Digestive System Flashcards
Four processes of digestion
ingestion, digestion, absorption, and elimination
____ is the term for the secretions of the three sets of salivary glands of the mouth.
Saliva
____ is an enzyme contained in saliva that begins the digestive process of starches
amylase
_____ is the involuntary movements of circular and longitudinal muscles, which begins and draws the bolus (ball of food) farther into the GI tract.
peristalsis
What are the four layers of tissues that form the tube of the GI tract
serosa, muscularis, submucosa, mucosa
The _____ is composed of mucous membrane and forms the inside layer of the GI tract
The mucososa
Under the mucosa is the ___, a layer of connective tissue.
submucosa
Surrounding the submucosa is a thick layer of muscle tissue called the ______
muscularis
The outermost layer of the GI wall is made of serous membrane called ______, which is actually the visceral layer of the peritoneum lining the abdominal pelvic cavity, and covers organs.
serosa
The combined effect of the circular and longitudinal muscles causes _____, a forward-and-backward movement that assists in controlling food mass movement through the GI tract.
segmentation
Functions of the _____ include: • Holding food for partial digestion
• Producing gastric juice
• Providing muscular action that, combined with gastric juice, mixes and tears food into smaller pieces
• Secreting the intrinsic factor for vitamin B12 absorption
• Releasing gastrin
• Assisting in the destruction, through its acidity of secretions, of pathogenic bacteria that may have inadvertently been consumed
stomach
____ is a semiliquid mixture of food mass that passes from the stomach into the small intestine
chyme
____ (also known as pancreozymin) is a hormone secreted by intestinal mucosa that stimulates the digestion of fat and protein
cholecystokinin (CCK)
enzyme
proteins that act as catalysts to break down food
hormone
Compounds formed in endocrine glands that affect the functions of specifically receptive organs or tissues when transported to them by the body fluids
Gastric motility, or movement of the food mass through the ____, requires 2-6 hours.
stomach
The hormone _____ sends the message that hydrochloric acid (HCl) must be secreted to break down food into chyme
gastrin
Every 20 seconds chyme is released into the _____, the upper portion of the small intestine;
duodenum
It takes about 5 hours for chyme to pass through the _____ because of the action of segmentation and peristalsis
small intestine
Finger-like projections called ____greatly increase the amount of mucosal layer available for the absorption of nutrients in the small intestine
villi
____ , which is secreted by the liver and stored in the gallbladder, is released to emulsify fats, aiding in the digestion of lipids.
Bile
____ is the hormone that causes the pancreas to send bicarbonate to the small intestine to reduce the acidic content of chyme
Secretin
_____ and _____ spur the gallbladder to release bile for the digestion of fats
CCK and secretin
The journey through the ____ takes about 9 to 16 hours.
large intestine
In the ____, final absorption of any available nutrients, usually water and some minerals, occurs.
colon (aka large intestine)
During passage through ____ more than 95% of the carbohydrates, fats, and proteins ingested are absorbed.
the GI tract
_____ is the process by which substances pass through the intestinal mucosa into the blood or lymph.
Absorption
Passive diffusion and osmosis, facilitated diffusion, energy-dependent active transport, and engulfing pinocytosis are all examples of ____
absorption
_____ occurs when pressure is greater on one side of the membrane and the substance then moves from the area of greater pressure to less pressure, allowing molecules to travel through capillaries.
Passive diffusion
_____ takes place when, despite positive pressure flow, molecules may be unable to pass through membrane pores unless aided. Specific integral membrane proteins support the movement by bringing the larger nutrient molecules through the capillary membrane.
Facilitated diffusion
Energy-dependent _____ happens when fluid pressures work against the passage of nutrients. Energy is supplied by the cell and a “pumping” mechanism, which are assisted by a special membrane protein carrier.
Active transport
______ takes place when a substance, either a fluid or a nutrient, contacts the villi membrane, which then surrounds the substance and creates a vacuole that encompasses the substance. Passing through the cell cytoplasm, the substance is then released into the circulatory system.
Engulfing pinocytosis
_____ is a membrane-bound cavity within a cell, often containing a watery liquid or secretion.
vacuole
cytoplasm
All of the material within a cell, enclosed by the cell membrane, except for the cell nucleus.
True or False: Nutrients such as fats, carbohydrates, and protein are easily absorbed by the body regardless of the level of need.
True
Soon after entering the bloodstream, nutrients pass by the ___ This arrangement allows it to have “first choice” of the available nutrients.
liver
Total number of hours from ingestion to elimination
16-27
_____ is a set of processes through which absorbed nutrients are used by the body for energy and to form and maintain body structures and functions.
Metabolism
The two main processes of _____ involve catabolism and anabolism and occur simultaneously
metabolism
_____is the breakdown of food components into smaller molecular particles, which causes the release of energy as heat and chemical energy.
Catabolism
_____ is the process of synthesis from which substances are formed, such as new bone or muscle tissue.
Anabolism
____ and ____ act as catalysts or coenzymes to initiate and support the transformation and use of carbohydrates, proteins, and lipids.
Vitamins; minerals
