digestive system
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what does lacteal consist of
fatty acids and glycerol
what are the 6 basic activities of the digestive system
ingestion of food and water mechanical digestion of food chemical digestion of food movement of food along the alimentary canal absorption of digested food and water into the blood and lymph
what is mechanical digestion
large pieces of food smashed into smaller pieces of food
what is chemical digestion
pieces of food turned into nutrients
what chemically digests food
enzymes
what is the process of mechanical digestion
• mouth - crushing • stomach - muscles turn food into chyme • peristalsis - rhythmical contractions of circular muscle push food along the small intestine • segmentation - small segments in the small intestine form due to the circular muscle contracting
what is peristalsis - draw a diagram
the circular muscle pushing food along the small intestine
what do these foods form after digestion: carbohydrates proteins lipids nucleic acid
glucose peptides and amino acids fatty acids and glycerol nucleotides
why is the small intestine fit for absorption
approximately 6m long large surface area folds in the inner lining providing more surface area contains digestive enzymes
describe simple diffusion in terms of absorption
the high concentration of nutrients on the interior of the small intestine is diffused into the low concentration of cells in the inner lining.
what does the lacteal absorb and how
fatty acids and glycerol via simple diffusion.
what do fatty acids and glycerol recombine to become, and what happens after they are recombined
they form fats, which then enter the lacteals and are transported to the lymph system
what does the blood capillary absorb
water, vitamins and minerals via diffusion glucose and amino acids via active transport
what does the small intestine consist of
duodenum, jejunum, ileum
where is bile produced, secreted and stored
liver liver gall bladder
what do bile salts do
emulsify fat into tiny droplets which increases the surface area for lipids
list 5 features of the large intestine
1.5m long rectum stores faeces no villi no enzymes secreted slow movement of material glandular cells secret muscus contents become more solid
what 3 muscles do the stomach have
oblique circular longitudinal
what is the mucosa specialised for
secretion of gastric juices containing Hal, mucus and digestive enzymes
what is gastric juice responsible for
chemical digestion
what does the acidic environment of the stomach allow
pepsinogen to be converted to pepsin
why is not nutrients not absorbed by the stomach
because the internal surface is covered by a layer of mucus which protects stomach cells from the acidic environment
what do the organs of the excretory system do
process and remove waste
describe how the lungs are involved in the excretory system
gaseous exchange