in the stomach?

What is the function of pepsin?

Back 63

- chief cells

- everywhere except for the pyloric section

- degrades proteins into peptides

Front 64

What is secreted by parietal cells (2)?

What is secreted by chief cells (2)?

What is secreted by G cells (1)?

Back 64

- intrinsic factor and HCl

- pepsinogen and gastric lipase

- gastrin

Front 65

What are the 5 functions of gastrin?

Back 65

- stimulates parietal cells to release HCl

- stimulates chef to release pepsinogen

- causes contraction of the lower eosophageal sphincter

- increases gastic motility

- relaxes the pyloric sphincter

Front 66

What are the three pathological classifications of GI ulcers?

Back 66

- H. pylori positive

- NSAID-associated

- H. pylori negative and non-NSAID associated

Front 67

Describe the pathology of H. pylori induced ulcers (essay answer)

Back 67

-three types: gastric (stomach), eosophageal (eosophagus) and duodenal(duedenum). Most sources state 2 (gastric and duodenal)

-three pathological groups: (1) H. Pylori positive, (2) NSAIDassociated and (3) H. Pylori negative and non-NSAID associated.

-caused by an imbalance between protective and aggravating factors(e.g. mucous bicarbonate layer/prostaglandins/cellular regenerationvs Hcl/pepsin/ethanol/bile salts/drugs)H.Pylori

-causes an inflammatory response in gastric mucosa

-causes production of interleukins from gastric epithelium – mainlyIl 8 and Il 1 beta-followed by recruitment of macrophages and neutrophils to the mucosa,and the release of (1) lysosomal enzymes, (2) leukotrienes, (3)reactive oxygen species. These factors impair mucosal defense.

- Th1 cells are also recruited but, as H. Pylori is not aintracellular pathogen, this leads to celllular damage. Activation ofT and B cells also leads to the production of further cytokines e.g.Ils 1, 2, 6, 10 and TNF alpha

-continued assault by ROS can lead to DNA damage, causing a risk ofneoplasias

-H Pylori expresses a high amount of the enzyme, urease, whichhydrolyses urea into ammonia and CO2. H Pylori needs this enzyme asthe ammonia is alkaline and protects it from the acidic gastricenvironment

-the excess production of ammonia inhibits D cells – cells found inpredominantly in the antrum. D cells are responsible for producingsomatostatin, a growth hormone-inhibiting hormone which inhibits therelease of gastrin from G cells. As there is less somatostatin (i.e.inhibition), there is an increase in gastrin production (>>hypergastrinaemia).

-high amounts of ammonia also promote the production of toxiccomplexes which, with bacterial phospholipases A and C, impairmucosal hydration and the overall integrity of the gastricepithelium. Also casues hyperplasia of parietal cells.

-colonisation of duodenal epithelium requires metaplasia, as H Pylorionly colonises gastric epithelial cells. This metaplasia of theduodenal mucosa leaves it susceptible to peptic acid and ulceration.

Front 68

How could a persons loss/gain in weight help you determine whether a person has a gastric or duodenal ulcer?

Back 68

-gastric ulcers cause pain during a meal and typically affect theantrum: patients tend to lose weight.

-pain tends to improve with a meal – pyloric sphincter tightensduring a meal (prevents acid flowing in the duodenum ulcer): patientstend to gain weight.

Front 69

For a duodenal ulcer, why would a patient experience greater pain at night?

Back 69

- dueto a hormone called, motilin, which increase digestion during sleep.

- this means the pyloric sphincter is open more and acid is able toflow from the stomach to the duodenum

Front 70

Discuss the pathology of NSAID induced gastroduodenal ulcers (essay answer)

Back 70

-main factor is inhibition ofcyclo-oxygenase 1 (COX1), which is the target – to varying degrees– of NSAIDs.

-use of COX2 selective NSAIDs reduce, though do not eliminate,gastroduodenal ulcers-NSAIDs also inhibit NO and hydrogen sulphide which have beneficialroles in preventing peptic ulcers, as they increase blood flow tomucosa, stimulate mucus secretion, and inhibit neutrophil adherence.

-neutrophil adherence is a major factor in the pathogenesis ofNSAID-induced peptic ulcers. Adherence of neutrophils to the mucosacauses damages due to (1) release of free radicals, (2) release ofproteases (breaks down proteins and peptides), and (3) obstructscapillary blood flow.

Front 71

Give 5 potential causes of gastroduodenal ulcers not including H. pylori or NSAIDs

Back 71

-gastrinomas: gastrin-secreting tumours secretingan excess of gastrin. Causes hypersecretion of HCl acid into theduodenum, which causes the ulcers. Commonly seen in Zollinger-Ellisonsyndrome, caused by a tumour or hyperplasia of non-beta islet cellsin the pancreas.

-drinking too much alcohol

-smoking and chewing tobacco

-radiation treatment in the area

-medications used to treat osteoporosis: biphosphonates and potassiumsupplements

Front 72

List and describe the different diagnostic tests for gastroduodenal ulcers (4)

Back 72

urea breath test: you will be given a special drink containing a chemical that is broken down by H. pylori; your breath is then analysed to see whether or not you have an H. pylori infection

- stool antigen test: a small stool sample is tested for the bacteria

- blood test – a sample of your blood is tested for antibodies to the H. pylori bacteria; this has now largely been replaced by the stool antigen test

- gastroscopy

Front 73

How would you treat a H. pylori associated ulcer?

Back 73

- antibioticswill be used in the case of H. pylori infection.

- Bismuthsubsalicylate may also be used: slows growth of bacteria.

Conventionfor a peptic ulcer caused by H. Pylori is H. Pylori Triple Therapy:

amoxicillin, clarithromycin and a PPI (e.g. omeprazole, lansoprazoleor pantoprazole)

if allergic to penicillins: metranizadole, clarithromycin and PPI (e.g. omeprazole)

Front 74

How do PPIs work?

Give 3 examples of PPIs

Back 74

- workby inhibiting the hydrogen-potassium adenosine triphosphatase enzymesystem ('proton pump'), effectively reducing acid production.

- Examples include: omeprozole, pantoprazole and lansoprazole.

Front 75

How do H2 antagonists work?

Give 3 examples

Back 75

- workby competing with histamine on H2 receptors of parietal cells in thestomach. Preventing the binding of histamine prevents their abilityto promote hydrochloric acid production by the parietal cells.

- Examples include ranatidine (zantac), cimetidine and famotidine.

Front 76

How do antacids work?

How do cytoprotetive/alginate agents (e.g. gaviscon) work?

Back 76

- composedof alkaline ions which neutralise the acidity of secretions in thestomach. They help to relieve pain but do not help healing.

- producea protective coating

Front 77

List and describe three surgical interventions for a gastric ulcer (one which is H. pylori negative and non-NSAID associated)

Back 77

- vagotomy: vagus nerve is cut. This nerve signals production ofstomach acid. As it is cut, less acid is produced)

- antrectomy: antrum is removed. Acid production is decreased as itsignals the stomach to release acid.

- pyloroplasty:performed when a ulcer is blocking the passage of food. Pylorus iswidened to remove the blockage.

Front 78

List 5 risk factors for ulcers

Back 78

- male gender

- smoking

- poor diet

- stress(?)

- age