digestive system Flashcards
food is essential for _____
life
what is digestion?
the process of breaking down larger food molecules into molecules which are small enough for use of body cells
what are the 5 steps of the digestive process?
- ingestion
- movement of food
- digestion
- absorbtion
- defecation
what is ingestion in the digestive process?
easting, taking in food
what is movement in the digestive process?
the movement of food along the gastrointestinal tract
what are digestions in the digestive process?
chemical and mechanical processes involved in the breakdown of food
What is absorption in the digestive process?
the absorption of nutrients and energy into the cardiovascular and lymphatic systems to be redistributed to other cells
What is defecation in the digestive process?
Elimination of indigestible substances
What is chewing called?
mastication
Where is saliva produced and why?
in glands in the mouth to aid the breakdown of food into a small mass called a bolus
Where does the tongue direct the bolus?
to the back of the mouth
what does the epiglottis do?
moves to cover the windpipe to ensure the bolus goes down the oesophagus
What are peristaltic waves? what do they do?
Involuntary muscle contractions that move the bolus down the oesophagus into the stomach
what letter is the stomach shaped like?
J
what is the stomach located under?
the diaphragm and liver
what is the main function of the stomach?
breaking down food into chyme
what is chyme?
semi fluid pulp
Why does the stomach act as a storage area for food?
because we eat food quicker than the digestive system can break it down
how many litres of chyme can the stomach hold and for how long?
4 litres of chyme for 2-4 hours
what is the role of the submucosa in the stomach?
to protect the rest of the body from harmful acids
what is chemical digestion?
Chemical digestion is a biochemical process that uses enzymes and water to break down complex molecules
what does the liver produce in chemical digestion? what does it do?
bile, helps break down fat
what does the pancreas produce in chemical digestion, what does it do?
digestive enzymes that help break down food further into really small molecules for absorption
What does the stomach lining produce? (1) what does this do? (2)
mucus, protects from acid, lubricates stomach,
different _________ break down different ________.
enzymes
foods
What are the 3 sections of the small intestine?
duodenum
jejunum
ileum
how long is the small intestine?
6m long
what is the longest and most convoluted part of the alimentary canal?
the small intestine
What part of the small intestine receives the digested food from the stomach?
the duodenum
What is the alimentary canal?
the continuous tube from mouth to anus
what are villi?
small finger like projections that line the small intestine wall
what do villi do?
they increase the surface area of the small intestine wall to maximise the rate of absorption
of digested food
digested nutrients are passed into the individual _______.
villus
what do microvilli cover? what does this do?
the wall of the villi, increasing the surface area
The villi have their own ______ ________, making it more ___________ to absorb __________ into the ________ _______.
blood supply
effective
nutrients
blood stream
Where does the large intestine receive digested food from?
the small intestine
what are the four sections of the large intestine (or colon) ?
1.ascending,
2.transverse,
3.descending
4. sigmoid
what are the two functions of the large intestine?
to form faeces
to absorb water
what does water absorption in the large intestine (or colon) do?
helps move the faeces through and avoid constipation
which are of the large intestine leads to the rectum and anus?
the sigmoid
What three organs help with digestion?
liver
gallbladder
pancreas
the liver produces ______ which helps with _____________
bile
metabolism
what is metabolism in the digestive system?
breaking down fats
how does the gallbladder help digestion?
by storing and releasing bile
How does the pancreas help with digestion?
it produces enzymes and regulated blood sugars
Enzymes are _________ which speed up a _________ reaction without being changed by that _________
protein
chemical
reaction
Where are most enzymes made?
in the pancreas
what does the enzyme amylase break down?
complex carbs
what does the enzyme lipase break down?
fats
what does the enzyme protease break down?
protein
What does the enzyme lactase break down?
lactose
what does the enzyme sucrase break down?
sucrose
what does the hormone gastrin do?
stimulate the release of gastric acids
where is the hormone gastrin produced?
in the stomach
what do gastric acids do?
help to break down proteins
What does the hormone secretin do?
prompts the pancreas to release bicarbonate
what does bicarbonate do?
neutralise stomach acid as it reaches the small intestine
where is the hormone secretin released?
in the small intestine
What does the hormone Ghrelin do?
stimulate appetite
what is the hormone ghrelin released by?
the stomach
What does the hormone cholecystokinin do?
aid digestion and reduce appetite
where is the hormone cholecystokinin released?
in the small intestine
what are the 4 common digestive diseases/problems?
ageing
cancers
diverticulitis
Crohn’s disease
when we age, in our digestive system there is _________ ________ ___________ which decreases _________ of digestive muscles. This causes changes in ________________ feedback. There is increased _____ of other diseases.
decreased secretory mechanism
motility
neurosensory
risk
what is motility in the digestive system?
the contraction and stretching of muscles in the gastrointestinal (GI) tract that move food through the body.
what are the two cancers of the digestive system?
colon and bowel
What does diverticulitis affect? what does this cause?
the diverticular in the large intestine
causes pain, bloating, constipation or diarrhoea
What is the diverticular in the large intestine?
the small pouches or sacks that form it
What type of disease is Crohn’s disease?
a type of inflammatory bowel disease
what happens in Crohn’s disease?
parts of the digestive system become inflames and in some cases ulcerated
Crohn’s disease can be very ________. Cause abdominal ______ and _________, blood in the _______, weight ____ and __________.
painful
pains
cramps
feaces
loss
tiredness
