Gastrointestinal system 1 Flashcards
- What are the layers that make up the mucosal wall
a. Epithelial cells
b. Lamina propria
c. Muscularis mucosae
- What structures are found in the submucosal layer
a. Collagen
b. Elastin
c. Glands
d. Blood vessels
- What are the layers that make up the gut wall
a. Lamina propria
b. Mucosa
c. Muscularis mucosae
d. Submucosa
e. Muscularis externa
f. Serosa
g. Mesentery (not a layer but on top)
- What are the two main plexuses that contain the nervous system
a. Submucosal plexus
b. Mesenteric plexus
- Where are the ganglions of the enteric nervous system found
a. The plexuses
- What do the enteric neurones release
a. Cholinergic or peptidergic
- What are the different types of contractions in the GI tract
a. Phasic – periodical
b. Tonic – constant
- What are slow waves
a. Subthreshold membrane potentials that allow membrane to be set up for depolarization
- What are the 5 main sphincters
a. Upper oesophageal sphincter
b. Lower oesophageal sphincters
c. Pyloric sphincter
d. Ileocecal sphincter
e. Internal/external anal sphincters
- What muscles and nerves are involved in chewing
a. Mastication muscles
b. Innervated by the mandibular nerve of the cranial nerve 5 – trigeminal
- What are the three stages of swallowing
a. Oral
b. Pharyngeal
c. Oesophageal
- What occurs in the first stage of swallowing
a. Tongue forces bolus to back of mouth
b. Stimulates somatosensory neurons
c. Signals the medulla
d. Stimulates the pharyngeal stage
- What occurs in the second stage of swallowing
a. The pharyngeal stage
b. Soft palette up
c. Epiglottis covers sphincter
d. Food enters oesophagus
e. Upper epigeal sphincter relaxes
f. Breathing inhibited
- What is the oesophageal stage
a. Closes upper oesophageal sphincter
b. Initiation of primary peristaltic wave
c. Lower oesophageal sphincter opened by vegus nerve
- What are the 2 regions of the stomach
a. Orad region
b. Caudad region
- What are the 3 sections of the stomach
a. Fundus
b. Body
c. Antrum
- How does the stomach prevent back flow
a. Lower oesophageal sphincter and orad contract
- What is the term for the mixture in the stomach
a. Chyme
- Why does the orad relax
a. In anticipation of food
b. Reduces pressure in stomach to allow for a pressure gradient
- Why is gastric emptying closely regulated
a. Provide enough time for neutralization of the acid
- What are the 3 sections of the small intestine
a. Duodenum
b. Jejunum
c. Ileum
- What are the 3 levels surface area is increased
a. Plicae
b. Villi
c. Microvilli
- What are the different types of contraction in the small intestine
a. Peristaltic contractions – propel chyme
b. Segmentation contractions – split and expose chyme to secretions
- What are the accessory organs
a. Pancreas
b. Liver
- What cells secrete exocrine pancreatic secretion
a. HCO3- secreted by centroacinar cells/ductal cells
b. Enzymes – acinar cells
- What nervous system stimulates the secretion of pancreatic juice
a. Parasympathetic
- What are the different phases of pancreatic juice secretion
a. Cephalic – conditioning/taste/smell
b. Gastric – distention of the stomach
c. Intestinal – 80% pancreatic secretions
- What does the liver secrete
a. Produced by hepatocytes – bile
- What is the role of the gall bladder
a. Concentrates and ejects bile
- What is the first part of the large intestine
a. Caecum
- How does the large intestine stop back flow into ileum
a. Proximal colon and ileocecum sphincter contract
- What are haustra
a. Pouches in the colon
- What are the 3 primary functions of the large intestine
a. Absorb water and electrolytes
b. Makes and absorbs vit K and B
c. Forming and propelling faeces
- What enzymes are secreted in the mouth
a. Amylase
b. Lingual lipase
c. Kallikrein
d. Mucus
- What is secreted in the Oesophagus
a. Mucus
b. HCO3
- What is secreted from the stomach
a. HCL
b. Pepsinogen
c. Intrinsic factor
- What is secreted in the large intestine
a. Mucus
- What glands are found in the body of the stomach
a. Oxyntic glands
- What cells are found in the oxyntic glands
a. Gastric pit
b. Epithelial cells
c. Mucous neck cells
d. Parietal cells
e. Chief cells
- What does epithelial cells release in the oxyntic glands
a. HCO3
- What do mucous neck cells release in the oxyntic glands
a. Mucus
- What do parietal cells release in the oxyntic glands
a. HCL, intrinsic factor
- What do chief cells release in the oxyntic gland
a. Pepsinogen
- What glands are found in the antrum
a. Pyloric glands
- What cells are not found in the pyloric glands
a. Parietal cells
- What cells are found in the pyloric glands
a. G cells – gastrin
b. D cells – somatostatin
- Why do parietal cells release HCL
a. To provide conditions to convert pepsinogen to pepsin
- What proteins are found on the apical side of the parietal cells
a. k/H ATPase
b. cl channel
- what cells are found on the basolateral surface
a. NA/K ATPase
b. HCO3/Cl
- What stimulates H secretion
a. Histamine binding to H2 GS coupled receptors
b. Ach – binds to M3 Gq receptor
c. Gastrin – binds to CCKB receptor
- What inhibits H secretion
a. Somatostatins and prostaglandins
b. Bind to Gi receptors inhibit cAMP
- What drugs prevent H secretion
a. Omeprazole
- In the SI what cells protect the lumen and how
a. Crypt cells secrete fluid and electrolytes
- What does cholera toxin do
a. Too much cAMP
b. More Cl channels open
c. Water follows too much water absorbed into lumen
- What is absorbed in jejunum
a. Na Cl
b. Sugar
c. Amino acids
d. Bicarb
- What is the pH of blood in the pancreas
a. Low
- What effect does aldosterone have on the large intestine
a. Synthesis of more Na channels
b. Increased internal conc of Na
- Where are lipids hydrolysed
a. Duodenum
b. Jejunum
- How are fatty acids absorbed into the blood from epithelial cells
a. Chylomicrons secreted via exocytosis
b. Enter lymphatic system
c. To thoracic duct where they are emptied into blood stream
- To access enterocytes what barriers do molecules have to cross
a. Mucus gel layer
b. Acidic unstirred water zone
- What are the islets main secretory cells
a. Beta – insulin
b. Alpha – glucagon
c. Delta – somatostatin
d. Epsilon – ghrelin
- What type of junction are between beta and alpha cells in iselts of langerhans
a. Gap junctions
- What type of junction Is between delta cells and beta cells in islets of langerhans
a. Dendrite like processes
- What neurotransmitters innervate the pancreas
a. Adrenergic
b. Cholinergic
c. Peptidergic
- What does the stimulation of beta adrenergic neurons lead to in the pancreas
a. Increase in secretion of insulin
- What does a stimulation of alpha adrenergic neurons do in the pancreas
a. Inhibits secretion of insulin
- What effect does the parasympathetic vagus nerve innervate when stimulated
a. Releases Ach increasing insulin release
- How does glucose release insulin
a. Glucose binds to glut2
b. Increases ATP
c. Opens potassium channels
d. Depolarizes
e. Calcium enters and triggers exocytosis of insulin
- What is the structure of the insulin receptor
a. 2 extracellular alpha chains
b. 2 membrane spanning beta chains
- What effect does the binding of insulin have
a. Decreases blood glucose levels
b. Insulin binds
c. Signal transduction cascade – glut4 proteins enter membrane
d. Allows glucose to enter
- What effect does insulin have in the liver
a. Promotes the conversion glucose to glycogen
- What effects does insulin have on muscle
a. Anabolic effect
b. Increasing uptake of amino acids
c. Stimulation of protein synthesis
- What are the effects of insulin of adipocytes
a. Increase in GLUT4 expression
b. Glucose converted to fatty acids
- What is type 1 diabetes
a. Autoimmune disease affecting Beta cells secrete inadequate insulin
- What are the signs of type 1 diabetes
a. Chronic hyperglycaemia
b. Increased fatty acid, amino acids and ketones in blood
c. Osmotic diuresis
d. Polyuria
e. Hypotension
f. Smelly breath
- How do you treat type 1 diabetes
a. Insulin replacement therapy
- What is type 2 diabetes
a. Insulin resistance
b. Downregulation of insulin receptors
- What are the signs of type 2 diabetes
a. Increased thirst
b. Hunger
c. Urination
d. Fatigue and blurred vision
- What are the treatments for type 2 diabetes
a. Sulphanyurea /tolbutamide – stimulates insulin secretion
b. Metformin – upregulate receptors on target tissues
c. Calorie restriction
what is the layer of fatty tissue over abdominal wall
superficialo fascia
how many layers is the superficial fascia over the abdominal wall
one layer over most of it, two layers in the lower anterior region below the umbilicus
