Module 2 Flashcards
How is food used by our bodies?
Growth, energy, fortification of immune system
Digestion process before food enters mouth
Cognition (thought of food can trigger saliva)
Sound (hearing a description of food)
Smells
Appearance
Taste
Digestion process once food enters mouth
Chemical process - enzyme, acids, bile, mucus
Mechanical process - chewing, churning
Peristalsis
What’s the role of enzymes?
Proteins that act as catalysts for chemical reactions to help break down large food particles into smaller particles
What is absorption in the scope of digestion?
Process of getting nutrients accross the gi tract wall and into cells
Innermost layer of the gi tract
Intestinal wall or mucosa
Role of muscles of the gi tract
Mix and move food along the way
Role of the circular bands of muscle of the gi tract which connect one segment to the other
Act as valves to control flow of food particles from one segment of the tract to the next segment
What are the types of absorption ?
Passive diffusion - no energy required
Facilitated diffusion - no energy required but uses a protein carrier
Active transport - requires energy (ATP) and moves nutrients from a low concentration to high concentration
How do the absorption types differ ?
Both passive and facilitated diffusion move nutrients from higher to lower concentration without using energy, but facilitated diffusion uses a protein carrier, where passive diffusion doesn’t.
Active transport uses energy to move nutrients from low to high concentration
What is peristalsis ?
Involuntary muscle contractions of the gi tract that move food along the tract.
6 main parts of the GI tract
Mouth
Esophagus
Stomach
Small intestine
Large intestine
Rectum
4 main organs that produce and secrete substances that aid in digestion but are NOT part of the GI tract
Salivary glands
Liver
Gallbladder
Pancreas
Mouth’s role in digestion
Alter food via mechanical and chemical processes to prepare them to be swallowed. Salivary glands secrete saliva.
What is saliva ?
Watery fluid containing both a lubricant (mucus) and enzymes to prepare food for the next step in the gi tract.
The role of mucus in the mouth for digestion
Mixes with food, lubricating particles to make them easier to swallow
Enzymes in the mouth and their role in digestion
Salivary amylase - breaks down starches
Lingual lipase - breaks down fats
What are the 5 flavors ?
Sweet
Salty
Sour
Bitter
Umami (meaty flavor)
Esophagus role in digestion
Connects throat to stomach. Transports food to stomach.
Epiglottis folds down over trachea (wind pipe) during swallowing to prevent aspiration.
Peristalsis begins, propelling food onward.
A sphincter muscle is located at the end of the esophagus to prevent backflow of stomach contents.
The stomach
Has a 4 cup capacity and can hold food for 2+ hours until it’s ready to pass into the small intestine.
It stores, mixes, dissolves, and continues the digestion of food.
Food is mixed with gastric juice and enzymes. The acid in the gastric juice prepares proteins for digestion and activates enzymes (pepsin and gastric lipase).
Participants in the stomach
Pepsin (enzyme) - breaks down proteins
Gastric lipase (enzyme) - begins fat digestion
Chyme - resulting substance when food mixes with stomach acids and enzymes. Watery mixture that slowly empties from the stomach into small intestine. This process occurs over a pd of 1 - 4 hours depending on meal size.
Gastrin - hormone that controls the concentration of acid in the stomach. It’s produced once we begin thinking about eating, as well as during ingestion. Levels of stomach acid must be closely regulated to prevent destruction of the stomach wall. Mucus is secreted to line and protect the stomach from its high acidity.
Intrinsic factor (IF) - a vital glycoprotein produced in stomach. IF must be present for vitamin B-12 to be absorbed.
Pyloric sphincter
Connects stomach to the small intestine and controls the release of chyme into small intestine.
Small intestine
Approx. 20 feet long, connecting stomach to large intestine. The vast majority of all digestion and nutrient absorption occurs here.
Duodenum - first and widest section
Jejunum - middle section
Ileum - final section, connects to large intestine
Villi
Finger-like projections within the folds of small intestine which help trap food. Necessary for digestion and absorption. They expand the absorptive surface area of the small intestine. Vast majority of nutrients absorbed here. Fat-soluble nutrients go into the lymph system, while other nutrients are absorbed into the blood.
Liver
Secretes bile
Gallbladder
Stores bile until a hormonal signal tells it that fat entered the small intestine. It then releases bile into duodenum through the common bile duct. Bile begins to emulsify the fat into smaller pieces that can be mixed with water.
Pancreas
Releases pancreatic juice (mix of water, bicarbonate, enzymes) which breaks down carbs, protein, and fats. Bicarb neutralizes the acidity of the chyme to protect intestinal wall. Glucagon and insulin are hormones released by pancreas to help with glucose regulation.
Why is bicarbonate important in the small intestine ?
It neutralizes the acidity of the chyme to protect intestinal wall. Without bicarb, the high acidity would destroy the lining of small intestine, resulting in an ulcer.
Ileocecal sphincter
Connects small intestine to large intestine. Prevents large intestine contents from reentering small intestine.
Large intestine
5 feet long, aka the colon. Sections are ascending, transverse, descending, and sigmoid. No major digestion or nutrient absorption here, but remaining water and certain minerals can be absorbed. As food waste passes through, feces is produced. Feces remains in rectum until muscular contractions push it to the anus. Feces expulsion is controlled by 2 anal sphincters.
Role of mucus in large intestine
Hold feces together and protect intestine from the bacteria which helps break down remaining food and some fiber.
Probiotics
Foods that contain good bacteria such as Bifidobacteria and lactobacilli. They help protect the body from disease causing bacteria and are important to immune system. Fermented milk and yogurt are examples of marketable probiotics.
Prebiotics
Substances that stimulate bacterial growth in large intestine
Heartburn
Acid reflux. Stomach acid climbs the esophagus. Esophagus not lined with mucus, so this can cause pain, coughing, gagging or hoarseness.
GERD
Gastro esophageal reflux disease, diagnosed when a person experienced heartburn several times /week. Primary cause is esophageal sphincter dysfunction. If sphincter is weak or relaxed, it doesn’t close to prevent stomach contents from traveling back into esophagus.
Dietary treatments include eating smaller low fat meals, not lying down for 2 hours following meal, chew food well, don’t overeat, and limit coffee/tea/alcohol/certain spices. Smoking and certain medications are also risk factors for GERD.
Constipation
Hard, dry, and infrequent feces resulting in slow movement through large intestine. Problematic meds include calcium and iron. Eating high fiber foods like fruit, veggies and nuts will stimulate the large intestinal muscles. Liquid intake should also increase with fiber increase to help form soft bulky stool. Ppl may experience gas without inreasing liquid intake.
Diarrhea
Loose, watery, frequent stools. Usually results from infection, disease, or antibiotics. Severe cases can cause dehydration, excess sodium loss and potassium loss. Fluids containing these minetals and sugar may be recommended as treatment. Broth, tea, toast, and low fiber foods should be eaten as tolerated.
Why did I stop the flashcards here?
This process was more time consuming than typing notes out in google doc and i feel more secure with them saved in google
