Human Nutrition Flashcards
Nutrition
How an organism gains and obtains their food
Digestion
The break down of food
Mouth digestion
Physical : teeth and tongue
pH: 7-8
Epiglottis closes over the trachea so make sure the bolus doesn’t go in your wind pipe
Chemical: saliva (amylase)
Types of teeth
Incisor:cutting and slicing
Canine: grip and tear food
Premolar/molar: crush and chew food
Amylase
Ph 7
Chemical digestion
Oesophagus
Carries food by peristalsis
Peristalsis: the contraction and relaxation of the oesophagus , ( the small intestine and fallopian tube)
Benefits of fibre
Function : stimulate peristalsis
Source: whole meal bread , cereal and fruit + veg
Stomach and muscles
A muscular bag that stores and digests food
Physical digestion: churning
Chemical: HCL , Pepsinogen , mucous
Sphincter muscles:cardiac and pyloric
HCL and pepsinogen and mucous functions
HCL(pH of 1-2): kill micro-organisms
Loosen fibrous foods
Activate pepsinogen
Pepsinogen (1-2) :Activated by a low pH
Forms Pepsin when active
(Protein-pepsin-peptides)
Mucous: Prevents the self-digestion of the stomach
Made in stomach lining
Small intestine
Composed of duodenum = enzyme digestion and neutralisation
Ileum=absorption of nutrients
Duodenum
Connects the stomach to the duodenum
Where the chemicals of both the liver and pancreas
Liver and pancreas are classified as glands
Liver
Location: under diaphragm
Function: produces bile , demination , stores glycogen , produces heat
Bile
Produced in the liver
Stored in the gallbladder
Acts in the duodenum
NOT AN ENZYME
Bile functions
Emulsifies lipids
Contains sodium hydrogen carbonate- a base that neutralises chyme
Pancreas
Leaf shaped
Function : secretes pancreatic juice into duodenum
(Lipids = lipase = glycerol and fatty acids)
Pancreatic juice
Contains sodium hydrogen carbonate (base neutralises chyme)
Contains enzymes amylase and lipase
Ileum
Function : absorption of nutrients by diffusion into the bloodstream (glucose-carbohydrates , amino acids-proteins , fatty acids and glycerol-lipids)
Ileum adaptations
Villi and microvilli (villus)
Rich blood supply (capillaries)
Walls are one cell thick
Contains lacteals
Villus
Absorbs nutrients by diffusion
Lacteal absorbs fatty acids and glycerol transports it into the lymphatic system
Capillaries absorb nutrients (glucose and amino acids and carry from the ileum to the liver via the hepatic portal vein.
MAIN FUNCTION: increase surface tension for absorption
Hepatic portal system
A portal system is blood pathway that begins and ends in the capillaries
Carries nutrients from small intestine to the liver
Nutrients in the liver are stored
Large intestine
Contains caecum , appendix , colon and rectum
Caecum and appendix
Now vestigial organs
Location of good bacteria to prevent colon cancer causing bacteria
Colon
Function: reabsorb water
Produce vitamin b (brain function) vitamin k (blood clotting)
Egestion: removal of un digested waste
Symbiotic bacteria in colon
Symbiosis: two organisms of different species live close contact where at least one of them benefit
Bacteria live in the large intestine and feed off undigested waste
Symbiotic bacteria Functions
Produce b and k vitamins
Compete with other bacteria that may be pathogenic
Heterotroph
An organism that cannot make its own food
Enzymes
Starch - amylase - maltose
Protein-pepsin-peptides
Lipids-lipase-glycerol+ fatty acids
Balanced diet
One that contains the correct amount of lipids , carbohydrates, proteins , vitamins + minerals and fibre
