About Disgestive System

1. SCIENCE PROJECT WORK
SUBMITTED BY:- AYUSH AND PARAS
SUBMITTED TO :- S.SAHU
VII “A”

2. 1. RESPIRATION

4. Summary: The health of the human respiratory system is
critical to our overall health. This discussion explores the
features of the lungs and respiratory tract, the breathing
process, and diseases of the respiratory system, including
tuberculosis and emphysema.
Your body consists of many different systems and functions in
order to keep your body effective. The respiratory system is one
that is very important when it comes to breathing and gas
exchange. The structure and the functions of respiration will
allow you to inhale and exhale in a consistent routine.
Diseases and illnesses might occur when something wrong
happens to the body. In order to help or prevent this from
happening, it is important to keep care of your system.

5. Other animals, such as insects, have respiratory systems
with very simple anatomical features, and in amphibians
even the skin plays a vital role in gas exchange.Plants also
have respiratory systems but the directionality of gas
exchange can be opposite to that in animals. The
respiratory system in plants also includes anatomical
features such as holes on the undersides of leaves known as
stomata.[2]

7. Plants use carbon dioxide gas in the process of photosynthesis,
and exhale oxygen gas as waste. The chemical equation of
photosynthesis is 6 CO2 (carbon dioxide) and 6 H2O (water)
and that makes 6 O2 (oxygen) and C6H12O6 (glucose). What is
not expressed in the chemical equation is the capture of energy
from sunlight which occurs. Photosynthesis uses electrons on
the carbon atoms as the repository for that energy. Respiration
is the opposite of photosynthesis. It reclaims the energy to
power chemical reactions in cells. In so doing the carbon atoms
and their electrons are combined with oxygen forming a gas
which is easily removed from both the cells and the organism.
Plants use both processes, photosynthesis to capture the energy
and respiration to use it. Plant respiration is limited by the
process of diffusion

8. Plants take in carbon dioxide through holes on the undersides
of their leaves known as stoma or pores. However, most plants
require little air.[citation needed] Most plants have relatively few
living cells outside of their surface because air (which is
required for metabolic content) can penetrate only skin deep.
However, most plants are not involved in highly aerobic
activities, and thus have no need of these living cells.

10. In most fish respiration takes place through gills. (See also
aquatic respiration.) Lungfish, however, do possess one or two
lungs. The labyrinth fish have developed a special organ that
allows them to take advantage of the oxygen of the air.
Gills mediate the gas exchange in fish. These organs, located
on the sides of the head, are made up of gill filaments, feathery
structures that provide a large surface for gas exchange. The
filaments are arranged in rows in the gill arches, and each
filament has lamellae, discs that contain capillaries. Blood
enters and leaves the gills through these small blood vessels.
Although gills are restricted to a small section of the body, the
immense respiratory surface created by the gill filaments
provides the whole animal with an efficient gas exchange. The
surrounding water keeps the gills wet.

11. A flap, the operculum, covers and protects the gills of bony
fish. Water containing dissolved oxygen enters the fish's
mouth, and the animal moves its jaws and operculum in such a
way as to pump the incoming water through the gills. As
water passes over the gill filaments, blood inside the capillaries
picks up the dissolved oxygen. Since the blood in the capillaries
flows in a direction opposite to the flow of water around the
gill filaments, there is a good opportunity for absorption. The
circulatory system then transports the oxygen to all body
tissues and picks up carbon dioxide, which is removed from the
body through the gills. After the water flows through the gills,
it exits the body behind the fish's operculum.

13. Cockroaches are insects of the order Blattaria or Blattodea, of
which about 30 species out of 4,500 total are associated with
human habitats. About four species are well known as pests.[1]
Among the best-known pest species are the American
cockroach, Periplaneta americana, which is about 30
millimetres (1.2 in) long, the German cockroach, Blattella
germanica, about 15 millimetres (0.59 in) long, the Asian
cockroach, Blattella asahinai, also about 15 millimetres
(0.59 in) in length, and the Oriental cockroach, Blatta
orientalis, about 25 millimetres (0.98 in). Tropical cockroaches
are often much bigger, and extinct cockroach relatives and
'roachoids' such as the Carboniferous Archimylacris and the
Permian Apthoroblattina were not as large as the biggest
modern species.

14. The name cockroach comes from the Spanish word
cucaracha, "chafer", "beetle", from cuca, "kind of caterpillar."
The scientific name derives from the Latinized Greek name
for the insect (Doric Greek: βλάττα, blátta; Ionic and
Attic Greek: βλάττη, blátte')
The English form cockroach is a folk etymology reanalysis
of the Spanish word into meaningful native parts, although
cock referred to a rooster and a roach is a type of fish.

16. The frog has three respiratory surfaces on its body that it uses
to exchange gas with the surroundings: the skin, in the lungs
and on the lining of the mouth. While completely submerged
all of the frog's repiration takes place through the skin. The
skin is composed of thin membranous tissue that is quite
permeable to water and contains a large network of blood
vessels. The thin membranous skin is allows the respiratory
gases to readily diffuse directly down their gradients between
the blood vessels and the surroundings. When the frog is out of
the water, mucus glands in the skin keep the frog moist, which
helps absorb dissolved oxygen from the air.
A frog may also breathe much like a human, by taking air in
through their nostrils and down into their lungs.

17. Frogs do not have ribs nor a diaphragm, which in humans
helps serve in expand the chest and thereby decreasing the
pressure in the lungs allowing outside air to flow in.
In order to draw air into its mouth the frog lowers the floor of
its mouth, which causes the throat to expand. Then the
nostrils open allowing air to enter the enlarged mouth. The
nostrils then close and the air in the mouth is forced into the
lungs by contraction of the floor of the mouth. To elimate the
carbon dioxide in the lungs the floor of the mouth moves
down, drawing the air out of the lungs and into the mouth.
Finally the nostrils are opened and the floor of the mouth
moved up pushing the air out of the nostrils.

18. 2. REPRODUCTION

19. Human reproduction is any form of sexual reproduction
resulting in the conception of a child, typically involving
sexual intercourse between a man and a woman. During
intercourse, the interaction between the male and female
reproductive systems results in fertilization of the woman's
ovum by the man's sperm, which after a gestation period is
followed by childbirth. The fertilization of the ovum may
nowadays be achieved by artificial insemination methods,
which do not involve sexual intercourse.

21. Organisms are relatively short-lived. When one considers that
new animals present on the earth today live longer than 150
years, this period of time seems small indeed when compared
with the time that life has existed on our planet.
Even the oldest known living plants, the bristle-cone pines,
some of which are well over 4,000 years old, make a very
slight impression upon the time scale. To draw a comparison,
if the period of time that life may have occupied the earth
were reduced to twenty-four hours, and the life span of the
bristle-cone pine were reduced accordingly, the latter would
be only about one-sixth of a second.

22. Because individual organisms do not live for a very long time,
it is obvious that reproduction is the only mechanism
whereby a species can maintain itself in time. As we have
already observed, even species are subject to changes.
Nevertheless, whatever stability is achieved in nature
depends upon the ability of organisms to produce other
organisms whose characteristics are essentially like their
own.

24. Plant reproduction is the production of new individuals or
offspring in plants, which can be accomplished by sexual or
asexual means. Sexual reproduction produces offspring by
the fusion of gametes, resulting in offspring genetically
different from the parent or parents. Asexual reproduction
produces new individuals without the fusion of gametes,
genetically identical to the parent plants and each other,
except when mutations occur. In seed plants, the offspring
can be packaged in a protective seed, which is used as an
agent of dispersal.

25. Plants have two main types of asexual reproduction in which
new plants are produced that are genetically identical clones
of the parent individual. "Vegetative" reproduction involves
a vegetative piece of the original plant (budding, tillering,
etc.) and is distinguished from "apomixis", which is a
"replacement" for sexual reproduction, and in some cases
involves seeds. Apomixis occurs in many plant species and
also in some non-plant organisms. For apomixis and similar
processes in non-plant organisms, see parthenogenesis.

26. • Natural vegetative reproduction is mostly a process found in
herbaceous and woody perennial plants, and typically
involves structural modifications of the stem or roots and in
a few species leaves. Most plant species that employ
vegetative reproduction do so as a means to perennialize the
plants, allowing them to survive from one season to the next
and often facilitating their expansion in size. A plant that
persists in a location through vegetative reproduction of
individuals constitutes a clonal colony, a single ramet, or
apparent individual, of a clonal colony is genetically
identical to all others in the same colony.

28. Binary fission is an effective way for bacteria to reproduce,
however it does produce problems. Since the cells produced
through this type of reproduction are identical, they are all
susceptible to the same types of antibiotics. In order to
incorporate some genetic variation, bacteria use a process
called recombination. Bacterial recombination can be
accomplished through conjugation, transformation, or
transduction. Conjugation Some bacteria are capable of
transferring pieces of their genes to other bacteria that they
come in contact with.

29. During conjugation, one bacterium connects itself to another
through a protein tube structure called a pilus. Genes are
transferred from one bacterium to the other through this
tube. Transformation Some bacteria are capable of taking
up DNA from their environment. These DNA remnants
most commonly come from dead bacterial cells. During
transformation, the bacterium binds the DNA and
transports it across the bacterial cell membrane. The new
DNA is then incorporated into the bacterial cell's DNA.
Transduction Transduction is a type of recombination that
involves the exchanging of bacterial DNA through
bacteriophages.

30. the bacterium binds the DNA and transports it across the
bacterial cell membrane. The new DNA is then incorporated
into the bacterial cell's DNA. Transduction Transduction is
a type of recombination that involves the exchanging of
bacterial DNA through bacteriophages.