alimentary canal Flashcards
What is Ingestion?
taking food in through the mouth and swallowing
What is digestion?
breaking down large insoluble molecules into smaller soluble molecules
What is absorption?
the movement of small molecules out of the gut and into the blood by diffusion and active transport
What is egestion?
passing out undigested food as faeces through the anus
What is assimilation?
building larger biological molecules from small soluble molecules
What is chemical digestion?
saliva is secreted which makes food easier to swallow. the amylase inside it breaks down the starch into maltose
What is mechanical digestion?
chewing, churning food in the stomach to increase the surface area for enzymes.
what is amylase?
an enzyme with optimum pH of 7
denatures in eh stomach because the pH is 2
how is food transported through the intestine and the oesophagus?
food is shaped into a bolus and it travels down the throat via peristalsis
what does protease do?
it breaks down proteins
what secretes pepsin?
gastric glands
functions of hydrochloric acid
maintains the optimum pH for pepsin
kills bacteria
what prevents hydrochloric acid from burning the stomach walls?
the mucus lining
what enzyme does the pancreas secrete into the duodenum?
trypsin, lipase, amylase
what also breaks down proteins?
trypsin in the duodenum
what breaks down lipids
lipase
what enzyme does the duodenum wall secrete?
maltase
what enzyme breaks down peptides?
peptidases
two functions of bile?
neutralises stomach acid
breaks down fatty droplets int more smaller droplets to increase surface area for lipase to work on
how is the small intestine adapted for diffusion?
many villi and micro villi which increases the surface area.
the villi cells are one cell thick for short diffusion distance
there is a capillary network and a lacteal which maintains the concentration gradient
What does the large intestine do?
egestion
