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+
40.One of these enzymes cleave single amino acids from the end of a peptide chain.
* Elastase
* Carboxypeptidase A
* Trypsin
* Chymotrypsin
Carboxypeptidase A
41.Regulates the GI tract by acting as a Paracrine mediator and an endocrine hormone:.
* Histamine
* Serotonin
* Prostaglandins
* Cholecystokinin
Cholecystokinin
Many substances can be both paracrine and endocrine regulators of GI function. For example, cholecystokinin, which is released from the duodenum in response to dietary protein and lipid, acts locally on nerve terminals in a paracrine fashion and also affects the pancreas
(Berne & Levy 7th edition Chapter 27 - Functional Anatomy and General Principles of Regulation in the Gastrointestinal Tract p. 515 and also refer to Table 27.1 p. 516)
The statements below pertain to the enteric nervous system; which statement is true?
* Contains all components of a reflex pathway
* Can act autonomously from extrinsic innervation
* Its functions can be modulated by the extrinsic nervous system
* Referred as “brain gut axis”
Referred as “brain gut axis”
Brain-gut peptides:
GI hormones (neurotransmitter) in the brain and ENS involved; Regulatory peptides
Brain-gut axis
Neurons in the ENS are innervated by Extrinsic and Intrinsic components innervating the gut.
43.Hypotonicity of saliva is maintained upon excretion by the following events, except:.
* K+ remains above plasma concentration
* Na+ concentration increases towards plasma levels
* Cl- and HCO3 concentrations are maintained.
* The duct epithelium lacks aquaporins.
Cl- and HCO3 concentrations are maintained.
When salivary secretion is stimulated, there is a small decrease in the K+ plasma concentrations), the Na+ concentration (but it always remains above concentration increases toward plasma levels, and Cl− and HCO3 − concentrations increase, thus the secreted fluid becomes even more alkaline. Note that HCO3− secretion can be directly stimulated by the action of secretagogues on duct cells. The duct epithelium is relatively tight and lacks expression of aquaporin, and therefore water cannot follow the ions rapidly enough to maintain isotonicity at moderate or high flow rates during stimulated salivary secretion. (Berne & Levy 7th ed. CHAPTER 28 The Cephalic, Oral, and Esophageal Phases of the Integrated Response to a Meal pg. 522)
Secretagogues exert their action on secretory cells by:.
- Endocrine regulation
- Neurocrine regulation
- Paracrine regulation
- All of the above
All of the above
Belching may occur when the smooth muscle of this part of the stomach contracts.
- fundus
- antrum
- cardia
- pylorus
cardia
Relaxation of the LES and cardia allows entry of food from the esophagus into the stomach and the release of gas, called belching.
Berne and Levy 7th ed, pg 539
46.Normal resting membrane potential (RMP) of GI smooth muscle cells is ___ mV
* 0
* -50 to -60
* -110-220
* 50 - 60
-50 to -60
47.The cephalic phase of the integrated response to a meal is indistinguishable from the oral phase except with the presence of:.
- Mechanical stimulus
- Olfactory stimulus
- Visual stimulus
- Auditory stimulus
Mechanical stimulus
Cephalic Phase
1. Thought of the food
2. Sight (Visual) of the food
3. Hearing (Auditory) of the food
4. Smell (Olfactory) of the food
48.Increasing the volume of milk consumption of lactase sufficient individual may develop diarrhea.
This is because enterocyte uptake of the lactose is easily overwhelmed because its transport is.
- not coupled to that of:Na+
- coupled to that of:H+
- coupled to that of:Na+
- coupled to that of:K+
not coupled to that of:Na+
Lactose is hydrolyzed by lactase into glucose and galactose. Glucose generated by digestion of starch or lactose is absorbed in the small intestine only by cotransport with sodium.
Ionic modification in the pancreatic ducts will make the final secretion in the duodenum: (3 choices only).
* Isotonic
* Hypertonic
* Hypotonic
Hypotonic
Parasympathetic efferent pathways to the GI tract functionally consist of the following:.
- Parasympathetic innervation via the CN 9 and pelvic nerves.
- Axons run to the wall of the gut where they synapse with postganglionic neurons.
- There is direct innervation of the efferent nerves to effector cells.
- Activates both the extrinsic and intrinsic sensory afferent pathways.
Axons run to the wall of the gut where they synapse with postganglionic neurons.
Axons from these neurons run in the nerves to the gut (vagus and pelvic nerves, respectively), where they synapse with postganglionic neurons in the wall of the organ, which in this case are enteric neurons in the gut wall. There is no direct innervation of these efferent nerves to effector cells within the wall of the gut; the transmission pathway is always via a neuron in the ENS.
(Berne and Levy Physiology chapter 27, page 516)
51.Regarding the concept of the alkaline tide, the alkaline pH is best observed in the:.
- plasma
- gastric lumen
- interstitium
- intracellular compartment
plasma
Which of the following is incorrectly paired?.
* Absorptive enterocytes: express proteins for digestion and absorption of micronutrients .
* Enteroendocrine cells: release regulatory peptides and amines to regulate GI function
* Intestinal stem cells: continuously renew and replace GI lining
* Mucin-producing cells: specialized for production of glycoproteins
Absorptive enterocytes: express proteins for digestion and absorption of micronutrients .
53.The major structures of the GI tract are divided into major functional segments by which of the following?.
* Specialized muscle structures
* Abdominal wall mesentery
* Blood supply
* Extrinsic and Intrinsic nervous system
Specialized muscle structures
The GI tract is a hollow tube divided into major functional segments; the major structures along the tube are the mouth, pharynx, esophagus, stomach, duodenum, jejunum, ileum, colon, rectum, and anus.
(Berne and Levy Physiology 7th ed. Page 511)
54.The role of H-pylori in the development of ulcer is that is primarily decreases:.
* acid secretion
* gastrin release
* bicarbonate secretion
* histamine release
bicarbonate secretion
Which of the following statement regarding inorganic secretory components of the GI tract is true:.
* Secretory components in the stomach neutralizes acids
* Secretory components in the duodenum initiates protein digestion
* Secretory components in the small intestine optimizes condition for digestive enzymes
* All of the above
Secretory components in the small intestine optimizes condition for digestive enzymes
The inorganic components are electrolytes, including H+ and HCO3. Two examples of different secretions include acid (HCl) in the stomach, which is important to activate pepsin and start protein digestion, and HCO3 in the duodenum, which neutralizes gastric acid and provides optimal conditions for the action of digestive enzymes in the small intestine. (Berne and Levy Physiology 7th ed. Page 521)
Gastric receptive relaxation reflex does not include which one below:.
* Distention in the stomach upon introduction of food
* Constriction of smooth muscles in the stomach
* Intraluminal pressure does not increase
* Results in filling of the stomach to occur
Constriction of smooth muscles in the stomach
receptive relaxation is a reflex in which the fundus of the stomach dilates in response to small increases in intragastric pressure when food enters the stomach.
Tight junctions characterized by the following, except..
* Link all GI epithelial cells
* Complexes of intracellular proteins
* Complexes of transmembrane proteins
* Regulated throughout postprandial period
Link all GI epithelial cells
D cell activation leads to the __________ of the G cells.
* inhibition
* activation
* excitation
* inactivation
inhibition
Regulation of Gastric Acid Secretion:
H+ threshold in lumen = <pH 3
- Somatostatin is released when reached.
- G cells decrease release of gastrin
*Note: Somatostatin is secreted by D Cells
Reference: (2024) Trans 6.03 - Page 01 (Oxyntic glands bullet) and 03
The following are true regarding the blood supply of the GI tract, except?.
- Venous drainage directly return to the heart bypassing the portal circulation.
- Lymphatic drainage is through the thoracic duct carrying lipids and other lipid soluble substances.
- Blood from the muscles can be diverted to the GI tract after a meal to absorb nutrients.
- Approximately 25% of cardiac output are received by the Splanchnic circulation, disproportionate to the mass of the GI tract.
Venous drainage directly return to the heart bypassing the portal circulation.
The blood supply to the intestine is important for carry- ing absorbed nutrients to the rest of the body. Unlike other organ systems of the body, venous drainage from the GI tract does not return directly to the heart but first enters
the portal circulation leading to the liver. Thus the liver is unusual in receiving a considerable part of its blood supply from other than the arterial circulation. GI blood flow is also notable for its dynamic regulation. Splanchnic blood flow receives about 25% of cardiac output, an amount disproportionate to the mass of the GI tract it supplies. After a meal, blood can also be diverted from muscle to the GI tract to subserve the metabolic needs of the gut wall and also to remove absorbed nutrients. Berne & Levy 7th edition page 512
The ENS consist of which of the following:.
* The Auerbach’s plexus is present in the submucosa
* The Meissner’s plexus is located in between the smooth muscle layers
* Pre ganglionic neurons synapse with Enteric neurons in the adventitia
* The ENS’ cell bodies are located at the serosa where GI function are dependent
The ENS’ cell bodies are located at the serosa where GI function are dependent
GLUT2 is the transporter involved in absorption of which of the following monosaccharide/s?.
* Glucose and Galactose
* Glucose
* Glucose, galactose and fructose
* Fructose
Glucose, galactose and fructose
The vagovagal reflex in the gut includes the following:.
* Consists of Cranial nerve X and IX
* Afferents, interneurons and efferents
* Interneuron drives activity in the efferents neurons
* Important in regulating GI function
Consists of Cranial nerve X and IX
These vagovagal reflexes which has both afferent and efferent fibers. The vagal afferents send sensory information to the CNS, where they synapse with an interneuron, which then drives activity in the efferent motor neuron. These extrinsic reflexes are very important in regulating GI function after ingestion of a meal. (Berne and Levy page 517)
Mixing and grinding of solid food in the stomach occur in predominantly in this are.
* pylorus
* cardia
* fundus
* antrum
antrum
The GI tract release secretions by a meal is initiated by:.
- Chemical
- Osmotic
- Mechanical
- All of the above
All of the above
The response to a meal is classically divided into phases: cephalic, oral, esophageal, gastric, duodenal, and intestinal. In each phase, the meal presents certain stimuli (e.g., chemical, mechanical, and osmotic) that activate different pathways (e.g., neural, paracrine, and humoral reflexes) that result in changes in effector function (e.g., secretion and motility). (Berne and Levy, page 518)
Major modifier of ionic composition and osmolarity of saliva:.
* Intercalated duct cells
* Striated duct cells
* Excretory duct cells
* Secretory duct cells
Striated duct cells
The ductal cells lining the striated ducts, in particular, modify the ionic composition and osmolarity of saliva. (Berne & Levy, p. 522)
66.As gastric acid secretion increases, gastric emptying: (3 choices only).
* time decreases
* decreases
* increases
decreases
As the meal enters the small intestine, it feeds back via both neural and hormonal pathways to regulate the rate of gastric emptying based on the chemical and physical composition of the chyme. Afferent neurons, predominantly of vagal origin, respond to nutrients, [H+ ], and the hyperosmotic content of chyme as it enters the duodenum. Reflex activation of vagal efferent outflow decreases the strength of antral contractions, contracts the pylorus, and decreases proximal gastric motility (with a decrease in intragastric pressure), thereby resulting in inhibition (slowing) of gastric emptying.
Peristaltic wave that are generated by the esophagus are caused by the sequences below, which one is not included?.
* Presence of a bolus on the UES initiates a primary wave.
* Waves move down fast to accomodate more food boluses.
* Distention of the esophagus initiates a secondary wave.
* Stimulation of the pharynx by bolus cause reflex relaxation of the LES
Waves move down fast to accomodate more food boluses.
Neural transmission of the ANS supplying the GI tract are consistent with other areas of the body, that is:.
- Pre and post ganglionic neuron is an obligatory nicotinic synapse
- Mediated by norepinephrine released from the nerve terminal
- Norepinephrine act on nicotinic receptors on the postganglionic neurons
- Transmissions may bypass neurons in the ENS.
Pre and post ganglionic neuron is an obligatory nicotinic synapse
The following statements are true regarding the sympathetic innervation of the GI tract, except:.
- Fibers that terminate in the prevertebral ganglia are Postganglionic neurons
- Pre ganglionic neurons synapse with post ganglionic neurons in the prevertebral ganglia
- They directly innervate blood vessels of GI tract
- They innervate glandular structures in the gut wall
Fibers that terminate in the prevertebral ganglia are Postganglionic neurons
Sympathetic innervation is supplied by cell bodies in the spinal cord and fibers that terminate in the prevertebral ganglia (celiac, superior, and inferior mesenteric ganglia); these are the preganglionic neurons. These nerve fibers synapse with postganglionic neurons in the ganglia, and the fibers leave the ganglia and reach the end organ along the major blood vessels and their branches. Rarely there is a synapse in the paravertebral (chain) ganglia, as seen with sympathetic innervation of other organ systems. Some vasoconstrictor sympathetic fibers directly innervate blood vessels of the GI tract, and other sympathetic fibers innervate glandular structures in the wall of the gut. (p. 516 Bern & Levy)
70.Congenital disorder where there is failure to pass meconium at birth or constipation in infancy due to absence of myenteric and submucosal neurons at the distal colon:.
* Irritable bowel syndrome
* Ulcerative colitis
* Hirschsprung disease
* Pseudomembranous enterocolitis
Hirschsprung disease
71.Which IS NOT considered as a primary function of the colon?
* Digest components of meal not digested proximally
* Excrete waste products
* Absorb components of meal not digested proximally
* Reabsorb remaining fluid used during movement of the meal
Excrete waste products
72.Which IS NOT a part of the mechanism of the biological ecosystem of the colon ?
* Expose colonic epithelium to invasion of pathogens
* Detoxification of xenobiotics
* Metaboism of bile acids and bilirubin
* Fermentation
Expose colonic epithelium to invasion of pathogens
73.What characterizes short duration contraction form of colonic motility?
* Purpose is for mixing
* Originates in longitudinal muscles
* Dynamic pressure waves
* Persists for 30 seconds on average
Purpose is for mixing
74.What condition has rapid turnover of colonic epithelium usually results from frequent or prolonged exposure to environmental toxins or bacteria?
* Colon cancer
* Hirschprung’s disease
* Diarrhea
* Irritable bowel syndrome
Colon cancer
The rapid turnover of the colonic epithelium, as well as frequent/prolonged exposure to bacterially synthesized or environmental toxins, or both, makes the large intestine especially vulnerable to malignancy.
75.What condition presents with alternating patterns of diarrhea and constipation, and in which the individual perceives normal signal originating from the bowel to be painful?
- Irritable bowel syndrome
- Colon cancer
- Hirschprung’s disease
- Diarrhea
Irritable bowel syndrome
76.What structure produce the long duration contractions form of colonic motility ?
* Produced by taenia coli
* Produced by circular muscles
* Originate from longitudinal muscles
* Produced from Brunner’s gland
Produced by taenia coli
What process is involved wherein the commensal bacteria metabolize components of the meal that are not digested by host enzymes and make their products available to the body ?
* Fermentation
* Conjugation
* Estherification
* Neutralization
Fermentation
What long reflex arc is stimulated when the stomach is filled with freshly masticated food which will increase colonic motility resulting to evacuation of the colonic contents ?
* Gastrocolic reflex
* Orthocolic reflex
* Duodenocolic reflex
* esophagocolic reflex
Gastrocolic reflex
Gastrocolic Reflex- Regulated by long reflex arcs, Involves release of 5-hydroxytryptamine (5-HT) &acetylcholine.
What reflex when stimulated results to early morning defecation ?
* Orthocolic reflex
* esophagocolic reflex
* Duodenocolic reflex
* Gastrocolic reflex
Orthocolic reflex
Orthocolic reflex can be triggered after waking up which helps produce bowel movement. Duodenocolic reflex is triggered in the duodenal wall, increasing speed of propulsion movements. Gastrocolic reflex is triggered in the stomach wall increasing motility.
What substance is synthesized by enteroendocrine cells localized in the terminal ileum and colon and is released in response to lipid in the lumen?
* Serotonin
* Tyrosine
* 5-HT
* Peptide YY
Peptide YY
Peptide YY is released in response to lipid in lumen. Decreases gastric emptying and intestinal propulsive motility.
81.What ion is decreases in response to action of Peptide YY in the colon to reduce fluid secretion?
* Hydrogen
* Chloride
* Potassium
* Calcium
Chloride
What is NOT a role of the colonic epithelium?
* Absorb water
* Absorb electrolyte
* Absorb nutrients
* Absorb fatty acids
Absorb nutrients
The major role of colonic epithelium is to either absorb or secrete electrolytes and water rather than nutrients. (L6.05 p.2)
What is the volume of fluid lost in stools a day?
* 200 L
* 200 ml
* 100 L
* 100 ml
200 ml
What hormone increase the expression of Epithelial Na+ Channel in both colon and kidney in restricted Sodium intake situations?
* Aldosterone
* Cortisol
* Angiotensin
* Cholecystokinin
Aldosterone
What ion secretion is excessively stimulated by Cholera toxin leading to large secretion of fluids in both small and large intestine?
* Calcium
* Chloride
* Potassium
* Sodium
Chloride
What gas production in the colon WILL NOT make your fart stink?
* Hydrogen sulfide
* Indole
* Hydrogen
* Skatole
Hydrogen
What substance in the stool serves as a sensitive marker for malabsoption and maldigestion?
* Fat
* water
* Carbohydrates
* Protein
Fat
88.What is the reason why Oral rehydration solutions in periods of diarrhea can drive water back into the body?
* Nutrient-linked Na+ absorptive processes remain intact
* Promotes HCO3 excretion
* Prevents K absoption
* It down regulates Cl secretion
Nutrient-linked Na+ absorptive processes remain intact
On the other hand, nutrient-linked Na+ absorptive processes typically remain intact. This provides the rationale for the effectiveness of oral rehydration solutions, which are prepackaged mixtures of salt and glucose. Uptake of Na+ and glucose from these solutions, mediated by SGLT1, restores fluid absorption.
(Berne & Levy 7th ed., Chapter 31, page 564)
89.What process is down regulated in the event of diarrhea?
* Na absorption
* Cl secretion
* H absorption
* K secretion
Na absorption
Fluid absorption by the colon is driven by three transport processes: 1) NaCl absorption
2) absorption of short-chain fattyacids, including acetate, propionate, and butyrate
3) Na absorption - last line of defense to prevent excessive loss of water in stool, given its strategic location in the distal part of the colon B&L C31 p563
What happens to the ammonia when it is metabolized by colonic bacteria from Urea?
* Ammonium is excreted
* Further metabolized to amino acids
* Converted to secondary bile
* Acid Ammonium is actively secreted
Ammonium is excreted
Ammonia is either passively absorbed or excreted as ammonium. (Berne & Levy 7th ed., Chapter 31, page 564)
91.What permits anal sampling in the process of defecation?
* Relaxation of internal anal sphincter
* Contraction of external anal sphincter
* Contraction of internal anal sphincter
* Relaxation of external anal sphincter
Relaxation of internal anal sphincter
92.Which is not included in the hepatic or portal triad?
* common bile duct
* hepatic artery
* bile ducts
* portal vein
common bile duct
A person with a chronic liver disease will have low levels of these substances EXCEPT?
* Glucose
* Immunoglobulins
* Clotting Factors
* Albumin
Immunoglobulins
With the exception of immunoglobulins, the liver synthesizes almost all the proteins present in plasma (especially albumin, which determines plasma oncotic pressure) as well as most of the important clotting factors.
Berne & Levy, p. 568
Which part of detoxification involves the conjugation of substances to promote excretion?
* Phase 1 detoxification
* Physical detoxification
* Phase 2 detoxification
* Detoxifications by Kupffer cells
Phase 2 detoxification
Phase II reactions conjugate the resulting products with another molecule (e.g., glucoronic acid, sulfate, amino acid, glutathione) to promote their excretion
What is activated from death of hepatocytes due to viral infection or over exposure to toxic substances like alcohol?
* Collagen
* Hepatocytes
* Kuffer Cells
* Stellate Cells
Stellate Cells
“In a normal, healthy liver, stellate cells are quiescent. When the liver is damaged by toxins or virus infection, hepatocytes and immune cells release factors that induce stellate cells to undergo a dramatic transformation into what is referred to as the activated state. They start to secrete a battery of extracellular matrix proteins that includes collagens, glycoproteins and proteoglycans.”
What forms from chronic synthesis of excessive amounts of collagen resulting to irreversible fibrosis of the liver?
* Liver cirrhosis
* Ascites
* Chronic hepatitis
* Liver failure
Liver cirrhosis
Cirrhosis is a late-stage liver disease in which healthy liver tissue is replaced with scar tissue and the liver is permanently damaged. Scar tissue keeps your liver from working properly. Many types of liver diseases and conditions injure healthy liver cells, causing cell death and inflammation. This is followed by cell repair and finally tissue scarring as a result of the repair process.
What cells in the liver are source of retinoids and growth factors?
* Hepatocytes
* Stellate Cells
* Collagen
* Kuffer Cells
Stellate Cells
They constitute roughly 5% of the cells in the liver. In addition to their role in responding to hepatic injury, stellate cells in the healthy liver are the major storage site in the body for vitamin A (retinoids). Stellate cells provide the liver with an ability to respond to injury and heal certain types of damage.
98.What cells in the liver are origination point for the biliary system and are considered to be epithelial cells with basolateral and apical membranes?
* Hepatocytes
* Stellate Cells
* Collagen
* Kuffer Cells
Hepatocytes
What hormone contracts the gall bladder resulting to ejection of a concentrated bolus of bile into the duodenal lumen?
* Acetylcholine
* Cholecystokinin
* Vasoactive peptide
* Nitric Oxide
Cholecystokinin
100.What product will result from reducing biliverdin?
* Yellow bilirubin
* Conjugated bilirubin
* Urobilinogen
* Stercobilin
Yellow bilirubin
