Chapter 2 Flashcards
what is digestion
digestion is the process where foods are broken down into their nutrients
what are the major components of digestion
the mouth, liver, stomach, pancreas, small and large intestines and the rectum
what are the 2 categories digestion is broken down into
mechanical digestion and chemical digestion
what is mechanical digestion
mechanical digestion includes chewing food, the churning actions of the stomach and peristalsis
what is peristalsis
peristalsis is the rhythmic contractions of the intestines
what does mechanical digestion do
mechanical digestion breaks food into smaller and smaller particles and mixes the food with digestive juices
what is chemical digestion
chemical digestion is the action of enzymes as they break down food into simpler forms which can be absorbed by the body
what are enzymes
enzymes are substances that cause a breakdown in other substances, they are specific to their action
what are co-enzymes
co-enzymes are required by enzymes to function, they are produced in the body from vitamins and minerals that have been ingested
what does digestion do
digestion prepares food for cellular intake by ensuring the nutrients must be small enough to be absorbed and are broken down by mechanical and chemical means, this occurs in the digestive tract and the food is moved by peristalsis
what is the mouths role in digestive actions
the chewing begins the breakdown of food into small pieces and mixes with saliva
what is insalivation
insalivation is the process of mixing food with saliva
what is released from the saliva
salivary amylase
what is salivary amylase
the enzyme found in saliva and it acts only on carbohydrates, it breaks them down into simple sugars that the body can use
what is the digestive process in the mouth
mastication breaks up the food along with the tongue, lips, cheek, and palate and mixes in saliva, the food is then passed into the pharynx, through the esophagus and into the stomach
what happens once food enters the stomach
the churning of the stomach further breaks down food by mixing with the enzymes pepsin and HCI
what is the stomachs process in the digestive system
the stomach provides the churning action needed for the breakdown of food and it serves as a temporary storage house for food
do proteins and fats break down in the stomach?
partial breakdown of proteins and fats occurs in the stomach
is food constantly churned in the stomach?
food is constantly churned and mixed with gastric juice until chyme is formed
what is chyme
chyme is a mixture that is the consistency of a liquid created from the mixture of food and gastric juice
what does gastric juice contain
gastric juice contains hydrochloric acid, and the enzymes protease, renin, and lipase
what part of digestion occurs in the small intestine
partially digested food passes through the stomach into the first part of the small intestine (duodenum)
when is digestion completed
digestion is completed after passing through other parts of the small intestine (jejunum and ileum)
where are digested nutrients absorbed
digested nutrients are absorbed into circulation, aided by villi
where does the most digestive activity occur
the most digestive activity occurs in the small intestine, absorption of the most nutrients including vitamins and minerals occurs here
what does the small intestine use to help breakdown food
bile, pancreatic juice, and intestinal juice
what is bile made by
bile is made by the liver
where is bile stored
bile is stored in the gallbladder
what is the function of bile
the main function of bile is to breakdown fat through emulsification, it is released directly into the small intestine for fat digestion
what is emulsification
emulsification is the process of breaking down fat into tiny globules which allows the fat splitting enzymes to have greater contact with the fat molecules
what is pancreatic juice
pancreatic juice is made by the pancreas and released directly into the small intestine, it contains trypsin, lipase, and amylase
what is trypsin
trypsin is an enzyme used to break down protein into smaller molecules and some amino acids
what is the function of lipase
lipase completes the digestion of fats
what is the function of amylase
amylase breaks down starch
what is intestinal juice
intestinal juice is produced by the intestine and contains additional protein and sugar splitting enzymes
what part of digestion occurs in the large intestine
digestion is essentially complete once the food reaches the large intestines, Vitamin’s K, B-complex, electrolytes and water are absorbed here, once the water is absorbed the intestinal contents become feces
how is feces eliminated from the body
feces are eliminated through the rectum
what is the process of digestion in the large intestine
it begins in the cecum and then travels through the ascending colon, transverse colon, and descending colon - waste material passes into the sigmoid colon
what is the function of the salivary glands
the salivary glands secrete enzymes that begin the digestion of starch
what is the function of the liver
the liver secretes bile to break down fats
what is the function of the gallbladder
the gallbladder stores bile until it is needed
what is the function of the pancreas
the pancreas produces a mixture of digestive enzymes
what is absorption
absorption is the process of taking the nutrients into circulation so that they can be stored in the body, most absorption occurs in the small intestine and when it is impaired the body cannot properly utilize the nutrients eaten
what is metabolism
the metabolism is the set of life-sustaining chemical transformations within the cells of living organisms, it is a biochemical process that allows an organism to live, grow, reproduce, heal, and adapt to its environment
what does metabolism also refer to
metabolism also refers to the sum of all chemical reactions that occur in living organisms, including digestion and the transport of substances into and between different cells
what are the 3 main purposes of metabolism
- the conversion of food/fuel to energy to run cellular processes
- the conversion of food/fuel to building blocks for proteins, lipids, nucleic acids and some carbohydrates
- the elimination of nitrogenous wastes
what do the reactions of metabolism allow
the reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments
what are the phases of metabolism
anabolism and catabolism
what is anabolism
anabolism refers to the process which builds the molecules the body needs, it usually requires energy for completion. it is concerned with the conversion of simple compounds derived from nutrients into substances the body cells can use
what is catabolism
catabolism is the process where substances are converted into simpler compounds which release the energy necessary for the proper functioning of the cell, it is the process that breaks down complex molecules into smaller molecules; it usually releases energy for the organism to use
what is metabolic rate
metabolic rate is a term that describes the speed and efficiency with which the body converts food into useful nutrients and it influences how much food the body will require
