Transcript B2 Topic 3 Digestion - South Newcastle Trust

Digestion is….
The chemical and physical breakdown of
large food molecules into smaller soluble
ones
Human Digestive System
TASK:
Using this
diagram
for help,
label your
digestive
system
Human Digestive System
Appendix
Rectum
Human Digestive System
Mouth
Oesophagus or gullet
Liver
Gall Bladder
Large Intestine
Appendix
Anus
Stomach
Pancreas
Small intestine
Rectum
Digestion
Mechanical digestion
• Physical breakdown of food (moving bits)
• Teeth, tongue
Chemical digestion (Mostly!)
• Digestion using chemicals called enzymes
• Other chemicals that help eg. Bile from liver
Digestive Enzymes
Amylase (a type of carbohydrase) breaks
down carbohydrates like starch into sugars
like glucose
Proteases break down proteins into amino
acids
Lipases break down fats (lipids) into fatty
acids and glycerol
Mouth
• The start of digestion
• Food broken down by teeth (chewing)
• Saliva added to soften food ready to
swallow. Saliva contains
amylase that breaks
down starch
(carbohydrate) into
sugars.
Oesophagus/Gullet
• A muscular tube (20cm long)
• Food travels down to the stomach after
swallowing. Food travels by a process
called PERISTALSIS
Stomach
• A muscular bag
• Produces proteases enzymes to break
down proteins in food.
• Contains hydrochloric acid to kill
microorganisms and help enzymes work
• Acid does not
digest your food
for you!
AfL:
Where would you find protease enzymes?
1-Mouth
2-Oesophagus
3-Stomach
AfL:
Where would you find protease enzymes?
1-Mouth
2-Oesophagus
3-Stomach
AfL:
What enzyme is found in saliva?
1-Amylase
2-Protease
3-Lipase
AfL:
What enzyme is found in saliva?
1-Amylase
2-Protease
3-Lipase
AfL:
Which enzyme breaks down fats into fatty
acids and glycerol?
1-Amylase
2-Protease
3-Lipase
AfL:
Which enzyme breaks down fats into fatty
acids and glycerol?
1-Amylase
2-Protease
3-Lipase
Digestion continued…
After the stomach…
Pancreas produces digestive juices with all
three enzymes which go into the first part of
the small intestine.
At the same time bile is released into the small
intestine from the liver (makes bile) and gall
bladder (stores bile). This helps to digest fat by
breaking it into droplets from large pieces.
Small intestine
• More enzymes added to finish digestion
• Absorption of digested food takes place
here
Large intestines
• Water adsorbed from food into blood
here
Rectum
• Where waste faeces (poo) is stored
before leaving the body
Anus
• A ring of muscle which prevents faeces
from leaving the body until ready
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