Digestive system Flashcards
what nutrients do our body need
Carbohydrates
-Protein
-fats/lipids
-vitamins
-minerals
-water
what are the 4 processes? Describe
- ingestion: taking in food
- Digestion: breaking down food into simpler substances
- absorption: digested food passes into the blood
- Egestion: Elimination of waste/ undigested food
what is food made of
- complex insoluble polymers
what is a monomer
- soluble micro-molecules
- simplest molecules are monosaccharides (eg. glucose, fructose, galactose)
what is a disaccharide
- more complex carbohydrates made of 2 monomers (eg. maltose, sucrose, lactose)
what is a polysaccharide
composed of many monomers (eg. starch, glycogen, cellulose)
the methods to breakdown food
- mechanical/ physical digestion (teeth, muscular contractions, bile)
- chemical digestion (enzymes)
what is the alimentary canal
pathway which the food enters the body and solid wastes are expelled
1. oral cavity
2. pharynx
3. esophagus
4. stomach
5. small intestines
6. large intestine
7. anus
what are the 4 accessory organs
- liver
- pancreas
- salivary glands
- gall bladder
the physical process and purpose of oral cavity/mouth
Teeth break food into smaller pieces that
increases the surface area for digestion
Saliva creates a basic pH of about 8 &
moistens food allowing soluble chemicals to
dissolve.
What is the chemical process of the oral cavity?
salivary glands produce the enzyme amylase, which begins the breakdown of starch
What is BOLUS?
Once the Chewed food is mixed with saliva from 3 pairs of salivary glands it is called the BOLUS
What is Peristalsis
Controlled wave like muscle contractions that pushes food down even when you are upside down.
What happens in the stomach?
Food enters the stomach through a valve known as the CARDIAC SPHINCTER or lower esophageal sphincter
The stomach churns the food like a blender using
muscles called RUGAE
Food is liquefied (Mechanical Digestion) and now is known as CHYME
Food stays in the stomach for several hours
What is the importance of Sphincters?
Prevents acid from entering esophagu
What is the Physical processes of the stomach?
Food is liquefied and now is known as CHYME
What are the chemical processes of the stomach?
Gastric juice contains
Hydrochloric acid: kills bacteria
& mechanical digestion
Mucus: protects stomach lining
How is protein digested?
HCL activates pepsinogen —> pepsinogen turns into its active form (pepsin) —> Pepsin breaks proteins into small polypeptides.
where does final digestion and absorption occur?
Small intestine
What is the small intestine?
Coiled tube(convoluted) over 3 meters long. Coils and
folding plus villi give this 3m tube the surface area of a
500-600m long tube.
What are the 3 parts of the small intestine and their parts
Duodenum: chyme enters from
the stomach & gets bathed in enzymes
Jejunum: site of MOST absorption
Ileum: some absorption. Connects with Large intestine
Villi?
increases surface area due to its
fingerlike projections
what is each villi covered with?
microvilli
what kind of enzymes does the small intestine produce?
enzymes that complete the
digestion of carbohydrates, proteins and fats.
Where does absorption occur?
ABSORPTION occurs primarily in the Jejunum but also
the ileum.
thin epithelium
The skin of each villus is 1 cell thick, this allows absorption to happen very fast
What is the lacteal?
The lacteal absorbs fatty acids and glycerol.
Good blood supply
The blood capillaries absorb simple sugars and amino acids.
we have 7m of the small intestine, why doesn’t it move around?
The Mesentery keeps everything secure.
What accessory organs secrete enzymes into the small intestine?
Liver, Pancreases , Gallbladder
What are the 4 things the pancreas produces, and what are they?
- Digestive juices released through the pancreatic duct
- Enzymes that digest Carbohydrates, proteins, and fats
- Bicarbonate salts, to neutralize stomach acids
- insulin (not an enzyme) to metabolize sugars
Where is the gall bladder found?
under the liver
What is the purpose of the gall bladder?
Stores bile (breaks fats into smaller pieces) but does not produce it.
The gallbladder shares the a common duct with the pancreas.
What is the purpose of the liver?
detoxifies poison (ex. Alcohol)
stores glycogen
breaks protein into urea
Produces bile salts
recycles hemoglobin from red blood cells
produce heat
What is the large intestines consist of?
ascending, transverse, descending and semi colen
what are the functions of the large intestines?
Absorb water, vitamins and minerals
Store waste
discard of waste through the anus
In herbivores, what does the appendix help digest?
cellulose
What is synthesis and digestion?
Synthesis (building molecules) l+l –> ll
Digestion )breaking down) ll—> l+l
what is the purpose of enzymes?
All chemical reactions in living organisms require enzymes, which speed by reactions.
Enzymes need to be the right shape for the job, and are specific to their helper. T or F
true
What breaks down sucrose
sucrase
What breaks down proteins
protease
What breaks down lipids
lipase
What builds DNA
DNA polymerase
What is an enzyme?
helper protein molecule
What is a substrate?
molecules that the enzymes work on
What is a product?
What enzymes help produce from the reaction
What is an active site
The part of enzyme that substrate molecule fits into
What effects enzyme action?
- correct protein structure
2.temp - pH
What happens to enzymes at the optimum temp?
The greatest number of collisions between enzymes and substrates occur.
Optimum temp is 35-40 degrees Celsius
What happens to enzymes when you raise the temp?
denature proteins, they unfold and lose shape.
What happens to enzymes when you lower the temp?
molecules move slower
fewer collisions between substrates and enzymes
What happens to human enzymes when the pH changes?
it denatures
What is the pH for human enzymes?
Depends on where in the body,
-pepsin (stomach) pH3
-Trypsin (Si) pH 8
Where does digestion of starch (carbohydrates) begin and finish?
-starts in the salivary glands where the salivary amylase starts breaking down the carbohydrates into maltose
- then the pancreas introduces the pancreatic amylase into the mix while the chyme is making its way to the small intestine
- the pancreatic amylase breaks the rest on the carbohydrates into maltose
-finally in the small intestine the maltase breakdown the maltose into glucose
Where does the digestion of proteins begin and start?
- starts in the stomach mucosa where pepsin starts breaking down the proteins into peptides
- next the pancreas adds trypsin to the chyme while it is moving toward the small intestine; the trypsin finishes breaking down the proteins into peptides in the small intestine
- finally in the small intestine the peptidases breaks down the peptides into amino acids
Where does the digestion of fats begin and end
- the pancreas introduces lipase which then breaks down fats into fatty acids & glycerol in the small intestine
