Bk2 Ch4.2 Flashcards
(76 cards)
<p>Digestion (definition)</p>
<p>Digestion is the process in which nutrients and energy are extracted from the food we eat.</p>
<p>Digestion occurs in a six to seven metre tube called the...</p>
<p> alimentary canal, digestive tract or sometimes simply the gut.</p>
<p>It takes food about \_\_ hours to pass through the entire length of the alimentary canal.</p>
<p>24</p>
<p>What are the two main types of digestion:</p>
<p>mechanical digestion & chemical digestion</p>
<p>Mechanical digestion occurs in the \_\_\_\_\_ when food is physically broken down or mashed into \_\_\_\_\_\_\_ \_\_\_\_\_\_.</p>
<p>mouth; smaller pieces</p>
<p>Chemical digestion occurs at various stages along the \_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_ when special chemicals called \_\_\_\_\_\_\_ chemically break down food.</p>
<p>alimentary canal; enzymes</p>
<p>When we eat, our face muscles go to work, moving our jaws so that our \_\_\_\_\_ cut and grind food to make it easier to \_\_\_\_\_\_.</p>
<p>teeth; digest</p>
<p>At around the age of 18, we generally have all our \_\_ adult teeth, with \_\_ in each jaw.</p>
<p>32; 16</p>
<p>Tooth decay is caused by \_\_\_\_\_\_, a thin film of food, saliva and bacteria that builds up on the teeth.</p>
<p>plaque</p>
<p>The bacteria in plaque transforms sugar into \_\_\_\_\_\_ that seeps into the enamel and cause weak spots.</p>
<p>acid</p>
<p>Regular \_\_\_\_\_\_\_\_ and \_\_\_\_\_\_\_\_\_ with toothpaste after each meal drastically reduce the chances of tooth decay.</p>
<p>flossing; brushing</p>
<p>If allowed to spread, tooth decay may enter the \_\_\_\_\_ where the nerves are.</p>
<p>pulp</p>
<p>Scientific research has shown that \_\_\_\_\_\_\_\_ helps prevent tooth decay by protecting the enamel and helping repair or rebuild the enamel.</p>
<p>fluoride</p>
<p>The digestive system consists of the \_\_\_\_\_\_\_\_\_ \_\_\_\_\_ together with several attached \_\_\_\_\_\_ producing organs.</p>
<p>digestive tract; enzyme</p>
<p>The digestive system produces an amazing \_\_ litres of digestive juices per day.</p>
<p> 8</p>
<p>Digestion begins in the mouth. Food is ground into smaller particles by the teeth, mixed with \_\_\_\_\_\_ and made into a smooth lump called a \_\_\_\_\_.</p>
<p>saliva; bolus</p>
<p>Saliva contains water, mucus and the enzyme \_\_\_\_\_\_\_, which begins breaking down the very large molecules of \_\_\_\_\_\_ into much smaller glucose molecules.</p>
<p>amylase; starch</p>
<p>The \_\_\_\_\_\_\_, or \_\_\_\_\_\_, is a 25 centimetre tube connecting the mouth to the stomach.</p>
<p>oesophagus; gullet</p>
<p>A bolus is moved down the oesophagus by wave-like contractions and expansions of muscles called...</p>
<p>peristalsis</p>
<p>The trachea (or windpipe) branches off the oesophagus and leads to the lungs. When food is swallowed, a flap called the \_\_\_\_\_\_\_ folds over to cover its entrance.</p>
<p>epiglottis</p>
<p>The stomach is a J-shaped organ that has a capacity of about \_\_\_ litres.</p>
<p>two</p>
<p>Muscles in the stomach churn food, helping it mix with \_\_\_\_\_\_ \_\_\_\_\_.</p>
<p>gastric juice</p>
<p>Gastric juice contains the enzyme \_\_\_\_\_\_, which helps break down large \_\_\_\_\_\_\_ molecules and \_\_\_\_.</p>
<p>pepsin; protein; fats</p>
<p>Hydrochloric acid in the stomach helps the enzyme and kills harmful \_\_\_\_\_\_\_\_.</p>
<p>bacteria</p>
A _____ ______ protects the stomach from the enzymes and acid (it stops the stomach from digesting itself!).
mucus lining
The entrance and exit of the stomach are controlled by rings of muscles called ________.
sphincters
A _______ at the top of the stomach ensures acid and other stomach contents do not rise into the ________.
sphincter; oesophagus
A _______ at the bottom of the stomach protects the next part of the digestive tract from acid and allows some partly digested, semi-liquid food (called _____) to squirt out every minute or so
sphincter; chyme
The pancreas is not part of the alimentary canal, but rather a 15 centimetre multipurpose ‘side attachment’. It produces __________ ______.
pancreatic juice
Pancreatic juice contains _______ that help digest carbohydrates, fats and proteins.
enzymes
The pancreas produces a chemical called _______ that controls the amount of sugar in the bloodstream.
insulin
_______ is a condition in which the pancreas does not produce enough insulin.
Diabetes
Pancreatic juice contains an ______ (a liquid which neutralises the acidic stomach chyme).
alkali
The gall bladder, a small muscular sac about eight centimetres long, stores ____ produced by the ______.
bile; liver
How much bile can the gall bladder hold?
about 50 millilitres
An entire chapter could be written about the liver, it is a living ‘chemical factory’ and is involved in over ___ chemical processes.
500
At ___ kilograms, the liver is the largest internal organ.
1.5
The liver consists of two parts or _____ and has an extensive blood supply, which gives it a rich _________ colour.
lobes; red-brown
The functions of the liver include: the conversion of glucose (an end-product of digestion that can be used by body cells) into ______.
glycogen
Glycogen can be stored in the liver and _______, and converted back into _______ when needed by the body.
muscles; glucose
The functions of the liver include: the storage of _______ and minerals, including ____.
vitamins; iron
The functions of the liver include: the production of a _____-_______ chemical.
blood-clotting
The functions of the liver include: the break-down (___________) of poisons such as alcohol.
detoxification
The functions of the liver include: the production of ____, which helps break down fats.
bile
The hundreds of jobs performed by the liver generate ____, which is transferred around the body by the blood.
heat
The _________ is really the start of the small intestine.
duodenum
About how long is the duodenum?
ten centimetres
At the duodenum, two small tubes come together (one from the _______ and one from the __________) to allow chemicals, such as bile, and enzymes to enter the small intestine.
pancreas; liver/gall bladder
The ____ ________ is the longest part of the digestive tract.
small intestine
How long is the small intestine?
four to six metres
Like the stomach, the small intestine contains muscles that ____ food, and produces ______ that continue the digestion of carbohydrates, proteins and lipids.
churn; enzymes
The digestive tract is called ‘small’ because of its narrow width of about _______ centimetres.
three or four
By the time it gets to the small intestine, food is broken down enough to be able to pass through the walls of the small intestine and into the ________.
bloodstream
The walls of the small intestine are lined with tiny bumps called _____.
villi
The villi increase the _______ ____ of the walls, so more nutrients may pass through.
surface area
The large intestine is about ___ metres long and _______ centimetres wide,
1.5; six to seven
The large intestine is made up of five parts:
the caecum, appendix, colon, rectum and anus.
Undigested ‘waste’ material passes into the large intestine, where _____ and a few remaining ________ are absorbed.
water; minerals
In the large intestine, ______ (lumps of faeces) form, to be expelled later from the body via the ____.
stools; anus
About one-third of faeces is made up from intestinal _______.
bacteria
Bacteria in our intestines feed on undigested food, breaking it down to produce useful vitamins, as well as gases such as _______ _______ (better known as rotten egg gas) and _______.
sulfur dioxide; methane
Acid in the stomach produces ________ gas, which has no odour.
hydrogen
Digestive gasses are released through the anus when we pass wind. Gas released this way is called _____.
flatus
Gas in the intestinal tract is called _________.
flatulence
One of the main products of digestion is _______.
glucose
Glucose reaches body cells via the bloodstream, where it provides ______ to cells.
energy
The liver converts glucose to a substance called ________, which is made of several glucose molecules joined together.
glycogen
Glycogen is stored in the liver and in ______ ______, where it may be converted back to glucose when energy is needed for movement.
muscle cells
Since the liver and muscles can store only so much glucose as glycogen, the excess is transported to various sites around the body, where it is stored as ____ ___.
body fat
One way the body gets rid of unwanted bacteria in the digestive tract is to move matter through much more quickly. This is called:
Diarrhoea
Sometimes certain foods or eating too quickly can result in excess acid being produced in the stomach. This acid may occasionally rise into the oesophagus, causing a burning sensation called:
Heartburn
Infections, extreme pain or stress can result in reverse peristalsis - contractions which force food up and out of the stomach and mouth. This is called:
vomiting
If the mucus lining of the stomach becomes damaged, a sore or ulcer may result. This is called:
Stomach ulcers
Australian scientist Barry Marshall announced in 1983 that many stomach ulcers were caused by the bacterium _________, rather than stress as previously thought.
Helicobacter
The appendix may become inflamed (eg due to a blockage or ulcers). This is called:
Appendicitis
The liver may be damaged by excessive _______ consumption or by diseases such as _______.
alcohol; hepatitis
