Module 6 Flashcards
The 3 primary functions of the digestive system of food molecules that can then be used for both energy and building blocks for the entire body are what?
- Aquisition
- digestion
- absorption
where does energy come from?
the organic molecules that we consume (carbs, fats, proteins)
organic molecules are broken down by what two things?
- Aerobic cellular respiration
- ATP
Carbohydrates: ___ Kcal/gram
Fats: __ Kcal/gram
Proteins: __ Kcal/gram
Carbohydrates: 4 Kcal/gram
Fats: 9 Kcal/gram
Proteins: 4 Kcal/gram
What should we eat to get the proper amounts of energy and the proper number of building blocks to maintain homeostasis in the human body?
Carbohydrates: 250-800 g/day; 2/3 starch, 1/3 (sucrose & lactose)
Fats: 25-160 g/day
Proteins: 40-50 g/day
(can differ depending on size of person and amount of exercise)
The two basic processes that occur in the digestive system
- Digestion
- Absorption
the breakdown of food either mechanically or chemically
digestion
the movement of food from the lumen of the gastrointestinal tract into the blood or lymph fluid
absorption
what is the process of physically separating two different food molecules to increase the surface area of food for an increase in the efficiency of chemical digestion?
provide an example
Mechanical digestion
ex: Chewing: teeth tear apart large clumps of food into smaller clumps of food that are easier to swallow and allow access of enzymes to more of the food’s surface at any given time
Oftentimes the GI tract is described as a “tube within a tube” because the inside of the GI tract is technically outside the body. (T/F)
True
What is the flow of the GI Tract?
Mouth & Pharynx > Esophagus > stomach > Small Intestine > Large Intestine > Rectum > Anus
What provides the first bit of mechanical digestion?
Chewing or “mastication”
How many pairs of salivary glands add saliva to food?
Three
when a single molecule of a food substance is broken down into smaller molecules that can be moved across the wall of the intestine in absorption?
provide an example
Chemical digestion
ex: Enzymes catalyze the chemical reactions that break apart food molecules.
What does saliva contain that lubricates food for swallowing?
Mucous
The wall of the GI tract consists of what 4 basic layers?
- mucosa (innermost)
- submucosa
- muscularis externa
- serosa (outermost, surface)
What does water in saliva help with?
breaking ionic bonds in food substances to facilitate taste
What is the role of salivary amylase?
start the digestion of carbohydrates
What tube leads from the mouth to the stomach?
Esophagus
T or F the mucosa consists of 3 layers
True
Peristaltic movements in the esophagus help with what?
moving food along the path
determine each layer of the mucosa as the following: Lamina propria, mucous membrane, muscularis mucosae.
- smooth muscle that contracts the mucosa into folds to stir the lumenal contents and promote contact between the digested material and the mucosal surface.
- composed of epithelial cells called “enterocytes”, absorptive cells, and endocrine cells including goblet cells that secrete mucous and endocrine cells that secrete hormones
- contains connective tissue that includes blood vessels, nerves, lymphatic vessels, lymph nodules, and Peyer’s patches.
- muscularis mucosae
- mucous membrane
- lamina propria
What three parts is the stomach composed with?
- fundus
- body
- antrum
the fundus, the body, and the antrum are about 1.______ ml when empty but can stretch to over 2._______ ml when full.
- 50 ml
- 1000 ml
What do parietal cells in the lining of the stomach secrete?
HCl
what 3 things does the secretion of HCl in the stomach do?
- solubilize food
- kill microbes
- activate pepsinogen to pepsin
determine each of the 4 layers for the wall of the GI tract as the following: mucosa, submucosa, muscularis externa
or serosa.
- thick layer of connective tissue that provides the intestinal tract with much of its distensibility and elasticity; contains Meissner’s (submucosal) plexus
- contains two layers of connective tissue; The inner layer is composed of fibrous connective tissue for structural support. The mesothelium is continuous with the mesenteries and secretes a watery fluid for lubrication.
- consists of 3 different layers: muscularis mucosae, mucous membrane, and the lamina propria
- two layers of smooth muscle and the Myenteric (Averbach’s) plexus; The layer of circular muscle is used for lengthening and narrowing the tube and the layer of longitudinal muscle is used for shortening and widening the tube.
- Submucosa
- Serosa (Adventitia)
- Mucosa
- Muscularis Externa
Parietal cells in the stomach secrete 1. __________ __________ that binds to _____________ ____ and allows it to be absorbed across the intestine wall?
- intrinsic factors
- Vitamin B12
Chief cells do what in the stomach
secrete pepsinogen that gets converted into pepsin
What breaks peptide bonds in long polypeptides to make shorter polypeptides?
Pepsin
not part of the direct pathway of food through the GI tract but add important substances to the GI tract or play an important role in digestion.
accessory organs
Why do mucous secreting cells secrete mucous in the stomach?
to protect the stomach lining from the gastric fluid which can have a pH below 1.
In response to food, endocrine cells secrete gastrin which regulates what 2 things?
- acid secretion
- muscle contraction
The small and long intestine are called that because of its length, not its diameter (T/F)
FALSE, it’s because of the diameter not the length
determine the accessory organ:
3 pairs, start chemical digestion of polysaccharides in mouth, secrete mucous for lubrication, and add water to food to aid in taste
salivary glands
determine the accessory organ:
secretes bicarbonate and digestive enzymes into small intestine
pancreas
determine the accessory organ:
stores and concentrates bile between meals
gallbladder
determine the accessory organ:
secretes bicarbonate to neutralize acid from stomach, secretes bile for the emulsification of fats, produces fibrinogen, synthesizes many proteins, cholesterol metabolism, endocrine function
liver
The pancreas releases what 5 substances into the small intestine to further chemical digestion of proteins, carbs, fats, and nucleic acids?
- proteases
- amylases
- lipases
- nucleases
- sodium bicarbonate
What increases surface area and allow for the absorption of the quantity of food a body needs in the small amount of time that food substances are actually in the GI tract.
Finger-like projections formed by the villi
Enzymes in the cells of the villi break 1. __________into amino acids, disaccharides into 2. ______________ and recombine fatty acids and 3. ___________ into fats inside the cells of the villi.
- Peptides
- monosaccharides
- glycerol
Fats move into the lymph system to be processed by the spleen before entering blood and everything else moves into blood stream. (T/F)
FALSE, before entering the LIVER not SPLEEN
The primary job of the large intestine
reabsorb water and SOME salts
An extremely small population of microorganisms populates the large intestine. (T/F)
FALSE, an extremely LARGE pop. does
What 2 things do microorganisms in the large intestine do?
- synthesize certain vitamins
- break apart bonds in carbs
Rectum
storage area for feces before it is expelled from the body.
How is movement of food through the GI tract is accomplished ?
peristalsis
Opening in the GI tract through which bacteria and undigested materials exit.
anus
Peristalsis is the alternate contraction of 1.__________and
2. ___________ muscles to create
3. “________” of contraction through the intestine to push food along the path.
- circular
- longitudinal
- waves
