human nutrition/digestive system Flashcards
define autotrophs
organisms that make their own food e.g plants + photosynthesis
define heterotrophs
organisms that cannot make their own food e.g humans
name the three types of heterotrophs
herbivores, omnivores, carnivores
define digestion
the physical and chemical breakdown of food into simpler forms which are soluble in the bloodstreams
what is mastication
chewing
what are two benefits to physical digestion
increases surface area, makes food particles smaller and easier to swallow
what is the alimentary canal
a long hollow muscular tube which runs through the body from the mouth to the anus
name 7 parts of the digestive system
mouth, pharynx, oesophagus, liver, stomach, pancreas, gall bladder, bile duct, duodenum, ileum, colon, caecum, appendix, rectum, anus
name the 5 stages of human nutrition
ingestion, digestion, absorption, egestion
name the two ways digestion takes place in the mouth
physical breakdown by teeth, chemical breakdown by enzymes
name two types of proteases
pepsin (stomach), trypsin(pancreas)
name the 4 types of teeth
inscisors, canines, premolars, molars
write down the dental formula
2( i2/2 c 1/1 p 2/2 m 3/3 )
what is saliva made of
water, mucus, salivary amylase
what does amylase do
breaks down starch into maltose… pH 7.5 needed
what is the oesophagus lined with
circular muscles
define peristalsis
rythmic relaxation and contravtion of circular muscles… pushes food along the oesophagus
where does food enter the stomach from
through the cardiac sphincter muscle from the oesophagus
what is secreted by the wall of the stomach
hydrochloric acid (pH1/2), mucus, enzymes
how is the stomach protected from gastric juices
mucus lines the stomach, cells lining the stomach are packed tightly together + can be replaced very rapidly
what is the name given to the churned food in the stomach
chyme
what does chyme pass through to reach the duodenum
pyloric sphincter muscle
what is the first part of the small intestine, the duodenum or the ileum
dudenum
list the three sections of the small intestine
duodenum, jejunum, ileum
name three adaptions of villi
numerous, large surface area, one cell thick
name one place from which the duodenum recieves juices/
wall of the duodenum, liver, pancreas
what does pancreatic juice consist of
water, sodium bicarbonate, enzymes
name 3 pancreatic enzymes
pancreatic amylase, pancreatic lipase, pancreatic protease
where do particles travel to after being absorbed into the blood
to the liver through the heptatic portal vein
what is the journey of fatty acids and glycerol after absorption through the lacteal
travel into lymph system, return to the bloodstream in the left subclavian vein and finally are transported to the liver
what does the heptaic artery do
carries oxygenated blood to the liver
what does the hepatic vein do
carries deoxygenated, nutrient rich blood away from the liver
what does the heptaic portal vein do
carries blood rich in nutrients from the small intestine to the liver
what does bile consist of
water, bile salts, pigments
whats the purpose of bile
emulsifies fats and neutralises chyme
where is bile stored
gall bladder
name 3 functions of the liver
prodction of bile, breakdown of dead red blood cells, detoxification of blood, storage of glycogen
name the 4 parts of the large intestine
caecum, appendix, colon, rectum
name 3 functions of the large intestine
absorption of water and mineral salts, waste becomes solid
what example of symbiosis can be found in the colon
bacteria produce vitamin B and K, and get a place to live in return
what is the importance of fibre in the diet
provides bulk (stimulates peristalsis), absorbs water prevents constipation, makes you feel full, prevents overeating
what is a balanced diet
contains correct proportions of carbs, fats, protein, minerals, vitamins,water, fibre
