167 Questions
What is the function of the Stem Cell in Gastric Pits?
To repair damaged epithelium
What is the effect of prolonged vomiting on potassium levels?
Hypokalemia
What is the main composition of saliva secreted by the salivary glands?
Amylase
What is the function of the Parietal Cell in Gastric Pits?
To secrete HCL
What is the main stimulant for gastric acid secretion?
Gastrin
What is the name of the constriction in the oesophagus where it is pierced by the diaphragm?
Diaphragmatic constriction
What is the main difference in the mucosa between the oesophagus and the stomach?
Stratified squamous to simple columnar/glandular
Which part of the small intestine is primarily located in the left upper quadrant?
Jejunum
What is the function of the pancreas in relation to the duodenum?
The pancreas empties all of its digestive enzymes into the duodenum
What is the name of the glands found in the jejunum and ileum?
Peyer's glands
What is the primary mechanism by which gastric contents flow back into the oesophagus in GORD?
Excessive reflux of normal gastric juice
What is the major control point of glycolysis?
Phosphofructokinase
Which of the following is NOT a characteristic of glucokinase?
High Km for glucose
What is the primary role of the pentose phosphate pathway in relation to glycolysis?
Providing NADPH and ribose 5-phosphate
What is the fate of pyruvate produced by glycolysis in the presence of oxygen?
Converted to acetyl-CoA and fed into the citric acid cycle
What is the term for a condition where there is too little glucose in the blood?
Hypoglycaemia
What happens to glucose in hepatocytes during glycogenesis?
It is stored in the form of glycogen
What is the role of insulin in hepatocytes?
It accelerates glycolysis and promotes glycogen synthesis
What is the result of excess ammonia in the body?
It depletes ketoglutarate used in the Krebs cycle
What is the function of transaminase in protein metabolism?
It catalyzes the transfer of an amino group to a keto-acid
What is the significance of high concentrations of ALT and AST?
It indicates hepatic injury
What is the purpose of the urea cycle?
To remove ammonia from the body
What is the primary function of apoproteins in lipoproteins?
To facilitate the transport of lipids through the bloodstream
What is the main difference between chylomicrons and VLDL?
The source of the lipoprotein
What is the fate of VLDL in the liver?
It is converted into LDL
What is the purpose of packaging TAG into lipoproteins?
To facilitate the transport of TAG through the bloodstream
What is the primary component of chylomicrons?
Triacylglycerol
What is the role of lipoprotein lipase in lipoprotein metabolism?
To break down lipoproteins into smaller components
What is the function of ICCs in the stomach?
Generating slow waves that propagate from the corpus
What is the primary function of the fundus and body of the stomach?
Storing food due to receptive relaxation
What is the significance of the greater curvature of the stomach?
It has a higher frequency of contraction
What is the third phase of gastric motility?
Retropulsion
What determines the rate of gastric emptying?
All of the above
How do liquids empty from the stomach?
Exponentially
What is the significance of the antrum in gastric motility?
It enables powerful contractions against a closed pylorus
What happens to large solid particles in the stomach?
They suffer a lag phase
What is the primary function of bile salts in the digestion process?
Emulsification of lipids to enhance absorption
What is the primary site of cholesterol synthesis?
Liver
What is the primary function of cholangiocytes in the bile duct?
Modulation of bile production by adding HCO3-
What is the fate of bilirubin in the liver?
Excretion into the bile
What is the primary stimulus for the secretion of bile from the gallbladder?
Presence of fatty acids in the duodenum
What is the consequence of unchecked bile salt accumulation in the colon?
Diarrhea
What is the primary mechanism of action of statins?
Inhibition of HMG-CoA reductase
What is the primary function of conjugation of bilirubin with glucuronate?
Increased solubility of bilirubin
What is the primary source of acetyl-CoA for extrahepatic tissues?
Ketone bodies
What is the primary mechanism preventing fat oxidation when glucose is plentiful?
Increased malonyl-CoA levels
What is the primary function of fructose 1,6-biphosphatase in gluconeogenesis?
To remove phosphate from sugar and dump it into water/cytoplasm
What is the primary role of AMP-activated protein kinase (AMPK) in exercise?
Regulating fat oxidation
Which of the following enzymes is involved in the conversion of pyruvate to PEP in gluconeogenesis?
Phosphoenolpyruvate carboxykinase
What is the primary adaptation occurring during fatigue?
Increased fatty acid oxidation
What is the byproduct of the reaction catalyzed by pyruvate carboxylase in gluconeogenesis?
CO2
Why is oxaloacetate not directly transported back into the cytoplasm in gluconeogenesis?
There is no oxaloacetate transporter in the mitochondria
What is the primary fate of acetoacetate in the liver?
Split into ketone bodies
What is the primary consequence of unregulated ketone production?
Ketoacidosis
What is the purpose of malate dehydrogenase in gluconeogenesis?
To transport oxaloacetate back into the cytoplasm
What is the result of fatty acid oxidation in the context of gluconeogenesis?
Production of ATP and NADH
What is the primary source of energy for the brain during starvation?
Ketone bodies
What is the primary mechanism by which AMP affects glucose handling in skeletal muscle?
Stimulating glycogen synthesis
Why can fatty acids not be used to directly produce glucose?
Fatty acids are not a source of carbon skeletons
What is the role of GTP in the conversion of oxaloacetate to PEP in gluconeogenesis?
GTP is used to drive the reaction of phosphoenolpyruvate carboxykinase
What is the purpose of rearranging glucose-6-phosphate to fructose-6-phosphate in glycolysis?
To make the steps chemically easier
What is the effect of high levels of ATP and citrate on the activity of Phosphofructokinase-1?
They inhibit the enzyme
What is the product of the cleavage of fructose-1, 6-biphosphate in glycolysis?
Two 3-carbon molecules
What is the role of glyceraldehyde phosphate dehydrogenase in glycolysis?
To oxidize glyceraldehyde-3-phosphate
What is the function of phosphoglycerate kinase in glycolysis?
To phosphorylate ADP
What is the fate of NADH in aerobic conditions?
It is fed into the respiratory chain
What is the role of pyruvate kinase in glycolysis?
To convert PEP to pyruvate
What is the significance of the conversion of fructose-6-phosphate to fructose-2,6-biphosphate?
It is a mechanism to regulate the concentration of fructose-6-phosphate
What is the function of the migrating motor complex in the small intestine?
To clear undigested material and prevent bacterial growth
What is the primary trigger for the contraction of the stomach during the gastric phase?
Mechanical effect of food in the stomach
What is the role of enteric sensory neurons in the regulation of peristalsis?
To detect intraluminal stimuli and initiate peristalsis
During swallowing, what is the function of the second peristaltic wave?
To back up the first peristaltic wave in case of obstruction
What is the primary function of the cephalic phase of food intake?
To prepare the gastrointestinal tract for food intake
What is the primary role of insulin in regards to glycogen synthesis?
It activates protein phosphatase-1 to increase glycogen synthase activity
What is the mechanism by which the migrating motor complex clears undigested material from the small intestine?
By stimulating the contraction of the intestinal muscles
What is the energy source for the conversion of glucose-1-phosphate to UDP-glucose?
UTP
What is the primary function of glycogen phosphorylase in the liver?
To break down glycogen to release glucose into the blood
What is the primary function of the gastric phase of food intake?
To stimulate the contraction of the stomach muscles
What is the effect of phosphorylation on glycogen synthase activity?
It decreases glycogen synthase activity
What is the role of the vagus nerve in the regulation of gastrointestinal motility?
To stimulate the contraction of the stomach and small intestine
What is the primary role of glucagon in regards to glycogen metabolism?
It breaks down glycogen to release glucose into the blood when glucose levels are low
What is the fate of glycogen breakdown in muscle cells?
It is fed into glycolysis and used for energy production in the muscle cell
What is the primary function of glycogenin in glycogen synthesis?
It synthesizes glycogen from UDP-glucose
What is the effect of dephosphorylation on glycogen synthase activity?
It increases glycogen synthase activity
What is the primary mechanism by which the TCA cycle rate is controlled?
Availability of NAD+
What is the role of calcium in the TCA cycle in muscles?
It stimulates the activity of dehydrogenases
What is the purpose of pyruvate carboxylase in the TCA cycle?
To top up oxaloacetate levels
What is the effect of hypoxia on oxidative metabolism?
It decreases ATP production
What is the role of HIF1 in hypoxia?
It inhibits biogenesis of mitochondria
What is the consequence of reduced mitochondrial density in hypoxia?
It reduces oxidative stress
What is the primary adaptation to hypoxia?
Increased anaerobic metabolism
What is the role of gene expression changes in hypoxia?
They stimulate HIF1 activity
What percentage of the liver's blood supply is derived from the portal circulation?
75%
What type of muscle fiber uses oxidative metabolism from glucose and fatty acids?
Type 1 Slow Twitch
What is the primary function of the hepatic lobule?
To metabolize carbohydrates, proteins, and fats
What is the primary fuel source for Type 2 Fast Twitch muscle fibers?
Glycogen
What is the primary fate of glucose in hepatocytes?
Glycogen synthesis
What is the purpose of AMP in skeletal muscle during exercise?
Increase glucose uptake in the short term and FA oxidation in the long term
What is the name of the vein that drains the liver and empties into the inferior vena cava?
Hepatic vein
What is the role of calcium in muscle contraction?
Bind to calmodulin
What is the function of the bile duct in the hepatic lobule?
To secrete bile into the small intestine
What is the primary source of ATP replenishment during exercise?
Phosphocreatine
What is the primary source of oxygenated blood to the liver?
Hepatic artery
What is the result of a decrease in ATP levels during exercise?
Increase in ADP and AMP levels
What is the term for the process of removing toxins from the blood?
Detoxification
What type of metabolism is used by Type 2 Fast Twitch muscle fibers?
Anaerobic metabolism
What is the primary function of the gallbladder?
To store bile produced by the liver
What is the function of phosphorylase kinase in muscle contraction?
Activate glycogen phosphorylase
What is the primary mechanism of IgA transport across the epithelium in the gut?
The polymeric Ig receptor
What is the role of MadCAM in the gut?
Ligand for alpha 4 beta 7
What is the function of the J chain in IgA and IgM?
Joining chain
Why is IgA not a good mediator of inflammatory reactions?
Agglutination mechanism
What is the role of breast endothelial cells in lactation?
Expressing MadCAM and facilitating IgA transport
What is the significance of IgA production in the gut?
Provides effective immunity against pathogens
What is the primary mechanism by which high glucose conditions inhibit fat oxidation?
High glucose conditions lead to increased citrate levels, which are then converted to malonyl-CoA, inhibiting the uptake of fatty acids by the mitochondria.
How does the brain adapt to starvation in terms of glucose and ketone body utilisation?
During starvation, the brain switches from using 100% glucose to using 50% ketone bodies.
What is the consequence of depleted oxaloacetate levels in the liver?
Depleted oxaloacetate levels in the liver lead to the accumulation of acetyl-CoA, resulting in the production of ketone bodies.
What is the role of AMP-activated protein kinase (AMPK) in exercise?
AMPK plays a regulatory role in exercise, promoting fat oxidation and glucose uptake in skeletal muscle.
What is the fate of acetoacetate in extrahepatic tissues?
Acetoacetate is converted back to acetyl-CoA and used for the TCA cycle in extrahepatic tissues.
What is the consequence of uncontrolled ketone production in the absence of insulin?
Uncontrolled ketone production in the absence of insulin can lead to ketoacidosis.
What is the purpose of phosphofructokinase-1 in glycolysis, and how is it regulated?
Phosphofructokinase-1 is responsible for converting fructose-6-phosphate to fructose-1,6-biphosphate. It is regulated by high levels of ATP and citrate, which inhibit this step, indicating that the cell no longer needs to make ATP.
What is the significance of the conversion of fructose-1,6-biphosphate to dihydroxyacetone phosphate and glyceraldehyde-3-phosphate in glycolysis?
The conversion of fructose-1,6-biphosphate to dihydroxyacetone phosphate and glyceraldehyde-3-phosphate is significant because it marks the point at which glycolysis has only used ATP and has not yet produced ATP.
Describe the peripheral branches of the facial nerve and their role in muscles of facial expression.
The facial nerve has five peripheral branches: the temporal, zygomatic, buccal, marginal mandibular, and cervical branches. These branches are responsible for innervating the muscles of facial expression, which include the orbicularis oculi, zygomaticus major, buccinator, and others.
Outline the peripheral course and distribution of the hypoglossal nerve, and its role in the motor innervation of the tongue.
The hypoglossal nerve emerges from the medulla oblongata and passes through the hypoglossal canal to reach the tongue. It innervates the extrinsic muscles of the tongue, including the genioglossus, hyoglossus, and styloglossus, which are responsible for tongue movements.
What is the role of glyceraldehyde phosphate dehydrogenase in glycolysis, and what is the significance of NADH production in this step?
Glyceraldehyde phosphate dehydrogenase is responsible for oxidizing glyceraldehyde-3-phosphate to form 1,3-biphosphoglycerate, and in this step, NAD+ is reduced to NADH. The significance of NADH production is that it is required for the first ATP production in glycolysis.
What is the role of phosphoglycerate kinase in glycolysis, and what is the significance of ATP production in this step?
Phosphoglycerate kinase is responsible for transferring a phosphate from 1,3-biphosphoglycerate to ADP to form ATP and 3-phosphoglycerate. The significance of ATP production in this step is that it marks the first point at which ATP is produced in glycolysis.
Describe the anatomy and nervous innervation of the salivary glands and ducts.
The salivary glands, including the parotid, submandibular, and sublingual glands, are innervated by the parasympathetic and sympathetic nervous systems. The parasympathetic fibers stimulate salivary secretion, while the sympathetic fibers inhibit it. The ducts of the salivary glands transport saliva to the oral cavity.
What is the fate of NADH in aerobic and anaerobic conditions, and what is the significance of this in terms of energy production?
In aerobic conditions, NADH feeds the respiratory chain, while in anaerobic conditions, NADH is regenerated to form lactate. The significance of this is that it allows the cell to adapt to different energy demands and produce ATP accordingly.
Define the boundaries and describe the major features of the naso, oro, and laryngopharynx.
The nasopharynx extends from the base of the skull to the soft palate, the oropharynx extends from the soft palate to the epiglottis, and the laryngopharynx extends from the epiglottis to the cricoid cartilage. The pharynx is lined with mucous membrane and contains the tonsils and adenoids.
Outline the nervous innervation of the pharynx, including the control of swallowing and the gag reflex.
The pharynx is innervated by the glossopharyngeal and vagus nerves, which control swallowing and the gag reflex. The glossopharyngeal nerve is responsible for the sensory innervation of the pharynx, while the vagus nerve is responsible for the motor innervation.
What is the role of pyruvate kinase in glycolysis, and what is the significance of pyruvate production in this step?
Pyruvate kinase is responsible for converting phosphoenolpyruvate (PEP) to pyruvate, and in this step, ATP is produced. The significance of pyruvate production is that it marks the end of glycolysis and the beginning of the citric acid cycle or fermentation.
Explain how the gastro-oesophageal junction contributes to the prevention of reflux.
The gastro-oesophageal junction, which is formed by the lower oesophageal sphincter and the crural diaphragm, prevents reflux by creating a high-pressure zone that prevents stomach contents from flowing back into the oesophagus.
What is the role of calcium in the contraction of muscle fibers, and how does it relate to the breakdown of glycogen?
Calcium binds to the subunit calmodulin, which activates phosphorylase kinase, leading to the phosphorylation of glycogen phosphorylase, resulting in the breakdown of glycogen.
How does the balance between type 1 and type 2 muscle fibers change in response to different types of exercise, and what are the implications for energy production?
The balance between type 1 and type 2 muscle fibers changes in response to different types of exercise, with type 1 fibers being more prevalent in endurance exercises and type 2 fibers in high-intensity exercises. This affects the primary source of energy, with type 1 fibers using oxidative metabolism and type 2 fibers using anaerobic metabolism.
What is the role of AMP as a metabolic signal, and how does it influence glucose uptake and fatty acid oxidation?
AMP serves as a metabolic signal, increasing glucose uptake in the short term and fatty acid oxidation in the long term.
How does the demand for ATP in skeletal muscle change during exercise, and what are the primary sources of ATP replenishment?
The demand for ATP in skeletal muscle increases significantly during exercise, and ATP can be replenished from phosphocreatine, glycogen, and triacylglycerol.
What is the significance of the different types of muscle fibers in terms of their metabolic characteristics and exercise performance?
Type 1 slow-twitch muscle fibers use oxidative metabolism, are rich in mitochondria, and are suited for endurance exercises. Type 2 fast-twitch muscle fibers use anaerobic metabolism, are rich in glycogen, and are suited for high-intensity exercises.
How does the metabolism of ethanol affect carbohydrate and fat metabolism, and what are the potential consequences for overall energy metabolism?
The metabolism of ethanol can alter carbohydrate and fat metabolism, leading to changes in blood glucose and lipid levels. This can have significant consequences for overall energy metabolism, particularly in individuals with compromised liver function.
The stomach has a thick wall with strong and frequent peristaltic contractions in the proximal area.
False
The pylorus is the region of the stomach where receptive relaxation occurs.
False
The frequency of contractions is higher at the greater curvature of the stomach.
True
The adaptive relaxation of the stomach is a reflex that occurs in response to food entering the pharynx.
False
The emptying of liquids from the stomach is a linear process.
False
The third phase of gastric motility is the propulsion of food into the duodenum.
False
The vagus nerve innervates the stomach.
False
The duodenum is primarily located in the left upper quadrant.
False
The oesophagus has five constrictions.
False
Peyer's glands are found in the duodenum.
False
The oesophagus enters the stomach at the pyloric orifice.
False
The AP receptors are activated directly by blood circulation.
True
Ischaemia activates 5-HT receptors in the NTS.
True
Hyoscine blocks the effects of dopamine in the brainstem.
False
Cannabinoid derivatives are effective against severe emesis.
False
D2 receptors are antagonized directly on the area postrema.
False
Vagus nerve links motion to AP receptors.
False
The masseter muscle is involved in the depression of the mandible.
False
The lingual tonsils are located in the anterior part of the tongue.
False
The parotid gland is supplied by the facial nerve.
False
The foramen cecum is located at the base of the tongue.
False
The lateral pterygoid muscle is involved in the elevation of the mandible.
False
The trigeminal nerve is responsible for the sensation of the upper teeth.
True
Metoclopramide, a D2 antagonist, reduces nausea by stimulating gastrointestinal propulsion.
True
Ghrelin receptor agonists decrease appetite and increase vomiting.
False
Lipoprotein lipase plays a role in the synthesis of triacylglycerol in adipose tissue.
False
Octreotide, a somatostatin analogue, reduces inflammation by increasing the expression of ghrelin receptors.
False
The main function of ICCs in nausea is to regulate the rhythmic contraction of the stomach.
False
Prucalopride, a 5-HT4 agonist, reduces nausea by inhibiting gastrointestinal propulsion.
False
This quiz covers the structure and function of salivary glands, including the composition of saliva and the action of enzymes like amylase. Learn about the control of salivary secretion and the breakdown of starch and oligosaccharides.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
