4: Digestive Tract In Health And Disease Flashcards
T/F: Probiotics and prebiotics are found in only supplements and not foods
False. Probiotics and prebiotics are found in BOTH foods and supplements
Probiotics
cultures of living organisms (bacteria)
- found in yogurt and kombucha
- cannot treat or cure any disease, but may help in management of certain conditions
Prebiotics
non living organisms
- act as food (carbs) for microbiome and support its function
- SCFAs are produced and released into the bloodstream
Health benefits of prebiotics
reducing inflammation, supporting immune system, enhancing mineral bioavailability and reducing cholesterol
Food sources of prebiotics
asparagus, beet sugar, garlic, onion, wheat, honey, banana, barley, tomato, rye, soymilk, peas, beans and seaweed
What are two main types of prebiotics
fructo-oligosaccharides and galacto-oligosaccharides – medium-chain carbohydrates made up of fructose and galactose
How is a food classified as a prebiotic?
must be able to past the acidic stomach environment, be fermented by intestinal microbiota and it must change the activity of the microbiota in a way that is beneficial to the health of the person or organism
Ulcers
open sores that can occur along the lining of a body structure
- caused by a weakening of the mucosal layer of the digestive tract wall
Where can ulcers occur?
multiple points of the digestive tract - mouth, esophagus, stomach and small intestine
Canker sores
Ulcers in the mouth
- typically disappear on their own
- caused by biting the cheek, eating a lot of acidic food or burning the inside of the mouth
Peptic ulcers
occur in esophagus, stomach or small intestine
- related to infection with H. pylori bacteria
- prescribe antibiotics
Gastroesophageal reflux (acid reflux)
Lower esophageal sphincter weakens; acidic stomach contents spill into esophagus resulting in a burning feeling (heart burn)
T/F: heartburn is a condition that does not directly involve the heart
True
Gastroesophageal Reflux Disease (GERD)
lead to the narrowing of the esophagus, promote an esophageal ulcer, which can then lead to a pre-cancerous condition called Barrett’s esophagus
Irritable Bowel Syndrome (IBS)
- affects the large intestine
- cause is unknown
Symptoms: abdominal pain, bloating, cramping, diarrhea, constipation and flatulence
IBS treatments focuses on alleviating symptoms like…
- Managing stress, finding/avoiding triggers, drinking plenty of fluids, getting adequate sleep and exercising
- Avoiding foods that promote gas, carbonated and alcoholic beverages, certain vegetables like broccoli, cauliflower and cabbage
Diverticula
- weakened walls of large intestine form outpouchings (common colon)
Diverticulitis
Diverticula becoming inflamed
Diverticulosis
Bleeding of the diverticula
Risk factors for diverticulitis
older, obese, smokers and physically inactive
- diet low in fibre and high in animal fat increase risk
Gallstones
hardened bile deposits that form stones in the gallbladder
- painful, especially when lipids are consumed and gallbladder contracts to release bile
Why do gallstones occur?
overabundance of cholesterol as compared to bile salts in bile
Risk factors that contribute to gallstones
- female, use of estrogen-containing contraceptives, obesity, rapid weight loss, physical inactivity, medications that increase cholesterol
- Diets higher in simple sugars, saturated fat and energy intake are also associated with a higher risk
Con of gallbladder removal
- less bile release during fat digestion
negatively impacts lipid digestion and individual may require reduced-fat diet to minimize symptoms (diarrhea, flatulence)
Cancer
- uncontrolled multiplication and spread of cells
- blocking important structures from performing and by consuming valuable energy required for proper tissue function
Colorectal cancer
- colon or rectum of large intestine
- highest mortality
- both genetic and lifestyle-related risk factors
Factors that increase risk of colorectal cancer
- Physical activity, obesity
- Diet high and processed meats
Factors that decrease risk of colorectal cancer
- physical activity, weight management, dietary modification
- Diet, high and vegetables, fruits, and fibre
Constipation
bowel movements that are difficult to pass or less frequent
- dry, hard, can be painful to excrete
T/F: Chronic constipation can increase the chance of hemorrhoids
True, swollen blood vessels in the anus and rectum that can become inflamed and painful
What causes constipation to occur?
- matter passes through large intestine more slowly
- allows for a greater degree of water absorption by large intestine, compacting the stool and making it more difficult to pass
Risk factors that cause constipation
Age, female, genetics, physical inactivity, certain medications, IBS
- diet low in fibre, vegetables, fruits and water
Diarrhea
matter passes quickly through the large intestine
- loose stools that have a liquid-like consistency
What causes diarrhea?
Bacterial and viral infections (food poisoning)
- protective mechanism to expel these infectious agents
T/F: Persistent diarrhea can promote dehydration
True, lot of liquid is lost in the stool
What does the liver do with nutrients delivered from veins via the capillary beds of small intestine villi
use them, store them, send them to the rest of the body or detoxify them
T/F: all nutrients end up in the liver
False. large lipids and fat-soluble vitamins are packaged and enter the lacteal vessels in the small intestine villi, moving through lymphatic vessels, which drain into the blood around the level of the collarbone.
- bypass the liver
What does the liver do if there is an immediate energy need
use absorbed sugars such as fructose
What does liver do if glycogen levels are low
store glucose in the form of glycogen until stores are full
Where do unused nutrients from liver go?
It enters the bloodstream and can then be sent throughout the body via the cardiovascular system
What organs help eliminate toxins
Skin, kidneys, lungs, digestive tract, liver
Persistent Organic Pollutants (POPs)
toxins are substances that can be found in food that can cause damage to the body
Metabolism
sum of all the chemical reactions that occur in an organism
What are the two types of metabolism?
anabolism and catabolism
Anabolism
- smaller molecules coming together to make larger ones
- require a net input of energy
Catabolism
- larger molecules breaking down into smaller ones
- net release of energy
Given an example of an anabolic reaction
Protein synthesis, which combines amino acids into specific chains requires an input of energy
Adenosine Triphosphate (ATP)
body’s energy currency
- 3 phosphate mlcs attached to an adenosine base
- catabolism of the energy-yielding nutrients (carbs, fats, proteins) leads to the release of energy
T/F: Cells break down energy-yielding nutrients through a catabolic process where energy is released
True
T/F: Cells break down energy-yielding nutrients through a catabolic process where energy is released
True
Adenosine Diphosphate (ADP)
ATP releases a phosphate group from the bond, releasing energy that can then be used for fuel
Adenosine Diphosphate (ADP)
ATP releases a phosphate group from the bond, releasing energy that can then be used for fuel
Where does cellular respiration occur?
mitochondria (“powerhouse”) of the cell
Cellular respiration
catabolism of the energy-yielding nutrients (sugars, triglycerides and amino acids) leading to the production of ATP
C6H1206 +602 →6C02 + 6H20 + ATP
Metabolic pathway
many metabolic steps
C6H1206 +602 →6C02 + 6H20 + ATP
Cellular respiration of glucose equation
C6H1206 +602 →6C02 + 6H20 + ATP
Glucose Metabolism
1: Glycolysis
Glycolysis = breakdown of glucose
- 6-carbon glucose broken down into 2 molecules of three-carbon pyruvate
- bonds are broken, energy released and captured in 2 mlcs of ATP
- Anaerobic reaction, no oxygen need
Anaerobic
Without oxygen
- useful when the body’s energy demands are high and we cannot deliver enough oxygen to the cells to fuel these needs
Lactate
increases blood acidity and causes discomfort
Ex: high intensity activities, sprinting, weight lifting
Glucose Metabolism
2: Breakdown of Pyruvate
- Condition depends on aerobic or anaerobic
Aerobic: pyruvate forms acetyl CoA with the addition of coenzyme (CO2)
Anaerobic: pyruvate is oxidized to lactate
Anaerobic Metabolism of Pyruvate
- some ATP is formed
- pyruvate is oxidized to lactate
- produces an acidic environment in the blood that is not sustainable
- process is reversible
- lactate converted back to pyruvate when oxygen is available again
- Pyruvate can then proceed through its aerobic breakdown
Aerobic Metabolism of Pyruvate
- pyruvate forms acetyl CoA with the addition of coenzyme A
- loss of some electrons, captured by electron transporter called NADH+H+
- Some carbon dioxide is also released in this process
Glucose Metabolism
3: Citric Acid Cycle
- series of chemical reactions that occur under aerobic conditions
- also called Tricarboxylic Acid (TCA) cycle and the Krebs cycle
- complex set of reactions that begins when acetyl CoA combines with oxaloacetate to form citrate
- Produces CO2 , water, and the capture of energy in GTP (≈ATP)
- electron transporters (NADH + H+, FADH2) capture electrons and move to the mitochondrial membrane to begin the electron transport chain
Glucose Metabolism
4: Electron Transport Chain
buildup of protons (H+) on one side of the membrane
- Electrons are exchanged between the electron transporters (NADH + H+, FADH2) and membrane-bound proteins
- protons enter a protein pump associated with enzyme ATP synthase
- process leads to the production of more than 30 molecules of ATP
ATP synthase
Step 4: The Electron Transport Chain
- bonding of phosphate group onto ADP, regenerating ATP
- Cellular respiration leads to the production of more than 30
molecules of ATP per molecule of glucose
Lipid metabolism
triglyceride molecule has three fatty acids attached to a glycerol backbone
- occurs in the liver
- Majority of energy is derived from fatty acids
- Beta-oxidation splits the fatty acid two carbon atoms at a time, entering citric acid cycle and then cellular respiration occurs
Beta-oxidation
Lipid metabolism
- Fatty acids broken down two carbons at a time to form acetyl CoA
What is main rule of amino acids in body?
promote the growth and repair of tissues
Amino acid metabolism
- nitrogen group of the amino acid must be removed (deaminated)
- 21 amino acids, each with unique side chain, so 21 possible products after an amino acid is deaminated
Amino Acid Metabolism:
Deaminated amino acids will be used to form what
Glucose, Acetyl CoA, Pyruvate or certain Citric Acid Cycle intermediates
Deamination
Removing the nitrogen containing amine group
Ketogenesis
- occur when diet is high in fat and very low in carbohydrates
- citric acid cycle requires carbs
- very low carb diet, fatty acids cannot enter citric acid cycle, instead form ketones
Non-energy uses of sugars, lipids, and amino acids
Consuming more energy than we need, most of the excess is stored as lipid in our fat tissue
T/F: The term microbiota refers to the different genetic material found in our body due to the presence of microorganisms such as bacteria
False, this is called the Microbiome
T/F: Foods such as broccoli, cauliflower and cabbage cause irritable bowel syndrom
False, cause is unknown, thought these food may trigger IBS symptoms
T/F: Prebiotics are typically medium-length carbohydrates
True
Once carbohydrates are absorbed, the first organ they encounter is the ________
Liver
Large lipids are absorbed into the ______________________ system
Lymphatic system
