bio ct 2

alimentary canal:

long muscular tube which runs from the mouth to the anus

digestion:

breaking down food so that it is small and soluble enough to pass through the wall of the small intestine

absorption:

transporting digested food molecules from the lumen of the gut into the blood

mouth:

chew and break down food into small pieces (amylase produced)

phorynx/oesophagus:

pushes food down the throat to stomach through muscular contractions aka peristalsis

stomach:

HCl acid lowers pH for protease to break down food, stomach muscles, churn food (HCl and protease produced)

liver:

produces bile which increases pH and emulsifies fats

gall bladder:

stores excess bile

pancreas:

produces digestive enzymes and releases them into small intestine (protease + lipase + amylase are produced)

small intestine:

produces digestive enzymes and where food is absorbed into blood (protease + lipase + amylase are produced)

large intestine:

absorbs water back into body

rectum and anus:

where faeces is stored and egested

starch test

iodine, turns blue-black

sugar test

benedicts solution, turns red

protein test

biuret test, turns purple

fats test

emulsion test, turns cloudy white

vitamin c

DCPIP, blue to colourless

sugar test uses a

water bath

protein test acids

5 drops of copper sulphate and 5 drops of sodium hydroxide

insoluble

starch, fat and large proteins

digestive enzymes:

break large insoluble food molecules into smaller soluble molecules

amylase produced in:

salviry glands, pancreas, small intestine

amylase breaks down

starch into glucose

where is amylase found

mouth and small intestine

protease produced in

stomach, pancreas, small intestine

protease breaks down

protein into amino acids

where is protein found

stomach, small intestine

lipase produced in

pancreas, small intestine

lipase breaks down

fats into fatty acids and glycerol

where is lipase found

small intestine

villi

digested food reaches the capillaries and lacteals (lymph capillaries) in the villi

absorbed food are transported to the liver by

hepatic portal vein

what is transported in the lymph

fatty acids and glycerol

movement of the gut:

empties the lacteal and the lymph moves slowly through lymphatic vessels, eventually to enter the blood near the heart. this means fat does not enter blood stream too quickly

the large intestine

water is absorbed here. the solid waste (faeces) is stored in the rectum. it is then egested through the anus

chlorea

a water borne disease caused by bacteria. symptoms include diarrhoea

oral rehydration therapy

a solution of salts and glucose to drink to treat chlorea

solution contains:

water, sodium ions to replace ions lost, glucose for energy, other ions such as potassium and chloride

mechanical digestion:

breaking down large pieces of food into smaller ones without changing the food molecules

where does mechanical digestion start

mouth - teeth

muscular contractions in the stomach

continue mechanical digestion

in the small intestine large globules of fat are broken into smaller ones by

emulsification of bile

Incisors:

cutting teeth used for cutting and biting pieces of food

Canines:

long and sharp teeth that are used to hold and tear at food

Premolecules:

teeth used to crush and grind soft food

Molars:

teeth used for chewing and grinding hard food

Step 1 of tooth decay

bacteria feeds on sugar and left over food particles (plaque)

Step 2 of tooth decay

bacteria produce acid which breaks down enamel

Step 3 of tooth decay

holes form called cavities