Physiology Exam 4

If a patient has inadequate bile secretion, which of the following could contribute to the condition? A. Excessive release of cholecystokinin B. Excessive release of motilin C. Excessive release of secretin D. Excessive steroid hormones. E. Excessive parasympathetic stimulation.

D. Excessive steroid hormones.

Choose the correct listing of the anatomical divisions of the stomach in the direction food normally passes. A. Corpus, fundus, antrum. B. Fundus, antrum, corpus. C. Antrum, corpus, fundus. D. Fundus, corpus, antrum. E. Corpus, antrum, fundus.

D. Fundus, corpus, antrum.

Which pair is correct concerning secretory glands/cells in the stomach and their products? A. Cardiac glands -- hydrochloric acid and intrinsic factor. B. Parietal cells -- pepsinogen C. Chief cells -- mucus D. G cells -- protease E. D cells -- somatostatin.

E. D cells -- somatostatin.

Which of the following is least likely to contribute to the beneficial effects of ACE inhibitors in the treatment of heart failure? A. Vasodilation B. Decreased cardiac growth C. Decreased cardiac afterload D. Increased PRA E. Decreased plasma aldosterone

E. Decreased plasma aldosterone

A patient who has undergone a partial gastric resection to remove a tumor reports to his primary care physician that he has experienced several episodes of nausea, cramping, dizziness, sweating and a rapid heart rate after ingesting sugary beverages. His symptoms are caused in part by hypoglycemia. What is the most likely diagnosis? A. Constipation-predominant irritable bowel syndrome (IBS-C) B. Hirschsprung disease C. Achalasia D. Peptic ulcer disease E. Dumping syndrome.

E. Dumping syndrome.

A child is brought to her pediatrician exhibiting signs of malnutrition, diarrhea, and edema of the extremities. Duodenal aspirates are obtained at endoscopy after intravenous administration of cholecystokinin, and are found to be incapable of protein hydrolysis at neutral pH unless a trace amount of trypsin is added that by itself would not result in appreciable hydrolysis. The patient is most likely suffering from a deficiency in which of the following? A. Pepsinogen B. PepT1 C. Trypsinogen D. Carboxypeptidases E. Enterokinase

E. Enterokinase

A surgeon is studying new methods of liver transplantation. She performs a complete hepatectomy in an experimental animal. Before the donor liver is grafted, a rise in the blood level of which of the following would be expected? A. Glucose B. Fibrinogen C. 25-Hydroxycholecalciferol D. Conjugated bilirubin E. Estrogens

E. Estrogens

A bed-ridden, 90-year-old man is referred for endoscopy because of difficulty in swallowing that developed rapidly after he took medication with water the night before, when he was supine. Endoscopy reveals a pill lodged in his esophagus that has triggered an inflammatory reaction. Compared to the upright position, a reduction in which of the following influences on esophageal motility likely contributed to the adverse outcome in this patient? A. Primary peristalsis B. Secondary peristalsis C. Nucleus ambiguus activity D. Pharyngeal contraction E. Gravity

E. Gravity

Following a natural disaster in Haiti, there is an outbreak of cholera among displaced persons living in a tent encampment. The affected individuals display severe diarrheal symptoms because of which of the following changes in intestinal transport? A. Increased K+-Cl− cotransport in the small intestine B. Decreased K+ secretion into the colon C. Increased K+ absorption in the crypts of Lieberkühn D. Increased Na+ absorption in the small intestine E. Increased Cl− secretion into the intestinal lumen

E. Increased Cl− secretion into the intestinal lumen

A child is brought to his pediatrician for an investigation of his failure to thrive. Genetic tests reveal a congenital absence of enterokinase. A decrease in which of the following is expected in this patient? A. Incidence of pancreatitis B. Carbohydrate assimilation C. Bile acid reabsorption D. Gastric pH E. Protein assimilation

E. Protein assimilation

A 50-year-old man who is markedly overweight comes to his primary care physician complaining of a nightly burning sensation in his chest, which is made worse if he has a snack before retiring. Which of the following would be the most effective treatment for this patient if his symptoms are not eliminated by weight loss and foregoing late-night meals? A. Cholinergic agonist B. Smooth muscle relaxant C. Nitric oxide donor D. Injection of Botox into the lower esophageal sphincter E. Proton pump inhibitor

E. Proton pump inhibitor

The _____ ion is both secreted and absorbed by the nephron

K

Normally, there is a net secretion of which ion in the colon?

K+

Of the approximately 9 liters of water that go through the GI tract daily, how much makes it out in the feces? A. 100 ml B. 1000 ml C. 2000 ml D. 1500 ml E. 500 ml

A. 100 ml

Circular smooth muscle in the GI tract: A. Accounts for the majority of smooth muscle in the stomach and intestine. B. Are coupled via gap junctions which increases the resistance and slows electrical signals through the fibers. C. Generates less propulsive force than longitudinal smooth muscle.

A. Accounts for the majority of smooth muscle in the stomach and intestine.

A 50-year-old female patient who has suffered for several years from severe dryness of her eyes due to inadequate tear production is referred to a gastroenterologist for evaluation of chronic heartburn. Endoscopic evaluation reveals erosions and scarring of the distal esophagus. Reduced production of which salivary product most likely contributed to this tissue injury? A. Bicarbonate B. Lactoferrin C. IgA D. Mucus E. Amylase

A. Bicarbonate

Which of the following is NOT involved in swallowing? A. Contracture of the upper esophageal sphincter. B. Coordination by the swallowing center in the medulla oblongata. C. The approximation of the vocal cords to close the glottis. D. The raising of the larynx to close its entrance. E. The elevation of the soft palate to close the nasopharynx.

A. Contracture of the upper esophageal sphincter.

Glucose reabsorption occurs in the _____ by _____. A. proximal tubule, cotransport B. distal tubule, passive transport C. proximal tubule, osmosis D. distal tubule, active transport

A. proximal tubule, cotransport

Which is NOT part of the renal/urinary system? A. uterus B. urethra C. ureter D. bladder

A. uterus

Digestive products of proteins can be absorbed as _____, _____, and _____

AAs, dipeptides, and tripeptides

The principal regulator of plasma osmolality is

ADH

The reabsorption of urea by the inner medullary collecting ducts is dependent on facilitation by

ADH

Motor neurons in the myenteric plexus that stimulate the contraction of visceral smooth muscle in the GI tract release

acetylcholine

How is pancreatic secretion formed?

acinar cells and ductal cells

Fundamental mechanism generating hypertonicity in the medullary interstitium

active transport of NaCl in thick ascending limb

Pancreatic secretions have many of the same ions that plasma does, only the concentrations and their rate of secretion are different. Which of the following is true? A. A higher rate of pancreatic secretion results in increased bicarbonate and sodium ion. Plasma has less bicarbonate and more sodium. B. A higher rate of pancreatic secretion results in increased bicarbonate and decreased chloride ion. Plasma has less bicarbonate and more chloride. C. A higher rate of pancreatic secretion increases its osmolarity and pH. Plasma has a lower osmolarity as pancreatic secretions. D. A higher rate of pancreatic secretion results in increased bicarbonate and potassium ion. Plasma has lower levels of both ions.

B. A higher rate of pancreatic secretion results in increased bicarbonate and decreased chloride ion. Plasma has less bicarbonate and more chloride.

Which of the following best describes a fast EPSP synaptic event? A. The depolarization persists several seconds to minutes after the termination of the presynaptic transmitter release. B. Acetylcholine activation of nicotinic cholinergic postsynaptic receptors results in a depolarization lasting less than 50 msec. C. requires K+ channel closure D. requires K+ channel opening

B. Acetylcholine activation of nicotinic cholinergic post-synaptic receptors results in a depolarization lasting less than 50 msec.

The interstitial cells of Cajal: A. fire action potentials to initiate the electrical slow waves propagating along the GI tract. B. Are found between the longitudinal and circular smooth muscle layers. C. Hormonally regulates peristalsis.

B. Are found between the longitudinal and circular smooth muscle layers.

Fecal material in distal colon

becomes semisolid, moves slowly, propelled into rectum by mass movements

The macula densa is located in the

beginning of distal tubule

The optimum pH for the activity of pepsin is

between 1.6 and 3.2

How are lipids digested in the small intestine?

bile acids and pancreatic lipases

What are the main functions of the liver?

bile formation and secretion, bilirubin production and excretion, carbohydrate metabolism, protein metabolism, lipid metabolism, detoxification

Physiologically, the most important choleretic is

bile salts

Micelles in bile are formed by

bile salts and phospholipids

What is the composition of bile?

bile salts, phospholipids, cholesterol, and bile pigments

When a woman who has been on a low-sodium diet for 8 days is given an intravenous injection of captopril, a drug that inhibits ACE, which of the following would be expected?

blood pressure to fall because peripheral resistance would fall

Vagovagal reflex

both afferent and efferent pathways are contained in the vagus nerve

What is the regulatory center for chewing?

brain stem

Disaccharides are present in

brush border of enterocytes

What does the macula densa sense?

Cl concentration of the fluid delivered to it volume of fluid delivered to it

Bile salts are synthesized starting from

cholesterol

The most abundant bile acid is

cholic acid

The volume of plasma needed each minute to supply a substance at the rate at which it is excreted in the urine is known as the

clearance of the substance

Removal of the liver is fatal because

clotting time is prolonged

Muscularis mucosa

contraction causes a change in the surface area for secretion or absorption

Circular muscle

contraction causes a decrease in diameter of the lumen of the GIT

Longitudinal muscle

contraction causes shortening of a segment of the GIT

What is the migrating myoelectric complex?

contractions that occur in 90 minute intervals to clear the stomach of residual food

What is the function of the ileocecal sphincter?

contracts to prevent reflux into the ileum when the proximal colon is distended with fecal material

In clinical practice, urinary clearance of which substance is most frequently estimated as a surrogate of GFR?

creatinine

The renal plasma flow (RPF) of a patient was to be estimated through the measurement of PAH clearance. The technician observed the procedures correctly but due to an error in weighing inadvertently used thrice the recommended dose of PAH. The RPF estimated thus is likely to be

falsely low

Gastric emptying is slowest after a meal containing

fat

What is lipid metabolism?

fatty acid oxidation and synthesis of lipoproteins, cholesterol, and phospholipids

In healthy humans, iron in tissues other than red blood cells is stored primarily in combination with

ferritin

How is H2O absorbed and secreted?

follows Na+

Retropulsion in stomach

food is propelled back into stomach to be mixed when the caudad stomach contracts

What stimulates saliva production?

food, smells, conditioned reflexes, nausea

Vagally mediated increase in gastric acid secretion is partly mediated by

gastrin releasing peptide (GRP)

Autoregulation of GFR is achieved through changes in

glomerular afferent arteriolar resistance glomerular efferent arteriolar resistance

What is carbohydrate metabolism?

gluconeogenesis (formation of glucose), glycogenesis (stores glucose as glycogen), glycogenolysis (releases stored glucose into circulation)

Renin is secreted by

granular cells in the juxtaglomerular apparatus

What are exopeptidases?

hydrolyze one AA at a time from the C-terminus of proteins and peptides

What is lingual lipase?

in saliva, fat splitting enzyme

What is α-amylase?

in saliva, starts to break down starch

The effect of ADH on the kidney is to

increase permeability of the distal nephron to water

A physiologist is studying the effect of food additives on GFR in order to determine what additives should be avoided in individuals with CKD. A caffeine was found to affect urine output through an effect on GFR. What is the effect and the mechanism involved?

increase urine output; afferent arteriole vasodilation

What does histamine do?

increases gastric H+ secretion by gastric parietal cells along with gastrin and Ach

Trypsin inhibitor

inhibits activation of trypsin in the pancreas deficiency is implicated in acute pancreatitis

What does somatostatin do?

inhibits release of GI hormones and gastric H+ secretion

Urea is reabsorbed from

inner medullary collecting ducts

Slow waves in the GIT are believed to be initiated by

interstitial cells of Cajal

The 'gold standard' for estimation of GFR is the estimation of urinary clearance of

inulin

How are lipids digested in the stomach?

mixing in the stomach, lingual lipase, and CCK slowing down gastric emptying

Postganglionic parasympathetic neurons innervating circular and longitudinal layers of GI smooth muscle are located in

myenteric plexus

Water deprivation fails to produce an increase in urine osmolality in

neurogenic diabetes insipidus nephrogenic diabetes insipidus

Where are enkephalins secreted from?

neurons in mucosa and smooth muscle of GIT

Where is VIP secreted from?

neurons in mucosa and smooth muscle of GIT

Phasic contractions

occur in the esophagus, gastric antrum, and small intestine, which contract and relax periodically

Tonic contractions

occur in the lower esophageal sphincter, orad stomach, ileocecal sphincter, and internal anal sphincter

When is pepsin denatured?

pH > 5

The most alkaline exocrine secretion is

pancreatic juice

Quantitatively, the most important enzyme in the digestion of fat is

pancreatic lipase

_____ stimulation increases intestinal smooth muscle contraction

parasympathetic

Extrinsic innervation

parasympathetic and sympathetic nervous systems

What are the gastric cell types?

parietal cells, chief cells, G cells, and mucous cells

What are the 3 salivary glands?

parotid, submandibular, sublingual

The pattern of intestinal motility that hastens transit of chyme in the small intestine in the digestive state is

peristalsis

Which parts of the GIT are striated muscle?

pharynx, upper 1/3 of esophagus, and external anal sphincter

In an ABG analysis, what is calculated?

plasma bicarbonate

A 20-year-old woman comes to the clinic for a routine physical that she needs as part of her application for work as a summer camp counselor. The physical exam was WNL. Her urinalysis shows a trace of protein. A defect in what cells could be causing the leakage of protein?

podocytes

Increases renal cortical blood flow

prostaglandin E2

Where does the most colonic water absorption take place?

proximal colon

In a healthy individual with a normal renal plasma flow, in which segment of the nephron would the concentration of PAH be the least?

proximal convoluted tubule

In the nephron, the highest amount of H+ ions is secreted into tubular lumen in the

proximal convoluted tubule

AAs are almost completely reabsorbed from the glomerular filtrate via active transport in the

proximal tubule

Glucose reabsorption occurs in the _______

proximal tubule

In an individual with normal renal function but with fluctuations in GFR of 10% around a mean GFR of 100 mL/min, fractional reabsorption of Na and Cl in which segment of nephron is relatively constant?

proximal tubule

In the absence of vasopressin, the greatest fraction of filtered water is absorbed in the

proximal tubule

In the nephron, glucose reabsorption occurs mainly in the

proximal tubule

In the presence of vasopressin, most of the water filtered by the kidneys is reabsorbed in the

proximal tubule

Most of the glucose that is filtered through the glomerulus undergoes reabsorption in the

proximal tubule

The greatest fraction of filtered Na+ is reabsorbed in what portion of the nephron?

proximal tubule

The primary renal site for the secretion of organic ions (e.g. urate, creatinine) is

proximal tubule

When the osmolality of urine is 1400 mOsm/Kg H2O, the greatest amount of water is reabsorbed in

proximal tubule

Principal cells (P cells) in the cortical collecting duct of the nephron are mainly involved in

reabsorption of Na+ and Cl- ADH-stimulated water reabsorption

The greatest amount of H+ ion secreted by the proximal tubule is associated with

reabsorption of bicarbonate ion

The rate-limiting step in the biosynthesis of angiotensin II is the secretion of

renin

They kidneys release _____, _____, and _____ into circulation

renin, erythropoietin, and 1,25-dihydroxy-vitamin D3

Haustra

saclike segments, appear after segmentation contractions in proximal colon

At highest flow rates

saliva closely resembles plasma

At lowest flow rates

saliva is most dissimilar to plasma

What are the 4 GI secretions?

saliva, gastric secretion, pancreatic secretion, bile

Where is saliva produced?

salivary glands

Where is somatostatin secreted from?

D cells throughout GI mucosa

Which of the following statements correctly describes a function of the parasympathetic innervation of the GI tract. A. Norepinephrine is the primary excitatory neurotransmitter. B. Excessive parasympathetic activity can lead to a pathological state called paralytic ileus. C. Inhibitory efferent Vagal innervation causes sphincters to contract. D. Afferent sensory input is received in the nucleus of the solitary tract and processed in the dorsal motor nucleus of the medulla oblongata. E. Glucose concentration, pH, osmolality, movement of material past mechanoreceptors, and level of contractile strength or stretch are monitored by efferent parasympathetic fibers.

D. Afferent sensory input is received in the nucleus of the solitary tract and processed in the dorsal motor nucleus of the medulla oblongata.

Which of the following is characteristic of the segmenting movements in the small intestine? A. It decreases particle size, which increases the surface area for digestion. B. It brings the products of digestion to the mucosal surface for absorption. C. It results in the mixing of the luminal contents in front of the propulsive segments (i.e. in the receiving segments) D. All of the above.

D. All of the above.

Which of the following pass through the thoracic duct before passing through the liver? A. Lecithin. B. Micelles C. VLDLs D. Chylomicrons. E. Small and medium chain fatty acids.

D. Chylomicrons.

A condition that results in too much acid in the stomach could be attributed to which of the following? A. Lack of taste buds or damage to olfactory nerves. B. Defect resulting in release of too much secretin. C. Defective G cells. D. Defect in D cells in the antrum. E. Loss of elasticity of small intestine making distension more difficult.

D. Defect in D cells in the antrum.

The major humoral mediator of pancreatic duct cell secretion of bicarbonate rich juice is

secretin

What stimulates pancreatic secretion?

secretin, CCK, and Ach via vagovagal reflex

Normally, the rate-limiting step in the metabolism of bilirubin is

secretion into bile

An increase in the concentration of plasma K+ causes increase in

secretion of aldosterone

The most frequent type of movement in the small intestine in the digestive state is

segmentation contraction

How are lipids absorbed?

simple diffusion

What inhibits saliva production?

sleep, dehydration, fear, anticholinergic drugs

What stimuli secretes CCK?

small peptides, AAs, fatty acids, monoglycerides

Bile salts are essential for absorption of fat because they

solubilize dietary lipids in micelles

The release of gastrin from G cells in the antrum of the stomach is inhibited by

somatostatin

What are the 2 GI paracrines?

somatostatin and histamine

The defecation reflex is integrated in the

spinal cord

What are slow waves?

spontaneous oscillating membrane potentials, determine pattern of APs and pattern of contraction

An increase in the osmolarity of the extracellular compartment will

stimulate the volume and osmoreceptors, and stimulate ADH secretion

What does GRP do?

stimulates gastrin release from G cells

What is the intestinal brush border?

surface of intestinal cells are covered with microvilli which increases the surface area for absorption

_____ stimulation decreases intestinal smooth muscle contraction

sympathetic

What is protein metabolism?

synthesis of nonessential AAs and plasma proteins

Reabsorption of Na+

takes place in association with Cl- and HCO3-

In healthy humans, active absorption of bile acids and bile salts occurs mainly in the

terminal ileum

Vitamin B12 is mainly absorbed in the

terminal ileum

As urine flow increases during osmotic diuresis

the osmolality of urine approaches that of plasma because an increasingly large fraction of the excreted urine is isotonic proximal tubular fluid

GFR will increase if

the plasma protein concentration decreases

The ability of the kidney to excrete a concentrated urine will increase if

the rate of blood flow through the medulla decreases

If the clearance of a substance that is freely filtered is less than that of inulin

there is net reabsorption of the substance in the tubules

Portion of tubule that is least permeable to water

thick ascending limb of Henle's loop

'Free water' is formed mainly in the

thick ascending limb of loop of Henle

The 'diluting segment' of the nephron is

thick ascending limb of loop of Henle

The major protein that transports iron in the plasma from the site of absorption to cells engaged in erythropoiesis is

transferrin

Most pancreatic zymogens are activated in the duodenal lumen by

trypsin

In the inner medullary interstitium, _____ contributes the most to osmolality

urea

In the presence of ADH, the distal nephron is least permeable to

urea

What is the immediate effect of spinal cord transection on bladder function?

urinary retention

What stimuli inhibits somatostatin secretion?

vagal stimulation

What stimulates gastric H+ secretion?

vagal stimulation, gastrin, histamine

What nerves carry information between GIT and medulla?

vagus and glossopharyngeal

Where is GRP secreted from?

vagus nerves that innervate G cells

When is gastric emptying fastest?

when stomach contents are isotonic

What is the orad region of the stomach?

- fundus and proximal body - receives ingested meal

In a patient who has become dehydrated, body water should be replaced by intravenous infusion of

0.9% NaCl solution

What inhibits gastric emptying?

- Fat which stimulates CCK release - H+ in duodenum

What stimuli secretes secretin?

- H+ and fatty acids in duodenum

What stimuli inhibits gastrin secretion?

- H+ in stomach - somatostatin

How are free AAs absorbed?

- Na+ dependent AA cotransport occurs in luminal membrane - AAs are transported from cell to blood by facilitated diffusion

How is Na+ absorbed and secreted?

- Na+ is absorbed through passive diffusion through Na+ channels and cotransport - Na+ is pumped out into blood by Na+/K+ ATPase - Na+ is secreted into the lumen by passively following Cl-

What regulates saliva production?

- PSNS and SNS - increased by both parasympathetic and sympathetic activity - parasympathetic activity is more important

How are dipeptides and tripeptides absorbed?

- absorbed faster than AAs - H+ dependent cotransport of dipeptides and tripeptides occur in luminal membrane - cytoplasmic peptidases hydrolyze them into AAs which are transported from cell to blood by facilitated diffusion

How is Cl- absorbed and secreted?

- accompanies Na+ absorption by passive diffusion by paracellular route, Na+/Cl- cotransport, and Cl-/HCO3- exchange - Cl- is the primary ion secreted into intestinal lumen, transported through Cl- channels

Where are G cells located and what do they secrete?

- antrum - gastrin

Where are mucous cells located and what do they secrete?

- antrum - produce thick and viscous mucous

What is the caudad region of the stomach?

- antrum and distal body - contracts to mix food and propel it into duodenum

What are chylomicrons?

- are transported out intestinal cells by exocytosis - they are too large to enter capillaries so they are transferred to lymph vessels and added to blood via thoracic duct

Where are parietal cells located and what do they secrete?

- body - HCl and IF

Where are chief cells located and what do they secrete?

- body - pepsinogen

Digestion and absorption

- carbohydrates, proteins, and lipids are digested and absorbed in the small intestine

Submucosal plexus and myenteric plexus

- comprise the ENS - integrate and coordinate the motility, secretory, and endocrine functions of the GIT

What is pancreatic secretions?

- contains a high concentration of bicarbonate to neutralize acidic chyme - contains enzymes for digestion of protein, carbohydrates, and fat - isotonic

Swallowing reflex

- coordinated in medulla - vagus and glossopharyngeal nerves carry information between GIT and medulla

Parasympathetic NS

- craniosacral output - usually excitatory - vagus and pelvic nerves

Mechanism of slow wave production

- cyclic opening of Ca2+ channels (depolarization) followed by opening of K+ channels (repolarization) - depolarization during each slow wave brings membrane potential closer to threshold and increases probability of APs - APs then initiate contraction

How is K+ absorbed and secreted?

- dietary K+ is absorbed by passive diffusion via paracellular route - actively secreted in colon, stimulated by aldosterone

What are the functions of the small intestine?

- digestion and absorption of nutrients - mixes nutrients with digestive enzymes - exposes digested nutrient to absorptive mucosa - propels nonabsorbed material to large intestine

Where is the highest frequency of slow waves and why?

- duodenum (12 SW/min) - mixing bile and pancreatic juice with chyme

How are vitamins absorbed?

- fat soluble vitamins are incorporated into micelles and absorbed with lipids - water soluble vitamins are absorbed by Na+ dependent cotransport mechanisms - B12 is absorbed in ileum and requires IF

Gastrocolic reflex

- food in the stomach increases motility of the colon and frequency of mass movements - rapid PS component initiated when stomach is stretched by food - slower hormonal component is mediated by CCK and gastrin

Gallbladder stones

- gallstones in the gallbladder - if lodged in cystic duct, lipids in fatty meals stimulate CCK secretion which causes pain contractions of the gallbladder against the stone - if lodged in the common bile duct, liver enzymes and bilirubin levels will be elevated - if the stone reaches the pancreas it will cause pancreatitis and amylase and lipase will be elevated

How are glucose, galactose, and fructose absorbed?

- glu and gal are transported into the cell by SGLT-1 (secondary active) and into the blood by GLUT2 (facilitated diffusion) - fruc is transported only by facilitated diffusion into cell and into blood

Carbohydrates must be digested to _____, _____, and _____ to be absorbed. Why?

- glucose, galactose, and fructose - only monosaccharides are absorbed

How is iron absorbed?

- heme iron or free Fe2+ - in intestinal cells heme iron is converted to Fe2+, binds to apoferritin, transported into blood - in blood Fe2+ binds to transferrin, stored in liver, then go to bone marrow to make hemoglobin

What does gastrin do?

- increases H+ secretion by gastric parietal cells - stimulates growth of gastric mucosa

What does secretin do?

- increases pancreatic and biliary bicarbonate secretion - inhibits H+ secretion by gastric parietal cells

Pancreatitis

- inflammation of the pancreas that occurs when pancreatic enzymes digest the pancreas - has various causes - causes malabsorption and steatorrhea

Gastroileal reflex

- mediated by extrinsic ANS and possibly gastrin - food in the stomach triggers increased peristalsis in ileum and relaxation of ileocecal sphincter, intestinal contents delivered to large intestine

What are mass movements?

- occurs 1-3 times/day - cause colonic contents to move distally for long distances

What is detoxification?

- potentially toxic substances are presented to liver via portal circulation - phase I reaction are catalyzed by cytochrome p-450 enzymes - phase II reactions conjugate the substances

What are the conditions official hormones must satisfy?

- present in gut - synthesized by an endocrine cell in gut - structure must be identifiable - released by appropriate physiological stimulus - produces appropriate physiological effect - can be blocked by antagonists

What does VIP do?

- relaxes GI smooth muscle, including lower esophageal sphincter - stimulates pancreatic bicarbonate secretion - inhibits gastric H+ secretion

What are paracrines?

- released from endocrine cells in GI mucosa - diffuse over short distances to act on target cells in GIT

How is Ca2+ absorbed?

- requires active vitamin D in small intestine - active vitamin D induces synthesis of intestinal Ca2+ binding protein which facilitates absorption of Ca2+

Formation of the common bile duct

- right and left hepatic ducts join and form the common hepatic duct - cystic duct unites with common hepatic duct and form the common bile duct

What is pepsin?

- secreted as pepsinogen by chief cells, activated to pepsin by gastric H+

What stimuli secretes gastrin?

- small peptides and AAs in stomach - distension of stomach - vagal stimulation via GRP

What do enkephalins do?

- stimulate contraction of GI smooth muscle, particularly lower esophageal, pyloric, and ileocecal sphincters - inhibit intestinal secretion of fluid and electrolytes

What does CCK do?

- stimulates contraction of gallbladder and relaxation of sphincter of Oddi - increases pancreatic enzyme and bicarbonate secretion - inhibits gastric emptying

Where is the lowest frequency of slow waves and why?

- stomach (3 SW/min) - increase gastric holding time and contractions are more forceful

What are neurocrines?

- synthesized in neurons of GIT and released by APs - diffuse across synaptic cleft to target cell

Sympathetic NS

- thoracolumbar output - usually inhibitory

What are the pancreatic proteases?

- trypsin, chymotrypsin, elastase, carboxypeptidase A, and carboxypeptidase B - they are secreted in inactive forms and activated in the small intestine

How do pancreatic proteases activate?

- trypsinogen is activated to trypsin by brush border enzyme enterokinase - trypsin converts chymotrypsinogen, proelastase, and procarboxypeptidase A and B to their active forms

Peptic ulcer disease

- ulcerative lesion of gastric or duodenal mucosa - occurs when there is loss of protective mucous barrier or excessive secretion of H+ and pepsin

What is 'receptive relaxation'?

- vagovagal reflex that's initiated by distension of stomach - orad region relaxes to accommodate ingested meal - CCK increases distensibility of orad

Frequency of slow waves

- varies along GIT - not influenced by neural or hormonal input (AP frequency is) - sets maximum frequency of contractions for each part of GIT

What fraction of renal plasma flow is normally filtered in the glomerular capillaries?

0.2 or 20%

How is bile formed?

1. cholic and chenodeoxycholic acids (primary bile acids) are synthesized from cholesterol by hepatocytes 2. in the intestines bacteria convert some of the primary bile acids into secondary bile acids (deoxycholic and lithocholic acids) 3. bile acids are conjugated with glycine or taurine to form bile salts 4. H2O and electrolytes are added to bile 5. when gallbladder is relaxed, sphincter of Oddi closes and gallbladder fills with bile 6. isosmotic absorption of solutes and water in gallbladder concentrates the bile

What are the 3 functions of saliva?

1. initial starch and triglyceride digestion 2. lubrication of ingested food by mucus 3. protection of mouth and esophagus by diluting and buffering ingested foods

What are the 3 functions of chewing?

1. mixes food with saliva to lubricate it 2. decreases size of food particles 3. mixes ingested carbs with salivary amylase to begin digestion

Sequence of events in swallowing

1. nasopharynx closes, breathing is inhibited 2. laryngeal muscles contract to close glottis and elevate larynx 3. peristalsis begins in pharynx, upper esophageal sphincter relaxes

What are the sequence of events for defecation?

1. rectum fills with feces, it contracts and the internal anal sphincter relaxes 2. rectum fills to 25%, get urge to poop, pooping is prevented because external anal sphincter is contracted 3. when convenient to poop, external anal sphincter relaxes voluntarily, smooth muscle of rectum contracts, force poop out

What is mixing and digestion?

1. slow waves depolarize smooth muscle cells 2. if it reaches threshold, fires an AP and contracts 3. contraction closes distal antrum, retropulsion 4. contractions increase via vagal stimulation and decrease via sympathetic stimulation 5. during fasting, contractions occur in 90 min intervals to clear the stomach of residual food

What happens as food moves down the esophagus?

1. upper esophageal sphincter relaxes, allow food to enter esophagus 2. upper esophageal sphincter contracts, prevents reflux of food into pharynx 3. primary peristaltic contraction moves food down, gravity accelerates it 4. secondary peristaltic contraction clears esophagus of any remaining food 5. lower esophageal sphincter relaxes, vagally mediated (VIP) 6. orad of stomach relaxes, allows food to enter

In healthy humans, the maximal rate of glucose absorption from the intestine is estimated to be about

120 g/hour

In a healthy adult, the urge to void urine is first felt at a bladder volume of about

150 mL

What is the clearance of a substance when its concentration in the plasma is 10 mg/dL, its concentration in the urine is 100 mg/dL, and urine flow is 2 mL/min?

20 mL/min

Fraction of filtered Na is reabsorbed in the loop of Henle

25%

In a healthy adult, the volume of urine in the bladder that initiates reflex contraction of the bladder is about

300-400 mL

The tubular Tmax for glucose in a healthy young man is about

375 mg/min

In humans, when urine is maximally concentrated, the ratio of osmolality of urine to plasma is about

4.6

Which of the following best describes type of saliva produced when parasympathetic stimulation increases the rate of salivary secretion? A. Copious, protein-poor, electrolyte-rich. B. Scant, transient protein-rich (mucin), electrolyte poor. C. Scant, protein-poor, electrolyte-poor. D. Copious, protein-rich (mucin), electrolyte-rich.

A. Copious, protein-poor, electrolyte-rich.

Which of the following swallowing disorders results from the failure of organized peristaltic behavior, or the simultaneous contraction all along the smooth muscle. A. Diffuse spasm. B. Dysphasia C. Achalasia. D. Myelphasia. E. Trachiasia.

A. Diffuse spasm.

How is the MMC controlled? A. Ingestion of food ends MMC at all points in the intestine. B. IV feeding ends MMC. C. Gastrin and CCK terminate MMC in stomach and entire small intestine. D. Vagal innervation completely controls MMC. E. The MMC increases in speed as it reaches the ileum.

A. Ingestion of food ends MMC at all points in the intestine.

Which of the following is true of smooth muscle in the proximal stomach? A. It has no action potentials. B. It contracts phasically. C. Its main purpose is to grind and mix food prior to propelling it to the gastroduodenal junction. D. Receptive relaxation is controlled by decreasing activity of excitatory vagal neurons.

A. It has no action potentials.

A 4-year-old boy is brought to his pediatrician for an evaluation because of failure to thrive and frequent diarrhea characterized by pale, bulky, foul-smelling stools. Sweat Cl- concentrations are measured and found to be elevated. Diminished secretion of which pancreatic product is most likely to be the primary cause of the patient's apparent fat malabsorption? A. Lipase B. Procolipase C. Monitor peptide D. Cholecystokinin E. Bicarbonate

A. Lipase

A deficiency of colipase would result in which of the following? A. Lipase would not be able to bind to the oil-water interface of the lipid. B. An inability to digest phospholipids. C. An inability to digest cholesterol. D. An inability to digest lipids in the stomach.

A. Lipase would not be able to bind to the oil-water interface of the lipid.

A patient is referred to a gastroenterologist for evaluation of suspected small bowel bacterial overgrowth. Motility studies reveal slowed gastrointestinal transit during fasting. The patient's symptoms are most likely due to a deficit in which of the following substances? A. Motilin B. NO C. CCK D. VIP E. Secretin

A. Motilin

17. What is the difference between normal peristalsis of the SI and giant migrating contractions? A. Normal peristalsis only propagates a short distance. B. Because of the distance giant migrating contractions travel, they contribute significantly to mixing chyme. C. Normal peristalsis can be initiated by vinegar on the mucosa, parasites, enterotoxins, and ionizing radiation. D. Normal peristalsis helps strip lumen clean as it travels. E. Normal peristalsis is sometimes associated with abdominal cramping and diarrhea.

A. Normal peristalsis only propagates a short distance.

A healthy individual who decides to have his DNA sequenced learns that he has a mutation in a protein responsible from the transport of neutral amino acids consistent with a diagnosis of Hartnup disease. The fact that he has experienced no nutritional consequence of this mutation is directly attributable to the presence of which of the following? A. PepT1 B. brush border peptidases C. Na+, K+ ATPase D. Cystic fibrosis transmembrane conductance regulator (CFTR) E. Trypsin

A. PepT1

If you increase the rate of salivary secretion which of the following changes in ionic composition results? A. Sodium concentration increases. B. Bicarbonate concentration decreases. C. Chloride decreases. D. Potassium increases. E. Osmolarity decreases.

A. Sodium concentration increases.

Which of the following is NOT a component of bile secretions? A. Stercobilin. B. Bile pigments C. Cholesterol D. Lecithin E. Bilirubin-glucuronide

A. Stercobilin.

Sodium ions play an important role in carbohydrate absorption. All of the following processes require it EXCEPT: A. Sugars leaving the intestinal cell to enter the portal blood system. B. Glucose absorption from gut lumen by second active transport. C. Process that brings potassium into the instestinal cell. D. Galactose absorption from the gut lumen.

A. Sugars leaving the intestinal cell to enter the portal blood system.

The system for the formation of concentrated or dilute urine does not include the: A. proximal convoluted tubule B. loop of Henle C. collecting ducts D. vasa recta E. medullary interstitium

A. proximal convoluted tubule

In an experiment in mice, a scientist infuses tyrosine intravenously. Compared with controls, these animals would be expected to display an increase in which of the following? A. Time taken to initiate the next meal B. Gastric emptying C. Lipid concentrations in the jejunal lumen D. Hydrogen ion concentrations in the gastric lumen E. Pancreatic secretion

A. Time taken to initiate the next meal

A 45-year-old woman is brought to the emergency room complaining of a 3-day history of colicky epigastric pain that suddenly increased in severity after a meal. Tests reveal she has a gallstone blocking her sphincter of Oddi. Which of the following substances would be found at reduced levels in her circulation? A. Unconjugated bile acids B. Conjugated bile acids C. Cholesterol D. Phosphatidylcholine E. Amylase

A. Unconjugated bile acids

Which of the following combinations will result in the most acid secretion through potentiation? A. Vagal input, histamine, gastrin B. Vagal input, histamine, secretin C. Histamine, gastrin, secretin. D. Gastrin, vagal input, secretin E. Gastrin, vagal input, cholecystokinin.

A. Vagal input, histamine, gastrin

Several hormones regulate tubular reabsorption of water and electrolytes at different sites in the nephron. Which of the following combinations is/are correct? A. angiotensin II acts in the DCT B. aldosterone acts in the collecting ducts C. ADH acts in the PT D. ANP acts in the loop of Henle

A. angiotensin II acts in the DCT B. aldosterone acts in the collecting ducts

All the following statements are true of the H+ secreted into the lumen of the distal nephron except: A. can combine with NH4+ B. can combine with HCO3 C. can combine with HPO D. can remains as free H E. is secreted by a H+ATPase pump

A. can combine with NH4+

Intestinal absorption of which of the following does not directly utilize a Na+ gradient? A. fructose B. galactose C. glucose D. phenylalanine E. tyrosine

A. fructose

Which of the following hormone(s) is/are normally released by the stomach into the systemic circulation? A. ghrelin B. gastrin C. pepsinogen D. secretin E. VIP

A. ghrelin

Which of the following favors filtration? A. high blood pressure in glomerular capillaries B. high osmotic pressure in glomerular capillaries C. high pressure in Bowman's capsule

A. high blood pressure in glomerular capillaries

Which of the following enzymes is located in the brush border of enterocytes in the small intestine? A. lactase B. colipase C. cholesterol ester hydrolase D. lingual lipase

A. lactase

In an animal study of biliary secretion, the common hepatic duct of a rat is cannulated under anesthesia and a sample of bile is collected. Bile is also collected from the gallbladder. Compared to hepatic bile, the gallbladder bile would be expected to contain a reduced concentration of which of the following? A. Bile acids B. Chloride ions C. Protons D. Glucose E. Calcium ions

B. Chloride ions

Which of the following does NOT regulate gastric acid secretion? A. Vagus nerve stimulation. B. Cholecystokinin. C. Histamine D. Gastrin E. Acetylcholine

B. Cholecystokinin.

A patient is referred to a gastroenterologist because of persistent difficulties with swallowing. Endoscopic examination reveals that the lower esophageal sphincter fails to fully open as the bolus reaches it, and a diagnosis of achalasia is made. During the examination, or in biopsies taken from the sphincter region, a decrease would be expected in which of the following? A. Esophageal peristalsis B. Expression of neuronal NO synthase C. Acetylcholine receptors D. Substance P release E. Contraction of the crural diaphragm

B. Expression of neuronal NO synthase

A scientist is performing studies on runners after a 10,000-m race. She finds that the urine of runners after the race is more concentrated and has reduced volume than before the race. What mechanism contributes to the change in urine concentration and output? A. Decrease in thirst response B. Increase in water permeability in the collecting duct C. Decrease in ADH secretion D. Increase in thirst during the race

B. Increase in water permeability in the collecting duct

Which of the following salivary components continues to be active in the acidic environment of the stomach? A. Alpha-amylase B. Lingual lipase.

B. Lingual lipase.

What is Hirshsprung's disease? A. A disease developed in adulthood. B. Loss of the intrinsic nervous plexus resulting in continuous contraction of circular muscle. C. Incompetence of internal or external anal sphincters. D. Inappropriate leakage of feces or flatus. E. A sensory malfunction where patients can't detect filling of the rectum.

B. Loss of the intrinsic nervous plexus resulting in continuous contraction of circular muscle.

Which of the following mechanisms allows complete absorption of glucose from the intestinal lumen into the cytosol of the enterocyte? A. simple diffusion through GLUT-5 B. Na-glucose cotransporter-1 (SGLT-1) C. Na channels in enterocyte membrane D. Paracellular uptake via gap junctions

B. Na-glucose cotransporter-1 (SGLT-1)

Which best describes the motility in the large intestine? A. Food clears the LI in about the same time as it takes to clear the small intestine. B. Of the parts of the large intestine, chyme spends the least time in the ascending colon. C. The ascending colon consists of haustra that aid in storage and dehydration of feces. D. Remnants of meals stay in the LI for approximately 6-8 days. E. Receptive relaxation allows the transverse colon to accept chyme without significantly increasing the pressure.

B. Of the parts of the large intestine, chyme spends the least time in the ascending colon.

Which of the following substances is cleared the most by the kidneys? A. inulin B. PAH C. creatinine D. urea

B. PAH

Which of the following is absorbed primarily by passive diffusion powered by a concentration gradient? A. Sodium B. Potassium C. Calcium D. Zinc E. Iron.

B. Potassium

An infant who was previously healthy but is displaying symptoms of acute diarrhea and dehydration after an infection is given an oral solution of glucose and electrolytes (Pedialyte). What membrane protein accounts for the ability of this solution to provide rapid hydration? A. Sucrase-isomaltase B. SGLT-1 C. CFTR D. Chloride-bicarbonate exchanger E. Lactose-phlorizin hydrolase

B. SGLT-1

Which of the following has little effect on pancreatic secretion or it's components? A. Acetylcholine. B. Sympathetic stimulation. C. Secretin D. Cholecystokinin E. VIP

B. Sympathetic stimulation.

Which of the following would not be expected to increase renin secretion? A. administration of a drug that blocks ACE B. administration of a drug that blocks AT1 receptors C. administration of a drug that blocks β-adrenergic receptors D. constriction of the aorta between the celiac artery and the renal arteries E. administration of a drug that reduces ECF volume

B. administration of a drug that blocks AT1 receptors

Which of the following will help you compensate for lung obstruction with resulting buildup of CO2 and acid in the blood (respiratory acidosis)? A. altered breathing B. buffers in the blood C. increased base excretion by the kidney D. all of the above

B. buffers in the blood

Which of the following is a bile acid synthesized by the hepatocyte? A. sodium taurocholate B. chenodeoxycholic acid C. deoxycholic acid D. lithocholic acid

B. chenodeoxycholic acid

Which of the following substances will be more concentrated at the end of the proximal tubule than at the beginning of the proximal tubule? A. glucose B. creatinine C. sodium D. bicarbonate

B. creatinine

Which of the following is the largest? A. total blood volume B. fluid filtered into Bowman's capsule each day C. volume of urine produced each day D. volume reabsorbed across proximal tubule into blood each day

B. fluid filtered into Bowman's capsule each day

Filtration occurs in the _____, most reabsorption occurs in the _____, and urine is transported from the kidney to the bladder in the _____. A. proximal tubule, distal tubule, urethra B. glomerulus, proximal tubule, ureter C. afferent arteriole, loop of Henle, collecting tubule

B. glomerulus, proximal tubule, ureter

Select the correct answer about proximal tubules: A. K+ is secreted in exchange with the Na+ which is reabsorbed under the effect of aldosterone B. glucose, AAs & proteins are completely reabsorbed C. only 10% of the filtered water is reabsorbed D. parathormone increase phosphate reabsorption

B. glucose, AAs & proteins are completely reabsorbed

Major determinants of plasma osmolarity include all the following except: A. sodium B. hemoglobin C. chloride D. albumin E. glucose

B. hemoglobin

About urea, all are true except: A. concentration rises in tubular fluid as the glomerular filtrate passes down the nephron B. is actively secreted by the renal tubular cells C. concentration in the blood rises slightly after a high protein diet D. causes osmotic diuresis when its blood concentration is increased

B. is actively secreted by the renal tubular cells

Which one of the following statements about aldosterone is correct? A. it produces its effect by activating cAMP B. it produces its effect by increasing membrane permeability to K+ C. it causes an increased reabsorption of H+ ion D. it has its main effect on the proximal tubule E. it is secreted in response to an increase in blood pressure

B. it produces its effect by increasing membrane permeability to K+

The glomerular filtration barrier is composed of all the following except: A. fenestrated capillary endothelium B. macula densa C. basement membrane D. podocytes E. mesangial cells .

B. macula densa

Which of the following strategies would most likely be therapeutic in an individual with achalasia? A. injection of tetanus toxin into the lower esophageal sphincter B. surgical division of the lower esophageal sphincter C. administration of a muscarinic receptor agonist D. administration of a nitric oxide synthase inhibitor

B. surgical division of the lower esophageal sphincter

Since bile acids are highly lipophilic, they would be rapidly absorbed through the small intestine wall before they could facilitate lipid digestion. Which of the following prevents that from happening? A. Addition of hydroxyl and carboxyl acid groups to steroid nucleus of cholesterol. B. Bile acids combine with phospholipids to become less easily absorbed. C. Bile acids are conjugated to glycine or taurine so they ionize readily. D. Cholesterol binds to the bile acids to keep them from being absorbed.

C. Bile acids are conjugated to glycine or taurine so they ionize readily.

Theoretically, which of the following deficiencies would make pepsin's role of protein digestion in the stomach more crucial? A. Lipase deficiency. B. A defect in the amino acid intestinal transport mechanism. C. Enterokinase deficiency. D. Cholecystokinin deficiency.

C. Enterokinase deficiency.

Following a forceps delivery of her third child, a woman returns to her physician complaining of mild fecal incontinence when lifting her older children, without any urinary incontinence. Her symptoms are most likely attributable to dysfunction of which of the following? A. Anal sensory nerves B. Internal anal sphincter C. External anal sphincter D. Pudendal nerves E. Puborectalis muscle

C. External anal sphincter

The child's mother does not have any Pedialyte available, and so gives her baby some boiled water in which she has dissolved salt and table sugar. Activity of which enzyme, in addition to SGLT-1, will be needed for this to be effective in rehydrating her baby? A. Salivary amylase B. Pancreatic amylase C. Glucoamylase D. Lactose-phlorizin hydrolase E. Sucrase-isomaltase

C. Glucoamylase

Emptying gastric contents into the small intestine is strictly controlled. Which of the following is most accurately represents this concept? A. High caloric meals empty faster. B. Liquid and solid meals empty at the same rate. C. Higher acidity in the stomach results in a slower rate of emptying. D. Tonicity of the gastric solution doesn't affect the rate of emptying.

C. Higher acidity in the stomach results in a slower rate of emptying.

Which of the following does NOT contribute to hydrochloric acid secretion in the stomach? A. A basolateral bicarbonate/chloride exchanger to maintain intracellular chloride ions also resulting in an "alkaline tide" in the bloodstream. B. Passive flow of chloride and potassium ions through apical channels. C. Hydrogen ions supplied by a basolateral hydrogen/sodium pump. D. Water passively follows acid into gut to maintain osmotic balance. E. The primary contributor to hydrochloric acid secretion is a hydrogen/potassium ATPase that pumps out hydrogen in exchange for extracellular potassium.

C. Hydrogen ions supplied by a basolateral hydrogen/sodium pump.

If duodenal mucosal release of CCK was not working properly, which phase of pancreatic secretion would be interfered with? A. Cephalic phase. B. Gastric phase. C. Intestinal phase. D. Duodenal phase.

C. Intestinal phase.

Which of the following is NOT a characteristic of the myenteric ganglia of the enteric nervous system? A. Also known as Auerbach's plexus B. Contains most of the motor neurons to circular and longitudinal muscles of the intestinal tract C. It is smaller than the submucosal ganglia and most prominent in the small and large intestine D. It is interconnected with the submucosal ganglia. E. Contains both excitatory and inhibitory motor nerves to the smooth muscle fibers.

C. It is smaller than the submucosal ganglia and most prominent in the small and large intestine

Which of the following statements about CCK is incorrect? A. it causes gallbladder contraction B. it relaxes the sphincter of Oddi C. It relaxes the pyloric sphincter D. It stimulates the secretion of an enzyme-rich pancreatic juice

C. It relaxes the pyloric sphincter

A scientist uses genetic approaches to selectively ablate the functions of the various cell types in the liver of mice. He finds that when a certain cell type is disabled, the mice show increased levels of sepsis when the barrier function of the intestine is reduced by instillation of ethanol. Ablation of which hepatic cell type would account for this finding? A. Hepatic stellate cell B. Cholangiocyte C. Kupffer cell D. Hepatocyte E. Gallbladder epithelial cell

C. Kupffer cell

What is the relationship of the pressures in the aorta, glomerular capillaries, tissue capillaries and vena cava? A. P vena cava > P tissue capillaries > P glomerular capillaries > aorta B. P glomerular capillaries > P tissue capillaries > P aorta > P vena cava C. P aorta > P glomerular capillaries > P tissue capillaries > vena cava

C. P aorta > P glomerular capillaries > P tissue capillaries > vena cava

Choose the FALSE statement regarding dietary fiber? A. Examples are cellulose, hemicellulose, pectin, and gums. B. Insoluble in water, poorly digested, excreted in feces. C. Pectin is readily absorbed. D. Binds to bile acids and promotes their excretion. E. Reduces colon transit time and may reduce the production of carcinogenic secondary bile acids.

C. Pectin is readily absorbed.

If you follow the path that food normally takes through the digestive system, which of the following is in the correct order? A. Upper esophageal sphincter, epiglottis, lower esophageal sphincter, pyloric canal, duct of Santorini, duct of Wirsung. B. Pharynx, epiglottis, lower esophageal sphincter, pyloric canal, duct of Wirsung, duct of Santorini. C. Pharynx, epiglottis, lower esophageal sphincter, pyloric canal, duct of Santorini, duct of Wirsung. D. Pharynx, upper esophageal sphincter, pyloric canal, lower esophageal sphincter, duct of Wirsung, duct of Santorini.

C. Pharynx, epiglottis, lower esophageal sphincter, pyloric canal, duct of Santorini, duct of Wirsung.

A 60-year-old man comes to his physician complaining of a progressive increase in girth despite attempts to diet. He is also jaundiced and complains of nausea and malaise. When a large needle is inserted into his abdomen, several liters of tan fluid drain out. An increase in which of the following is not involved in this fluid accumulation? A. Portal pressure B. Hepatic collagen C. Plasma albumin D. Stellate cell activity E. Plasma transudation

C. Plasma albumin

A 50-year-old woman comes into the emergency department with complaints of "hearing her heart beat." She is concerned that she may be having a heart attack. When her blood pressure is measured, it is elevated. The physician gives her a diuretic, and although the blood pressure drops, he decides to perform some additional tests to determine the cause of the hypertension. The woman's PRA level is elevated and CT scans show that her left kidney is smaller than her right. What is the physician's diagnosis likely to be? A. Myocardial infarction B. Stroke attack C. Renal artery stenosis D. Renal denervation

C. Renal artery stenosis

An imaging study shows that a patient has a gallstone lodged in her biliary system, although her ability to assimilate fat-soluble vitamins is normal. In which location would the stone need to be lodged to increase bile acid flux through the left side of the liver? A. Cystic duct B. Common hepatic duct C. Right hepatic duct D. Left hepatic duct E. Common bile duct

C. Right hepatic duct

A newborn baby is brought to the pediatrician suffering from severe diarrhea that worsens after feeding. The symptoms diminish when nutrients are delivered intravenously. The child most likely has a mutation in which of the following intestinal transporters? A. Na+, K+ ATPase B. NHE3 C. SGLT-1 D. H+, K+ ATPase E. NKCC1

C. SGLT-1

A researcher conducts a study of the regulation of salivary secretion in a group of normal volunteers under various conditions. Which of the following conditions would be expected to be associated with the lowest rates of secretion? A. Chewing gum B. Undergoing a mock dental exam C. Sleep D. Exposure to a nauseating odor E. Resting control conditions

C. Sleep

Which of the following is NOT a polysaccharide? A. Dextrin B. Glycogen C. Sorbitol D. Amylose E. Amylopectin.

C. Sorbitol

Many factors influence the gastric action potential of the stomach. Which of the following is false? A. Acetylcholine, gastrin, and cholecystokinin increase amplitude of the plateau phase. B. Gastrin increases AP frequency. C. The initial contraction coincides with the plateau phase while the trailing contraction coincides with the rising phase of the AP. D. Epinephrine and VIP decrease the amplitude of the plateau phase. E. It is a single action potential originating in the orad boundary of the distal stomach.

C. The initial contraction coincides with the plateau phase while the trailing contraction coincides with the rising phase of the AP.

Components of the intestinal mucosa combine to increase the surface area to 600 times that of a cylinder. Which component makes the greatest contribution to increasing the surface area? A. The folds B. The villi C. The microvilli D. The cilia

C. The microvilli

A newborn infant who was delivered vaginally is noted to be mildly jaundiced, but no bilirubin is found in the urine. The child's symptoms are most likely attributable to a developmental delay in the expression or establishment of which of the following: A. Colonic bacterial colonization B. MDR2 C. UDP glucuronyl transferase D. Heme oxygenase E. Biliverdin reductase

C. UDP glucuronyl transferase

Of the following water soluble vitamins, which one CANNOT be absorbed by passive diffusion if the concentration is high enough? A. Vitamin B1 B. Niacin. C. Vitamin B12 D. Biotin.

C. Vitamin B12

Diabetes leads to glucose in the urine because A. proximal tubule reabsorbs less glucose than normal B. proximal tubule secretes glucose instead of reabsorbing glucose C. blood glucose concentrations are elevated, and proximal tubule cannot reabsorb all the filtered glucose D. blood glucose concentrations are elevated, causing damage to the glomerular capillary membranes and leakage of glucose and extra fluid into the renal tubules

C. blood glucose concentrations are elevated, and proximal tubule cannot reabsorb all the filtered glucose

ADH cause water permeability of the _____ to _____ and urine production to _____. A. proximal tubule, increase, decrease B. distal tubule, decrease, increase C. collecting tubule, increase, decrease

C. collecting tubule, increase, decrease

Which of the following composes the juxtaglomerular apparatus? A. proximal and distal tubule B. loop of Henle + distal tubule C. macula densa + juxtaglomerular cells D. afferent artery + glomerulus

C. macula densa + juxtaglomerular cells

ADH is secreted from the ___ into the ___. A. anterior pituitary gland, brain B. anterior pituitary, blood C. posterior pituitary gland, blood D. posterior pituitary gland, CSF

C. posterior pituitary gland, blood

Urinary volume is increased by all the following except: A. diabetes insipidus B. diabetes mellitus C. sympathetic stimulation D. increased renal arterial pressure E. infusion of mannitol

C. sympathetic stimulation

In infants, defecation often follows a meal. The cause of colonic contractions in this situation is A. histamine. B. increased circulating levels of CCK. C. the gastrocolic reflex. D. increased circulating levels of somatostatin. E. the enterogastric reflex.

C. the gastrocolic reflex.

Which of the following is an endopeptidase? A. carboxypeptidase A B. deoxyribonuclease C. trypsin D. dipeptidase

C. trypsin

The major humoral mediator of gallbladder contraction in response to a fat meal is

CCK

The major humoral mediator of meal-stimulated enzyme secretion is

CCK

What stimulates contraction of the gallbladder?

CCK and Ach

What are the general functions of the kidneys?

Excretory, endocrine, and regulatory functions

A 50-year-old man comes to see his clinician complaining of severe epigastric pain, frequent heartburn, and unexplained weight loss of 20 lb over a 6-month period. He claims to have obtained no relief from over-the-counter H2 antihistamine drugs. He is referred to a gastroenterologist, and upper endoscopy reveals erosions and ulcerations in the proximal duodenum and an increased output of gastric acid in the fasting state. The patient is most likely to have a tumor secreting which of the following hormones? A. Secretin B. Somatostatin C. Motilin D. Gastrin E. Cholecystokinin

D. Gastrin

Two medical students studying for their physiology final decide to take a break for a lunch. Before reaching the cafeteria, nervous impulses from the dorsal vagal complex will initiate gastric acid secretion by triggering release of which neurotransmitter from the enteric nervous system? A. Norepinephrine B. Vasoactive intestinal polypeptide C. Substance P D. Gastrin-releasing peptide E. Nitric oxide

D. Gastrin-releasing peptide

A scientist uses genetic approaches to selectively ablate the functions of the various cell types in the liver of mice. He finds that when a certain cell type is disabled, the mice show increased levels of sepsis when the barrier function of the intestine is reduced by instillation of ethanol. Ablation of which hepatic cell type would account for this finding? Kupffer cell In the study described in the question above, another set of mice with a different defect is created in which behavioral defects are observed consistent with encephalopathy. The function of which of the following cell types has likely been abrogated in this second group of animals? A. Hepatic stellate cell B. Cholangiocyte C. Kupffer cell D. Hepatocyte E. Gallbladder epithelial cell

D. Hepatocyte

Which of the following sphincters does NOT prevent reflux of material? A. Lower esophageal sphincter B. Gastroduodenal sphincter. C. Ileocolonic sphincter D. Internal anal sphincter.

D. Internal anal sphincter.

A patient suffering from anemia comes to his physician complaining of frequent bouts of gastroenteritis. A blood test reveals the presence of antibodies directed against gastric parietal cells. The anemia in this patient is attributable to the hyposecretion of which gastric product? A. Histamine B. Gastrin C. Pepsinogen D. Intrinsic factor E. Hydrochloric acid

D. Intrinsic factor

A patient with obstructive jaundice who is scheduled for gallbladder surgery is found to have an elevated prothrombin time. This laboratory finding is most likely due to malabsorption of which of the following vitamins? A. A B. C C. B12 D. K E. E

D. K

A 20-year-old man with a history of mild cystic fibrosis notices that his stools are becoming bulky, pale-colored and oily. Laboratory tests confirm steatorrhea. Which of the following would not be involved in his apparent decrease in fat assimilation? A. Lipase inactivation B. Decreased pancreatic lipase output C. Reduced pancreatic bicarbonate secretion D. Loss of the anatomic reserve E. Decreased colipase synthesis

D. Loss of the anatomic reserve

A 60-year-old woman undergoes total pancreatectomy because of the presence of a tumor. Which of the following outcomes would not be expected after she recovers from the operation? A. Steatorrhea B. Hyperglycemia C. Metabolic alkalosis D. Ongoing weight gain E. Decreased absorption of amino acids

D. Ongoing weight gain

Which of the following is NOT a component of saliva? A. Alpha-amylase and lingual lipase. B. Mucin and muramidase. C. Bicarbonate and magnesium. D. Protease and peptidase. E. Lactoferrin and ABO blood group substances

D. Protease and peptidase.

A 56-year-old man is admitted to the ED with an acute myocardial infarction. The man was transferred to the CCU and was placed on 24 h intake and output. A few days later his 24 h urinary output was decreased lower than normal. An increase in which of the following contributes to the reduced urine flow in a patient with congestive heart failure and reduced effective circulating volume? A. ANP B. Urodilatin (renal natriuretic peptide) C. Renal perfusion pressure D. Renal sympathetic nerve activity E. Sodium delivery to the macula densa

D. Renal sympathetic nerve activity

Muscles in the propulsive and receiving segments of the GI tract respond differently to food movement through the gut. Which of the following statements correctly describes activity in the propulsive segment? A. The circular and longitudinal muscles are contracted. B. The longitudinal muscles are contracted and the circular muscles are relaxed. C. Both the longitudinal muscles and circular muscles are relaxed. D. The circular muscles are contracted and the longitudinal muscles are relaxed.

D. The circular muscles are contracted and the longitudinal muscles are relaxed.

The enteric or intrinsic nervous system includes all of the following except: A. The same number of neurons as the spinal cord. B. Motor programs and reflex circuits. C. Sensory neurons capable of detecting chemical, mechanical and thermal conditions in the GI tract. D. Vagus innervation to the esophagus, stomach, and pancreas.

D. Vagus innervation to the esophagus, stomach, and pancreas.

Defective parietal cells would result in malabsorption of which vitamin? A. Vitamin B1 B. Vitamin B2 C. Niacin D. Vitamin B12 E. Folic acid.

D. Vitamin B12

A patient is treated with cholestyramine, a bile-acid binding resin, for hypercholesterolemia. Absorption of which of the following is likely to be abnormal in this patient? A. Long-chain triglyceride B. Medium-chain triglyceride C. Starch D. Vitamin D E. Vitamin B6

D. Vitamin D

A premenopausal woman who is physically active seeks advice from her primary care clinician regarding measures she can take to ensure adequate availability of dietary calcium to ensure bone health later in life. Which of the following dietary components should enhance calcium uptake? A. Protein B. Oxalates C. Iron D. Vitamin D E. Sodium

D. Vitamin D

Which of the following will help you compensate for diarrhea with resulting loss of excess bicarbonate (metabolic acidosis)? A. altered breathing B. buffers in the blood C. increased acid excretion by the kidney D. all of the above

D. all of the above

About the proximal convoluted tubules , all are true except : A. reabsorb most of Na+ ions in glomerular filtrate B. reabsorb most of Cl- ions in glomerular filtrate C. reabsorb most of K+ ions in glomerular filtrate D. contains JGCs which secrete renin

D. contains JGCs which secrete renin

Which of the following substances should not be used to measure GFR? A. inulin B. creatinine C. iothalamate D. glucose E. phenol red

D. glucose E. phenol red

A scientist studies the regulation of gastric motility by placing a pressure sensor in the stomach of a mouse that remotely reports intragastric pressure over time. She notes that gastric pressures seldom rise above the levels that breach the lower esophageal sphincter, even when the stomach is filled with a meal and its volume is expanded considerably as a result. Which process is responsible for this finding? Receptive relaxation The physiological gastric pressure response to feeding described in the question above could be partially inhibited experimentally by all of the following pharmacological agents except: A. cholinergic antagonist. B. nitric oxide synthase inhibitor. C. cholecystokinin antagonist. D. histamine antagonist. E. VIP antagonist.

D. histamine antagonist.

A patient who has undergone a partial gastric resection to remove a tumor reports to his primary care physician that he has experienced several episodes of nausea, cramping, dizziness, sweating and a rapid heart rate after ingesting sugary beverages. His symptoms are caused in part by A. increased blood pressure. B. increased secretion of acid. C. increased secretion of CCK. D. hypoglycemia. E. hyperglycemia.

D. hypoglycemia.

Which of the following statements regarding somatostatin is incorrect? A. it inhibits release of growth hormone B. it inhibits release of insulin C. it decreases blood flow to the intestine D. it stimulates gastric acid secretion

D. it stimulates gastric acid secretion

Osmotic concentration in the kidney is highest in the A. glomerulus B. proximal tubule C. distal tubule D. medulla near loop of Henle

D. medulla near loop of Henle

Which of the following enzymes is not synthesized by the pancreas? A. DNAase B. proelastase C. aminopeptidases D. pepsin

D. pepsin

When amino acids and vitamins are reabsorbed in the proximal tubule, these substances are transported into the A. distal tubule B. collecting tubule C. glomerular capillaries D. peritubular capillaries

D. peritubular capillaries

Blocking production of renin in juxtaglomerular cells might cause a number of effects. What happens to Na transport by the distal tubule and collecting ducts?

Decrease

Blocking production of renin in juxtaglomerular cells might cause a number of effects. What happens to aldosterone concentration in the blood?

Decrease

Blocking production of renin in juxtaglomerular cells might cause a number of effects. What happens to angiotensin concentration in the blood?

Decrease

A scientist studies the regulation of gastric motility by placing a pressure sensor in the stomach of a mouse that remotely reports intragastric pressure over time. She notes that gastric pressures seldom rise above the levels that breach the lower esophageal sphincter, even when the stomach is filled with a meal and its volume is expanded considerably as a result. Which process is responsible for this finding? A. Peristalsis B. Gastroileal reflex C. Segmentation D. Stimulation of the vomiting center E. Receptive relaxation

E. Receptive relaxation

In a study of the secretion of gastrointestinal hormones, portal concentrations are measured in a rat during luminal perfusion of buffered salt solutions at various pH levels. Which of the following hormones will increase during perfusion with a buffered solution at pH 3.0? A. Cholecystokinin B. Gastrin C. Glucose-dependent isulinotropic peptide D. Motilin E. Secretin

E. Secretin

A 40-year-old woman comes to her primary care clinician complaining of severe, episodic abdominal pain that is particularly intense after she ingests a fatty meal. An imaging procedure reveals that her gallbladder is acutely dilated, and a diagnosis of cholelithiasis is made. A gallstone lodged in which location will also increase her risk of pancreatitis? A. Left hepatic duct B. Right hepatic duct C. Cystic duct D. Common bile duct E. Sphincter of Oddi

E. Sphincter of Oddi

Power propulsion is controlled by many factors in the large intestine. Which of the following is NOT one of them? A. Castor oil acts on mucosal receptors to initiate it. B. May be triggered by ileal chyme delivery to the ascending colon. C. Can be triggered by parasites, enterotoxins, and food antigens. D. Normally starts in middle of transverse colon after the relaxation of circular muscles and downstream disappearance of haustral contractions. E. The influx of material will stimulate a mass movement 6-7 times daily.

E. The influx of material will stimulate a mass movement 6-7 times daily.

A patient suffering from severe ulcerative colitis undergoes a total colectomy with formation of a stoma. After a full recovery from surgery, and compared to his condition prior to surgery, which of the following would be expected to be decreased? A. Ability to absorb lipids B. Ability to clot the blood C. Circulating levels of conjugated bile acids D. Circulating bilirubin E. Urinary urobilinogen

E. Urinary urobilinogen

In controlling the synthesis and secretion of aldosterone, which of the following factors is least important? A. renin B. angiotensin II C. concentration of plasma Na+ D. concentration of plasma K+ E. adrenocorticotropic hormone (ACTH)

E. adrenocorticotropic hormone (ACTH)

Dehydration increases plasma protein concentration of all the following hormones except: A. vasopressin B. angiotensin II C. aldosterone D. norepinephrine E. atrial natriuretic peptide

E. atrial natriuretic peptide

Which structures are located in the medulla of the kidney? A. glomerulus incl. Bowman's capsule and glomerular capillaries B. proximal tubule C. glomerulus + proximal tubule D. glomerulus + proximal tubule + distal tubule E. collecting tubule and loop of Henle F. glomerulus + proximal tubule + distal tubule + collecting tubule and loop of Henle

E. collecting tubule and loop of Henle

On which of the following does aldosterone exert its greatest effect? A. glomerulus B. proximal tubule C. thin portion of the loop of Henle D. thick portion of the loop of Henle E. cortical collecting duct

E. cortical collecting duct

Which of the following is freely filtered in the glomerulus into Bowman's capsule and reabsorbed entirely in proximal tubule? A. water B. sodium C. chloride D. urea E. glucose

E. glucose

Which of the follow inhibits gastric acid secretion by an action on the parietal cell? A. acetylcholine B. epinephrine C. gastrin D. histamine E. prostaglandin E

E. prostaglandin E

Where is gastrin secreted from?

G cells of the gastric antrum in response to a meal

Filtration fraction

GFR/RPF

What are the 4 official GI hormones?

Gastrin, Cholecystokinin (CCK), Secretin, and Glucose-dependent Insulinotropic Peptide (GIP)

What stimuli secretes somatostatin?

H+ in lumen (decreased luminal pH)

Where is CCK secreted from?

I cells of duodenum and jejunum

Blocking production of renin in juxtaglomerular cells might cause a number of effects. What happens to urine production?

Increase

The amount of K+ excreted by the kidney will decrease if

Na+ reabsorption by the distal nephron decreases

Normally, the main function of the colon is absorption of

Na, Cl, H2O

Where is secretin secreted from?

S cells of duodenum

Which segment of the nephron is permeable to urea?

Thin ascending limb of loop of Henle

What are the 3 GI neurocrines?

VIP, GRP, enkephalins

Glomerular filtration rate would be increased by

a decrease in the concentration of plasma protein

From a physiological standpoint, the advantage of a 'parietal cell vagotomy' over truncal vagotomy for treating duodenal ulcer is that in parietal cell vagotomy

a gastrojejunostomy is not required

The most potent stimulus for release of secretin from the duodenum is

a reduction in duodenal lumen pH < 4.5

What is peristaltic contractions?

a section behind bolus contracts and in front of bolus relaxes, propels the chyme, occurs after digestion and absorption

What is segmentation contractions?

a section of small intestine contracts and relaxes, this back and forth movement causes mixing of intestinal contents without moving the chyme forward

What does bile salts do?

aid in intestinal digestion and absorption of lipids by emulsifying and solubilizing them in micelles

Hormone that directly induced proton secretion by α-Intercalated cells in the collecting ducts

aldosterone

K+ excretion is markedly influenced by

aldosterone

Plasma K+ concentration is chiefly regulated by

aldosterone

In the distal tubules, Na+ reabsorption is increased directly by increased

aldosterone secretion

In the absence of medication or disease processes affecting transport in the nephron, fluid entering the early distal tubule is

always hypotonic

Normally, in urine, most of the H+ ions is tied up with

ammonia

The substrate for renin is

angiotensinogen

The types of contraction that normally occurs only in the colon are

antiperistalsis mass action contraction (mass peristalsis)

GI hormones

are released from endocrine cells in GI mucosa into portal circulation, enter general circulation, have physiological actions on target cells

Epithelial cells

are specialized in different parts of the GI tract from secretion or absorption

Efferent fibers

carry information from the brainstem and spinal cord to the GIT

Afferent fibers

carry sensory information from chemoreceptors and mechanoreceptors in the GIT to brain and spinal cord

What is gastric emptying?

caudad region of stomach contracts to propel food into duodenum

Movement of fecal material

cecum --> ascending colon --> transverse colon --> descending colon --> sigmoid colon --> rectum --> anal canal

Erythropoietin is secreted by

cells in the peritubular capillary bed

What are endopeptidases?

degrade proteins by hydrolyzing the interior peptide bonds

'Concentrating segment' of the nephron

descending limb of loop of Henle

'Free water' formation in the lumen of the nephron is essential for production of

dilute urine concentrated urine

Vasa recta receive blood from

efferent arterioles of juxtamedullary nephrons

What are the 3 layers of the glomerular filtration barrier?

endothelial cells, basement membrane, podocytes

Intrinsic innervation

enteric nervous system

The term "brain of the gut" is used to refer to the

enteric nervous system

Trypsinogen, a pancreatic proenzyme, is activated by

enterokinase

What is pancreatic amylase?

enzyme that breaks down carbohydrates

What is pancreatic lipase?

enzyme that breaks down fats

What is pancreatic protease?

enzyme that breaks down proteins

What does the vagus nerve innervate?

esophagus, stomach, pancreas, upper large intestine

_____ inhibits ADH secretion

ethanol

Calcium absorption from the intestine

is facilitated by vitamin D is decreased by phytates and oxalates occurs mainly in the upper small intestine

The tubular fluid at the end of the PT is _____ with respect to plasma

isotonic

Normally, most of the water in the GI lumen is absorbed from

jejunum

Renin in the circulation originates mainly from

juxtaglomerular cells

K+ secretion occurs mainly in

late distal tubule or cortical collecting ducts

What are the 3 layers of smooth muscle in the stomach?

longitudinal, circular, oblique

When a person is dehydrated, hypotonic fluid will be found in the

loop of Henle

What inhibits gastric H+ secretion?

low pH, somatostatin, prostaglandins

What does the pelvic nerve innervate?

lower large intestine, rectum, and anus

Conjugation of bilirubin with glucuronic acid in the liver

makes it hydrophilic

Where is histamine secreted from?

mast cells of gastric mucosa

Where is the swallowing reflex coordinated?

medulla

The pattern of electrical and motor activity in the GI tract during periods of fasting is called

migrating motor complex