Nutrition in Animals Video Lecture | Science & Technology for UPSC CSE

nutrition in animals introduction we see
that whatever we or animals eat is
either a plant or an animal product
since we cannot photosynthesize because
we lack the green pigment chlorophyll we
have to depend on green plants and other
animals for our nutrition so our mode of
nutrition and that of other animals and
of some plants is heterotrophic
heterotrophic nutrition in animals is of
the following four types whole azoic
s'prise oeq parasitic mutualistic hollow
zoic nutrition most animals are hollow
zoic it involves taking in ready-made
solid or liquid food substances as a
whole these are broken down in the
animal's body into simpler substances
that can be easily digested to provide
nutrition whole azoic animals may be
herbivores plant-eating carnivores eat
other animals or omnivores diet having
both plant and animal material surprised
oeq nutrition many fungi and bacteria
feed by suprise oeq methods the cells of
the organism dissolve the dead remains
of living organisms by secreting
chemicals the soluble products are then
absorbed into the cell body a good
example is mushrooms parasitic nutrition
parasites are organisms that for part or
all of its life derives nutrition
through other organisms called the host
this interaction between the host and
the parasite is called parasitism
parasites are generally smaller than
their hosts and absorb nutrients from
the host body fluids example mosquito
mutualistic nutrition in mutualistic
nutrition two organisms interact in a
manner such that both are benefitted
this is also called symbiosis
is a very good example of mutualistic
nutrition is the association between
bacteria called rhizobia and plants
belonging to the pea family rhizobia
make their home in the nodules of the
plant roots and obtain food from these
plants while the plants obtain nitrogen
through them digestion in grass eating
animals have you observed cows buffaloes
and other grass eating animals
chewing continuously even when they are
not eating actually they quickly swallow
the grass and store it in a part of the
stomach called rumen here the food gets
partially digested and is called cud but
later the cut
returns to the mouth in small lumps and
the animal chews it this process is
called rumination and these animals are
called ruminants the grass is rich in
cellulose a type of carbohydrate many
animals including humans cannot digest
cellulose ruminants have a large
sac-like structure called cecum between
the small intestine and the large
intestines the cellulose of the food is
bacteria which are not present in humans
nutrition in amoeba amoeba are organisms
made up of a single cell usually found
in ponds and ditches their food consists
of the microscopic plants and animals
floating in these waters ingestion when
amoeba comes into contact with one of
these organisms it sort of flows around
the organism forming a cup-shaped
projection this is called a food cup or
food vacuole which completely encloses
and ingest the food this mode of
nutrition is called phagocytosis cell
eating digestion in amoeba digestion is
very simple and direct once a prey is
engulfed certain chemicals call
enzymes are released into the food
vacuole enzymes along with other
digestive juices break down the food
forming a solution absorption the food
in solution form is now ready to be
absorbed and assimilate nutrition in
humans mouth
food is broken down by the process of
chewing liver the liver secretes bile
which plays a vital role in digestion in
the small intestine gallbladder the
liver connects to the gallbladder and
bile is stored and concentrated here
before release into the small intestine
pancreas this gland secretes bicarbonate
and digestive enzymes into the small
intestine the bicarbonate neutralizes
the acid from the stomach large
intestine water and useful minerals are
absorbed through the walls of the large
intestine back into the blood the
remains are formed into feces saliva
glands enzymes produced by these glands
break down starches into smaller sugar
molecules esophagus it is a long tube
connecting the mouth to the stomach it
uses rhythmic wave-like movements called
peristaltic movements to move food from
the mouth to the stomach stomach the
stomach is a large sack like organ which
secretes HCL enzymes and mucous this
initiates and prepares the food for
chemical and enzymatic digestion small
intestine it is the longest section of
the digestive tube about 6 meters in
length and almost all of the nutrients
is absorbed here rectum and anus the
rectum stores the feces which is then
adjusted out of the body through the
anus milk teeth and permanent teeth the
first set of teeth grows during infancy
and they fall off at the age between 6
to 8 years these are termed milk teeth
the second set that replaces them are
the permanent teeth the permanent teeth
may last through
life or fall during old age or due to
some dental disease types of teeth in
sis's they are also called biting teeth
they are eight in number four in each
jaw the incisors are the front teeth and
are so called because they help to
incise cut food they are flat blade like
teeth can ions they are also called
tearing teeth they have very sharp edges
and help in tearing the food and are
four in number premolars they have
broader grinding surfaces and therefore
help in chewing and grinding of food
there are eight premolars in the human
set molars molars are large back teeth
having a wide grinding surface and are
used primarily to chew food humans have
12 molars human teeth we humans develop
two different sets of teeth in our
lifetime the temporary set and the
permanent set the temporary set this is
the set that starts appearing at the age
of about two and a half to three months
and completes in about two years these
teeth are also called
milk teeth there are 20 milk teeth in
the temporary set front teeth usually
erupt when a child is from 6 to 12
months of age second molars between 13
and 19 months old and canines usually
erupt at 19 months or older although the
temporary set is replaced by the
permanent set the temporary set plays a
very important role in the proper
alignment and spacing of the permanent
teeth around the age of 6 the milk teeth
start giving way to the developing
permanent teeth the temporary set sheds
earlier and permanent teeth erupt
earlier in girl human teeth
the permanent set there are 32 teeth in
a permanent set 16 in each jaw adult
humans have eight incisors four in each
jaw arranged in the middle there are
four canines two in the upper and two in
the lower behind the canines are the
premolars again four in each jaw two on
the left and two on the right the molars
are found at the back of the jaws behind
the premolars
they are twelve in number six each in
the upper and lower jaw three on the
left and three on the right the
permanent set is larger in number and
size then the temporary set their enamel
is thicker though less white and
appearance when compared with the milk
teeth wisdom teeth wisdom teeth are the
third molars which appear between the
ages of eighteen and twenty they are
called
wisdom teeth because they appear so late
after the other teeth have already
erupted in early childhood at the age of
eighteen you are an adult
hence believed to be wiser than you were
as a child