GI case Flashcards

1
Q

Healthy Diet: (2)

A

A diet containing:

  • An appropriate balance of food groups to obtain appropriate nutrients
  • The right amount of energy to maintain an energy balance
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2
Q

Energy requirements:

  • Man
  • Woman
A
  • 2,500 calories a day

- 2,000 calories a day

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3
Q

Overweight/Obesity statistics among adults:

A
  • 7/10 men are overweight/obese

- 6/10 women are overweight/obese

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4
Q

Obesity definition:

A
  • Generally a result of energy intake being greater than energy expenditure
  • Determined by Body Mass Index (BMI), 30 or higher
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5
Q

BMI classifications:

  • Underweight
  • Normal
  • Overweight
  • Obese
  • Morbidly obese
A
  • < 18.5
  • 18.5-24.9
  • 25-29.9
  • 30-39.9
  • > /= 40
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6
Q

Obesity Aetiology: (7)

A

Many potential factors:

  • Psychological
  • Cultural
  • Psychiatric
  • Environmental factors
  • Genetics
  • Medications
  • Endocrine disorders
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7
Q

Obesity consequences:

A
  • A modifiable risk factor for disease
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8
Q

Obesity: treatment options

A
  • Lifestyle changes
  • Pharmacotherapy
  • Bariatric surgery
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9
Q

Consequences of malnutrition:

A
  • Literally everything is negatively effected
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10
Q

Malnutrition in hospital

A
  • Significant proportion of patients admitted to hospitals, care homes and mental health units are at risk of malnutrition
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11
Q

Functions of the liver and gallbladder: (3)

A
  • Metabolism
  • Synthetic function
  • Biliary circulation
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12
Q

Liver metabolism: carbohydrates (3)

  • Description
  • 2 functions
A
  • Liver is an ‘altruistic’ organ - releases glucose into the blood stream
  • Glycogen storage
  • Gluconeogenesis
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13
Q

Liver metabolism: proteins

A
  • Transamination: Aminotransferases break the amino acid down to glutamic acid
  • Oxidative deamination produces carboxylic acid and ammonia (which needs to be removed)
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14
Q

Aminotransferases:

  • Location
  • Indication
  • Clinical
A
  • Should be in the hepatocytes, not the bloodstream
  • Large quantities in bloodstream indicates hepatocyte damage
  • ALT monitored clinically for hepatocyte damage
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15
Q

Urea cycle:

A
  • Removes ammonia from the liver

- May be affected by liver damage

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16
Q

Hyperammonaemia

A
Elevated levels of ammonia.
Mostly caused by a defect in the urea cycle, causes:
- Confusion 
- Excessive sleepiness 
- Hand tremors 
- Coma
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17
Q

Hyperammonaemia:

A
  • Excess ammonia in the blood stream

- May be seen in urea cycle disorders, other inborn metabolic errors and liver failure

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18
Q

Liver metabolism: lipids

A
  • Essential in lipid metabolism

- Liver problems may disrupt lipid levels (cholesterol, triglyceride)

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19
Q

Synthetic function of the liver: albumin:

  • % of plasma proteins
  • Maintains:
  • Also acts as:
A
  • Makes up 50% of plasma proteins
  • Main factor in maintaining osmotic pressure
  • Also acts as a carrier protein: calcium, bilirubin
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20
Q

Hypoalbuminaemia:

  • Definition
  • Cause
  • Effect
A
  • Low levels off albumin in the blood
  • Caused by liver disease, nephrotic syndrome, malnutrition and burns
  • causes Peripheral oedema
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21
Q

Liver disease and bleeding: (3)

A
  • Clotting factors synthesised in the liver
  • Cholestasis: malabsorption of Vitamin K
  • Decreased platelet count
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22
Q

Biliary system:

  • Globin route
  • Haem route
A

Breaks down old/damaged RBCs:
- First into Haem and globin (protein)

  • Globin broken down to amino acids
  • Haem is then broken down to Biliverdin and iron by Haemoxygenase
  • Biliverdin to bilirubin via biliverdin reductase
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23
Q

Biliary system:

  • Globin route
  • Haem route
A

Spleen breaks down old/damaged RBCs:
- First into Haem and globin (protein)

  • Globin broken down to amino acids
  • Haem is then broken down to Biliverdin and iron by Haemoxygenase
  • Biliverdin (soluble) to bilirubin (non-soluble) via biliverdin reductase
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24
Q

Conjugation of bilirubin:

A
  • Bilirubin transported to liver bound to albumin
  • Bilirubin taken up by the liver via facilitated diffusion: conjugated to glucuronic acid
  • Conjugated bilirubin released into bile
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25
What can go wrong with bilirubin?: - Increase in unconjugated bilirubin - Fault in conjugation system - Fault in biliary system
- Increase in unconjugated bilirubin: result: inc. in unconjugated bilirubin - Fault in conjungation system: benign for the most part - Fault in biliary system (cancer, gallstone): Excess CONJUGATED bilirubin, leaks into circulation, no urobilinogen in faeces (pale)
26
Use of blood tests in biliary problems:
- state of excess bilirubin helps to figure out where a problem is located - Liver isoenzyme alkaline phosphatase (ALP) found in the biliary ducts - Raised ALP suggests CHOLESTASIS (biliary system blockage)
27
Bile salts: - Synthesis - Role
- Synthesised from cholesterol | - Emulsify lipids prior to intestinal absorption
28
Enterohepatic circulation:
- Bile salts continuously recirculated via hepatic portal vein from gut -
29
Liver failure: - Carbohydrate metabolism: - Protein synthesis: - Protein metabolism: - Lipid metabolism: - Drug metabolism: - Haem catabolism: - Bile acid metabolism:
- Carbohydrate metabolism: hypoglycaemia - Protein synthesis: hypoalbuminaemia, clotting problems - Protein metabolism: hyper ammonaemia - Lipid metabolism: Increased TG and cholesterol - Drug metabolism: altered drug half life - Haem catabolism: incr. bilirubin - Bile acid metabolism: increase bile acids
30
GENERAL layered structure of GI tract: (4)
- Mucosa - Submucosa - Muscularis externa - Serosa
31
Mucosa structures: interior to exterior (3)
- Epithelium: specialised polarised cells, sight of cell absorption - Lamina propria: loose connective tissue - Muscularis mucosae: responsible for local movement (squeezing glands)
32
Muscularis externa structure: (2)
- Circular muscle: inner layer, circles the lumen | - Longitudal muscle: outer layer, runs length of tube
33
Submucosa:
- connective tissue containing organelles
34
Serosa:
- Connective tissue, keeps the GI tract together
35
Gut associated lymphoid tissue (GALT): - Location - Role
- Lymph nodes found throughout the lamina propria | - Recognise food stuffs and defend against pathogens
36
Crypts and villi:
- Villi: finger like projections of the epithelium. Responsible for absorption - Crypts: Innermost gaps between, secretion
37
Epithelial cells in the GI tract:
- Specialised polarised cells - Absorptive cells: Small intestine - Secretory cells: stomach
38
Five major sites of secretion in the GI tract:
- Salivary glands - Gastric glands - Exocrine pancreas - Liver-billiary system - Small intestine
39
GI tract secretion: - Daily total: - Contains: - Function:
- 6-7 Litres/day - Enzymes, ions, water and mucus - Breakdown large compounds, regulate pH, dilute and protect
40
Basic Regulatory mechanisms control GI function: (3)
- Endocrine - Paracrine - Neuronal
41
Gastrointestinal hormones that regulate secretion and motility (2)
- Gastrin: gastric secretion, gastric motility | - CCK: Gallbladder contraction and pancreatic secretion
42
GI hormones: That regulate blood flow
- CCK: stimulates blood flow
43
Innervation of GI tract: - structure - Sensors - Neuronal plexus - Effectors
- Intrinsic to the GI tract (short-range) - Monitored by chemo and mechanoreceptors - Submucosal and myenteric plexus (neurones) - Effectors: smooth muscle, secretory cell, blood vessel
44
Innervation of GI tract: extrinsic nervous system
- Intrinsic receptors send signals to CNS - ANS nerves innervate intrinsic effectors - Vasovagal reflex
45
Functions of GI tract musculature 3:
- Non-propulsive movements (segmentation) - Peristaltic movements (propulsive) - Reservoir functions
46
GI tract muscle contraction time frames:
- Phasic (seconds) | - Tonic (minutes-hours)
47
GI smooth muscle properties: (2)
- Single-unit action (function as one) | - Membrane potential oscillates (slow waves), frequency of slow waves controls frequency of contractions
48
location of sphincters: (6)
- Upper oesophageal sphincter (UES) - Lower oesophageal sphincter: (LOS) - Pyloric sphincter - Sphincter of oddi (bile duct to pancreatic) - Ileoceacal sphincter (small to large intestine) - Internal and external anal sphincters
49
Pyloric sphincter: - Junction - Type of sphincter
- Gastro-duodenal | - Anatomical sphincter: formed by large inwards bulge of circular muscle
50
Lower oesophageal sphincter: - Junction: - Type of sphincter:
- Gastro-oesophageal - Physiological sphincter (only): no bulging of circular muscle - Epithelium changes from stratified squamous to simple columnar
51
The swallowing reflex: (5) - Initiation - Food triggers .... - Signal sent to .... - ....... nerves send motor signals to ...... - ........ nerves innervate pharynx and ......
- Initiated voluntarily, then entirely under reflex control - Food triggers touch receptors near the pharyngeal opening - Signal sent to medulla and lower pons - Vagal nerves send motor signal to oesophagus - Cranial nerves innervate the pharynx and upper oesophagus
52
Process of swallowing: 1. Oral/voluntary phase (2) 2. Pharyngeal phase (3) 3. Oesophageal phase (1)
1. Oral/voluntary phase: - Tongue presses food against the hard pallet - Bolus forced into pharynx, stimulating touch receptors 2. Pharyngeal phase: - Soft palate elevates - Epiglottis closes trachea - Upper oesophageal sphincter relaxes 3. Oesophageal phase - Upper oesophageal sphincter closed, peristalsis starts
53
The stomach and swallowing: - Orad role - Orad and caudad role: - During swallowing
- Orad: accommodation of food - Orad and caudad: gastric emptying - During swallowing the orad relaxes
54
Vomiting: 1. Reverse .... 2. relaxation of 3. forced inspiration 4. Sharply elevated 5. Reflex relaxation
- Reverse peristalsis - Pyloric sphincter and stomach relax - Forced inspiration against a closed epiglottis - Sharply elevated intra-abdominal pressure - Reflex relaxation of upper oesophageal sphincter
55
Stomach Peristalsis: (4) - Contractions begin in the .... and travel to the ...... - Increases in ... - Mixing occurs in the ..... - Retropulsion
- Contractions begin in the corpus and travel to the pylorus - They increase in force and velocity as they approach the gastroduodenal junction - Mixing occurs in the antrum - Retropulsion is effective at mixing and breaking down contents
56
Small intestine motility: Non-propulsive movements: - Caused by - Effect
- Non-propulsive movements: caused by rhythmic contraction and relaxation of the muscular external - Mixes chyme and brings nutrients to mucosal surface
57
Small intestine motility: peristalsis - Frequency - Cause - Allows
- Occurs at low frequency - Caused by contraction of successive sections of muscularis externa - Propels chyme for a short distance, allowing time for digestion/absorption
58
Functions of colonic contractions: (3)n - Chyme - Semi-solid contents - Moves to
- Mixes chyme, improves absorption of water and salts from the colon - Kneading semi-solid contents - Moves contents toward anus
59
Mass peristalsis: - Effect - Controlled by
- Specialised type of movement, 1-3/day, moves the colonic contents towards the anus - Directly controlled by enteric nervous system (gastrocolic reflex)
60
Defaecation: Rectosphincteric reflex (internal)
- Distension in the sigmoid colon triggers afferent nerves to send a signal to the sacral spinal cord - Efferent pelvic nerves cause relaxation of the internal anal sphincter
61
Defaecation: external process (3)
- Rectospinteric reflex - Relaxation of external anal sphincter - Contraction of abdominal wall muscles and relaxation of pelvic wall muscles
62
Glands around the mouth:
- Parotid glands: serous (watery) secretion rich in alpha-amylase - Submandibular and sublingual glands: seromucous secretion - Minor salivary glands: mucous secretion rich in glycoproteins
63
Salivary secretion Stats: - Quantity/day - Osmolarity - pH - Composition
- 1.5 litres a day - Hypotonic (only one in GI tract) - pH: 7 - Composition: mucin glycoproteins, lysosome, a-amylase
64
Functions of saliva: (3) - Mucin glycoproteins, water - Lysozome - A-amylase
- Lubricate the food to aid swallowing (mucin glycoproteins, water) - Clean and protect mouth cavity (lysosome) - Reduce starch to oligosaccharides (a-amylase)
65
Role of stomach in digestion: (3)
- Reservoir: gastric motility - Digests proteins (pepsins) - Essential for the absorption of vitamin B12 (intrinsic factor)
66
Gastric (acid) secretion - Amount/day - Composition - pH
- 2.0 L/day - HCl, pepsins, intrinsic factor, mucus HCO3- - 0.9-1.5
67
Structure of gastric mucosa: - Description - Secretory cells (5) top to bottom - HCO3- - Mucous - HCL, IF - Pepsinogens - Histamine, somatostatin
- Arranged into gastric pits, lined by different secretory cells - Surface epithelium cell: HCO3- - Mucous neck cell: Mucus - Parietal cell: HCL, IF - Chief cell, pepsinogens - Endocrine cell, Histamine, somatostatin
68
Secretion of pepsins: - Origin - Role - Optimal pH - Reason for pH
- secreted by chief cells - Digest proteins - Optimal pH: < 3 - Low pH required for pepsinogen activation and pepsin activity
69
Functions of HCl: (3)
- Promotes activation and activity of pepsins - Kills or inhibits microorganisms - Stimulates secretions in the small intestine
70
Morphological changes that accompany HCl secretion: - Parietal cells contain.... - Stimuli causes ..... to surface, forming ...... - Increases ......
- Parietal cell contains tubulovesicles containing H+ pumps and K+, Cl- channels - Stimuli causes tubulovesicles to surface, forming canaliculus - Increases secretory membrane SA (50-100X) with more H+ pumps, K+ channels and Cl- channels
71
Cellular mechanism for HCl secretion: stages 1-4 - ATP hydrolysis - K+ movements - Carbonic anhydrase - HCO3- movements
1- Energy from ATP hydrolysis used to pump H+ into the lumen and K+ into the cell 2- Apical membrane K+ channels recycle K+ ions across the apical membrane 3- H+ secretion causes intracellular pH to rise, triggering passive uptake of CO2 and H2O across the basolateral membrane. Carbonic anhydrase catalyses their conversion to H+ and HCO3- 4- HCO3- ions are then removed across the basolateral membrane by the anion (CL-/HCO3-) exchanger
72
Cellular mechanism of HCL secretion: (5-8) - Alkaline tide - Cl- movement - Na+/K+ATPase - K+ CL- relation
5. HCO3- ions that exit the cell across the basolateral membrane cause the alkalinisation of local blood vessels termed “alkaline tide” 6. The Cl- ions that enter the cell across the basolateral membrane via the Cl-/HCO3- exchanger exit passively across the apical membrane via a Cl- channel to complete the process of acid (HCl) secretion 7. The Na+-K+-ATPase creates the inwardly directed Na+ gradient across the basolateral membrane. 8. Basolateral membrane K+ channels maintain the driving force for Cl- exit across the apical membrane
73
Secretion of mucus and bicarbonate: - Secretes mucous - Secretes HCO3- - Regulatory ligands (2)
- Surface epithelial cells and mucous neck cells - Surface epithelial cells (majority) - Acetylcholine: via calcium signalling - Prostoglandins: stimulates mucous and HCO3-. Inhibits acid secretion
74
Gastric mucosal barrier: - Reliant on: (2) - Neutralisation zone
- A HCO3- rich mucous blanket covers the epithelial cells (pH 7) - Gastric lumen has pH 1.5 - Mucus gel neutralisation zone: zone between the two layers that is neutral due to opposing flows of H+ and HCO3-
75
Gastric mucosa protection: anatomical:
- Apical membrane impermeable to H+ | - Tight junctions don't allow H+ paracellular movement
76
Viscous fingering:
- Acid is shot out of gastric glands into the lumen
77
Direct Regulation of HCl secretion: Histamine - Originates from - Binds to - Action
- ECL cell - H2 receptor - Acts on cAMP
78
Indirect HCl regulation:
- Nerves and gastrin both stimulate the ECL cell, increasing histamine production
79
control of gastric secretion: cephalic phase - Secretory signals - Dependant on: - Total % volume of secretion - Occurs when?
- Sight, smell, taste, chewing - Entirely dependant on vagus nerve - 30% of total secretion volume - Occurs before food enters stomach
79
Control of gastric acid secretion: mechanisms - Distention - Amino acids - Inhibition
- Distension: triggers mechanoreceptors, triggering vagovagal reflex - Amino acids: trigger chemoreceptors on G cells, releasing gastrin, stimulating parietal cells - Inhibition: Chemoreceptors on D cell detect HCL, releasing somatostatin, shutting down G cells and parietal cells
80
Control of gastric acid secretion: gastric phase stats - Controlled by - Amount
- controlled by vasovagal reflexes, hormones and paracrine factors - Accounts for >50% of gastric secretion
81
``` Control of gastric secretion: intestinal phase: - Early in gastric emptying - Later in gastric emptying Distension: Digested proteins ```
- Early in gastric emptying: gastric chyme pH>3, STIMULATION predominates - Later in gastric emptying: gastric chyme pH<3, INHIBITION predominates - Distension of duodenum: mechanoreceptors stimulated, vasovagal reflex initiated, stims G cell and parietal cell - Digested proteins: chemoreceptors stimulated, causes indirect stimulation
82
Control of gastric secretion: intestinal phase | - Stimulation of secretion: mechanism
- Distension of duodenum: mechanoreceptors stimulated, vasovagal reflex initiated, stims G cell and parietal cell - Digested proteins: chemoreceptors stimulated, causes indirect stimulation
83
Control of gastric secretion: intestinal phase: inhibition (HCl detected) - Detection, secretion - Secretin action (1) - Secretin action (2)
- HCl detected in duodenum by S cell chemoreceptor, S cell then secretes secretin. - Secretin travels via blood vessels to stomach. Inhibits parietal cells and G cells (antrum) - Secretin also stimulates D cells to release somatostatin (direct or hormonal)
83
Control of gastric secretion: intestinal phase: inhibition (HCl detected) - HCl detected in ....... by S cell, S cell secretes ..... - .......... inhibition route, targets .... cells, .... cells - Also stimulates D cells to release ...
- HCl detected in duodenum by S cell chemoreceptor, S cell then secretes secretin. - Secretin travels via blood vessels to stomach. Inhibits parietal cells and G cells (antrum) - Secretin also stimulates D cells to release somatostatin (direct or hormonal)
84
Gastric emptying: - Definition - Speed varies by food type - Rate of GE does not exceed:(4)
- Delivery of chyme from stomach to duodenum - Speed varies: carbs>proteins>fats>indigestibe solids - Rate of GE does not exceed: . Acid neutralisation rate . Fat emulsification rate . Time for small intestine to process chyme
85
Mechanisms of digestion and absorption: brush-border hydrolysis
- brush-border hydrolysis of oligomer (sucrose) to monomer (glucose)
86
Mechanisms of digestion and absorption: Luminal hydrolysis
- Polymer (protein) is hydrolysed in the lumen, then the monomer (amino acid) is absorbed
87
Mechanisms of digestion and absorption: Intracellular hydrolysis
- Peptide absorbed into the apical membrane then hydrolysed to its monomer (amino acid)
88
Mechanisms of digestion and absorption: Lunminal hydrolysis followed by intracellular resynthesis
- Triglyceride hydrolysed into monomers, Absorbed vial apical membrane - Re-synthesised to triglyceride in the cell
89
Digestion and absorption: carbohydrates - Pathway (2) - Transport mechanisms (3)
- Starch converted to maltose via alpha amylase - Maltose converted to glucose via maltase - SGLT1: Na+ coupled glucose transporter (apical) - GLUT2: Glucose transporter 2 (basolateral) - GLUT5: transports fructose (apical)
90
Digestion and absorption of proteins: 3 routes - Simple - Brush-border - Intracellular
1. Proteins broken down to amino acids by proteases and absorbed 2. Dipeptides hydrolysed by peptidases (brush-border hydrolysis) 3. Dipeptides and tripeptides undergo intracellular hydrolysis
91
Digestion and absorption of proteins facts: (2) - Apical membrane - Absorption varies in intestine
- Amino acids cross apical membrane by Na+ dependant and independent mechanisms - Amino acid and peptide absorption: duodenum>jejunum>>ileum
92
Digestion and absorption of fat: part 1 - emulsification - Pancreatic lipase - Products
- Triglycerides grouped and emulsified, creating emulsion droplets - Pancreatic lipase works at the interphase between the lipid environment and aqueous environment, - produces fatty acid and monoglyceride
93
Digestion and absorption of fats: part 2 - Mixed micelle formation - Mixed micelle breakdown/diffusion - Chylomicron formation
- Phospholipid cholesterol and bile salt micelle bind to fatty acids and monoglycerides, forming a mixed micelle - Mixed micelle enters unstirred layer (acid), fatty acids and monoglycerides leave mixed micelle and diffuse across the apical membrane - Chylomicrons form in SER and leave the cell via exocytosis into lymph duct
94
Digestion and absorption of fat simplified: (4)
- Emulsion droplet key step in fat digestion - Fatty acid and monoglyceride diffuse across the apical membrane; no transport proteins required - Triglyceride reformed in villus epithelial cells, delivered to lacteals -
95
Substances used in glucose synthesis: (3)
- Lactate to Pyruvate - Triglycerides to Glycerol - Glucogenic Amino acids
96
Difference between gluconeogenesis (GNG) and glycolysis
- GNG (anabolic) is almost the reverse of glycolysis (catabolic) - 3/10 glycolysis steps (1,3,10) are irreversible so glycolysis and GNG use different enzymes for these steps
97
Gluconeogenesis transversing the mitochondria: (3)
- Inner mitochondrial membrane not permeable to oxaloacetate - Oxaloacetate converted into PEP or malate - Lactate precursor prefers conversion to PEP - Oxaloacetate converted to PEP within the inner mitochondrial membrane, malate leaves mitochondria before converting to oxaloacetate then PEP
98
glycogen synthesis;
- glycogen synthase activated when blood glucose levels are high (via insulin)
99
glycogen breakdown
- Glycogen phosphorylate activated by AMP and Ca2+ in muscle, converts glycogen to glucose-1-phosphate
100
Gluconeogenesis (GNG): costs
- 4 ATP, 2 GTP and 2 NADH per glucose
101
Relationship between rate of reaction and conc. substrates: (2)
- Rates are more sensitive to concentrations at concentrations near or below their Km - Rate becomes insensitive at high substrate concentrations
102
[ATP], [ADP] and [AMP] in regulation for glycolysis and GNG - Glycolysis:
- Glycolysis: Phosphofructokinase | - inhibited by ATP and citrate, stimulated by ADP and AMP
103
[ATP], [ADP] and [AMP] in regulation for glycolysis and GNG | - GNG
- GNG: fructose-1,6-phosphatase | - Inhibited by AMP
104
AMPK: AMP-acttivated protein kinase - Effects on: - extrahepatic tissue: AMPK shifts metabolism to - Liver: Triggers ......... to provide glucose for the brain - Brain: stimulates
- AMP-activated Protein kinase is activated by AMP via sympathetic NS Effects on: - extrahepatic tissue: AMPK shifts metabolism towards the use of fatty acids for fuel - Liver: triggers gluconeoenesis to provide glucose for the brain - Brain: stimulates feeding behaviour
105
Acetyl CoA role in metabolism: (3)
- Regulates the fate of pyruvate - Stimulates GNG: activates Pyruvate carboxylase - Inhibits citric acid cycle: inhibits PDC (pyruvate dehydrogenase complex)
106
Pyruvate can be a source of new glucose:
- Used to store energy as glycogen | - Generates NADPH for lipid synthesis
107
Pyruvate can be a source of Acetyl-CoA:
- Used to store energy as body fat | - Used to make ATP via citric acid cycle
108
Fatty acid oxidation: 1. Beta oxidation 2. Citric acid cycle 3. oxidative phosphorylation
1- Beta oxidation. FA's are oxidised two carbons at a time and combine with CoA 2- acetyl CoA enters the citric acid cycle and is used to form NADH and FADH2 3- high energy electrons in NADH and FADH2 are used to synthesise ATP in oxidative phosphorylation
109
- Energy yield from Beta-oxidation of palmitic acid (C16); - Acetyl CoA inCitric acid cycle: - Oxidative phosphorylation: - TOTALS
- Beta-oxidation: 8 acetyl CoA, 7NADH, 7 FADH2 - Acetyl CoA: 3 NADH, 1 FADH2 and 1 GTP - Oxidative phosphorylation: - 1 NADH = 2.5 ATP - 1 FADH2 = 1.5 ATP - TOTALS: 106 ATP NADH = 7 + (8X3) = 31 = 77.5 ATP FADH2 = 7 + (8X1) = 15 = 22.5 ATP GTP = 8 = 8 ATP
110
Acetyl CoA produces three types of ketone: (3)
- Acetone - Acetoacetate - D-beta-Hydroxybutate
111
Ketone body function:
- Mobile acetyl-CoA, ketone bodies used to form acetyl-CoA | - Acetyl-CoA then enters the citric acid cycle and produce ATP as normal
112
Metabolism in the liver during starvation: - Preference for GNG - Ketone bodies - Use of ketone bodies
- Oxaloacetate is preferentially used for GNG to maintain [glucose] - This slows the citric acid cycle in the liver, enhancing the formation of ketone bodies, releasing CoA to allow b-oxidation to continue - Ketone bodies used as extra source of fuel as glucose is low
113
Functions of ATP:
- Carrying energy - Building block of DNA, RNA - Part of CoA, VitB also required - As cyclic AMP (signalling) - Synthesise NADH
114
NADH and NADPH: (4) - Synthesised from - Form - Oxidised form - Role - Pathways (2)
- Both are synthesised for vitamin. B3 and ATP - Both are activated carrier molecules - NADH and NADPH are both reduced forms. NAD+ and NADP+ are the oxidised forms - Both transfer high energy electrons between molecules - NADH: catabolic pathways - NADPH: anabolic pathways
115
Vitamin facts: - Definition - Deficiency - Roles
- Organic molecules that cannot be synthesised - Deficiency leads to disease - Most act as coenzymes or antioxidants
116
Vitamin facts:
- Measured in micro/milligrams | - RDA's don't vary much with age or sex
117
Consequence of dietary deficiency: Vit.A
- Impaired vision and more
117
Consequence of dietary deficiency: Vit c
- Scurvy
118
Direct Regulation of HCl secretion: Gastrin - Originates from - Binds to - Action
- G cell - CCK-B receptor - Ca2+
119
Direct Regulation of HCl secretion: Acetylcholine (neuronal) - Originates from - Binds to - Action
- Enteric neuron - M3 receptor - Ca2+
120
Indirect regulation of HCl secretion:
- Gastrin and Acetylcholine can both stimulate the ECL cell, increasing the amount of Histamine secreted