Digestion (week 1) Flashcards

Question

Carbohydrate digestion

Answer 1

salivary enzymes begin the breakdown of sugars minimal chemical or enzymatic carbohydrate digestion in the stomach pancreatic and brush border enzymes in the small intestine/duodenum break complex carbohydrates down into absorbable monosaccharides: -glucose, fructose, galactose -undigested/absorbed resistant starch, fibers, FODMAPs will be passed into the colon for bacterial fermentation and bulking of stool saccharide is another name for sugar carbohydrate digestion is based on the ability to break glycosidic bonds between saccharides microbes have different carbohydrate enzymes basis for prebiotics, fibers, and some elimination diets

Answer 2

chewed and swallowed as bolus HCL and pepsin in stomach cleavage of peptide bonds amino acids move to small intestine, for additional breakdown by pancreatic proteases microvilli in small intestine absorb amino acids carried through bloodstream to parts of body tissue repair, hormones, enzymes, muscle, etc

Answer 3

lingual lipase starts lipid digestion dietary fat in duodenum triggers release of CCK, which triggers release of bile bile emulsifies larger fat droplets into small micelles lipase is released into small intestine by pancreas, which continues fat breakdown primary dietary lipids include triglycerides, phospholipids, and cholesterol esters -triglycerides are hydrolyzed into monoglycerides (one glycerol bond to fatty acid chain), free fatty acids, and glycerol molecules -phospholipids are hydrolyzed into free fatty acids and smaller phospholipid particles -cholesterol esters are hydrolyzed to free cholesterol and free fatty acids fat soluble nutrients lipids are absorbed through the microvilli in the small intestine pathway depends on size: -glycerol molecules, short & medium chain fatty acids can be absorbed directly into blood stream -long chain fatty acids, monoglycerides, fat soluble vitamins, and cholesterol will be incorporated into chylomicrons are absorbed into the lymphatic system used for energy, stored fuel, immune balance, cell membrane synthesis & regulation, tissue repair, hormone function

Answer 4

the idea that some foods pair well and others do not some plans categorize by dominant macronutrient, others by pH, etc largely based on the observation that foods are digested at different speeds and require different enzymes to be digested physiological perspective: -humans have always eaten a combination of nutrients -digestive tract can digest multiple macros at the same time -whole foods contain multiple macronutrients -enzymes are released regardless of whether certain macronutrients are present

Answer 5

pH of blood is tightly managed to ensure survival pH compartmentalization in different tissues and secretions breathing regulates system pH by exhaling carbon dioxide kidneys regulate systemic pH: -excrete hydrogen ions (H+) into urine -recycle bicarbonate back into the bloodstream buffering systems exist within individual cells acidic foods increase the acidity of urine, but in most healthy individuals, they do not change to systemic pH diets rich in alkaline minerals are always helpful individuals with impaired kidney or lung function may need additional care

Answer 6

Central nervous system (CNS) includes the brain and spinal cord Peripheral nervous system (PNS) includes all of the nerves that exist outside of the brain and spinal cord The PNS is further divided into the sensory division (also called afferent with an “a”) and the motor division (also called efferent with an “e”). You can remember this because “affect” is a verb – so think of being affected by the world around you...the beautiful sights, sounds, and smells that tell you about your environment. Whereas effect is a noun – it is the result of your response - it is what you create. You receive information from the world through the afferent parts of the PNS, integrate it into the CNS, and then use the efferent nervous system to respond using the efferent nervous system. Somatic is related to the more superficial parts of the body such as the musculoskeletal system and the skin, and is associated with voluntary functions like moving your body or touch Visceral is related to the internal organs and glands and is associated with involuntary functions and sensations like heart rate or blood pressure. Visceral/efferent = ANS - autonomic nervous system

Answer 7

Sympathetic Nervous System: -governs stress response -fight or flight -shuttles resources to immediate survival -decreases gastrointestinal activity Parasympathetic Nervous system: -rest and digest -increases blood flow to GI tract -activates digestive functions

Answer 8

Dual innervation: -sympathetic: thoracic nerve branches -parasympathetic: cranial and sacral nerves -vagus nerve connects the gut brain -a dynamic balance between autonomic branches, spoken of in terms of tone or dominance -vagus nerve connects the gut brain increasing the parasympathetic tone before eating is an upstream "northernmost" approach to digestive wellness

Answer 9

"Second brain" complex neural network in the wall of digestive tract functions on its own, as well as in coordination with central nervous system and endocrine system two main plexuses (or systems): -myenteric plexus: gastric motility -submucosa plexus: gastric secretions and blood flow regulation constant cross talk with brain to coordinate appetite, immune response, hormone secretions, intestinal barrier functions, and more

Answer 10

-secreted from stomach -stimulates hunger -levels increase while fasting and decrease when fed

Answer 11

-secreted from the adipose tissue -acts as an appetite suppressant -counter-regulatory to ghrelin's signal -tells the brain about food intake need over the long term -dysregulation can result in leptin resistance and increased appetite

Answer 12

-secreted from the ileum and upper large intestine after eating -slows digestive transit to aid absorption and increase satiety -high levels are associated with poor food intake, low levels are associated with increased food intake

Answer 13

-secreted from the small and large intestines -stimulated by food intake, slows gastric emptying, decreases appetite, and promotes the release of insulin to help regulate blood glucose levels -GLP-1 receptor agonists are drug targets in the treatment of T2DM

Answer 14

trillions of bacteria, fungi, viruses, parasites, and other microbes ~90% gut bacteria are obligate anaerobes (oxygen sensitive) making research challenging genetic sequencing - human microbiome projects (launched 2007) initiated a new era in microbiome research metabolic capacity 100x greater than the liver

Answer 15

-structural integrity of mucosal lining -protections against pathogenic organisms -metabolizes complex carbohydrates to produce SCFA's -synthesizes B vitamins and Vitamin K -helps breakdown and metabolize polyphenols -converts amino acids into neurotransmitters -reduce antigenicity of foods and induce oral tolerance -interfaces with our immune system

Answer 16

Refers to nutrients, primarily carbohydrates, that preferentially feed strains that are associated with health benefits. The key word here is preferentially – so we are selecting the nutrients that the beneficial strains thrive on, and are simultaneously less likely to fuel the growth of pathogenic strains

Answer 17

Refers to the actual living organisms themselves (used to refer to the food and supplements that contain the microorganisms)

Answer 18

Refers to the metabolic byproducts from microbes, which are more and more recognized for eliciting biological responses in the host and other members of the microbiota

Answer 19

Strains of microbes that have a stable colony in your GIT. They often colonize in early life, and populations can ebb and flow over a lifetime based on environmental factors like the rest of the microbiota, diet, medications, health status, etc. Resident microbes can adhere to the surfaces of the intestines, taking up those parking places in your intestinal terrain. When we talk about altering the microbiome with prebiotics, we are generally talking about shifting the existing populations of resident microbes by altering their food supply, rather than ingesting new microbes (both are valid approaches).

Answer 20

Commensal is another term that often refers to healthy indigenous populations and the way they live in balance with a healthy level of non-competition that allows them all to “eat from the same dish,” so to speak. Webster's dictionary defines commensalism as “a relation between two kinds of organisms in which one obtains food or other benefits from the other without damaging or benefiting it.”

Answer 21

Microbiota consumed in things like food or supplements, but only remain in the GIT for 2-3 weeks after ingestion. While they may not adhere and set up permanent colonies, they can still have a major impact on health while they are present. They can exert influences that help alter the resident terrain as well.

Answer 22

Describes microbial populations that are not typically considered pathogenic in normal situations/levels but have become problematic after expanding their population in number or location as a result of certain environmental conditions. These microorganisms may be present in very small amounts in healthy individuals while the immune system and commensal microbes are able to suppress populations but can escalate into an infection when the host immune system is compromised. An example is the overgrowth of candida that is normally present but may get overgrown after a course of antibiotics depletes the beneficial bacteria populations.

Answer 23

-imbalances between the beneficial and harmful microbiota -changes in population numbers, types, function, or shift in their location -resident microbes can be healthy or problematic depending on the balance -no one single type of dysbiosis -altered ratio between the two major phyla groups, Firmicutes and Bacteroides -complex ecosystems tend to self regulate = biodiversity is key

Answer 24

-refined carbohydrates (a-cellular) linked to more inflammatory and less diverse microbial profile -artificial sweeteners have varying impacts -excessively high saturated fat and/or undigested protein content can have negative impacts, which are mitigated by the presence of fiber/prebiotics/polyphenols -diets rich in fruits, vegetables, and fibers are clearly associated with a more robust and diverse gut microbiome

Answer 25

Probiotic rich/fermented foods: -sauerkraut -kimchi -kefir -miso -natto -kombucha Prebiotic rich foods/indigestible fiber: -legumes -dandelion greens -artichokes -berries -garlic, onion, leeks -asparagus -bananas -seaweed -flax some dysbiotic conditions like SIBO should be approached with caution some high FODMAP foods can worsen symptoms of gastrointestinal conditions like IBS

Answer 26

begins developing at time of birth, diversity matches adult by 2.5 years maternal vaginal microbiome is primary source of inoculation in vaginal birth prenatal exposure to antibiotics and C-section deliveries can delay or alter colonization research into vaginal seeding and supplementation with pre and probiotic strains to support development of healthy microbiome: -vaginal seeding: not currently endorsed by major gynecological organizations, research is ongoing -pre and probiotics shown to restore normal microbial profiles in both infants exposed to antibiotics at birth and cesarian delivery by 6 months of age prebiotic sugars, fatty acids, and immune factors in breast milk influence colonization adding prebiotics to formula can promote microbiome diversity similar to breastfeeding

Answer 27

* Age * Geographical location * Environmental exposures * Smoking * Infections * Chemical consumption including pesticides, insecticides, and herbicides( glyphosate) * Chronic antibiotic or prescription medication use * Poor dental hygiene * High levels of stress and anxiety, or a history of trauma * Regular alcohol consumption * Excessive hygiene/lack of exposure to soil, plants, and other animals

Answer 28

overuse can promote dysbiosis degree of impact and return to pre-treatment status depending on: -microbiota before treatment -age -genetics -diet & lifestyle -duration of treatment, dosage, antibiotic class can have far reaching effects throughout the body concurrent use of oral probiotic supplements mitigates damages and reduces risk of opportunistic infection

Answer 29

GALT = gut associated lymphoid tissue ~70% of total immune system ~80% of activated B cells impacts intestinal permeability, food tolerance, immunity against pathogens, self recognition, dampen or amplify systemic inflammation Peyer's patches: lymphoid follicles in intestinal mucosa that contain immune cells: macrophages, T cells, B cells, and dendritic cells