Mini 2 - Digestive + Renal Flashcards
1
Q
Which digestive hormones/substances stimulate the PLC pathway?
A
ACh (M3), Serotonin (5HT), CCK (CCK1).
2
Q
Does the gallbladder have all the layers of the gut tube>
A
Not submucosa.
3
Q
What is special about PAH?
A
Totally secreted - C=RPF = 600mL/min
4
Q
Where is the macula densa?
A
Thick ascending loop of Henle.
5
Q
What is alkaptinuria?
A
Deficiency of homogentisate oxidase. Homogentisate accumulates, black pigment deposits in cartilage, arthritis in elderly.
6
Q
What are the functions of Vitamin E (Tocopherol)? What is the active form?
A
alpha-tocopherol is the most active. Works as an antioxidant, scavenges free radicals.
7
Q
How much energy is obtained from carbs?
A
4kcal/g
8
Q
Does the small intestine have a muscularis mucosa?
A
Yes.
9
Q
What percent of daily calories should be gotten from simple sugars and disaccharides?
A
<10%
10
Q
What are the fat-soluble vitamins?
A
A (Retinol), D (Cholecalciferol), E (Tocopherol), K (Quinone).
11
Q
In Farber disease, what enzyme is defective and what accumulates?
A
Defective - ceraminidase Accumulates - ceramides in joints, CNS, liver, heart, kidney
12
Q
What do Intercalate cells reabsorb and secrete?
A
Reabsorb potassium (but can secrete) and chloride paracellularly. Secrete H+.
13
Q
In the filtration apparatus, what do the glomerulus capillary endothelium and the basement membrane do?
A
Capillary endothelium prevents cell penetration (pores 50-100nm), basement membrane prevents penetration of plasma proteins.
14
Q
Where is enteropeptidase made and as what zymogen? What does it target?
A
Made in the duodenal and jejunal brush border cells as proenteropeptidase. Targets a residue of 4XAsp Lys, hydrolysis occurs on the Lys c-term.
15
Q
What is in the esophageal submucosa?
A
Esophageal glands that secrete mucus.
16
Q
Desctibe the submucosa of the stomach.
A
No glands, large blood vessels, Meissner’s plexus.
17
Q
What tissue besides epithelium is in the kidney?
A
LCT renal intetstitium.
18
Q
Describe tubuloglomerular feedback.
A
More fluid means more sodium coming in with the macula densa NCCK. This activates the Na+/K+ pump. More ATP is produced (and adenosine), binding to the P2X (and A1) receptor on smooth muscle calcium channel, causing vasoconstriction. Ca2+ also enters granular cells, decreasing renin release.
19
Q
What are the functions of Vitamin B6 (Pyridoxine)? What is the active form?
A
Found as pyridoxine (plants), pyridoxal, and pyridoxamine (ianimal products). Active form is pyridoxal phosphate (PLP). PLP it the cofactor for many enzymes - e.g. decarboxylation, transamination, deamination, condensation. In high doses can be used to treat carpal tunnel.
20
Q
What are the types of papillae and which have taste buds?
A
Filiform (most abundant), Fungiform (taste buds on dorsal surface, less keratin), Circumvallate (generally nonkeratinized, 250 taste buds/papilla facing laterally), Foliate (rudimentary in human).
21
Q
What class of drug is Omeprazole and how is it administered?
A
PPI, oral. Given as acid-resistant enteric coated formulation.
22
Q
What is WIlson’s disease?
What are the levels of Cu and ceruloplasmin, and how do you treat it?
A
An autosomal recessive mutation in ATP7B which encodes a Cu@+ ATPase that transports copper into the ER/golgi. Copper accumulates in the liver and brain leading to dementia, movement disorders, Kayser-Fleisher rings. Will result in high blood copper, low blood ceruloplasmin. Treat with penicillamine (Cu chelator).
23
Q
How does somatostatin affect the GI system?
A
It inhibits parietal cells, inhibits ECL cells, inhibits G cells. Decreases acid.
24
Q
Describe a Vitamin D (Cholecalciferol) deficiency.
A
Rickets (lack of bone mineralization) if in a child, but in adults it is osteomalacia (demineralization).
25
Where is dipeptidase made and as what zymogen? What does it target?
Made in SI enterocytes, acts in and on brush border. Has no zymogen. Targets dipeptides.
26
What enzymes make a type A blood antigen and which make type B?
A = N acetylgalactosamine B = galactose trasferase Added onto terminal galactose.
27
What is lined by urothelium?
Calyces, ureter, bladder, urethra.
28
How much H+ is excreted via the two methods of H+ excretion?
40mmol with each but ammonia can increase to as much as 500mmol.
29
Describe a Vitamin B9 (Folate) deficiency.
Common in pregnant women and alcoholics. Causes megaloblastic anemia - can leadt to neural tube abnormalities in the fetus.
30
What enzyme in the GI besides trypsin can autocatalyze in acidic conditions? And where is it activated?
Pepsin. In the stomach (the rest of the enzymes are cleaved in the SI).
31
Where in the lower intestinal tract is crypt cell bicarbonate secretion highest?
Proximal colon.
32
Of the water-soluble vitamins, which areconsidered energy-releasing?
B1 (Thiamine), B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic acid), B7 (Biotin).
33
What enzyme do you use in beta oxidation is there is an even double bond?
2,4 dienoyl CoA isomerase. Uses NADPH.
34
What is normal RPF?
600mL/min.
35
How are branched chain amino acids metabolized?
Transaminated to alpha-ketoacids and then and then dealt with by branched chain alpha keto acid dehydrogenase. Val and Ile completion goes through propionylCoA, Leu goes through a purely ketogenic degradation.
36
How do bacteria aid in digesting lipids?
It makes SCFAs that the colon can absorb via secondary active transport. Byproducts can be gas, pain, etc.
37
What is homocystinuria? How do you treat it?
Deficiency of cystathione synthase (B6). Osteoporosis, ectopia lentis, thromboembolism (arterian and venous), mild mental deficiency, psychiatric problems. Give B6, maybe B9/B12, restrict methionine, give betaine to stimulate homocystine-to-methionine converstion.
38
What are the food sources of Vitamin E (Tocopherol)?
Vegetable oil, oil seeds, wheat germ.
39
Describe the muscularis externa of the large intestine.
The outer longitudinal layer is formed into 3 longitudinal strips - teniae coli.
40
Describe a Vitamin A (Retinol) deficiency.
Common in developing countries. Night lindness, eventual loss of retinal cells, xeropthalmia.
41
What controls the ileocecal sphincter?
The SNS, vagus, ENS. Ileal distension/irritation leads to relaxation, cecal distension/irritation leads to contraction.
42
What is special about inulin?
Ms = Mr = 0 C=GFR = 120mL/min
43
What class of drug is misoprostol and how is it administered?
Mucosal protective agent, oral, vaginal, rectal.
44
How are bile acids and salts reabsorbed?
Through enterohepatic circulation, reabsorbed in the terminal ileum. Primary and secondary bile acids passively diffuse in. Na+ dependent carrier mediated secondary active transport beings in primary bile salts only.
45
Describe glycerophospholipids and name the 4 relevant ones.
Glycerol backbone, 2FAs (middle one usually unsaturated) attached through ester bonds. Phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol.
46
What is clearance?
The volume of plasma cleared of a substance per unit of time.
47
What is metoclopramide used to treat?
Diabetic gastroparesis, good for advancement of nasoenteric feeding tube, can do GERD but is not preferred - may be given with a PPI in patients with reractory heartburn or regurgitation.
48
What substances stimulate the lower esophageal sphincter?
Between swallows - vagal excitatory fibers (ACh, SP). During swallow - vagal inhibitory fibers (VIP, NO).
49
What is the effect of dietary cholesterol on serum cholesterol?
Currently we think none.
50
What is kwashiorkor?
A diet inadequate in protein (high carb subsistence diet) resulting in a pot belly, fatty liver, hypoalbuminemia, edema.
51
How do omeprazole and esomeprazole work?
They are proton pump inhibitors on the apical parietal cell H+/K+ ATPase. They covalently, irreversibly bind.
52
What does Adipose Triglyceride Lipase (ATGL) have a preference for?
End FA.
53
What is Menkes Disease?
X-linked recessive mutation in ATP7A gene, wwhich encodes an intestinal Cu2+ translocase. Cupper accumulates in the small intestine and kidneys, lowly in the brain. Results in kinky hair, seizures, unstable body temperature. Will result in low blood copper and ceruloplasmin. Poor prognosis, usualy death by 3 years of age, give copper supplements.
54
What are the food sources of Vitamin B1 (Thiamine)?
Most foods, yeast, lean pork, legume seeds.
55
What cells are in the crypts of the large intestine epithelia?
The lower 2/3 entirely goblet cells. Has EECs, SCs too.
56
What is the net H+ from metabolism that isn't balanced out by OH-?
80mmol.
57
What enzymes break down lipids?
Lingual (~pH 5) and gastric lipases (pH 3-6) - 10% digestion in the stomach. Pancreatic lipase in the duodenum (uses colipase and cholesterol esterase and PLA). Colipase attaches to a TG on the surface of an emulsion droplet, and serves as an anchor for lipase which hydrolyzes the ester bonds.
58
What class of drug is magnesium hydroxide and how is it administered?
Antacid, oral. Also considered an osmotic laxative.
59
What are some adverse effects of aluminum hydroxide?
Constipation.
60
What sizes and charges of molecules are filtered better or worse?
under 18A are freely, \>42A not filtered. If between 18 and 42 then positively charged are filtered more and negatively charged are filtered less. If smaller than 18A, negatively charged are filtered more, positively charged are filtered less.
61
What triggers renin release?
Decreaed renal perfusion or hyponatremia.
62
How much energy is obtained from alcohol?
7kcal/g
63
How is CPSI regulated?
N- acetylglutamate is an allosteric activator, arginine regulates its synthesis.
64
What is special about kidney circulation?
Has two capillary beds, an afferent arteriole -\> CN (glomerulus) -\> efferent arteriole -\> CN -\> venule. The second capillary network is either peritubular capillaries or vasa recta.
65
How does metoclopramide work?
A dopamine D2 receptor antagonist. It enhances gastric emptying, speeds up digestion, antinausea and antiemetic action.
66
Where is secretin made?
By S cells mainly in the duodenum (some in the jejunum).
67
In Sandhoff disease, what enzyme is defective and what accumulates?
Defective - Hex A and B (A has alpha and beta subunits, B is beta homodimer). Accumulates - GM2 and globosides.
68
What are the functions of VItamin B1 (Thiamine)? And what's its active form?
Thiamine pyrophosphate. It is a cofactor in several metabolic enzymes carrying out aldehyde transfer or oxidative decarboxylation. E.g. PDH, alpha KG dehydrogenase, transketolase (in HMP, assayed by erythrocyte transketolase reaction).
69
What are the three types of intestinal segmentation movements?
Regularly spaces, isolated, irregularly spaced.
70
How does an increase in total resistance in kidney circulation affect filtration/reabsorption?
Increased reabsorption.
71
What is molybdenum needed for? Where is it found?
Nitrogenases and oxidizing proteins. Found in legumes, grains, nuts.
72
What is the normal plasma pH?
7.37-7.45.
73
What is special about the appendix?
It has the most lymphatic nodules per unit area of any GI organ.
74
What is GIP's target?
Pancreatic beta cells (potentiates insulin secretion), parietal cells, G cells (inhibit gastric secretion and motility).
75
What is the relationship between urine flow rate and potassium excretion?
Proportional.
76
How do parasympathetic and sympathetic stimulation affect the medullary salivatory nucleus?
PNS increases flow and stimulates watery parotid secretions. SNS reduces flow (still flow though) and stimulates thicker, enzyme rich submucosal secretions. Both have both, neither have neither.
77
How is Tay-Sachs inherited and what are the symptoms?
Autosomal recessive. Classic version is infantile onset (3-6mo), death by 3 years. Growth retardation, dysphagia, seizures, decreaed mental skills and muscle tone, deafness, blindness, paralysis, cherry red spot in the macula surrouned by grey-white.
78
In which parts of the small intestine is folate/B9 absorbed?
Duodenum.
79
What's the gallbladder muscularis externa like?
Muscle fibers oriented in all directions to facilitate emptying.
80
What is methylmalonc acidemia? How do you treat it?
Deficiency of methylmalonyl CoA mutase (needs B12). Causes acidosis, ketosis in acute attacks. Treat with adenosyl-cobalamin or dietary protein restriction, avoidance of stress, avoidance of fasting and low-carb diets.
81
What are the food sources of Vitamin B6 (Pyridoxine)?
Liver, fish, whole grains, nuts, egg yolk.
82
Describe vomiting/emesis.
Peristalsis suppressed, powerful abdominal muscle contraction creating strong pressure gradient, stomach, LEX, esophagus relax. Sometimes there is antiperistalsis/retroperistalsis.
83
How is the carnithine shuttle regulated?
Malonyl CoA inhibits CPTI.
84
What does fluoride do? What can deficiency cause?
It helps form hard bones and teeth. fluoroapatite is harder than hydroxyapatite. Deficiency can cause tooth decay.
85
What are the three ketone bodies?
Acetoacetate, 3-hydroxybutyrate, acetone/
86
What is the specific target of salivary alpha amylase?
alpha 1-\>4 glycosidic linkages in starch. Produce is maltose and smaller starches.
87
What percent of the diet should be fat?
25-35%.
88
Describe a deficiency in Vitamin B1 (Thiamine).
Can occur if polished rice is the primary diet. Can cause Beriberi - mild has GI complaints, weakness, burning feet sensation. Severe has peripheral neuropathy, mental abnormality, ataxia. Dry beriberi means there are neurological deficits, wet beriberi means there is edema due to cardiac dysfunction. Can also cause Wernicke-Korsakoff syndrome (common in alcoholics). Acute has Wernicke encephalopahty (mental deramgement, ataxia, eye paralysis), chronic has Korsakoff psychosis (severe debilitating anterograde amnsia, frontal lobe damage). Mamillary bodies disappear.
89
What is the amino acid you want for the urea cycle?
Glutamate.
90
How does K+ secretion change as you move down the colon?
Decreases. Passive secretion paracellular and greatest in distal colon. Active secretion transcellular and greatest in proximal colon.
91
What is the main signal of motilin?
Not very well understood, lack of nutrients.
92
What is the effect of calcitriol on the kidney?
Increases calcium reabsorption in the DCT.
93
What does phospholipase C do?
Cleaves the headgroup in a glycerophospholipid between glycerol and the phosphate.
94
How is the venous blood relatively in respiratory acidosis compared to the arterial?
Increased PCO2, increased bicarbonate concentration, lowered pH.
95
How many tongue muscles are there - how are they aligned and with what nerve are they controlled?
3, orthogonally, CN XII.
96
How is bicarbonate concentration affected by an increase of CO2 in and not in the presence of additional buffer?
An increase in CO2 barely affects the bicarbonate concentration, but having other buffers present will cause it to increase because it will reduce the H+.
97
What separates the anterior/oral and posterior/pharyngeal surfaces of the tongue?
The sulcus terminalis. (Foramen cecum at its apex is the origin of the thyroid gland).
98
What is non-ketotic hyperglycinemia? How do you treat it?
Lack of glycine cleavage enzyme. Give NMDA receptor blockers or Benzoic aid.
99
What's the gallbladder mucosa like?
Simple columnar, lamina propria, no muscularis mucosa.
100
What are the essential amino acids?
Ones that must be obtained from the diet. Val, Ile, Leu, His, Lys, Met, Thr, Phe, Trp, .
101
Describe a Vitamin D (Cholecalciferol) toxicity.
Toxic in very high doses. Is stored in body fat. Loss of appetite, nausea, thirst, stupor, hypercalcemia.
102
List the crypt cell channels.
103
How do lipolytic digestion products (FAs) enter enterocytes? Where do they go?
Through FAT or just through diffusion. They reform as triglycerides and go to golgi, released as chylomicrons that go into lymph.
104
How is ADH stimulated to be released.
Osmoreceptors (neurons) in the Nucleus Paraventricularis and Nucleus Supraopticus in the hypothalamus cause ADH to be released from the posterior pituitary (neurohypophysis). Baroreceptors also input to these neurons (low BP).
105
How is the recommended daily intake determined for vitamins/minerals?
Such that 98% of people won't show signs of a deficiency.
106
Describe triglyceride synthesis.
A G3P backbone (made from DHAP or glycerol in the liver) is taken. A FA Coa is added (usually unsaturated at the middle position) and then the phosphate is removed to add the third fatty acid.
107
What is the mucosa like in the cardia of the stomach and what cell types are there?
No goblet cells, glands are as big as the pits, long, branched, coiled. Mucus secreting cells, SCs, EECs, few parietal cells.
108
Describe Vitmain B6 toxicity.
Toxic in high doses (400X RDA, 500mg/day), can have neuro symptoms. But in less high doses (100mg.day\_ can be used to treat carpal tunnel.
109
How is acetoacetate ketone body generated?
Ac CoA is made into acetoAcCoA, which is then made into HMG COA with HMG CoA Synthase. Then HMG CoA Lyase catalyzes it into AcCoA and acetoacetate.
110
What does the liver do?
Makes and secretes bile acids and pigments, excretes heavy metals, cholesterol, bile pigments, drugs and hormones, detoxifies, has hematopoietic functions in fetal life, some defense (Kupffer cells), activates Vitamin D.
111
How are bile salts moved into the lumen from the hepatocytes?
Transporter Z ATPase moves the ones conjugated to taurine/glycine, Transporter Y ATPase moves the ones conjugated to sulfate/glucuronate.
112
What kind of muscle is in the esophageal muscularis externa?
Starts out skeletal, then mixed, then just smooth.
113
How are proteins usually absorbed in the GI tract?
As mono/dipeptides.
114
How is phosphatidylserine synthesized?
From phosphatidylethanolamine in the liver using phosphatidylethanolamine serine transferase. PS can also be decarboxylated to PE which can then be methylated to PC.
115
What is an adverse effect of bismuth subsalicylate?
Black stool.
116
What receptors do parietal cells have?
CCK, M3, H2 (histamine).
117
Where is triglyceride synthesis carried out?
In the liver, and a little in the muscle and adipose.
118
Describe the classic hepatic lobule.
Central vein in the center, hexagonal. Emphasizes the endocrine function of the hepatocyty.
119
What is the contraction pattern of the gut wall from the stomach down (besides the sphincters).
Phasic. A slow wave - phasically changing membrane potential. A spike (AP) is a consequence of the slow wave reaching the threshold.
120
How does ADH work?
It binds, stimulates a Gs mechanism, causes aquaporins to be moved to the luminal membrane.
121
What is the contraction pattern of the esophagus and bladder?
Normally relaxed, tightens for short bursts - opposite of sphincters.
122
Describe the structure of a hepatocyte.
Can be binucleated, are cube-like with 6 major surfaces (2 sinusoidal and 4 lateral). Sinusoidal domains covered in microvilli that project into the space of Disse. The lateral domains form the bile canaliculi.
123
Where besides the GI are there lipases?
Muscle and adipose have it in their capillary lumen.
124
Describe the muscularis externa of the small intestine.
Has Myenteric Plexus between the two layers.
125
What are the functions of Vitamin B7 (Biotin)?
Prosthetic group for many ATP-dependent carboxylases, typically covalently bound.
126
What is propionic acidemia? How do you treat it?
Deficiency of propionyl carboxylase (needs B9). Comes with recurrent metabolic acidosis, neurologic complications. Treat with dietary restriction.
127
What are hepatic sinusoids?
Specialized capillaries that carry blood through the parenchyma; have sinusoidal endothelium, Ito cells (fat storing in space of Disse, store vit A, secrete lipid collagen), and Kupffer cells (macrophaces, APCs).
128
In which parts of the small intestine is calcium absorbed?
The whole thing.
129
What can Histidine be metabolized into?
Histidase can remove NH3 to make FIGlu, which can be converted to glutamate. FIGlu accumulates after an oral histidine load if there is a B9 deficiency.
130
Where is the ENaC found and what is it?
Epithelial sodium channel. Found in the distal colon.
131
What is normal renal blood flow?
1100mL/min (25% of CO)
132
Which side of the cell does minor hormone guanylin come from?
The apical side.
133
What is salivary ductal processing?
Na+ and Cl- reabsorbed from primary saliva.
134
Describe the regulation of Acetyl CoA carboxylase.
Activated by citrate and in dephosphorylation. Downregulated by accumulation of LCFAs and AMP kinases.
135
What does ALT do?
Transfers a nitrogen from Ala to alpha-ketoglutarate, making a glutamate.
136
What is phenylketonuria? How do you treat it?
Autosomal recessive phenylalanine hydroxylase deficiency. Excess Phe causes mental retardation, light skin and hair, eczema, 'mousy' odor of infant. Tyrosine is now an essential amino acid. Treat by limiting Phe in diet, especially in pregnancy.
137
What does the Meissner's/Submucosal Plexus control?
GI secretions.
138
What is the glycocalyx?
Outer carb coating on membranes, made from glycolipids. It is dark staining on EM.
139
What is a chylomicron remnant?
A chylomicron that has been depleted of triglyceride. It goes to the liver, fatty acids are repackaged back into VLDLs.
140
What sets the pace for slow waves? What are the paces n the different organs?
Insterstitial cells of Cajal (ICCs) in the stomach and within the walls of the SI and LI. Stomach - 3-4/min Duodenum - 10-12/min Colon - 3-7/min
141
What is saliva like at high and low flows?
Very hypotonic at the slowest flow (highest K+). At fastest flow, elevated bicarbonate and NaCl (inefficient reabsorption). Less hypotonic.
142
What sort of tissue is the kidney primarily made of?
Epithelium.
143
What is cystathionuria?
A deficiency in cystathionase, no clinical symptoms. Cystathione accumulates.
144
Where is carbohydrate breakdown done
In the duodenum and jejunum.
145
How much linoleic acid is needed in the daily diet?
12g or 17g
146
What are the two important primary bile acids to know?
Cholic acid/cholate and chenodeoxycholic acid.
147
What is the end result of beta oxidation of an odd chain fatty acid and how do you deal with it?
Propionyl CoA. Propionyl CoA carboxylase (B7 cofactor) uses ATP to turn it into methylmalonyl CoA which is processed by methylmalonyl CoA mutase (B12 cofactor) into succinyl CoA.
148
How does reduction in ECV affect calcium reabsorption?
Increases it.
149
What are the cells of the thin Loop of Henle like?
Simple squamous.
150
What are the types of cells in the distal tubule and collecting duct?
Principal cells and intercalated cells (both cuboidal). Principal is more abundant, have numerous basal infoldings, distinct lateral margins, few microvilli. Intercalated cells are far fewer and actively secrete H+.
151
What's the difference between amylose and amylopectin?
Amylose is linear and digested slower, amylopectin is branched and digested faster.
152
How are urea cycle deficiencies treated?
Avoid protein, fasting, low carbs, stress, replace amino acids with their alpha ketoacids. In the case of an arginosuccinate lyase deficiency, just give arginine (it can be excreted).
153
What are the 5 patterns of digestion/absorption?
1. monomer, no digestion needed 2. digestion in lumen into monomers 3. digestion in lumen into oligomers, further digestion at brush border into monomers 4. dimers and trimers absorbed into enterocyte, digested into monomers inside cells 5. digested into monomers in lumen, absorbed into enterocytes, repackaged into larger molecules before exiting enterocytes
154
Is the stuff coming out of pancreatic ducts acidic or basic?
Basic.
155
What are the functions of Vitamin B3 (Niacin)?
Converted to NADH and NADP - coenzymes for numerous reactions and also redox carriers. Can also be used to treat hyperlipidemia.
156
What is an adverse effect of lubiprostone?
Nausea.
157
What is a sphingolipid?
Ceramide (sphingosine + FA) + headgroup.
158
What are EECs alternate names? What do they look like in histological staining?
APUDs (Amine precursor uptake and decarboxylation), Gastro/entero endocrine cells. G cells (gastrin), D cells (somatostatin), EC cells (serotonin).
159
If the Sphincter of Oddi is closed, where does bile back up into?
The gallbladder.
160
What does the macula densa do?
Senses sodium concentration in the urine (or lowered blood volume), and signals juxtaglomerular cells.
161
Describe the effect of vagal neurons on gastric acid secretion.
Increases - stimulate parietal cells, ECL cells, G cells, inhibit D cells.
162
What are bile canaliculi? Where do they drain into?
Small, tubular, PM-bound enlargements in the EC space between two adjacent hepatocytes, sealed by zonula occludens. They drain into the canals of Hering (short simple epithelia), which drain into bile ducts.
163
What are the portions of the collecting duct?
Collecting tubule, cortical collecting duct, medullary collecting duct, papillary ducts/ducts of Bellini (end at renal papilla).
164
What is secretin's signal?
pH under 4.5 in the duodenal lumen - minorly in the jejunal lumen.
165
What are the functions of Vitamin D (Cholecalciferol)? What is its active form?
Active form is calciferol. Maintains plasma calcium concentration - increases intestinal absorption, mininmizes kidney loss through resorption.
166
What is a glycemic load?
How much a typical serving of a food raises blood [glucose].
167
What is the headgroup on sphingomyelin?
Choline.
168
What is iodine needed for? What can deficiency cause?
Thyroid hormone - goiter.
169
How do blood and bile flow through the hepatocyte?
Blood goes into the center through the periphery, bile goes outward.
170
How does acidosis affect potassium and calcium?
Decreases calcium reabsorption, increases potassium reabsorption.
171
What are the sources of dietary fiber?
Bran, navy beans, shredded wheat, cranberry beans, lentils, peas.
172
What increases CFTR activity?
ACh (M3 ENS receptors), VIP, prostaglandins, histamine, (AC action), serotonin (5HT, PLC), anything that increases guanylyl cyclase.
173
Describe Hormone sensitvive Lipase (HSL).
Has a preference for the middle position FA. Epinephrine (cAMP) stimulates its activity by the kinase action, insulin activates phosphatase.
174
How does bicarbonate secretion change as you move down the colon?
Decreases (highest in proximal colon).
175
When sphingomyelin is made from phosphatidylcholine, what is the other product?
DAG.
176
What can Serine be metabolized into?
3PG (from which it originates), pyruvate, Glycine.
177
What class of drug is lactulose and how is it administered?
Osmotic laxative, oral and rectal.
178
What does warfarin do?
Blocks Vitamin K epoxide reductase, which regenerates Vitamin K.
179
What does fatty acid synthesis require and where is it done?
Requires ATP and reducing equivalents NADPH. It takes place in the cytosol.
180
Is salive hypo, iso, or hypertonic to plasma?
Hypotonic. Watery, contains ions.
181
How does calcium leave the cell?
Basolaterally - via a calcium/hydrogen exchanger (primary active transport) or a Na+/Ca++ antiport using the sodium potassium pump.
182
What is the medullary ray?
Straight tubes (straight prox and distal tubules and also collecting duct) going to and from medulla.
183
How does alanine contribute to the urea cycle?
In the liver amines are sent to glutamate (generating pyruvate).
184
What is marasmus?
Calorie intake is relatively less than protein intake (weaning to low calorie foods) resulting in emaciation, anemia, low subcutaneous fat, weakness.
185
What are the food sources of Vitamin K (Quinone)?
Cabbage, spinach, kale, egg yolk, liver, is also synthesized by gut flora.
186
What is the effect of ADH on tubule fluid osmolarity?
Tubular fluid is hypoosmolar as it reaches the late distal tubule, if ADH is present water will be reabsorbed to equalize osmolarity.
187
In Tay-Sach's disease, what enzyme is defective and what accumulates?
Defective - Hexasominisade A Accumulates - GM2 ganglioside
188
What is the mucosa like in the fundus/body of the stomach and what cell types are there?
Shallow puts and deep glands (straight). Neck of glands has mucus cells, SCs, lots of parietal cells. Base of glands has few parietal cells, chief cells, mucus cells, EECs.
189
What is MSUD?
Maple syrup urine disease, accumulation of branched chain amino acids and their alpha ketoacids.
190
What do Chief cells produce and what are their alternate names? In what part of the glands are they? What do they look like in histological staining?
Peptic/Zymogenic cells. They produce pepsinogen and a weak lipase. Lower 1/3 of gland. Basophilic, granules are visible, triangular in shape, smaller than parietal cells.
191
How is calcium kept in the cell before being moved across the basolateral membrane? How does it come into the cell?
Held in place with calbindin. It can come in paracellularly or transcellularly.
192
What are the two essential fatty acids?
Linoleic acid (C 18:2 cis 9,12) - omega 6. Linelenic acid (C 18:3 cis 9,12,15) - omega 3
193
How does increased efferent arteriolar resistance affect GFR and RPF?
Increases glomerular capillary pressure, increasing filtration but decreases RPF. So GFR effect unclear.
194
What is the contraction pattern of blood vessels/airways?
Normally partially contracted, has tone/
195
Where is K+ absorption in the GI tract?
In the distal colon only. Exchanged with hydrogen at surface epithelial cells.
196
What class of drug is bismuth subsalicylate and how is it administered?
A musosal protective agent, oral.
197
How is clearance calculated?
Urine flow X urine concentration / Arterial plasma (must make sure plasma concentration is constant) mL/min units.
198
How is calcium reabsorbed in the kidney?
In the proximal tubule and the thick ascending loop of henle, there is an apical calcium channel, and a basolateral Ca++/3Na+ exchanger and a Ca++/2H+ ATPase.
199
How do you calculate amount filtered?
GFR X Pa
200
What is a phosphate buffer good for?
In ECF, bad in erythrocytes.
201
What does phospholipase A do?
Cleaves FAs from glycerol (A2 can release arachidonic acid from PI or PE).
202
What is the primary function of the large intestine?
Resorbtion of water and salts.
203
What is acrodermatitis enteropathica?
A defect in zinc absorption. Results in inflammation with pimples, diarrhea, abnormal nails. Congenital form is chromosome 8 SLC39A mutation.
204
What are osmotic laxatives good for?
Clearing for imaging procedures.
205
What epithelium lines the stomach?
Simple columnar.
206
What is manganese needed for?
Many enzymes - ATPases, arginase, pyruvate carboxylase, peptidases, etc. Important in healthy bones and cartilage, metabolism and reproductive functions.
207
How are protein/peptide hormones metabolized?
Quickly - act fast and are secreted quickly, fast on and fast off.
208
Which vitamins can have toxicity?
A (Retinal), D (Cholecalciferol), K (Quinone), B3 (Niacin), B6 (Pyridoxine).
209
List the parietal cell channels.
210
What are the adverse effects of mineral oil?
Impaired absorption of fat-soluble vitamins, pneumonitis upon aspiration.
211
How does increased afferent arteriolar resistance affect GFR and RPF?
Decreases both. Decreased filtration.
212
How is Metachromatic Leukodystrophy (MLD) inherited and what are the symptoms?
Autosomal recessive. Difficulty walking, muscle wasting, blindness, convulsions, dysphagia, paralysis, dementia (infantile or juvenile), psychiatric disorder (in adults).
213
When in the esophagus is it adventitia and when is it serosa?
Adventitia in the thorax, serosa in the abdomen.
214
What are globosides?
Ceramides with more than one sugar in a linear linkage.
215
How many grams of protein generate how much urea?
3g protein to 1g urea.
216
Is the muscle sensitive to glucagon?
No.
217
How does sucralfate work and what is it best used to treat?
It is negatively charged and binds to positively charged proteins on ulcerated tissue. It is best as a short term therapy for duodenal ulcers, also reduces incidence of upper GI bleeding in critically ill patients.
218
How much water and salts reabsorption is done in which parts of the kidney tubular system?
2/3 in proximal tubule, 1/3 in distal.
219
What is a normal standard bicarbonate?
24
220
Describe the hepatic acinus.
Blood from each acinus supports two or more classic lobules. It emphasizes the different oxygen and nutrient contents of blood. The closer to the central vein the lower the oxygen content - periportal, mid-zonal, centrilobular spaces.
221
What are the food sources of Vitamin D (Cholecalciferol)?
Fatty fish, liver, egg yolk, milk (if fortified). Gotten from diet as ergocalciferol, can be made in the skin.
222
What are plasmalogens?
Similar to phospholipids except the end FA group has an ether linkage and a double bond rather than an ester linkage.
223
How much energy is obtained from protein?
4kcal/g
224
Describe the functions of Vitamin B5 (Pantothenate).
Part of CoA, coenzyme in FA synthetase.
225
What is Olestra?
An 8 FA indigestible disaccharide.
226
What are some adverse effects of Cimetidine?
Inhibits several enzymes of the hepatic cyt p450 metabolism pathways. Inhibits binding of DHT to androgen receptors and inhibits estradiol metabolism - gynecomastia, loss of libido, impotence.
227
Where are aminopeptidases made and as what zymogen? What does it target?
Made in IC compartments and have no zymogen. A brush border enzyme. Target is amino terminal peptide bonds.
228
Desribe fatty acid synthesis.
Acetyl CoA is turned into Malonyl CoA using Acetyl CoA carboylase. Then the FAS enzyme cysteine site is primed with a starter chain, and the malonyl CoA is added to the ACP on the pantethiene arm of the enzyme. A condensation reaction adds the starter chain to the malonyl CoA (one CO2 lost). THen there is a reduction with ketoreductase, a dehydration, and a reduction with enoyl reductase (each reduction is at the cost of an NADPH). The new chain is translocated to the enzyme Cys-SH and everything is repeated until there is a saturated 16 carbon palmitate.
229
How does bile go from the canaliculi?
Interlobular ducts, septal ducts, lobar ducts, R&L hepatic ducts.
230
What are the trace elements?
Fe, Zn, Cu, Mn.
231
How frequently does the proximal colon do mass peristalsis?
1-3x a day. May move the contents 20cm or more.
232
Are all size fatty acids made into chylomicrons?
No, just ones 14-18 carbons. Small and medium FAs just go to the liver.
233
When insulin drops, what tends to last longer, glucose or chylomicrons?
Chylomicrons.
234
What lipid does E. coli not have in its membrane?
Cholesterol.
235
How is lactose intolerance diagnosed?
With the H2 test (exhaled in breath in the case of lactose intolerance).
236
In Fabry disease, what enzyme is defective and what accumulates?
Defective - alpha galactosidase A Accumulates - globosides in eyes, kidneys, cardiovascular, autonomic NS.
237
What sort of transporter are peptide transporters usually?
Antiports using H+, Na+, K+ and their counter ion.
238
What are the food sources of Vitamin B12 (Cobalamin)?
Animal products.
239
How is Tyrosine degraded/metabolized?
1) Transaminated to p-hydroxyphenyl pyruvate. 2) Turned into homogentisate via p-hydroxyphenyl pyruvate oxidase. 3) Turned into maleylacetoacetate via homogentisate oxidase. 4) Isomerized to fumarylacetoacetate. 5) Turned into fumarate and acetoacetate via fumarylacetoacetate hydrolase.
240
Where is the Myenteric/Auerbach's plexus located?
In the muscularis externa.
241
What are the functions of Vitamin K (Quinone)? WHat is the active form?
K1/phylloquinone is found in plants, K2/menaquinone, K3/menadione is synthetic. It acts as a substrate for gamma-glutamyl carbozylase which matures clotting factors II, VII, IX, X.
242
How can you tell apart gallbladder and hepatic bile? How much gallbladder bile is secreted every day?
Hepatic bile is yellow-green, gallbladder is dark green - osmotically similar but just less Cl- and typically with more green bile acids. The gallbladder secretes ~50mL of bile a day.
243
What follows what in absorption?
Chloride follows sodium, water follows NaCl
244
What is the parasympathetic and sympathetic control of the colon?
Vagal and sacral PNS fibers, SNS fibers are mesenteric and hypogastric plexi.
245
Where is carboxypeptidase A made? Where does it act? What does it target?
Made in the acinar cells of the pancreas. Acts in duodenum. Targets c-term of aliphatic and aromatic AAs.
246
What effects do dietary fiber have?
Decreases absorption of dietary fat and cholesterol, delays gastric emptying, generates feelings of fullness, reduces post prandial blood glucose.
247
What affect does aspirin have on the GI system?
Reduces bicarbonate secretion.
248
What % of the GFR does ADH regulate?
20%.
249
How is arterial pressure related to urine volume?
Increased because blood flow from the vasa recta increases.
250
What class of drug are bisacodyl and senna and how is it administered?
A stimulant laxative. Oral.
251
What does phospholipase D do?
Cleaves the headgroup in a glycerophospholipid after the phosphate. Found primarily in plants.
252
How does glutamate contribute to the urea cycle?
Converted to glutamine via glutamine synthetase in the tissues. Glutamine then goes to the liver and releases nitrogens via glutaminase to go to urea (regenerates glutamate).
253
How is Vitamin B12/Cobalamin absorbed?
Initially bound to salivary transcobalamin I, then in stomach it binds IF and after absorption is swapped onto transcobalamin II and carried through the blood with it.
254
What is the average male and female BMR?
1 and 0.9 kcal/kg/hr
255
What is gastric accommodation and receptive relaxation.
Vagally mediated fundus gastric wall relaxation in the cephalic phase (before swallowing) and gastric phase (after food is swallowed) respectively.
256
In which parts of the small intestine is cobalamin/B12 absorbed?
Terminal ileum.
257
What is cobalt needed for? Where is it found? What can deficiency cause?
Needed in B12. Found in meat and dairy. Deficiency can lead to pernicious anemia.
258
What does AST do?
Transfers a nitrogen from Glu to oxaloacetate, making Aspartic Acid.
259
What does magnesium hydroxide treat?
GERD, PUD, acid peptic diseases. Also good for imagine procedures.
260
Does the GI tract net ingest or net secrete liquid?
Secrete.
261
What does the Myenteric/Auerbach's Plexus control?
GI motility.
262
What are primary cilia?
SOlitary projections found on almost all eukaryotic cells, immotile, act as antennae. In the kidney they are the primary sense for fluid flow coming out of the collecting tubule.
263
Describe a deficiency in Vitamin B2 (Riboflavin).
Deficiency is rare, more common in alcoholics. Assayed in urine. Causes dermatitis, glossitis, cheilosis, sore throat.
264
What are mesangial cells?
They are located between capillaries in the kidney - cover capillary surfaces not covered by podocytes. The extraglomerular ones are called lacis cells.
265
How does potassium affect aldosterone?
Increased K+ concentration in plasma raises aldosterone.
266
What can Glycine be metabolized into and with what enzyme?
Oxalate, CO2 and NH3. Use of glycine cleavage enzyme.
267
What sort of cells surround salivary secretory portions?
Myoepithelial cells.
268
What is the difference between a trace element and a trace mineral?
Trace element is RDA \<100mg, trace mineral is RDA \<1mg.
269
What are some adverse effects of sodium bicarbonate?
Hypernatremia, edema, heart failure exacerbation.
270
How is arachidonic acid turned into prostaglandin G2 and leukotrienes?
COX1 and COX2 convert it to prostaglandin E2 (which can be made into thromboxanes)/ Aspirin blocks the action of COX1 and COX2. Lipoxygenase will convert it to leukotrienes.
271
How is nitrogen carried back to the liver and kidney?
Via alanine and glutamine. Muscle preferably sends Ala, most peripheral tissues send Gln. Alanine goes straight to the liver, Glutamine can be broken to Alanine in the intestine, or the kidney can just use Glutamine for energy.
272
List the pancreatic acinar and ductal cell channels.
273
Describe a Vitamin B5 (Pantothenate) deficiency.
There is no deficiency of B5.
274
What things comprise the renal lobule?
The medullary ray and cortical labyrinth.
275
What enzymes does a deficiency in biopterin metabolism affect?
Tyr, Trp, Phe hydroxylase.
276
What are the functions of 'Vitamin' B4 (Choline)?
Needed in acetylcholine, phosphatidylcholine synthesis, source of methyl groups for 5-adenosylmethionine.
277
In Krabbes disease, what enzyme is defective and what accumulates?
Defective - beta galactosidase Accumulates - galactocerebroside. Presence of globoid cells, breakdown of myelin in nerves, destruction of brain cells.
278
How does RPF affect GFR?
If it increases, GFR increases.
279
What class of drugs are docusate and mineral oil and how are they administered?
Stool softeneres, oral and rectal.
280
Where does the migrating motor complex begin?
In the proximal stomach.
281
Where is elastase made and where does it act? What does it target?
Made in the acinar cells of the pancreas. Acts in duodenum and jejunum, target is the c-term of any hydrophobic AA.
282
What are the layers of the ureter?
Urothelium, basal lamina, muscularis mucosa, serosa (simple squamous epithelium).
283
Where do the pancreatic acinars drain into? How are those things lined?
Centroacinar cell into intercalated duct (squam or cuboidal) into intralobular duct (cuboidal) into small and then large interlobular ducts (columnar) then into the main pancreatic duct (of Wirsung) (cuboidal).
284
How do prostaglandins affect the GI system?
Inhibit parietal cells. Decreases acid.
285
What is the difference between mucus made by mucus neck cells in the neck and base?
Neck ones secrete less viscous mucus than on the surface.
286
What class of drug is Esomeprazole and how is it administered?
PPI, oral, IV. IV given as prodrug, oral as acid-resistant enteric coated formulation.
287
What is the position of things when the bolus of food is in the mouth and then the pharynx?
Mouth - nasopharynx closed, tongue up and back. Pharynx - larynx pulled up against epiglottis, UES relaxed.
288
What is the specific target of pancreatic alpha amylase?
alpha 1-\>4 glycosidic linkages in amylose. Product is maltose and smaller starches.
289
Where do water and lipid soluble things go once they're absorbed from the intestines?
Water soluble goes to blood. Lipid soluble are packaged into chylomicrons to join the lymph.
290
What are the cells of the ascending thick loop of Henle like?
Identical to distal tubule, simple cuboidal, no microvilli, lumen larger and 'emptier' than proximal tubule, has modified region called Macula Densa (taller).
291
Where does the urea cycle take place (what organ and what part of the cell)?
In the liver in the mitochondria, but citrulline is sent to the cytosol.
292
What are some adverse effects of magnesium hydroxide?
Diarrhea.
293
What is cardiolipin?
A 4 FA lipid with a polar head that is made in the mitochondria and makes membranes permeable to ions.
294
What are the inhibitory substances in the digestive system smooth muscle?
Vasoactive Intestinal Peptide (VIP), NO. NO made by myenteric inhibitory motor neurons. NorE can also inhibit smooth muscle contraction but the ENS neurons typically do not use it.
295
What class of drug is sodium bicarbonate and how is it administered?
Antacid, oral.
296
What is the lining of the salivary interlobular ductal system?
Variable, but right before emptying into the oral cavity, the main duct if each gland is stratified squamous nonkeratinized epithelium.
297
How is Gaucher's inherited and what are the symptoms?
Autosomal recessive. Hepatosplenomegaly, mental retardtion in type 2 and 3, skeletal disorders and anemia in type 1.
298
What is Hirschprung's disease?
The absence of parasympathetic cells in the myenteric and submucosal plexus of the distal colon/rectum. (due to the arrest of the migration of neural crest cells). This leads to an aganglionic region that cannot relax - functional colonic obstruction.
299
Describe high flow rate pancreatic juice.
Mostly from ducts, high in bicarbonate and low in Cl-.
300
Where does the liver get its blood supply?
From all of the abdominopelvic GI prgans and the spleen. It gets 1/4 of the body's cardiac output.
301
What class of drug is methylcellulose` and how is it administered? How does it work?
Bulk-forming laxative, oral. Is indigestible colloids and fibers that absorb water - forms a bulk and distends the abdomen.
302
Does the large intestine have a muscularis mucosa?
Yes.
303
What is the renal corpuscle?
The glomerulus and Bowman's capsule. It has a vascular pole where the arterioles enter/leave, and a urinary pole where the PCT begins.
304
What are the functions of Vitamin B2 (Riboflavin)?
Redox cofactor in many enzymes in the form of FMN, FAD - typically remains tightly bound to the enzyme. E.g. succinate dehydrogenase, NADH dehydrogenase.
305
What are the cutoffs for hypo and hyperkalemia?
\<3.5 and \>5.0.
306
What is the portal triad that all the portal canals contain areas of?
Portal vein, hepatic artery, bile duct.
307
What does angiotensin II do?
A vasoconstrictor, causes release of aldosterone, causes thirst, causes release of ADH.
308
What is the primary salivary secretion?
Made by acinar cells, found in acinar lumen. Ions are similar to plasma, contains some proteins.
309
Where is CCK made?
I cells found mainly in the duodenum and duodenum.
310
Where is motilin made?
M cells in the duodenum and jejunum.
311
How does licorice affect kidney metabolism?
It has glycyrrhetinic acid, which is an inhibitos of 11beta-HSD2.
312
What is the space of Mall?
The periportal space between the CT and hepatocytes, where lymph originates.
313
How is Krabbes inherited and what are the symptoms?
Autosomal recessive. Mental and motor deterioration, irritability, fever, seizures, vomiting, weakness, feeding issues, deafness, blindness. Presence of globoid cells, breakdown of myelin in nerves, destruction of brain cells.
314
What comprises the juxtaglomerular apparatus?
The Macula Densa, Lacis cells, and Juxtaglomerular cells (in aferent arteriole, secrete renin).
315
What is the motility pattern the SI in the fasting state?
90-120 min pattern of virtually no activity followed by a short intense peristalsis (migrating motor complex).
316
Describe the urea cycle.
Bicarbonate and ammonia converted to carbamoyl phosphate via carbamoyl phosphate synthetase I. Costs 2 ATPs. With ornithine and via ornithine transcarbamoylase, CP is made to citrulline. With aspartate and via arginosuccinate synthase, arginosuccinate is made. Costs 2ATPs. Via arginosuccinate lyase, fumarate and arginine are made. Arginine is then added to water and converted to ornithine and urea.
317
What are some adverse effects of calcium carbonate?
Hypercalcemia, cnostipation, hypophosphatemia, milk-alkali syndrome (alkalosis, hypercalcemia, renal insufficiency).
318
Where is the water processed in salivary glands?
All in the acini. Ducts have tighter junctions than acini.
319
.What does a lack if iron/hemoglobin result in?
Microcytic hypochromic anemia.
320
Describe manganese deficiency. Can there be a toxicity?
Deficiency can cause osteoporosis. There can be toxicity.
321
What is reabsorbed in the thick ascending loop of Henle?
Na+, Cl-, calcium.
322
How are phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol synthesized?
G3P is made from DHAP (or straight from glycerol in the liver) then 2FAs are added to make phosphatidic acid (DAG phosphate). Phosphatidic acid can also be converted to DAG. Either the lipid or the headgroup are primed with cytidine triphosphate.
323
What are the four layers of the gut tube?
Mucosa, submucosa, muscularis externa, adventitia/serosa?
324
How is thirst and salt hunger regulated?
By the hypothalamus - osmolarity must increase by over 4mosm/L. Salt hunger also regulated by the hypothalamus, thirst developed immediately but salt hunger over hours or days.
325
What is the functional unit of the kidney?
Uriniferous tubule (nephron + collecting duct).
326
What are the functions of Vitamin C (Ascorbic Acid)?
It functions as an antioxidant, and is required as a coenzyme to hydroxylate Pro and Lys in collagen. Required in carnithine, NorE, and bile acid synthesis.
327
Are the IAS and EAS voluntary or involuntary?
IAS is involuntary, EAS is voluntary.
328
What is the effect of Vitamin D on salt absorption?
Increases calcium reabsorption in the kidney and interstitium, increases deposition of calcium in newly formed bone.
329
What are the food sources of Vitamin C (Ascorbic Acid)?
Many fresh fruits and vegetables.
330
What is hyperphenylalanemia?
A deficiency in any BH4 synthesis enzyme or in dihydropteridine reductase. Decreaed formation of catecholamines and serotonin.
331
What are the natriuretic peptides? Where are they made?
ANP (atrium), BNP (kidney), urodilatin (CD), uroguanylin and guanylin (SI).
332
What is the mucosa like in the pylorus of the stomach and what cell types are there?
Deep pits and short glands (coiled). Mucus secreting cells are predominant, G cells, D cells.
333
Where is chymotrypsin made and what is its target?
The acinar cells of the pancreas. ALpha is the active form, pi can cleave. Phe, Trp, Tyr.
334
Describe the submucosa of the small intestine.
Includes Meissner's Plexus. Duodenum has Brunner's Glands, ileum has Peyer's patches covered by M (microfold) cells.
335
What is Autosomal Dominant Polycystic Kidney Disease.
Primary cilia can no longer detect fluid dlow so the cell forms bigger tubules, eventually cysts form. Symptoms between 30-40 years of age.
336
What class of drug is erythromycin and how is it administered?
A prokinetic drug, oral, IV.
337
Describe the mucosa of the large intestine.
Simple columnar epithelium, no villi just crypts, no plicae circularis. Goblet cells, EECs, SCs, lamina propria (cellular, prominent lymphocytes, scattered nodules).
338
What is reabsorbed and secreted in the second half of the proximal tubule?
Potassium (80%), NaCl, water, calcium reabsorbed. Anions secreted.
339
What class of drug is lubiprostone and how is it administered?
Chloride channel activator laxative, oral.
340
In which parts of the small intestine is iron absorbed?
Duodenum.
341
What class of drug is sucralfate and how is it administered?
Mucosal protective agent, oral.
342
What does the gallbladder reabsorb?
NaCl and water.
343
How is H+ excreted in urine?
HPO4- filtered from the blood can react with some excreted H+ and make H2PO4 which is excreted 40mmol/day. Or inside the cell glutamine can release NH4+ which becomes NH3 and H+, which both leave and make NH4+ again ni the lumen (20-40mmol/day).
344
What kind of glands are in circumvallate papillae?
Serous Von Ebner's glands.
345
What percent of secreted bile acids and salts are returned ot the liver on each pass?
95%. About 20% of the bile acid pool is replaced every day through synthesis of new bile acids.
346
What is zinc needed for?
300+ proteins including DNA Polymerase, Carbonic Anhydrase, carboxypeptidase, DNA regulatory proteins, Superoxide dismutase.
347
How much bile reaches the duodenum?
~500mL
348
Describe a Vitamin E (Tocopherol) deficiency.
Rare but can occur in newborns before they have developed their own stores, otherwise it would be due to poor absorption of chylomicrons.
349
What is the fate of fumarate?
Converted to malate, then oxaloacetate, then aspartate.
350
Where is the Meissner's plexus located?
In the submucosa.
351
In what foods is selenium found?
Nuts, cereals, meats, mushrooms, fish, eggs/
352
Does the stomach have adventitia or serosa?
Serosa.
353
What is a ceramide (not the group, the lipid).
A ceramide group, with a linear chain of sugars starting with glucose.
354
What are the dietary sources of zinc?
Seafood, eggs, meat, legumes, cereals.
355
What do lipases break triglycerides into?
Two fatty acids and a monoglyceride.
356
Where is carboxypeptidase B made? Where does it act? What does it target?
Made in the acinar cells of the pancreas. Acts in duodenum. Targets c-term of Basic AAs.
357
How does erythromycin work? What is it good for treating?
Stimulates motilin on the GI smooth muscle. Good for before an endoscopy, gastroparesis. It is also an antibiotic.
358
What percent of the diet should be carbs? How many grams?
45-65%. Should be \>130g/day.
359
What happens to carbs that weren't digested in the small intestine?
In the large intestine, enterobacteria help break them down (indigestible carbs) to short chain fatty acids which are absorbed by the colonic mucosa.
360
How is Fabry Disease inherited and what are the symptoms?
X-linked. Kidney failure, heart failure/stroke, burning in hands, red-purple skin rashes.
361
What does CCK do?
Acts on gallbladder smooth muscle and makes it contract and secrete bile,acts on pancreatic acinar cells and stimulates pancreatic enzyme secretion. Also acts on ANS sensory neurons and causes pylorus constriction and gallbladder contraction (ACh) and Sphincter of Oddi relaxation (VIP) - reduces gastric emptying and increases concentrated bile secretion. Reduces gastric secretions (parietal cells?)
362
Describe myogenic kidney autoregulation.
Increased perfusion causes stretch in the smooth muscle, calcium enters via the stretch channels, influx causes constriction.
363
What is the recommended iron intake?
Males 8g, females 18g.
364
Where are stem cells in gastric pits?
The neck region.
365
What vitamins/things does hte liver store?
Vitamin A, D, B9, B12, glycogen, iron.
366
How do systemic capillaries allow for filtration and reabsorption?
Pc drops significantly along the capillary.
367
Describe Vitamin A (Retinol) toxicity.
Dry skin, enlarged and eventually cirrhotic liver, increaesd intracranial pressure.
368
What is the contraction pattern of sphincter smooth muscle?
Normally contracted, relaxes for a short burst.
369
What does the small intestine mucosa look like in Celiac's disease?
Flattened villi.
370
What is Zellweger syndrome?
A peroxisomal assembly issue "empty peroxisomes". VLCFAs are not oxidized. Adrenal insufficiency, reduction in plasmalogens, white matter insufficiency.
371
What does renin do?
Activates angiotensinogen to angiotensin I. ACE converts ATI to ATII.
372
Does the gallbladder have serosa or adventitia?
Adventitia when it's in contact with the liver.
373
What class of drug is pancrelipase and how is it administered?
A prokinetic drug, oral.
374
What hormones to ECL cells respond to?
ACh and Gastrin.
375
How do free bile acids enter hepatocytes?
With a sodium dependent transporter (secondary active transport).
376
Where in the body can bile salts be deconjugated?
In the small intestine, by bacteria.
377
What do sulfonamates do?
Interfere with B9 synthesis in bacteria.
378
What is the maximum human urine concentrating ratio?
5X
379
What is medium chain AcCoA desaturase deficiency?
An autosomal recessive condition. Medium chain AcCoA desaturase is used in all fatty acid processing. It causes sudden death, hypoketotic hypoglycemic state, seizures, coma at 2 months - 6.5 years.
380
Of the water-soluble vitamins, which are considered hematopoietic?
B9 (Folate) and B12 (Cobalamin).
381
What is in the lumen of pancreatic acini?
Centroacinar cells that form the beginning of the duct system. They are a distinguishing characteristic of this gland.
382
How much fluid does the small intestine secrete per day?
~1L a day.
383
Describe the portal lobule.
A triangle with a central vein at each vertex. Each triangle is drained by a single bile duct. It emphasizes exocrine areas and flow of bile.
384
How do you calculate the amount excreted?
Urine flow rate X urine concentration.
385
What are the functions of Vitamin B12 (Cobalamin)? What is the active form?
Common in -CN, CH3, -deoxyadenosyl forms. Required only for methionine synthase (get 5-methyl THF to THF) and methyl malonyl CoA mutase.
386
What is orlistat?
A competitive inhibitor of most lipases.
387
How does misoprostol work and what is it best used to treat?
It is an analog of PGE1 - an agonist of prostaglandin receptors (EP3 on parietal cell). It stimulates mucus, electrolyte, bicarbonate, and fluid secretion, enhances mucosal blood flow, reduces histamine-stimulated cAMP production and gastric acid secretion, stimulates intestinal motility, stimulates uterine contractions. It is best used to treat as a prophylactic for NSAID-induced ulcers.
388
How is Phenylalanine metabolized?
Made into Tyrosine via phenylalanine hydroxylase. Needs tetrahydrobiopterin and O2.
389
How is cholesterol made into primary bile acids?
Double bond on the B ring is reduced, 3 carbons removed from the hydrocarbon chain, carboxyl group introduced at the end of the chain.
390
How does cortisol not cause aldosterone effects? They're similar compounds.
We have 11beta-hydroxysteroid dehydrogenase 2 which metabolizes cortisol. A deficiency may mimic mineralocorticoid excess.
391
What are enterogastrones?
Peptide hormones secreted by the duodenum to inhibit gastric function.
392
How do the islets of Langerhans stain in the pancreas?
Light.
393
What is arachidonic acid?
Linoleic acid has 2 carbons and 2 double bonds added. to make it. Arachidonic acid is typically bound to the middle position of phospholipids and typically releaed in response to PLA2.
394
What do peritubular capillaries do?
Absorption and secretion.
395
What do glomerular capillaries do?
Only filtration.
396
List the salivary acinar and ductal cell channels.
397
Describe the structure of FAS (Fatty Acid Synthase).
Giant, has an acyl carrier protein domain covalently bound to a long phosphopantathiene arm.
398
How is a bile salt made from a bile acid?
Amide bond added - conjugated to glycine or taurine or to sulfate or glucuronate.
399
How much fluid does the pancreas exocrinely secrete per day?
~1.5L
400
What class of drug is aluminum hydroxide and how is it administered?
Antacid, oral.
401
What is the relationship between urine excretion rate and urinosmolality?
Inverse.
402
Where is GIP made?
K cels in the duodenum and jejunum.
403
What does larynx/hypopharynx pepsin exposure in the absence of low pH result in?
The upregulation of inflammarion, may lead to tumours.
404
What are free fatty acid bound to in the blood?
Albumin.
405
How does platelet activating factor (PAF) differ from plasmalogen structure?
Has no double bond and the middle FA is replaced by acetate.
406
What are cerebrosides?
Ceramides with a single sugar residue (usually glucose or galactose).
407
What are the two important bile salts to know?
Glycocholic acid, taurochenodeoxycholic acid.
408
What is PDCAAS?
Protein digestibility corrected amino acid score - the proportion of amino acids that are needed by the body. 1.0 is the highest. Gelatin and plants have a poor score.
409
What do the natriuretic peptides do?
Dilate the afferent arteriole and constrict the efferent (increased GFR). Decreased aldosterone action, decreased sodium absorption, inhibition of water absorption by decreasing ADH action and release.
410
What is a common cofactor for aminotransferases?
B6.
411
Which amino acids go through propinoly CoA in their degradation?
Val, Ile, Met, Thr.
412
What are the types of nephrons?
Cortical (6/7) and juxtamedullary (1/7).
413
How does too little propulsion in the colon affect stool?
Too-hard stools.
414
In Metachromatic Leukodystrophy (MLD), what enzyme is defective and what accumulates?
Defective - arylsulfatase A Accumulates - sulfatides in liver, kidney, nervous system
415
Describe the kidney filtration apparatus.
In the bowman's space, the pore of the glomerular endothelial cell + the discontinuous basal lamina + the slit in the membrane between Pedicels. The filtration slits are covered in nephrin (hooked to an IC signalling pathway that communicates with the Podocyte).
416
How does PLA2 act on lecithin?
Makes FAs and lysolecithin.
417
How are amino acids broken down?
First a nitrogen is transgered to an alpha-ketoglutarate by aminotransferase, making glutamate. The nitrogen can be released as ammonia by glutamate dehydrogenase (uses an NADP or an NADPH).
418
What are some causes of hypokalemia?
Cell shifts, diarrhea, vomiting, direct renal loss (increased mineralocorticoid activity, increased distal sodium delivery), alkalosis.
419
What are the food sources of Vitamin B3 (Niacin)?
Unrefined grains, milk, lean meat, liver.
420
What are the food sources of 'Vitamin' B4 (Choline)?
Trick question! Not a real vitamin, is made de nobo.
421
How much dietary fiber should be obtained per day in the diet?
25-35g
422
What are the food sources of Vitamin B7 (Biotin)?
Yeast, liver, eggs, peanuts, milk, chocolate, fish.
423
When are AST and ALT elevated?
In liver disease. Also both are elevated in MI, muscle disorders. ALT is somewhat more specific for liver disease.
424
What are the qualities of a good buffer?
pH and pKa difference less than 1.3, high concentration.
425
Where is pepsin made and what is its target?
The chief cells of the stomach. N-terminal of aromatic aas.
426
What digestive hormones/substances stimulate the AC pathway?
VIP, Prostaglandin, Histamine, Secretin (CCK2), Gastrin (CCK2).
427
What is pancrelipase good for treating?
Pancreatic insufficiency - can be caused by CF, pancreatic resection, chronic pancreatitis.
428
What comprises the nephron?
Glomerulus (filters blood, makes ultrafiltrate) and tubular sustem (PCT, LOH, DCT) (filters ultrafiltrate, makes urine).
429
Describe beta oxidation.
Acyl CoA dehydrogenase oxidizes the FA (creating an FADH2) into enoy-CoA (2-trans, unsaturated). Next an enoyl-CoA hydratase turns it into 3-hydroxyacyl CoA. 3-hydroxyacyl CoA dehydrogenase oxidizes (makes an NADH) and turns it into 3-ketoacyl CoA. 3-ketoacyl CoA thiolase removes the Ac CoA.
430
What kind of ingested fats affect the serum cholesterol and how?
Saturated and trans increase, unsaturated decrease.
431
What does secretin do?
Target pancreatic acinar cells and ducts, gallbladder bile ducts - increases secretion of bicarbonate (increases glalbladder bile secretion?)
432
How is urea processed in the kidney?
50% reabsorbed in proximal tubulr, 60% secreted in LOH (UT2), 70% reabsorbed in CD (UT1). ~40% excreted.
433
In Niemann-Pick disease, what enzyme is defective and what accumulates?
Defective - sphingomyelinase Accumulates - sphingomyelin in spleen, liver, lungs, brain, bone marrow
434
Where is gastrin made?
In G cells - most in the antrum of the stomach but some in the duodenum.
435
In glomerular capillaries, how is there such high filtraton?
Pc stays constant but pic increase (though never past Pc).
436
What is the urine osmolarity by the end of the collecting duct?
Approaches the osmolarity of the IF in the deepest part of the medulla (~900-1100mosm/L).
437
What is Addison's disease?
When you can't make aldosterone.
438
What are the adverse effects of PPIs?
Reduced B12, increased rick of hip fracture for \>1 year PPI therapy (possibly due to decreased calcium absorption), increased risk of community acquired respiratory infections/nosocomial pneumonia, increased risk of ECL and parietal hyperplasia in \>2 year PPI therapy.
439
Describe Vitamin B3 (NIacin) deficiency.
Pellagra - dermatitis, diarrhea, dementia, death, sun sensitivity. It is poorly absorbed from maize unless the maize has been treated with lye.
440
What is the epithelial lining of the rectum and anus?
Upper 1/2 of rectum - simple columnar, lower 1/2 of rectum - stratified squamous non keratinized, anus - stratified squamous keratinized.
441
What is diabetes insipidus?
ADH deficiency.
442
How is Farber disease inherited and what are the symptoms?
Autosomal recessive. Impaired motor and mental ability, dysphagia, arthritis, swollen lymph nodes and joints, hoarness (infantile).
443
What is bismuth subsalicylate used to treat?
H. pylori, dyspepsia, diarrhea.
444
What are the functions of Vitamin A (Retinol)? What is its active form?
Found as retinol, retinoic acid, retinal, beta-carotene. Retinol and retinoic acid act as transcription factors. It is critical for epithelial cell development, mucus secretion, spematogenesis. Retinal is a bound cofactor to rhodopsin - important in vision. Retinoic acid can treat psoriasis and acne.
445
What are the purely ketogenic essential amino acids?
Ile, Phe, Trp.
446
What percentage of transporter defect diseases are due to amino acid malabsorption?
60%.
447
Describe the Bowman's space.
Has a parietal layer (simple squamous) and visceral layer (Podocytes).
448
What are the four steps of processing for secretion in hepatocytes?
Uptake from basolateral blood, transport within cell, chemical modification, secretion through apical membrane.
449
How do stool softeners work?
Allows water and lipids to penetrate stool, prevents water loss.
450
What does gastrin do?
Stimulates ECL (enterochromaffin-like) cells to secrete histamine, and parietal cells to secrete HCl-rich juice. This increases gastric motility but also pyloric constriction.
451
How is Methionine and Serine metabolized?
Serine is added to homocysteine and via cystathione synthase (B6), cystathione is made. Cystathione is degraded via cystathioninase into cysteine and alpha-ketobutyrate. alpha ketobutyrate made into propionyl-CoA, Cysteine made into pyruvate and sulfite is released.
452
Describe zinc deficiency.
Loss of taste (dysgeusia), anosmia, poor wound healing, peroral rash.
453
Describe a Vitamin K (Quinone) deficiency.
Unusual, can occur in newborns (usually get a shot of Vitamin K), can result in clotting disorders.
454
Describe a Vitamin B6 (Pyridoxine) deficiency.
Rare but can occur with alcoholics, infants with deficient formula, women on oral contraceptives. Glossitis, dermatitis, sideroblastic anemia.
455
Where is the swallowing center? What's it stimulated by?
Medulla and lower pons. Touch receptors in the oropharynx.
456
What are the transporters involved in small intestine amino acid absorption?
Apical sodium/AA symporter, PepT1 H+/di or tri peptide symporter, basal channel bringing out amino acids (peptides digested inside cell).
457
How is total metabolic energy calculated?
BMR + thermic effect of food (5-10% BMR) + physical activity (light is 30-50% BMR, active is 100% BMR, can be up to 800%).
458
What are the renal effects of Angiotensin II?
Constricts both the afferent and efferent arterioles in the kidney. Decreases RBF, increases filtration fraction, increases peritubular osmotic pressure but decreases peritubular hydrostatic pressure. Increases sodium reabsorption in the proximal tubulr, decreases renal sodium and water excretion. Also decreases medullary blood flow (and so also washout), increasing medullary solutes. Lowers the set point of TGF. Promotes sodium reabsorption in the proximal tubule, thick aLOH, and early CT.
459
What is the regulated step in cholesterol synthesis?
HMG CoA (made from Ac CoA) being made into mevalonate by HMG CoA reductase.
460
What can Threonine be metabolized into?
Pyruvate, Succinyl-CoA (via propionyl-CoA), can be made into Glycine and AcCoA.
461
Describe the cells in the mucosa of the small intestine.
Simple columnar absorptive enterocytes (striated brush border with microvilli, decrease in frequency towards LI, coated in glycocalyx). Goblet cells (increase in frequency towards LI). EECs (D cells, EC cells, G cells, S cells, I cells, K cells). Paneth cells (base of crypts). Stem cells.
462
When is it adventitia and when is it serosa?
Adventitia when the outer layer is attached to the surrounding tissue. Serosa when the outer layer is adjacent to the peritoneal cavity.
463
What is the sodium concentration in gastric juice at different flow rates?
High at low flow, low at high.
464
Describe the two muscle layers and how they act in peristalsis when there is a bolus.
Oral to bolus - circular SM contracts, longitudinal SM relaxes. Anal to bolus - circular SM relaxes, longitudinal SM contracts.
465
What are the dietary sources of copper?
Meats, shellfish, nuts, cereals.
466
What is GIP's signal?
Carbs, proteins, lipids in the intestinal lumen.
467
What does the early distal tubule reabsorb and secrete?
Reabsorbs NaCl, can secrete potassium if necessary.
468
How do fatty acids enter the mitochondria?
First they enter the cell and immediately have a CoA added. THen they diffuse into the OM and CPTI exchanges carnithine for CoA, creating FA-carnithine. On the IM, CPTII brings FA-carnithine in.
469
Wheat are the phases of the migrating motor complex?
I - quiescent, little activity II - increasing activity III- peak electrical/mechanical activity IV - declining activity transitioning into quiescence
470
What is intrinsic and extrinsic control of the digestive system?
Intrinsic control is when it's 100% mediated by the enteric NS "short loop", extrinsic control is when the autonomic system is involved (can completely override the ENS) "long loop".
471
Where is isomaltase made, where does it act, and what is the specific target?
Made in enterocytes, acts in SI. Targets alpha 1-\>6 glycosidic linkages in starch, product is maltose.
472
Which part of the distal tubule is permeable to water?
Late.
473
What are primary vs secondary bile acids?
Primary is made by hepatocytes - enhances solubility, allows for 'soap action'. Secondary is primary modified by intestinal bacteria (generally slightly reduces solubility).
474
What are the cells of the PCT and straight proximal tubule like?
Simple cuboidal - long, dense, apical microvilli. Boundaries between adjoining cells not clear or sharp. Many infoldings of BM and mitochondria to capacitate transporters, abundant pinocytotic pits and vesicles.
475
What are the lengths of the duodenum, jejunum, and ileum?
Duodenum - 25cm Jejunum - 2.5m Ileum - 3.5m
476
What class of drug is metoclopramide and how is it administered?
A prokinetic drug.Oral, IM, IV.
477
What is a positive and negative N balance?
A net synthesis of body protein or a net breakdown
478
What is the urine osmolarity in the proximal tubule?
Isoosmolar to plasma.
479
What are the adverse effects of misoprostol?
Stimulates uterine contractions! If given with mifepristone it will terminate a pregnancy \<70 days. Should start on 2nd or 3rd day of period.
480
What is selenium needed for? What can deficiency cause?
Oxidoreductases (can substitute sulfur) - hypothyroidism.
481
What are the food sources of Vitamin B9 (Folate)?
Green leafy vegetables, yeast, liver, fruits.
482
How much linolenic acid is needed in the daily diet?
1.1 or 1.6g
483
What is the epithelial lining of the anterior 2/3 of the tongue?
Ventral - nonkeratinized stratified squamous. Dorsal - keratinized stratified squamous.
484
Where is glucoamylase/ glucan alpha 1-\>4 glucosidase made, where does it act, and what is the specific target?
Made in brush border enterocytes, acts in SI. Targets alpha 1-\>4 glycosidic linkages of alpha 1-\>6 linkages right next to the alpha 1-\>4 ones. Produce is D-glucose.
485
What are the food sources of Vitamin B2 (Riboflavin)?
Liver, eggs, yeast, milk, enriched breads and cereals.
486
What is motilin's target?
Stimulates intense contractions in the migrating motor complex.
487
What is the effect of calcitonin on the kidney?
Inhibits calcium reabsorption in the LOH and DCT - increases calcium excretion.
488
What stimuli trigger vomiting/emesis?
Gastric/upper intestinal irritation, vestibular stimuli, gastric outlet constriction.
489
What is histidemia?
AR histidase deficiency. No clinical phenotype.
490
What is CCK's signal?
Fatty acids in the duodenal/duodenal lumen. Minorly - oligopeptides and amino acids in duodenal lumen.
491
Describe a deficiency in Vitamin C (Ascorbic Acid).
Scurvy - sore and spongy gums, loose teeth, fragile blood vessels, swollen joints, microcytic anemia.
492
Describe the muscularis externa of the stomach.
3 muscle layers - inner oblique, middle circular, outer longitudinal.
493
At what plasma osmolarity and blood volume is ADH releaed?
Plasma osmolarity \> 280, blood volume/pressure more than 10% reduced.
494
What part of the GI system is responsible for most absorption?
Small intestine.
495
What enzymes break down carbohydrates?
Salivary amylase (ptyallin) - active at pH \>4, still slightly active in fundus. Pancreatic amylase takes over. They are both alpha amylases, digest starches and glycogens into di/trisaccharides. Digestion into monosaccharides requires additional glycosidases.
496
Is the small intestine serosa or adventitia?
Serosa where it lies free in the abdominal cavity, adventitia where it is attached to the body wall.
497
What is reabsorbed in the first half of the proximal tubule?
Bicarbonate (lumen becomes more acidic), calcium, sodium, water, molecules (AAs, etc.)
498
What is special about glucose?
Totally reabsorbed, C=0 except for transport maximum.
499
Describe a Vitamin B7 (Biotin) deficiency.
Virtually unknown unless consuming raw eggs (avidin is high affinity for biotin and can deplete it). Glossitis, dermatitis, appetite loss, nausea.
500
What are the functions of Vitamin B9 (Folate)? What is the active form?
Tetrahydrofolate is the active form. Participates in 1-carbon transfer reactions.
501
What is copper needed for?
Cofactor in oxygen binding enzymes, required for cytocorome c oxidase, superoxide dismutase, lysyl oxidase, ferroxidase/ceruloplasmin, dopamine oxidase, tyrosinase (makes melanin). Important for healthy nerves and joints.
502
What % of acid secretion happens in what phases of swallowing?
30% in cephalic (mediated by vagal signals), 60% in gastric (feedback from stomach signals), 10% in intestinal (feedback from duodenal signals).
503
What is the difference between vomiting and retching?
If the UES is closed, retching occurs.
504
List the gastric mucosal barrier cell channels.
505
How much energy does the urea cycle net use or make?
Makes 1 ATP.
506
What is fractional excretion?
Cx/GFR
507
How can water reabsorption be measured with inulin?
U/Pa
508
How is Acetyl Coa moved out of the mitochondria for fatty acid synthesis to begin?
A pyruvate is turned into oxaloacetate with pyruvate carboxylase. Then Citrate is made with AcCoA and the oxaloacetate and this is exported out to the cytosol and turned back into acetylCoA and oxaloacetate at the cost of 1 ATP. The oxaloacetate is made into malate at the cost of an NADH and the malate comes back in and turns to pyruvate, generating an NADPH.
509
What is the preferred gastric drug type for severe conditions?
PPI.
510
What is the normal urine flow rate, and what is it at max diuresis and antidiuresis?
Normal = 1mL/min Max diuresis = 16mL/min Max antidiuresis = 0.3mL/min
511
What is the effect of aldosterone?
Affects the late distal tubule and collecting duct. Increases expression of apical sodium channels, permeability of those channels, ATP synthesis, and the sodium/potassium pump. Increases potassium secretion and paracellular chloride reabsorption.
512
What do the different cells in the islets of langerhans produce?
Alpha cells make glucagon, beta cells make insulin, delta cells make somatostatin.
513
How is sphingosine synthesized?
Serine and palmitoyl CoA are combined to make sphingamine (C-C bond with serine). Then a second hydrocarbon chain is added to the amine (forming and amide bond) and this makes sphingosine. The first hydrocarbon is oxidized to introduce a double bond, while another fatty acyl CoA is added (making ceramide).
514
What is the Donnan Distribution?
r. Equal to the ultrafiltrate sodium concentration over hte plasma sodium concentration, or the plasma chlorine concentration over the ultrafiltrate chlorine concentration.
515
What are the excitatory substances in the digestive system smooth muscle?
Acetylcholine, Substance P. Substance P made by myenteric stimulatory motor neurons.
516
What are the effects on fatty and acidic meals on digestion?
Slow it down - acidic meals moreso.
517
How does alkalosis affect potassium and calcium?
Increases calcium reabsorption, decreases potassium reabsorption.
518
How do pancreatic acinar cells stain?
Blue at the base (more RNA/nuclei) and pink at the amex (lots of zymogens).
519
What are adverse effects of metoclopramide? Any contraindications?
Tardive dyskinesia, also possibly depression, extrapyramidal symptoms, parkinsonian-like symptoms. GI obstruction is a contraindication.
520
What percentage of max enzyme secretion is the pancreas at at the different stages of digestion?
Cephalic - 25%, gastric - 10-20%, intestinal - 50-80%.
521
How do you calculate filtration rate/load of a freely filtered substance?
M = P x GFR
522
Does the pancreas have a capsule?
Yes it does, CT divides it into lobes and lobules.
523
Where do most secondary bile acids go?
Mostly lost in feces.
524
How much energy is obtained from fat?
9kcal/g
525
What is a glycemic index?
How quickly glucose is absorbed from a certain food.
526
What are some adverse effects of sucralfate?
Bezoar formation, constipation.
527
What are the components of bile?
Cholesterol, cholesterol-derived bile acids/salts, bile pigments (from hemoglobin), phospholipids, ions, water. It is pH 6.0-7.5
528
Where can potassium be secreted?
DCT and CD.
529
How can hyperammonemia be treated?
Benzoate (reacts with glycine to make hippuric acid), and phenybutyrate (converted to phenylacetate in body, reacts with glutamine).
530
Describe the mucosa of the esophagus.
Nonkeratinized stratified squamous epithelium, cardiac glands, thin lamina propria. Upper esophagus has no muscularis mucosa, lower has a single longitudinal layer. At the gastroesophageal junction it becomes simple columnar.
531
What are the food sources of Vitamin A (Retinol)?
Carrots, vegtables, yellow/gree/orange fruits, liver, kidney, meat, eggs, cream, butter.
532
What class of drug is calcium carbonate and how is it administered?
Antacid, oral.
533
What is an important role that glycerosphingolipids play?
They are in the PM outer membrane, play an important role in intracellular communication. ABO blood groups, essential membrane component (6% of gray matter membrane lipids).
534
What is the name of the capsule encapsulating the liver?
Glisson's capsule.
535
What are the food sources of manganese?
Grains, nuts, leafy vegetables, soy.
536
What does esophageal pepsin exposure in the absence of low pH result in?
Downregulation of protective proteins.
537
What is filtration fraction? What is the normal?
GFR/RPF. 20%
538
Are bile salts absorbed in digestion?
No, they always stay in the lumen.
539
How do the mediterranean and vegetarian diets differ from the normal recommended diets?
In the mediterranean one, there's more seafood and fruit and less dairy. In the vegetarian one it's less protein and dairy is back up.
540
What is the effect of PTH on the kidney? What stimulates PTH release?
Increases calcium reabsorption, praticularly on the LOH and DCT. Increased plasma phosphate stimulates PTH release.
541
Where do the central veins drain into?
The hepatic veins, which go into the IVC.
542
Which cells secrete erythropoietin?
Fibroblasts in the PCT between the basement membrane of the tubule and the capillary.
543
Describe a deficiency of Vitamin B12 (Cobalamin).
Pernicious anemia, later stages show neuropsychiatric symptoms.
544
What drains into the central vein?
The hepatic artery (nutrient poor, oxygenated blood) and portal vein (nutrient rich, deoxygenated).
545
How is Niemann-Pick disease inherited and what are the symptoms?
Autosomal recessive. Type A - jaundice, hepatomegaly, profound infantile brain damage. Type B - hepatosplenomegaly in teens. Type C/D - moderate splenohepatomegaly, extensive brain damage as an adult. Bone marrow transplant can be done.
546
How much hepatic bile is secreted every day?
~900mL, about half is diverted to the gallbladder.
547
What is the Henderson-Hasselbach equation?
pH=pKa + log [A-]/[HA]
548
What are the purely glucogenic essential amino acids?
His, Met, Thr, Val.
549
How do you generate 3-hydroxybutyrate and acetone from acetoacetate?
It takes an NADH to make it into 3-hydroxybutyrate, and it can spontaneously decarboxylate into acetone which cannot be metabolized.
550
Describe hemochromatosis.
Iron overload. More prevalent in older men from northern Europe - exacerbated by a mutation in the HFE gene. Liver, heart, endocrine glands affected.
551
What are the cells of the collecting duct like?
Simple cuboidal, distinct lateral boundaries. As the tube widens, the cells increase in height.
552
What is isomazid?
A tuberculosis drug that reacts with vitamin B6, lowering bioavailability.
553
What are the effects of chloride channel activators (including lubiprostone)? What are they good for treating?
Stimulate intestinal motility, shorter transit time - good for opioid induced constipation, IBS with predominant constipation, IBS with predominant constipation, chronic idiopathic constipation.
554
What do you use to determine metabolic influence in acidosis and alkalosis?
Standard bicarbonate concentration (under 40mmHg and 37C), buffer bases/base excess (total concentration of all bases).
555
What are the essential amino acids that are both ketogenic and glucogenic?
Leu, Lys.
556
How do ACh, VIP, and NO affect gallbladder bile secretion.
All increase, ACh stimulates GB muscle contraction, VIP&NO inhibit sphincter of Oddi contraction.
557
How much fluid does the small intestine absorb per day?
6.5L
558
What percent of the diet should be protein? How many grams?
10-30%. About 56g for males, 46g for females
559
What kind of secretions are in sublingual, submandibular, parotid glands?
Sublingual - mixed, mainly mucous Submandibular - mized, mainly serous Parotid - just mucous
560
All the metabolic breakdown reactions are hydration reactions.
Just a reminder.
561
What does calcium carbonate treat?
Acid peptic diseases, hypocalcemia, osteoporosis prevention, hyperphosphatemia.
562
What much happen to starches to be effectively digested?
They must be cooked!
563
How is trypsinogen made into trypsin (active form)?
Cleaved by enterokinase/enteropeptidase. Can also cleave and activate it back. It is also able to autocatalyze in the presence of bile salts or weak acid conditions (pH 5.4-7.8)
564
How is Sandhoff disease inherited and what are the symptoms?
Autusomal recessive. More severe than Tay-Sachs, also includes macrocephaly.
565
What important things is tyrosine involved in the synthesis of?
Melanin, catecholamines, serotonin.
566
What do parietal/oxyntic cells produce? In what part of the glands are they?
HCl and IF. Upper 1/2 of gland.
567
What are the transporters involved in small intestine carbohydrate absorption?
Apital GLUT5 (brings in fructose), apical SGLT1 (brings in sodium with glucose or gapactose), basal GLUT5 (sends fructose into blood), basal GLUT 2 (sends glucose, galactose, fructose into blood)
568
What is gastrin's signal?
Main is oligopeptides and amino acids in the gastric lumen (minor is the in the duodenal lumen).
569
Describe the salivary intralobular ductal system.
Acini empty into intercalated ducts (cuboidal epithelium), which join to form striated ducts (has basal striations, actively moves Na+ from saliva into the EC space).
570
In Gaucher's disease, what enzyme is defective and what accumulates?
Defective - glucocerebrosidase Accumulates - glucocerebroside in spleen, liver, lungs, bone marrow, brain.
571
How is colonic active potassium secretion stimulated?
By aldosterone (epithelial cells) or cAMP in crypt cells. There is also more secretion in dehydration.
572
Describe Vitamin K (Quinone) toxicity.
Large menadione doses can cause jaundice and hemolytic anemia.
573
What is a ganglioside?
A type of glycosphingolipid. A ceramide group, branch structure of sugars, first sugar typically glucose. Key feature is 1 or more N-acetylneuraminic acid (NANA/sialic acid) residues. It is broken down in lysosomes.
574
What are some causes of hyperkalemia?
Cell shifts, direct renal retention (decreased mineralocorticoid activity, decreased distal sodium delivery), acidosis.
575
What is hepatorenal tyrosinemia? How do you treat it?
Deficiency of fumaryl acetoacetate hydrolase. Liver and kidney failyre, common in French Canadians. Treat with Phe/Tyr restriction, and inhibitor of p-hydroxyphenylpyruvate (NTBC).
576
What are the H2 receptor antagonists and how are they administered? What sort of antagonists are they?
Cimetidine, Ranitidine, Famotidine. Oral, IV, IM. Competitive inhibitors.
577
What class of drug is polyethylene glycol and how is it administered?
Osmotic laxative, and oral.
578
Where is trypsin made and what does it target?
The acinar cells of the pancreas. Stored in granular vesicles in the duodenum, where it acts. C-term of Lys or Arg.
579
Describe low basal pancreatic juice secretions.
Mostly acinar fluid, high in Cl-, low in bicarbonate.
580
What enzyme do you use in beta oxidation is there is an odd double bond?
cis delta3 enoyl CoA isomerase.
581
What do Principal cells reabsorb and secrete?
Reabsorb Na+, Cl- paracellularly. Can secrete potassium.
582
Which digestive system cells allow for the passage of water?
Salivary acinar, pancreatic acinar, pancreatic ductal, cholangiocytes, crypt cells, and gallbladder cells (though reabsorb).
