Digestive System Flashcards
Taking food and water into the
mouth
Ingestion
chewing, mixing, and churning
food
mechanical digestion
digestive, enzymes breakdown food
chemical digestion
movement of nutrients from
the GI tract to the blood or
lymph
Absorb nutrients
elimination of indigestible solid
wastes
Release of waste
Two groups of organs in the
digestive system
- Digestive tract
- Accessory digestive organs
A muscular tube that runs through the body and is responsible for the digestion and absorption of food -oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, and anus.
Digestive tract
Aid in the breakdown of foodstuffs- teeth, tongue, salivary glands, liver,
gallbladder, and pancreas
Accessory Digestive Organs
The process of digestion
includes six activities:
The process of digestion
includes six activities:
- Ingestion
- Propulsion
- Mechanical or physical
digestion - Chemical digestion
- Absorption
- Defecation
Taking food into the mouth
Ingestion
Movement of food through the digestive tract.
Propulsion
voluntary process
swallowing
Consists of sequential, alternating waves of contraction and relaxation of alimentary wall smooth muscles, which act to propel food along.
Peristalsis
involuntary process
Peristalsis
These waves also play a role in mixing food with digestive juices.
Peristalsis
Does not change the chemical
nature
Mechanical digestion
The mechanical churning of food in the stomach also serves to further break it apart and expose more of its surface area to digestive juices, creating an acidic “soup” called_________.
chyme
occurs mainly in the small intestine, consists of localized contractions of circular muscle of the muscularis layer of the
alimentary canal that isolate small sections of the intestine
Segmentation
By moving food back and forth in the intestinal lumen, segmentation mixes food with digestive juices and facilitates
Absorption
Starting in the mouth,_________ break down complex food molecules into their chemical building blocks (for example, starch into smaller polysaccharides).
digestive secretions
These secretions vary in composition, but typically contain water, various enzymes, acids, and salts. The process is completed in the______.
small intestine
Iron is absorbed in the_______
duodenum
Water and lipids are absorbed
by_____. What type of diffusion?
Passive Diffusion
The final step in digestion, undigested materials are?
removed from the body as feces
In the mouth, the food is chewed and mixed with saliva, which contains
enzymes
Further mechanical and chemical digestion takes place.
In the stomach
Most nutrients are absorbed from the lumen of the
alimentary canal
From the stomach, chyme is propelled to the?
small intestine by
peristalsis
Undigested food is propelled to the large intestine for?
final absorption of water and excretion
proteins that speed up chemical reactions in the body
Digestive enzymes
Digestive enzymes are released or secreted by what organs?
Digestive system
produced in the mouth; helps break down large starch molecules into smaller sugar molecules
Amylase
produced in the stomach; helps break down proteins into amino acids
Pepsin
produced in the pancreas; also breaks down proteins
Trypsin
produced in the pancreas; breaks down fats
Pancreatic lipase
Pepsin is active only when?
there is food to digest.
A layer that stomach secrets to protect itself from the acidic environment
layer of mucus
Functions of HCl
1) Activates inactive pepsinogen into active pepsin
2) Kills bacteria
3) Makes the medium acidic which is suitable for pepsin to
act on proteins
