Human Digestive System - Life Processes, Science Video Lecture - Class 10

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the human digestive system is a system
of organs and associated glands it
begins with the mouth and ends with the
anus and in an uncalled State it can run
up to eight meters mouths it's guarded
in the front with lips the roof of the
mouth is called the palate and at the
base of the mouth is the tongue the
mouth leads into a common cavity called
as the pharynx it's from here the two
tubes a food tube that is the ease of
Vegas as you can see leads into the
stomach there is a provision for another
tube that's the respiratory troupe the
trachea stomach is lying on the
left-hand side of the abdominal cavity
the stomach leads into the first part of
the small intestine that's the do denim
and this highly coiled structure here
are the other parts of the small
intestine the jejunum and the ileum the
small intestine is about six meters in
length the portion visible here highly
convoluted is the large intestine which
is about 1.5 meters long it is made up
of the cecum a colon rectum which opens
out through the anus let's get back to
the mouth and see what are the
mechanisms that aid in digestion inside
our mouth we have in an adult 32 teeth
the human teeth are diffident and yet
rodent what do you understand by the
word diffident diffident means we have
two sets of teeth in our lifetime the
temporary teeth the deciduous teeth in
children up to the age of nine and then
the permanent teeth in adults heterodon
that means we have four types of teeth
the incisors the canines the premolars
and the molar you can have a look at the
glans present in the mouth the saliva
glands are of three pairs parotid
sublingual and submandibular as the name
suggests parotid glands lie below the
year
sublingual below the tongue and
submandibular below the lower jaw the
saliva glands secrete saliva a highly
alkaline fluid containing a lot of water
and salts and ions of sodium bicarbonate
and more importantly it contains an
enzyme which is a Miley's saliva of my
lays or Thailand
now the teeth break down the food
mechanically that is we choose the food
once the food is chewed it is mixed with
saliva only the digestion of
carbohydrates is initiated in the mouth
Thailand converts the polysaccharides
into a disaccharide that a starch
converted into maltose which is a
disaccharide then with the help of the
tongue the food is rolled into a bolus
it passes through the ease of aigis
aided by a wave-like motion called as
the peristaltic motion ISA Vegas is 25
centimeters in length and at the point
of joining the stomach there is a
cardiac spinto which is the passage of
food into the stomach in the stomach the
food is subjected to the action of yet
another juice the gastric juice secreted
by the gastric glands hydrochloric acid
is also present in the stomach it plays
a very vital role it destroys the
bacteria
let's oftens the fibrous content of food
and remember the stomach is a muscular
bag it churns up the food maximum time
is spent in the stomach for the food to
be mixed up by the gastric juice must be
wondering what are the food items that
would be digested in the stomach
well the digestion of the proteins
begins and this is brought about by
pepsin pepsin is not present in the form
of pepsin it is in an inactive form that
is pepsinogen its hydrochloric acid that
converts inactive pepsinogen into active
pepsin it acts on proteins converts them
partially digest them to proteases and
peptides no digestion of carbohydrate
not even the one that was initiated in
the mouth is carried on in the stomach
this semi digested food from the stomach
is called as the chyme it passes through
the pyloric Spencer enters into the
duodenum well do denim is a very
important point for the digestion of
food you can see a huge land the liver
1.4 kgs it secretes the bile juice by
juice contains no enzymes but it has a
vital role to play the bile duct carries
the bile juice to the Jew dynam now bhai
has a function of emulsifying facts must
be wondering what's emulsification of
fats it's something like the action of
detergents the fat globules which are so
big are broken down into smaller
molecules of fat to provide greater
surface area for enzymes to act on them
in the loop between the stomach and the
Jew denim there is a leaf shaped gland
called as the pancreas yet another
whiter gland associated with the
digestive system from the pancreas is
secreted a juice called as the
pancreatic juice carried by the pancreas
ducked to the Jew denim now pancreatic
juice contains three enzymes trypsin am
i lace and lipase trypsin acts further
on the proteins the digestion of
proteins have to be completed by the
juices present here proteins are
digested into their final products and
that is amino acids and then we have
amylase the digestion which of
carbohydrates which was not complete in
the mouth is now accomplished in the do
denim a mindless acts on carbohydrates
which are of different types and finally
it has to be converted into glucose what
about lipase well lipase has a very
important role it acts on the facts
converts them into fatty acids and
glycerol yet it may be possible many of
the food items are not yet digested they
are still in the complex form so there
is yet another juice that is the
intestinal juice secreted by the small
intestine which acts on proteins
carbohydrates and fats now acting upon
the proteins could be the dye peptidases
carboxypeptidase --is and finally the
proteins have to be converted into amino
acids we have enzymes like lactase
maltese sucrase that act on different
forms of carbohydrates like lactose
maltose sucrose and converted eventually
into glucose and further after this
digestion has been completed in the
small intestines there is a very
important function to be performed on
the walls of the small intestine are
present finger-like projections called
as the villi which absorb the end
products of digestion
what is the role then of these large
intestines the large intestine absorbs
excess of water back to the body the
undigested unassimilated food is to be
thrown out from our body in the form of
feces it travels all the way through the
paths of the large intestine collects in
the rectum and it is thrown out through
the anus
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