physical digestion Flashcards
what is physical digestion?
physical digestion is the breakdown of food into smaller pieces without chemical change to the food molecules and performed by the teeth. prepares food for chemical digestion
importance of physical digestion
increases the surface area of food for the action of enzymes in chemical
digestion.
what does physical digestion involve (1)
chewing (in the mouth), mixing, churning (in the
stomach and intestine) and segmentation (in the
intestine).Large pieces of food are broken down
into smaller pieces to increase the surface area of
the food.
what does physical digestion involve (2)
Bile physically digests fats and oil by emulsifying them –turning them into small
droplets to increase the surface area for
chemical digestion.
what does physical digestion involve (3)
Peristalsis- Wave-like movement of food along the oesophagus and intestine.
Chewing
Physical digestion, performed by the teeth.
Pieces of food are mixed with saliva. They
become smaller, easier to swallow and have a
larger surface area for enzymes to work on.
types of teeth
incisors, canines, premolars, molars
incisor (position in mouth, description and function)
found in the front of the mouth, chisel shaped(sharp edge) and used for biting pieces of food
canine (position in mouth, description and function)
found in the either side of the incisors, slightly more pointed than incisors, and used for biting of pieces of food
premolar (position in mouth, description and function)
found behind the canines, 2 points(cusps), 1 or 2 roots, used for tearing and grinding food
molar(position in mouth, description and function)
found in the back, 4 or 5 cusps or 2 or 3 roots, used for chewing and grinding food
peristalsis
The walls of the oesophagus have an inner, circular
muscle fibre coat and an outer, longitudinal muscle
fibre coat.
As the ball of food (bolus) formed in the mouth
enters the pharynx, a reflex action is initiated.
This produces slow, wave-like contractions in the
walls of the oesophagus and later along the whole
length of the tract (peristalsis). Peristaltic waves involve the contraction
of the circular muscle fibres behind the bolus and their relaxation in front of the
bolus. Longitudinal muscles provide the wave-like action. The two function together to push the ball down the tract
example of mechanical digestion
emulsification. breaking something into smaller pieces. it doesn’t break bonds or change the chemical structure of the molecules which make it uo.
how does someone choke
choking is caused when food goes into the windpipe instead of the oesophagus.
what is peristalsis
this is when food is moved through the alimentary canal by wave like muscle contractions
