The Digestive System Flashcards
What are the beliefs of diet and nutrition culture? And how should we look at nutrition and diet culture?
Calories in vs calories out.
Eat less, move more.
Need to appreciate the complexities of our bodies and the environment we live in.
What are the factors causing obesity?
Many factors cause obesity, not straightforward.
Involves more than just the individual or calories consumed.
Factors influencing obesity will be different in other countries.
What are the functions of the digestive system?
Break down the foods you eat, release their nutrients, and absorb those nutrients into the body.
Digestion
the enzymatic breakdown of food to components that can be absorbed into the blood for transport throughout the body.
Absorption
The movement of nutrients, salts, and water across the GI tissues into the bloodstream or lympathetic system.
Occurs mainly in small intestine but also a little bit in the large intestine.
Digestive tract (gastrointestinal tract or alimentary canal)
Hollow tube from mouth to anus that’s modified along the way to provide different functions
What are the components of the alimentary canal?
pharynx, esophagus, stomach, small intestine, large intestine
Accessory organs
Aid in digestion, but are outside of the alimentary canal
What are the accessory organs that aid in digestion?
Liver, gallbladder, and pancreas
What are the processes of digestion?
Propulsion involves swallowing and peristalsis.
Chemical digestion involves enzymes that breakdown food more to allow for absorption.
Mechanical digestion involves chewing, churning, segmentation. First occurs in the mouth, then stomach and sometimes in the large intestine before being expelled.
Absorption involves the nutrients and water move to blood vessels and lymph vessels. Occurs in the small intestine and large intestine.
What are the major functions of the stomach?
Storage of ingested food.
Mechanical breakdown of ingested food - chyme.
disruption of chemical bonds in food material by acid and enzymes.
Production of intrinsic factor, a glycoprotein required for absorption of vitamin B12 in the small intestine.
What are the three parts of the small intestine?
Duodenum, jejunum, and ileum
The Small Intestine
Chyme from the stomach enters the small intestine.
Name is based on diameter and not length; small in diameter and large in length.
Primary digestive organ in the body; where all absorption occurs (90% of water absorption).
Circular folds increases surface area therefore increasing absorption.
The Large Intestine
Consists of the cecum, colon, and rectum
Shorter in length but larger in diameter.
No circular folds but some villi.
What are the functions of bacteria flora in the large intestine?
Facilitate chemical digestion and absorption.
Synthesize certain vitamins, mainly biotin, pantothenic acid, and vitamin K.
Linked to increased immune response.
What are the functions of the large intestine?
Reabsorption of water (last 10%).
Compaction of intestinal contents into feces.
Absorption of important vitamins produced by bacteria.
Storage of fecal material prior to defecation.
The Liver
Largest gland in the body.
Has 2 lobes.
All substances leaving the absorptive surfaces of the digestive tract passes through the liver via the hepatic portal vein.
What are the functions of the liver?
Metabolic regulation: extract and stores excess nutrients and remove toxins from the blood; releases stored or synthesized fats, proteins, CHO, vitamins, and minerals.
Hematological regulation: synthesizes plasma proteins, removes circulating hormones, antibodies, and damaged red blood cells.
Bile production: breaks up fat droplets improving fat breakdown and absorption.
What are the two functions of the pancreas?
Exocrine function: produces pancreatic juice that is released via the pancreatic duct from digestive purposes.
Endocrine function: releases insulin and glucagon into the bloodstream to control blood sugar levels.
What is the main function of the gallbladder?
Stores and concentrates bile prior to excretion into small intestine.
What is the goal and process of chemical digestion?
Large food molecules must be broken down into subunits that are small enough to be absorbed by the lining of the GI tract.
Chemical digestion occurs from enzymes through hydrolysis (water breaks down a compound).
18 different enzymes are involved in chemical digestion.
What is lactose intolerance?
When the body does not have enough lactase enzyme produced by the small intestine (needed to digest milk).
Lactose in the chyme is not digested resulting in it moving into large intestine where the bacteria ferments it and leads to the production of gas, abdominal cramps, bloating, and diarrhea.
What occurs in absorption of nutrients in the body?
GI tract processes up to 10L of food, liquids, and GI secretions, but most of this is absorbed in the small intestine.
What is the main goal of the mechanical and digestive processes?
Convert food into molecules small enough to be absorbed by the epithelial cells of the intestinal villi of the GI tract.
