Exam 1 Flashcards
What are the 6 classes of nutrients?
Carbohydrates (O)
Proteins (O)
Fat (O)
Water (I)
Vitamins (O)
Minerals (I)
Type 1 Diabetes Mellitus
Condition in which the body can no longer produce insulin due to the destruction of pancreatic beta cells. Glut-4 receptors are no longer signalled to take up blood glucose. In turn, blood glucose levels increase.
Hyperglycemia also results in increased fatty acid metabolism, which increases Acetyl CoA production and therefore, oxaloacetate is limited, so the TCA cycle does not turn. This causes Acetyl CoA to form ketone bodies which will eventually lead to diabetic ketoacidosis.
Why can a type 1 diabetic no longer produce insulin?
Pancreatic Beta cells have been destroyed by bodies own immune cells.
Hyperglycemia in a type 1 diabetic also results in ____________ due to excess Acetyl CoA forming ketone bodies.
Diabetic Ketoacidosis
Phenylketonuria (PKU)
A genetic condition in which the enzyme phenylalanine hydroxylase is defective. This results in the termination of phenylalanine forming tyrosine.
What are the symptoms of long-term phenylalanine buildup in the body?
High levels of phenylalanine are toxic to the brain. If left untreated, it can result in disabilities, seizures, mental disorders, and more.
How is PKU treated?
PKU cannot be treated because it is an inherited genetic disorder. Treatment is avoiding foods that contain the chemical phenylalanine. Foods include artificial sugars, fish, eggs, chicken, and more.
Anemia
An issue in which the body does not have enough red blood cells to oxygenate all tissue needs properly.
What are the common symptoms of anemia?
Extreme fatigue and poor appetite
What can be the possible causes of anemia?
In terms of nutrients, it is typically due to deficiencies in key vitamins and minerals like iron, folate, B6, and B12.
Nutrigenetics
The concept that our inherited genetic characteristics influence the body’s response to specific nutrients.
Nutrigenomics
The idea that the nutrients we consume can affect gene expression.
What is an example of nutrigenomics?
Saturated fatty acids bind to TLR4 receptors on cells. This induces a cell signalling cascade that increases the transcription of inflammatory-related genes. On the other hand, EPA and DHA reduce inflammation by blocking this cell signalling pathway.
What is the difference between testing for single-gene disorders and direct-to-consumer panel testing?
Single-gene disorders are done in a medical setting that provides counselling and data regarding your results. DTC panel testing only looks for mutations in the form of SNPs, and it is not done in a medical setting.
What are the issues with DTC panel testing?
Many SNP associations are not known or well-understood leading to confusion based on possible results.
Catabolism
Breakdown of nutrients.
Anabolism
Building of larger molecules from smaller ones.
What are the primary components of the GIT?
Mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus.
What are the accessory organs of the GIT?
Teeth, tongue, salivary glands, pancreas, liver, and gallbladder.
What type of muscle are sphincters made out of?
Circular smooth muscle
What are the 4 layers of the GIT from inside to outside?
- Mucosa
- Submucosa
- Muscularis externa
- Serosa
What are the 3 layers of the mucosa lining the lumen?
- Epithelium- lines the lumen
- Lamina propria- made of connective tissues and filled with small blood and lymph vessels
- Muscularis mucosa- a thin layer of smooth muscle that acts as a protective barrier covered in mucus
What does the submucosa layer contan?
Connective tissue called the neural network called the submucosal plexus.
What does the muscularis externa layer contain?
Contains circular and longitudinal smooth muscles used in peristalsis.
What does the outer layer of the Serosa in the GIT contain?
The serosa is a thin layer of connective tissue covered by single squamous epithelium.
What regulates the swallowing reflex?
The swallowing center in the medulla of the brain.
What is in saliva?
Water and salts that dissolves food.
Mucus made of glycoproteins calls mucins to protect and lubricate mouth and throat.
Enzymes including alpha-amylase and lingual lipase.
Antibacterial and antiviral components for dental health.
What is the function of alpha-amylase enzyme in saliva?
Breaks alpha 1,4 glycocidic bonds in starch
What is the function of the lingual lipase enzyme in saliva?
Hydrolyzes triglycerides
What is anosmia?
Complete inability to detect odors
What is hypoanosmia?
Inability to detect odors
What is ageusia?
Total lost of taste
What is hypoageusia?
Decreased ability to taste
What is peristalsis?
Progressive wavelike motion that moves bolus through esophagus into stomach. Takes around 10 seconds and is initiated by the bolus moving through the upper esophageal sphincter.
The upper esophageal sphincter seperates the _________ from the ________.
Pharynx; esophagus
The lower esophageal sphincter seperates the _________ from the __________.
Esophagus; stomach
Sphincters are made of ______ ________ muscle.
Cirular smooth
How do we treat heartburn?
Antacids and proton pump inhibitors
Which portion of the stomach is the site of major production of gastric juices?
Upper 3/4 of stomach called the body
What are in gastric juices?
Water, electrolytes, HCL, enzymes, mucus, and intrinsic factor
What is the role of hydrochloric acid in gastric juice?
HCL acttivates the zymogen pepsinogen to pepsin. It denatures that 2nd and 3rd protein structures preparing for hydrolysis. Releases nutrients from organic complexes and is a bacterocide.
What is the function of the gastric juice enzyme pepsin?
Pepsin breaks down proteins into smaller peptides through hydrolysis of the peptide bond.
Why do we have mucus in gastric juices?
They hold glycoproteins and they lubricate and protect the gastric mucosa which prevents ulcers.
Once the bolus enters the pharynx, swallowing is primarily an __________ process
involuntary
Which layer of the GIT protects against oxidative damage?
Muscularis Mucosa
What enzymes is present in saliva?
Alpha-amylase and lingual lipase
Gastrin ________ and secretin _________ gastric motility.
Increases; decreases
Which is not an example of mechanical digestion?
Enzyme secretion from the pancreas
The pH of chyme leaving the pyloric sphincter is approximately?
2
What sphincter is impaired in a person experiencing heartburn?
Lower esophageal
What is the function of pepsin?
Produces large peptide fragments, some free amino acids
The majority of nutrients are absorbed within ________ of entering the ________.
30 minutes; duodenum
Which of the following lowers LES pressure?
Smoking and alcohol
What controls gastric emptying and gastric motility?
When food is swallowed, the proximal portion of the stomach relaxes to accommodate the ingested food. The pacemaker of the stomach is located between the fundus and the body of the stomach and determines the frequency of contraction and rate at which chyme enters the distal stomach.
What is the migrating motility complex?
Series of contractions that moves chyme distally through GIT in wavelike motions every 90-230 minutes between meals. Sweeps prevent bacterial overgrowth.
What is the rate at which chyme is released from the stomach into the duodenum?
1 teaspoon every 30 seconds
What is stomach emptying primarily controlled by?
Milling/grinding action of stomach
What are some specific nutrients that slow gastric emptying?
Fiber, free amino acids, and fat (most potent inhibitor of gastric emptying)
How long after a meal does gastric emptying typically take place?
2-6 hours after meal
What is dumping syndrome?
When the stomach contents empty too quickly into the duodenum of the small intestine. Symptoms include diarrhea, nausea, and lightheadedness after a meal. It is caused by a defect in the pyloric sphincter. It can be improved by eating small meals, lying down after meals, and eating more protein, fat, and fiber.
What is gastritis?
Inflammation of the stomach lining. Symptoms include gnawing or burning ache and pain in the upper abdomen. It can be caused by damage to the stomach lining, gastric acid irritation that causes vulnerability to H pylori, regular use of NSAIDs, alcohol, age, and stress.
Enzymatic digestion of protein begins in the stomach through the activity of _______ that cleaves ________ bonds.
Pepsin; peptide
What is the longest portion of the GIT?
The ileum at 5-9 feet long
Why is the small intestine called what it is?
It is only about 1 inch in diameter
What is segmentation?
Regular contraction/relaxation of circular muscle. It is a form of mechanical digestion that gradually moves chyme through GIT.
What is the equivalent to the surface area of the small intestine?
A tennis court
What are the 4 different types of projections in the small intestine to improve absorption?
Folds of Kerckring
Villi
Microvilli
Crypts
What are the folds of Kerckring?
The largest folds of the mucosa, which is the innermost layer of GIT.
What are villi?
Finger-like projections
What are microvilli?
Hair like extensions of plasma membrane
What are crypts?
Pits between the villi in constant mitosis turn over every 3 to 5 days. Crypts secrete digestive juices.
What is the length and diameter of the large intestine?
5 feet long and 2 inches in diameter
Defection typically occurs ________ hours after chyme enters to the colon.
36
What are the 2 key functions of the colon?
- Complete the nutrient absorption in the proximal/ascending colon like Na+, Cl-, H2O, vitamin K, and biotin.
- Bacterial production with over 400 different types of bacteria calling the colon home.
What is the source of energy for the bacteria in the gut?
Fiber is fermented for energy from carbohydrates. Products are short-chain fatty acids like acetate, which is reabsorbed by the colon. Bacteria also synthesize B and K vitamins
What is prebiotics?
Nutrients that increase bacterial production. Includes foods like garlic, bananas, onions, leeks, apples, etc.
What are probiotics?
Foods that contain live beneficial bacteria. Includes yogurt, sauerkraut, and kimchi
What is NAFLD?
Condition in which excess fat is stored in the liver.
What does the liver synthesize?
Synthesizes bile, plasma proteins, growth factors, VLDL, and more
What does the liver store?
Fat-soluble vitamins, iron, glycogen, and more
What are the two components of the pancreas?
Exocrine and endocrine component
How much does the exocrine component of the pancreas account for in total pancreatic mass?
98% of total mass
What is the function of the exocrine component of the pancreas?
Produces pancreatic juices (1/2 L/day)that support normal digestion and absorption. It also releases enzymes that break down nutrients like trypsinogen, elastase, carboxypeptidase, and more.
What are the components of pancreatic juice?
Bicarbonate to neutralize acid and protect and enzymes to breakdown fat, carbs, and protein. Bicarb and enzymes
What is the function of the endocrine component of the pancreas?
2% of the pancreas is used for this function. Includes islets of Langerhans like beta and alpha cells. Beta cells secrete insulin into the blood, while alpha cells secrete glucagon into the blood.
What is pancreatitis?
Inflammation of the pancreas which can be caused by gallstones, heavy alcohol use, and more. Symptoms include of pain in upper abdomen, fever, nausea, vomiting, pain, diarrhoea, and greasy stools.
What is the function of the gallbladder?
It stores bile. Bile is originally made in the liver from cholesterol.
How many bile acids and salts are reabsorbed by active transport in the ileum?
90%`
The recirculation of bile is highly inefficient (T/F)
False, it is very efficient.
How does fiber impact the enterohepatic circulation of bile?
Fiber binds to bile in the GIT and reduces the reabsorption of bile from the ileum. Fiber traps bile salts which will be excreted instead of reabsorbed. This creates a deficit in recycled bile, so the body compensates by increasing bile production made from circulating cholesterol which lowers plasma cholesterol levels.
What are gallstones?
Gallstones are hardened deposits of bile that are very painful. Risk for these include obesity, weight loss, diet, and genetics (females more likely than males).
What are the two types of gallstones?
Cholesterol stones (8% of stones; made of harder cholesterol and pigment stones (dark color primarily bilirubin)
What dietary advice would you provide for someone who has their gallbladder removed?
Eat a low fat diet and eat small and spaced out meals.
What is the function of the hormone gastrin?
Increases HCl secretion, gastric and intestinal motility, the release of pepsinogen, and cellular growth of GIT.
Where is gastrin secreted from, and what triggers it?
Gastrin is secreted from the stomach and is triggered by food entering the stomach and gastric distention
What is the function of the hormone secretin?
Increases the release of pancreatic juice and decreases gastric and intestinal motility.
Where is secretin secreted from, and what triggers it?
Secretin is secreted from the small intestine and is triggered by acidic chyme (pH 2) entering the duodenum
What is the function of cholecystokinin (CCK)?
Increases secretion of pancreatic juices, contraction of the gallbladder, and intestinal motility. Decreases gastric motility.
Where is CCK released from and what triggers it?
CCK is released from the small intestine and is triggered by fat and breakdown products of protein entering the duodenum.
What is the function of gastroinhibitory peptide (GIP)?
Increases intestinal secretion and insulin release. Decreases gastric secretions and motility.
Where is GIP secreted from, and what triggers it?
GIP is secreted from the small intestine and is triggered by the presence of glucose or fatty acids in the duodenum.
What is the enteric nervous system?
The GIT nervous system that lies in the wall of GIT. Sympathetic NS activation will decrease gastric motility and secretions throughout GIT. Parasympathetic NS activation increases motility and secretions through GIT.
What are the two portions of the Neural Plexus (Enteric Nervous System)?
Myenteric Plexus of Auerbach and Submucosal plexus of Meissner.
What is the function of the myenteric plexus of Auerbach?
Lies in the muscarlis externa between circular and longitudinal muscle layers. Important in peristalsis and GIT motility.
What is the function of the submucosal plexus of Meissner?
Lies in the submucosa. Important in GIT secretions and blood flow.
What is the brain-gut axis?
Bidirectional communication between the brain and gut, which links the emotional and cognitive centers of the brain with peripheral intestinal function.
Only about ___________ of food energy is ultimately available for basal metabolism and physical activity.
25-40%
Energy can be released in what two forms?
Heat and ATP
1 calorie= ________ joule (J)
4.18
1 kcal= _________ calories
1000
What is zero energy balance?
When body metabolism and energy consumption matches the energy spent (weight maintenance)
What is a non-zero energy balance?
A change in intake or energy expenditure leads to weight gain or loss.
What are the three regulators of energy in?
Appetite, decision making around food intake, and nutrient absorption
What regulates energy out?
Total energy expenditure
What accounts for total energy expenditure?
Basal Metabolic Rate, physical activity thermogenesis, and thermic effect of food
How much does basal metabolic rate account for in energy expenditure?
2/3rds
What is BMR for males?
1 kcal/kg/hr
What is BMR for females?
0.9 kcal/kg/hr
What is thermogenesis, and how much does it account for in TEE?
Thermogenesis is the heat generated from the metabolism of food. 5-10% of TEE
Positive energy balance leads to weight gain, which ________ basal metabolic rate.
Increases
Negative energy balance leads to weight loss, which ________ basal metabolic rate.
decreases
Durable weight loss is limited to ____________ of body weight.
3-10%
Most people regain some or most of the weight lost after ______ months.
12
What is metabolic adaptation?
A collection of biological responses that favor weight regain. Reduces energy expenditure, changes food intake and satiety to increase food intake, and changes insulin sensitivity and adipocyte number to favor fat storage.
What is the set-point theory?
Based on genetic factors, your body weight stays within a certain range or set point. In order to maintain balance, the brain adjusts the body’s hunger and metabolism to stay within this set point weight range.
What are some techniques for weight loss that can help avoid the negative effects of metabolic adaptations?
Eating various nutrient-dense foods, no crash weight loss, eating balanced meals, honoring hunger and satiety cues, and rethinking the timing for nutrient intake.
A ________ decrease in body weight decreases the risk factor for cardiovascular disease.
2-3%
What are chemotrophs?
Humans are chemotrophs. These obtain energy from oxidation of food.
ATP is produced from the complete oxidation of ___________.
Acetyl Unit of Acetyl CoA
What is free energy?
Energy released that can be used to do work.
If G is greater than zero, the reaction is ________ and _________.
endothermic; uphill
If G is less than zero, the reaction is ________ and ________.
Exothermic; downhill
What is the free energy released from the breakdown of ATP to ADP and Pi?
-7,300 kcal/mol
What is the free energy released from the breakdown of ADP to AMP and Pi?
-7,300 kcal/mol
What is the free energy released from the breakdown of AMP to adenosine and Pi?
-3,400 kcal/mol
The free energy liberated in the ___________________ is harnessed to drive reactions that require an input of free energy.
Hydrolysis of ATP
The breakdown of food is called _________, and the buildup of large molecules is called _________.
Catabolism; anabolism
_________ cycle is the fundamental mode of energy exchange in biological systems.
ATP-ADP
A resting human consumes about _____ kg of ATP within 24 hours.
40
What is white fat?
White fat has 1 fat droplet and it used in energy storage and release.
What is brown fat?
Multiocular cell used in fatty acid oxidation and thermoregulation. Brown fat is very vascular and has a large number of pigmented mitochondria. Brown fat dissipates food energy in the form of heat.
Brown fat accounts for about ______% of the average healthy adult’s body weight.
1.5
What triggers thermogenesis?
Consumption of food and prolonged exposure to cold temperatures.
What are short-chained fatty acids?
This is produced when fiber is fermented for energy by healthy gut bacteria. SCFA includes acetate, propionate, and butyrate. SCFA are then absorbed by the colon and used in the vitamin synthesis of K, B12, B6, folate, and biotin.
What are the three types of good gut bacteria?
Bifidobacteria, escherichia coli, and lactobacilli
What are some sources of short-chained fatty acids?
Whole grains, fruits, nuts, vegetables, human milk, and mushrooms
What is the role of short-chained fatty acids in the body?
Reabosbed by the colon and used in vitamin synthesis. It also improves intestinal immunity.
What is the low FODMAP diet?
This diet is low in fermentable oligosaccharides, disaccharide monosaccharides and polyols. This is a diet that some with IBS could follow. Elimination of FODMAP foods minimizes gas and water production leading to distension in the GIT.
What are some examples of high FODMAP foods?
Artichokes, asparagus, cauliflower, apples, cherries, mango, milk, ice cream, yogurt, beans, some processed meats, wheat-based bread, biscuits, sweeteners like high fructose corn syrup, and pistachios, and cashews.
What are some examples of low FODMAP foods?
Eggplant, green beans, bell peppers, cantaloupe, grapes, kiwi, almond milk, brie, feta cheese, eggs, firm tofu, tempeh, oats, rice cakes, sourdough, dark chocolate, table sugar, peanuts, pumpkin seeds, and walnuts.
What is Non-Alcoholic fatty liver disease (NAFLD)?
Condition in which excess fat is stored in the liver. Higher risk in those with obesity and exacerbated with alcohol use. Treated with weight loss, physical activity, and healthy diet.
What are the beneficial effects of weight loss due to semaglutide?
The injectable form has shown a decrease in HbA1c. This drug improves liver histology and cardiovascular health with weight loss.
How does Semaglutide act in the body?
This drug is a GLP-1 receptor agonist. When it binds, it activates the GLP-1 receptor. This triggers insulin release and inhibits glucagon secretion. This combination results in reduced hunger and increased energy levels, which leads to weight loss. It also delays gastric emptying and decreases appetite.
What are the three stages of energy extraction from food?
- Large molecules in food are broken down into smaller units.
- Via various metabolic pathways, the smaller molecules are degraded to a few simple units that play a central role in metabolism
- ATP is produced from the complete oxidation of the acetyl unit of Acetyl CoA
Brown fat mitochondria have special H+ pores in their inner membrane, formed by an integral protein called _____________.
Thermogenin/ Uncoupling protein (UCP)
Thermogenin is a ________ of protons. It allows H+ pumped out of the electron transport chain to flow ________ into the mitochondria instead of through ATP-synthase. The energy is dissipated as ______ rather than stored in the high-energy phosphate bonds of ATP.
Translocator; back; heat
Systemic effects of SCFA include ___________ blood pressure.
lowering
What are the risk factors for NAFLD?
obesity and metabolic syndrome.
Multi-ingredient workout supplements?
Lots of random ingredients are supposed to enhance performance and includes things like creatinine, caffeine, amino acids, and more. These could be dangerous because they are not FDA approved which allows for inaccuracies in measurements.
