aminal nutrition Flashcards
balanced diet
a diet that provides all the necessary nutrients in their required amounts
carbohydrates
starch: potatoes, cassava, cereal
sugars: fruits, cane, honey
- contain energy which is released in cells as they are broken down in respiration
fats
- provide more energy than carbs + stored under skin and around kidneys
- fat meat, dairy foods, nuts
proteins
- growth and repair + make up muscle
- meat, egg white, fish
vitamin c
- healthy gums + skin repair
- citrus fruits, fresh cabbage
vitamin d
- uptake of calcium + bone formation
- sunlight, fish liver
calcium
- healthy bones and teeth + muscle action
- milk, flour
iron
- for haemoglobin (oxygen carrying pigment in RBC)
- red meat, spinach
fibre
- forms bulk in intestines, preventing constipation
- fruit, vegetables
water
- medium of all chemical reactions + cools body
- all food, drinks
vitamin c deficiency
scurvy: bleeding gums + wounds do not heal properly
vitamin d deficiency
rickets: bow legs or knock knees because growing bones become soft + fractures for older people (because no calcium uptake)
ingestion
taking in of substances into the body through the mouth
digestion
the breakdown of large insoluble food molecules into small soluble molecules using mechanical and chemical process
mechanical digestion
chopping and grinding food using teeth and muscular churning of food in the stomach
chemical digestion
breakdown of large insoluble molecules into small soluble ones using enzymes
absorption
movement of small food molecules and ions into the blood through the walls of the intestines
assimilation
movement of digested food molecules into cells where they are used becoming part of the cells
egestion
passing out food that has not been digested or absorbed through the anus
mouth
- teeth mechanically digest food
- salivary glands release saliva with amylase which digests starch
- tongue rolls the food into a bolus
oesophagus
waves of muscular contractions (peristalsis) push bolus to the stomach
stomach
churns food + walls release gastric juice containing
- enzyme pepsin (protein to polypeptides)
- hydrochloric acid (optimum pH for pepsin to digest protein + kill pathogens)
duodenum
receives bile
pancreatic juice
walls release intestinal juice containing:
- maltase (maltose to glucose)
- protease (polypeptides to amino acids)
- lipase (fat to fatty acid + glycerol)
pancreas
pancreatic juice containing:
- amylase (remaining starch to maltose)
- lipase (fat to fatty acid + glycerol)
- trypsin (remaining protein to polypeptides)
liver
produces bile which:
- emulsifies fat (increase surface area for enzyme to operate)
- neutralises acidic chyme so enzymes can work
ileum
where most of digested food is absorbed + most water too
features of ileum
- about 6m long
- folded walls
- walls have microscopic finger-like projections called villi
villi adaptations
- very thin walled so
- blood capillaries just beneath walls
- special structures (lacteals) to absorb fatty acids and glycerol
- numerous so large surface area
- can move
colon
where water is absorbed
rectum
muscular chamber where undigested food is stored before being pushed out of anus
anus
closed by a ring of muscle (anal sphincter) which is relaxed during egestion
glucose + amino acids after absorption
carried by a blood vessel called the hepatic portal directly to liver for first stage of treatment in body
fats after absorption
travel in the lymphatic system, bypassing the liver and enter the circulatory system through a vein at the neck
four types of teeth
- incisors
- canines
- pre-molars
- molars
incisors function
biting + cutting
canine function
biting + cutting/tearing
pre-molar function
crushing + grinding
molar function
crushing + grinding
enamel
hardest substance in human body
dentine
living part of the tooth + similar to bone
pulp cavity
contains nerves + blood vessels
cement
holds tooth in socket + allows little movement, preventing damage when chewing hard substances
gums
soft tissue that surrounds + protects jawbone + roots of teeth
