Digestive system Flashcards
carbs
provide immediate enegry and act as a structular element
llipids
stored energy that act as struucual componets, hormones, energy, storage, insulation and shock absorption
proteins
structural componets that are required for growth and repair, act as receptors
Define digestion
the process by which food is broken down into a simpler form to be absorbed into the blood for the transfer to the cells.
Digestive system funciton
to ingest food, digest it, absorb nutrients from the food, and eliminate undigested material.
2 types of digestion:
Physical/mechanical digestion:
Chmeical digestion:
Chmeical digestion:
Chemical breakdown of food through enzymes and acids such as lipase, amylase and protease.
Physical/mechanical digestion:
Physical Breakdown of food through chewing, muscle contractions and churning.
4 STEPS OF DIGESTION:
Ingestion
digestion
Absorption
Elimination
Elimination
undigested food is removed from the body as fecaces
Absorption
most of the nutrients and water are absorbed into the small intestine and any remaining nutrients pass into the large intestine to be absorbed into the blood stream, whilst any nutrients that are not absorbed are excreted faces
Ingestion
phhysical digestion occurs as food is mashed in the teeth and chemical digestion occurs as amylase breaks down carondyrtaes
Ingestion
phhysical digestion occurs as food is mashed in the teeth and chemical digestion occurs as amylase breaks down carondyrtaes
digestion as a stepof digestion
bolus moves inot the stomach where stomach acids and digestive juices further break down the food into a liquid called chyme.
how does the oral cavity aid in digestion
food is grinded and where amylase breaks down carbs
how does Salivary glands aid in digestion
release saliva and releases amylase
how does the osopehagus aid in digestion
where pertalsis occurs
how does the stomach aid in digestion
food churns to become chyme, where protease digests protein, hydrhcolric acid is released
how does the liver aid in digestion
produces bile
lipase breaks dwon fat
regulates metabiolsim
removes and process nutrients
produces proteins
how does the pancreas aid in digestion
Digestive enzymes are produced when food reaches the duodenum in pancrease
regulates blood sugar level
responsible for secreting bicarbonate which neutralises acids in chyme
hwo does hte Gallbladder: aid in digestion
Where bile is stored and further concentrated before being released into small intestine
what 3 parts is the small intestine broke down into and function of small intestine
donedum, jejunum and ileum
function is to absorb nutrinets
Large intestine aid in digestion
Final absorption of water, vitamins and minerals
Appendix function
Plays a role in immune functions
anus function
remove s faceses
What is peristalsis
waves of muscle contractions that push food into the stomach which occurs in the esophagus
What does pertalsiis do:
The contractions push food from the esophagisu into the stomach
helps mix chyme in the intestines with digestive enzymes nad bile
aids in reabsorption
diffDifferienate the digestive systems in omnivores, canrvovores and herbivior
Omnivores:
Have sharp teeth to tear meat and blunt teeth to grind down PLANTS
Herbivore:
blunt teeth to grind down plants
Large digestive system
Carnivore:
Sharp teeth to tear meat
Small digestive system
Why do carnviorse have a smaller digestive system:
because meat is easier to digest
Why should humans not eat too many plants paritcularuraw?
Plants contain cellulose and humans don’t have the required enzymes to break cellulose down.
2 distinct types of herbviores
Hingut fermenters
-Foregut fermenters
hingut fermenters include example
contain single-chambered stomachs and extremely large cecums(fermenatation sites) eg. horse
Foregut fermenters
multi-chambered, more complex stomachs and their fermentation site is the very large first stomach chamber eg. squirrels
Amino acids
are used to construct and transport globular proteins
vitamins
organic molecules needed by the body in small amounts for growth nad metbaolic processes
Minerals
are inorganic compounds required by the body and are co factros that assist with enzyme function
explain the whole process of digestion
Food enters the mouth where the physical breakdown occurs as the teeth mash the food and chemical breakdown occurs as amylase breaks down carbohydrates into sugars.
The bolus is then swallowed in the esophagus by pertaslsis and moves into the stomach
Once in the stomach, the bolus mixes with digestive juices such as hydrochloric acid to produce chyme.
After 8 hours, chyme moves to the small intestine where the nutrients are absorbed.
Then, it moves to the large intestine where water is absorbed.
Anything remaining moves the rectum to be stored as waste before it is released out of the anus
compare digesivte system of cats nad humans:
Human intestines are longer than cats,
and cats have sharp teeth to tear down meat whilts humans have both sharpteeth for meat and blunt teeth for plants
why do herbviores have longer intestines
their body requires more time to digest and absorb plants
and because the intestines contain flora/gut microbacteria which leads to more fermination and aids in digestion
LARGER OR LONGER INTESTINAL TRACT/DIGESTIVE SYSTEM
MEANS
- more length and therefore more time for digestion and absorption to occur
- more length means more space for more intestinal flora/gut microbiota –> leads to more fermentation which helps in digestion
why is it that cows always eat:
its difficult to break dwon cellulose as herbivores eat slowly ocnsntalty to give time for the body to digest the food to preven strain on digestive system
How does ingestion and egestion vary
ingestion is the first step of digestion and is the intake of nutrients, whilst egestion is the last step of digestion and the excretion of waste
what organs make up the GI tract
mouth
esophagus
small/large intestine
rectum
anus
what is the purpose of mechncailca digestion
increase SA:V of food to make it easier for enzymes to break it down chemically
why are enzymes biologicla catayalsyts
they speed up chemical reacitons
Enzymes are sensitivie to and how
temperatuee and PH
If enzymes are transported to the wrong PH or temperature. enzymes will denature as the active site has changed thus the receptor are no longer complemematry to the enzyme
In chemica dgestion, chemical break down…. to become….
chemicals breka down complex polymers to monomers.
4 TYPES OF TEETH
Incisors-cut food
Canines-tear food
Premolars and molars ridigid surfaces to grind food
EXPLAIN THE MOVEMNET OF FOOD THROUHG THE GI TRACT
Food is sawllowed into the esophagus
the epilgotsiss stops food from entering the trachea
food is moved through the GI tract by pertaslsis
epiglottis
stops food frm etnering the trachea to prevent choking
what is the bolus
mixture of food and salivia
what are the 3 parts of the large intestine
cecum
colon
rectum
lipids
break down lipase into glycerol and fatty acids
what would happen if there was no bile
most ingested lipids would be excreted as faeces
how do chickens break dwon food if they dont have teeth
the food is stored in the crop then down moves into the gizzard which grinds the food through stones
fibirous plant eating animals that have 4 chamebered stomachs are called
ruminants
what do the 4 chmabers of a rumiant do
the firts 2 chambers are responsible for ferminatiion of food before the food is regurgitated, chewed and passed into the second two chambers for chemicla digetsion.
hydrchoirc acid do
kills pathoens that enter the stomahc
optimal ph of pepsin
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