6th Physiology Lecture Exam - GIT (Batch 2024) Flashcards
1.The ion that acts as a driving force to increase HCl secretion by the parietal cell is.
- Hydrogen
- Chloride
- Bicarbonate
- Potassium
Chloride
2.The H/K ATPase pump in an inactive parietal cell is located in which of the following choices below?.
- Apical membrane
- Tubulovesicular membrane
- Basolateral membrane
- Canalicular membrane
Tubulovesicular membrane
3.The afferent fibers of the GI tract are carried by the ANS to the CNS, These are:.
- Both sensory and motor in nature
- Located in all the layers of the gut wall
- Relays the nature of the luminal contents
- Degree of stretch and contraction of the smooth muscles.
Both sensory and motor in nature
4.The epithelial cells of the gastrointestinal tract are characterized by the following, except?.
Varies depending on the part and predominant function of the region.
Small intestine cells mediate non-discriminatory uptake of nutrients, ions and water.
Esophageal cells give protection and are designed for non-absorption of nutrients .
It is continuously replaced every 3 days.
Small intestine cells mediate non-discriminatory uptake of nutrients, ions and water.
5.In the canalicular membrane, which ion channel will contribute to HCL secretion once the parietal cell is activated?.
chloride
potassium
bicarbonate
hydrogen
chloride
6.During normal salivary secretion, the primary secretion is from the secretory endpiece is:.
- alkaline
- hypertonic
- isotonic
- hypotonic
alkaline
7.Overall, sympathetic stimulation in the GI tract _______ smooth muscle function.
- All are correct
- decreased
- increases
- regulates
decreased
- 8.Property of saliva essential for long term maintenance of the lining of the GI tract:.
- Large flow rate
- High K+ concentration
- Low osmolarity
- Organic constituents
Organic constituents
9.The mixed micelle absorbed by the enterocyte contains which of the all of the following EXCEPT:.
* Free fatty acids
* Triglycerides
* Cholesterol
* Monglycerides
Triglycerides
10.Amino acids not utilized by the enterocytes are exported across the basolateral membrane and enter the.
* Lacteal
* Blood capillaries
* Thoracic duct
* Portal vein
Blood capillaries
11.In acute pancreatitis, this is most likely due to which of the following?.
* Increased proenzyme production in the acinar cells
* Increased conversion of proenzymes in the duodenum
* Increased conversion of proenzymes in the acinar cells
* Increased pancreatic fluid flow along the ducts
Increased conversion of proenzymes in the acinar cells
Pancreatitis can result when enzymes secreted by pancreatic acinar cells become proteolytically activated before they have reached their appropriate site of action in the small intestinal lumen.
(Berne & Levy 7th ed., Chapter 30, page 543)
12.Main salivary functions that are important for the integrative response to a meal.
Disruption of food to produce smaller particles
Initiation of starch and lipid digestion
Formation of bolus for swallowing
Aid in speech
Initiation of starch and lipid digestion
13.Regarding G cell activation, which of the following luminal factors will most likely inhibit its activity?.
- low acid secretion
- high intragastric volume
- low pH
- high protein diet
low pH
When the concentration of H+ in the lumen reaches a certain threshold (<pH 3), somatostatin is released from endocrine cells in the antral mucosa. Somatostatin has a paracrine action on neighboring G cells to decrease the release of gastrin and thereby decrease gastric acid secretion. Basically, negative feedback due to increase acidity in stomach.
(Berne & Levy 7th ed., Chapter 29, page 536)
14.Cells in the GI tract involved in endocrine regulation except?.
- Secretes a peptide or hormones that acts on nearby target cells.
- Target cells express specific receptors for the hormone.
- Hormones have effects in other regions and on glandular structures.
- GI hormones have effects on other tissues that have no direct role in digestion and absorption.
Secretes a peptide or hormones that acts on nearby target cells.
15.The predominant peristaltic movement observed in individuals who go on intermittent fasting.
- retropulsive movements
- migrating motor complex
- haustral movement
- segmentation
migrating motor complex
16.The pharyngeal phase of swallowing involves the following events. Which one is not included?.
- The soft palate is moved upward and the palatopharyngeal folds move inward.
- The vocal cords are pulled apart and the larynx is moved upward.
- The upper esophageal sphincter relaxes.
- The superior constrictor muscles of the pharynx contract strongly.
The vocal cords are pulled apart and the larynx is moved upward.
The vocal cords are pulled together and the larynx is moved forward and upward against the epiglottis; these actions prevent food from entering the trachea and help open the upper esophageal sphincter (UES). B&L p525-526
17.To rule out the possibility of an existing acid- secreting tumor, serum levels of this hormone was utilized in the case.
- gastrin
- CCK
- histamine
- secretin
gastrin
18.Secondary secretion of salivary glands occurs due to the following, which is false?.
Excretory ducts and striated duct cells modify the ionic concentration
Na+ and Ca+ are reabsorbed by duct cells
K+ and HCO3- are secreted into the lumen
Final secretion is hypotonic and slightly alkaline
Na+ and Ca+ are reabsorbed by duct cells
“There are two main stages to the secretion of saliva: First, once stimulated, acinar cells secrete primary saliva which is isotonic and contains amylase, mucus, and extracellular fluid. This isotonic form of saliva is made by secreting sodium chloride. In the second stage, the primary saliva gets modified as it passes down the ductal tree. The sodium gets actively reabsorbed, potassium is actively secreted, chloride is passively absorbed, and bicarbonate secreted. Of note, the ductal epithelium has poor water permeability. The final saliva product will be hypotonic.”
Regulatory mechanisms of the GI tract are responsible for the following events, except:.
Undergoes periods of quiescence and intense activity
Detecting and responding to food intake
Detect micronutrient content of a meal and mount appropriate response.
Events in the proximal portion are signaled to the more distal parts
Detect micronutrient content of a meal and mount appropriate response.
The digestive system ingests and digests food, absorbs released nutrients, and excretes food components that are indigestible. The six activities involved in this process are ingestion, motility, mechanical digestion, chemical digestion, absorption, and defecation. These processes are regulated by neural and hormonal mechanisms.
20.During colonic movements, which of the following peptides may act as an “ILEAL BREAK”?.
- VIP
- substance P
- Peptide YY
- motilin
Peptide YY
Peptide YY (PYY) also known as peptide tyrosine tyrosine is a peptide that in humans is encoded by the PYY gene. Peptide YY is a short (36-amino acid) peptide released from cells in the ileum and colon in response to feeding. In the blood, gut, and other elements of periphery, PYY acts to reduce appetite; similarly, when injected directly into the central nervous system, PYY is also anorexigenic, i.e., it reduces appetite
21.Which of the following pairs of GI hormones and its functions is not correct?.
Secretin: stimulates pancreatic duct secretion
GIP: glucose homeostasis
Cholecystokinin: stimulation of pancreatic enzyme secretion
GLP: epithelial cell proliferation
GIP: glucose homeostasis
22.Increasing the rate of salivary secretion can make the final salivary secretion:.
* hypotonic
* alkaline
* hypertonic
* isotonic
isotonic
This is because when there is an increased activity of the salivary gland, there is an increased in saliva production which increases the bicarbonate (HCO3) secretions. From the cells, bicarb is released towards the saliva. This happens in the ductal cells. This makes the saliva alkaline.
23.Dipeptides and tripeptides absorption is coupled usually with this ion.
* H+
* Bicarbonates
* 2K+
* Na+
H+
24.GLP-1, is a regulatory peptide released by EECs cell in the gut wall, which is not true of its attribute?.
- Respond with the presence of carbohydrates and lipids.
- Stimulates insulin secretion and biosynthesis.
- Hasten gastric emptying time.
- Improves glucose tolerance.
Hasten gastric emptying time.
25.Which of the following functions of secretions from the GI tract are incorrect?.
* Efficient enzyme action
* Generation of osmotic gradient
* Synthesis of macronutrients
* Lubrication
Synthesis of macronutrients
The food contains three macronutrients that require digestion before they can be absorbed: fats, carbohydrates, and proteins. Through the process of digestion, these macronutrients are broken down into molecules that can traverse the intestinal epithelium and enter the bloodstream for use in the body. it IS NOT being synthesized. it is being ABSORBED.
26.These products of lipolysis is more likely to be absorbed via tight junctions, and directly enter the bloodstream.
* Monoglycerides
* Cholesterol
* Medium-chain fatty acids
* Lysophospholipids
Medium-chain fatty acids
27.Pancreatic lipase activity is sustained even in the presence of bile acids by which of the following?.
* Phospholipase A2
* Colipase
* Cholesterol esterase
* Emulsification
Colipase
A colipase is present in the pancreatic secretion, which facilitates the interaction of lipase with its triglyceride substrate and protects lipase from inactivation.
Chloride secretion in the small and large intestine is regulated by which of the following tranporters?.
* CFTR channel
* NBC-1
* DRA counter transporter
* Na/H exchanger
CFTR channel
Specialized cells which function as electrical pacemakers for smooth muscle cells and are interposed between the smooth muscle layers.
- Ganglion cells
- Enterochromaffin cells
- Interstitial cells of Cajal
- Myenteric cells
Interstitial cells of Cajal
The interstitial cells of Cajal are specialized pacemaker cells located in the wall of the stomach, small intestine, and large intestine. These cells are connected to the smooth muscle via gap junctions and the myenteric plexus. The cell membranes of the pacemaker cells undergo a rhythmic depolarization and repolarization from -65mV to -45mV.
EECs response to a stimulus includes the following, except:.
- Via neural input and other factors not associated with meal
- A “sensing” basolateral membrane in contact with the gut wall
- “Open type” have apical membrane in contact with the GI lumen
- “Close type” has no part of the membrane in contact with the GI lumen.
A “sensing” basolateral membrane in contact with the gut wall
EECs can be stimulated via neural inputs or toher factor snot associated with a meal. The most common EECs in the gut wall are “open” types, which have an apical membrane that is in contact with the lumen of th eGI tract, and a basolateral membrane through whichs ecretion occurs. there are also “closed” types EECs that do not have part of their membrane in contact with the luminal surface of the gut. (Berne & Levy 7th ed., Chapter 27, pp. 514)
31.Stretch causes this change in the RMP
- none of the above
- Repolarization
- Depolarization
- Hyperpolarization
Depolarization
Action potential in GI smooth muscle are more prolonged than those in skeletal muscle and have little or no overshoot. The rising phase of the action potential is caused by flow of ions through channels that conduct both CA+ and Na+ and are relatively slow to open. The Ca+ that enters the cell during the action potential helps initiate contraction. The extent of depolarization of the cells and the frequency of action potential are enhanced by some hormones and paracrine agonists and by neurotransmitters from the excitatory enteric nerve endings.
Which of the following will occur if parietal cell activity increases?.
* K secretion in the apical membrane decreases
* HCO3 reabsorption increases
* Luminal pH increases
* Plasma pH decreases
HCO3 reabsorption increases
When parietal cell activity is stimulated it produces HCl, which is acidic. To maintain intracellular pH, parietal cell secretion of H+ is accompanied by an increase in transport of HCO3−into the bloodstream.
Regarding Cl-/HCO3- exchanger which of the following may increase its activity?.
* intracellular K+
* intracellular H+
* intracellular HCO3-
* intracellular Cl-
intracellular HCO3-
The increase in electronegativity of which compartment may enhance gastric acid secretion in the lumen?.
* luminal
* plasma
* interstitial
* intracellular
intracellular
Composition of saliva is dependent on the following, excluding?.
* Type of stimulus
* Rate of flow
* Heterogeneity
* Osmotic pressure
Heterogeneity
The inorganic composition of saliva is entirely dependent on the stimulus and the rate of salivary flow. Saliva flows out into the duct lumen and establishes an osmotic and electrical gradient.
The average secretion generated by the exocrine pancreas is ______L/day.
* 2.5
* 2
* 1.5
* 1
Humans produce ~1.5 L of pancreatic fluid each day. The pancreas has the highest rates of protein synthesis and secretion of any organ in the body.
Composition of saliva is dependent on the following, excluding?.
* Type of stimulus
* Rate of flow
* Heterogeneity
* Osmotic pressure
Heterogeneity
This may inhibit HCL acid secretion.
* Acetylcholine
* Histamine
* Gastrin
* Somatostatin
Somatostatin
Neural regulation of the GI tract are multifarious, which of the following statement below is not included functionally:
- It is innervated by a complex, single set of nerves
- GI function are highly dependent on the extrinsic nervous system.
- Extrinsic nervous system can modulate the enteric nervous system.
- In some areas, there are no synapse between motor nerves and effector cells.
It is innervated by a complex, single set of nerves
The following pertains to the primary secretion produced by salivary gland, except:.
* Concentration of major ions follows that of plasma
* Driven by Ca+ dependent signaling
* Osmotic/ electrical gradient is by Na+
* Na+ and water follows through tight junctions
Osmotic/ electrical gradient is by Na+