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