Digestive System Flashcards
Mouth
Digestion begins here
Teeth mechanically break down large food particles to small
Ingestion of food
Salivary glands
Saliva contains the enzyme analyse (starch to maltose)
Lubricates food
Protects teeth against bacteria
Epiglottis
Used to seal off the windpipe during consumption of food
Oesophagus
Connects the mouth to stomach
Completes peristalsis
What is peristalsis
An involuntary wave of muscular contraction that moves the boils along the alimentary canal
Liver
Produces bile (dark green fluid which neutralises acids and emulsified lipids ) Detoxifies chemicals
Stomach
Contain pepsin (protease) - breaks down proteins Contains hydrochloride acid to kill bacteria
Gallbladder
Stores and concentrates bike
When a hormone is released, this signals the gallbladder to contract and discharge bile into the small intestine
Pancreas
Contains pancreatic amylase which produces glucose
Makes trypsin
Lipase = lipids into fatty acids
Contains specialised cells that produce insulin (regulates blood sugar)
Small intestine
Made up of 3 parts - the duodenum, illeum and jejunum
Illeum
Absorption of food molecules into the bloodstream
Duodenum
Where food comes into contact with bile
What do the folds do
Increase the surface area
What do villi do
Help absorb digested food
1 cell thick (short diffusion distance)
Extensive blood supply (helps maintain a concentration gradient)
Lacteal (absorbs glycerol and fatty acids)
Microvilli (increases surface area)
Large intestine
Takes the remains of digested food and prepares it for excretion
Caecum colon and rectum
Rectum
Store and realises faecus to Amy’s by contracting
What is assimilation
The movement of digested food molecules into the cells of the body where they are then used (becoming part of the cells)
What is digestion
The breakdown of large insoluble food molecules into small, water soluble molecules using chemical and mechanical processes
What is ingestion
The process of taking in food
What is absorption
The movement of digested food molecules through the wall of the intestine into the blood or lymph
What is egestion
Involves the material not passing through the cells whereas excretion does
How is the small intestine adapted for diffusion
Large internal surface area for absorption to happen quickly + efficiently
Folds increase the surface area
Contain villi - 1 cell thick (short diffusion distance)
- extensive blood supply (helps maintain a concentration gradient)
- lacteal ( transports fatty acids and glycerol away from the SI)
Villi contains microvilli - further increases surface area
