Difference between
buccal pumbing
and suction
pumbing
In mammals while breathing, the diaphragm and muscles around the
rib cage cause a change of volume in the lungs. The increased
volume of the chest cavity decreases the pressure inside, creating
an imbalance with the ambient air pressure, resulting in
suction.
In frog, buccal pumping is used to force water into the
“stomach,” which will increase 50–100-fold in volume.
Frogs do not have ribs nor a diaphragm, which
in humans helps serve in expand the chest and
thereby decreasing the pressure in
thelungs 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 toexpand.
Buccal pumbing
- It is "breathing with one's cheeks":
- Method of ventilation used in respiration in which the animal
moves the floor of its mouth in a rhythmic manner that is
externally apparent.
- It is the sole means of inflating the lungs in amphibians.
There are two methods of buccal pumping, defined by the number
of movements of the floor of the mouth needed to complete both
inspiration and expiration.
Four stroke
- Four-stroke buccal pumping is used by some basal ray-finned
fish and aquatic amphibians.
- This method has several stages.
- First, the glottis (opening to the lungs) is closed, and the
nostrils are opened. The floor of the mouth is then depressed
(lowered), drawing air in. The nostrils are then closed, the
glottis opened, and the floor of mouth raised, forcing the air into
the lungs for gas exchange.
- To deflate the lungs, the process is reversed.
Two stroke
Two-stroke buccal pumping completes the process more quickly
which seen in most extant amphibians.
- In this method, the floor of the mouth is lowered, drawing air
from both the outside and lungs into the buccal cavity.
- When the floor of the mouth is raised, the air is pushed out
and into the lungs
- The amount of mixing is generally small, about 20
percentage.
Mammal's ventilation
In mammals, pulmonary ventilation occurs via inhalation .
- During inhalation, air enters the body through the
nasal cavity located just inside the
nose
- As air passes through the nasal cavity, the air is warmed to
body temperature and humidified.
- Particulate matter that is floating in the air is removed in
the nasal passages via mucus and cilia.
- The processes of warming, humidifying, and removing particles
are important protective mechanisms that prevent damage to the
trachea and lungs.
- Thus, inhalation serves several purposes in addition to
bringing oxygen into the respiratory system.
- From the nasal cavity, air passes through the
pharynx and the larynx, as it
makes its way to the trachea .
- The main function of the trachea is to funnel the inhaled air
to the lungs and the exhaled air back out of the body.
- The human trachea sits in front of the esophagus and extends
from the larynx into the chest cavity where it divides into the two
primary bronchi at the midthorax.
- It is made of incomplete rings of hyaline cartilage and smooth
muscle
- The trachea is lined with mucus-producing goblet cells and
ciliated epithelia.
- The cilia propel foreign particles trapped in the mucus toward
the pharynx.
- The cartilage provides strength and support to the trachea to
keep the passage open.
- The smooth muscle can contract, decreasing the trachea’s
diameter, which causes expired air to rush upwards from the lungs
at a great force.
- The forced exhalation helps expel mucus when we cough.
- The end of the trachea bifurcates (divides) to the right and
left lungs.
- The right lung is larger and contains three lobes, whereas the
smaller left lung contains two lobes .
- The muscular diaphragm, which facilitates
breathing, is inferior to the lungs and marks the end of the
thoracic cavity
- In the lungs, air is diverted into smaller and smaller
passages, or bronchi.
- Air enters the lungs through the two primary
bronchi.
- Each bronchus divides into secondary bronchi, then into
tertiary bronchi, which in turn divide, creating smaller and
smaller diameter bronchioles as they split and
spread through the lung.
- In humans, bronchioles with a diameter smaller than 0.5 mm are
the respiratory bronchioles.
- They lack cartilage and therefore rely on inhaled air to
support their shape.
- The terminal bronchioles subdivide into
microscopic branches called respiratory bronchioles.
- The respiratory bronchioles subdivide into several alveolar
ducts.
- Numerous alveoli and alveolar sacs surround the alveolar
ducts.
- Terminal bronchioles are connected by respiratory bronchioles
to alveolar ducts and alveolar sacs.
- Each alveolar sac contains 20 to 30 spherical alveoli.
- Air flows into the atrium of the alveolar sac, then circulates
into alveoli where gas exchange occurs with the capillaries.
- Mucous glands secrete mucous into the airways, keeping them
moist and flexible.
- In the acinar region, the alveolar ducts are
attached to the end of each bronchiole.
- At the end of each duct are approximately 100 alveolar
sacs, each containing 20 to 30 alveoli
that are 200 to 300 microns in diameter.
- Gas exchange occurs only in alveoli. Alveoli are made of
thin-walled parenchymal cells, typically one-cell thick, that look
like tiny bubbles within the sacs.
- Alveoli are in direct contact with capillaries (one-cell thick)
of the circulatory system.
- Such intimate contact ensures that oxygen will diffuse from
alveoli into the blood and be distributed to the cells of the body.
In addition, the carbon dioxide that was produced by cells as a
waste product will diffuse from the blood into alveoli to be
exhaled.
- The anatomical arrangement of capillaries and alveoli
emphasizes the structural and functional relationship of the
respiratory and circulatory systems.
- Because there are so many alveoli within each alveolar sac and
so many sacs at the end of each alveolar duct, the lungs have a
sponge-like consistency.
- This organization produces a very large surface area that is
available for gas exchange.
- This large surface area, combined with the thin-walled nature
of the alveolar parenchymal cells, allows gases to easily diffuse
across the cells.
Birds respiratory
system
- Birds have a larynx. An organ termed the "syrinx" serves as the
"voice box."
- Birds have lungs, but they also have air sacs.
- Depending upon the species, the bird has seven or nine air
sacs. Air sacs do not play a direct role in oxygen and carbon
dioxode exchange, however they do keep oxygen rich air moving, in
one direction, through the avian respiratory system.
- The air sacs of birds extend into the humerus the femur, the
vertebrae and even the skull.
- Birds do not have a diaphragm; instead, air is moved in and out
of the respiratory system through pressure changes in the air
sacs.
- Muscles in the chest cause the sternum to be pushed
outward.
- This creates a negative pressure in the air sacs, causing air
to enter the respiratory system.
- Expiration is not passive, but requires certain muscles to
contract to increase the pressure on the air sacs and push the air
out.
- Because the sternum must move during respiration, it is
essential that it is allowed to move freely when a bird is being
restrained.
- Bird lungs do not expand or contract like the lungs of
mammals.
- In mammalian lungs, the exchange of gases
occur in 'alveoli.'. In the avian
lung, the gas exchange occurs in the walls of microscopic tubules,
called 'air capillaries.'
The respiratory system of birds is more efficient than that of
mammals, transferring more oxygen with each breath.
Birds have a slower respiratory rate than mammals.
Respiration in birds requires
two respiratory
cycles to move the air through the entire
respiratory system. In mammals, only
one respiratory cycle is
necessary.
Respiratory cycle
- During the first inspiration,
the air travels through the nostrils, also called nares, of a bird,
which are located at the junction between the top of the upper beak
and the head.
- Air moves through the trachea to the syrinx, which is located
at the point just before the trachea divides in two.
- It passes through the syrinx and then the air stream is divided
in two as the trachea divides.
- The air does not go directly to the lung, but instead travels
to the caudal (posterior) air sacs.
- A small amount of air will pass through the caudal air sacs to
the lung
- During the first expiration,
the air is moved from the posterior air sacs through the
ventrobronchi and dorsobronchi into the lungs.
- The bronchi continue to divide into smaller diameter air
capillaries.
- Blood capillaries flow through the air capillaries and this is
where the oxygen and carbon dioxide are exchanged
- When the bird inspires the
second time, the air moves to the cranial air
sacs
- On the second expiration, the
air moves out of the cranial air sacs, through the syrinx into the
trachea, through the larynx, and finally through the nasal cavity
and out of the nostrils.