CLASS X | SCIENCE | RESPIRATION
RESPIRATORY ORGANS:
The respiratory organs are the parts of the body involved in the process of respiration, which is the exchange of gases between the body and the environment.
All the respiratory organs have three common features:
All the respiratory organs have a large surface area to get enough oxygen.
All the respiratory organs have thin walls for easy diffusion and exchange of respiratory gases.
All the respiratory organs like skin, gills and lungs have a rich blood supply for transporting respiratory gases.
Air reaches cells directly in only one type of system of
respiration known as Tracheal system of
respiration.
AMOEBA:
Amoeba is a single-celled
organism that does not have a specialized respiratory organ. Instead, it uses a
simple diffusion process to exchange gases with the environment.
The cell membrane of
Amoeba is permeable to gases such as oxygen and carbon dioxide. This means that
these gases can pass through the cell membrane via diffusion. As Amoeba moves,
the cytoplasmic streaming within the cell also helps to circulate gases throughout
the cell.
When oxygen is available
in the surrounding environment, it diffuses across the cell membrane into the
cytoplasm of the Amoeba. From there, it enters the mitochondria where it is
used in the process of aerobic respiration to produce energy. The waste product
carbon dioxide is also released through diffusion across the cell membrane into
the environment.
During respiration, Amoeba
breaks down glucose molecules and other organic compounds in the presence of
oxygen to release energy in the form of ATP (adenosine triphosphate). The
process of respiration can be divided into two types: aerobic and anaerobic
respiration.
Aerobic respiration is the
most common type of respiration in Amoeba. In this process, glucose is
completely broken down in the presence of oxygen, producing carbon dioxide,
water, and energy in the form of ATP. The chemical equation for aerobic
respiration in Amoeba can be represented as:
C6H12O6
+ 6O2 → 6CO2 + 6H2O + energy (ATP)
Anaerobic respiration
occurs in the absence of oxygen. In this process, glucose is partially broken
down, producing energy and various byproducts such as lactic acid or ethanol.
This process is less efficient than aerobic respiration and is usually used by
Amoeba as a backup energy source when oxygen is not available.
Respiratory
organ in aquatic animals:
Aquatic animals have
evolved various structures for respiration, depending on their environment and
the availability of oxygen. Here are some examples of respiratory organs in
aquatic animals:
1. Gills: Gills are the most common respiratory organ in aquatic
animals, including fish, crustaceans, mollusks, and some amphibians. Gills are
specialized organs that extract dissolved oxygen from water and release carbon
dioxide.
2. Skin: Some aquatic animals, such as frogs and some salamanders, can
absorb oxygen through their skin. The skin must be moist for this to
occur.
3. Lungs: Some aquatic animals, such as turtles, crocodiles, and some
species of fish, have lungs that allow them to breathe air when they come to
the surface. Some aquatic insects also have specialized structures that
function as lungs.
4. Tracheae: Some aquatic insects, such as water beetles and mosquito
larvae, have a system of tubes called tracheae that allow them to breathe air
from the surface.
5. Rectal gills: Some aquatic animals, such as certain species of sea
cucumbers, have respiratory structures called rectal gills that extract oxygen
from water passing through the anus.
Respiration
in Fishes:
Fish have gills that
extract oxygen from water. The gills are located in chambers on either side of
the fish's head, where water flows in through the mouth and over the gill
filaments. The gill filaments are covered in tiny blood vessels that extract
oxygen from the water and release carbon dioxide. The oxygen-rich blood is then
transported to the rest of the fish's body. Fish also have a swim bladder,
which is a gas-filled sac that helps them control their buoyancy.
Respiration
in Frogs:
Frogs, on the other hand,
can breathe through their skin as well as their lungs. When a frog is in water,
it can extract oxygen through its skin, which needs to be moist to function
properly. However, when a frog is on land, it primarily uses its lungs to
breathe. Frogs have a specialized breathing mechanism where they draw air into
their lungs by lowering the floor of their mouth and inflating their throat
sacs. They then force the air out by contracting their throat muscles. This
process is called positive pressure breathing.
Respiratory
Organs in Insects:
Insects have a unique
respiratory system consisting of a network of tiny tubes called tracheae. These tubes open to the
outside through small openings called spiracles,
which are located on the insect's abdomen and thorax. The spiracles can be
opened and closed by valves, allowing the insect to control the amount of air
that enters and exits.
The tracheae branch out
into smaller tubes called tracheoles,
which reach individual cells throughout the insect's body. The tracheoles are
extremely thin, allowing for efficient gas exchange with the surrounding
tissues.
Insects also have
specialized respiratory structures called air
sacs, which are located in some larger species like grasshoppers, beetles,
and some butterflies. The air sacs increase the volume of air that the insect
can take in and store, allowing for increased efficiency during flight.
The respiratory system of
insects allows for efficient gas exchange, and it has been crucial to the
evolutionary success of insects. The tracheal system allows for quick and
efficient transport of oxygen to all parts of the body, allowing insects to
sustain high levels of activity and adapt to a wide range of
environments.
Respiratory
system of land animals
The respiratory system of
land animals, including mammals, reptiles, birds, and some amphibians, is
responsible for taking in oxygen and expelling carbon dioxide. It consists of
the following organs and structures:
Nose and mouth: These are the entry points for air into the respiratory system.
In some animals, such as dogs and cats, the nose plays a particularly important
role in filtering, warming, and moistening the air before it enters the lungs.
Trachea: This
is a tube made up of cartilage rings that runs down the neck and connects the
nose and mouth to the lungs.
Bronchi: The
trachea divides into two branches, called the left and right bronchi, which
lead to the left and right lungs.
Lungs: The
lungs are the main organs of respiration, where oxygen is exchanged for carbon
dioxide. They are made up of millions of tiny air sacs called alveoli, which
are surrounded by capillaries that allow for gas exchange.
Diaphragm: This
is a muscle located at the base of the chest that helps to control breathing.
When it contracts, it flattens out and expands the chest cavity, causing air to
rush into the lungs. When it relaxes, the chest cavity gets smaller and air is
expelled from the lungs.
Overall, the respiratory system is essential for the survival of land animals, as it allows them to obtain the oxygen they need to produce energy and carry out cellular functions.
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