Download BIO 250 System and Maintainance (Plants and

BIO 250
System and Maintainance
(Plants and Animals)
Chapter 2.4
Respiratory System
By
Mohd Azuraidi bin Harun
http://yeddah.net/azuraidi/bio250
Objectives
At the end of this topic, students should be able to
understand about the respiratory system of
a) fishes,
b) insects,
c) sea stars,
d) birds,
e) amphibians
Definition
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Respiratory System – a biological system that
introduces respiratory gases to the interior and
performs gas exchange.
In human and other mammals – respiratory
system include airways, lungs, and respiratory
muscles.
In fishes – respiration takes place through gills.
Definition
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In insects – respiratory system include
openings called spiracles, and a network of
tubes called tracheae and trachioles.
In birds – respiratory system include air sacs
that.
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Amphibians – skin plays a vital role in gas
exchange.
Respiratory System in Fish
Gills
Respiratory System in Fish
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Respiration takes place through gills.
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Gills have:
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A large surface area to allow as much oxygen to
enter the gills as possible due to the fact that more
gas comes into contact with the membrane,
Good blood supply to maintain the concentration
gradient needed,
Thin membrane to allow for a short duration
pathway,
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Each gill arch has two rows of gill filaments,
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Each gill filament has many lamellae.
Respiratory System of Insect
Respiratory System of Insect
Grasshopper
Caterpillar
Spiracles
Respiratory System of Insects
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Air enters the respiratory system of most
insects through a series of external openings
called spiracles.
The opening acts as muscular valves.
The openings lead to internal respiratory
system – tracheae and trachioles.
Respiratory System of Insects
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The internal respiratory system is composed of
a densely networked array of tubes called
tracheae.
The tracheae branch repeatedly, eventually
forming tracheoles.
Tracheoles are blind-ended, water-filled
compartments.
Respiratory System of Insects
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At this level of tracheoles, the oxygen is
delivered to the cells of respiration.
Respiratory System of Insects
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Insects have spiracles on their exoskeletons to
allow air to enter the trachea.
The tracheal tubes primarily deliver oxygen
directly into the animals' tissue.
The spiracles can be opened and closed to
reduce water loss. This is done by contracting
closer muscles surrounding the spiracle.
Respiratory System of Insects
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The closer muscle is controlled by central
nervous system, but can react by localized
chemical stimuli.
Respiratory System of Sea Stars
Starfish / sea star – echinoderms belonging to the class Asteriodea. The name “starfish”
and “sea star” refer to this member of this class.
Respiratory System of Sea Stars
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Gas exchange in sea stars occurs over their surface: they
have neither gills nor lungs.
Folds of skin on their dorsal surface permit gas exchange,
as do the tube feet on their ventral surface. Also, they have
water-based vascular system, which performs gas
exchange.
The starfish has a water vascular system in which the
exchange between oxygen and carbon dioxide occurs.
The tube feet of the starfish act like gills. The Oxygen
enters the water vascular system through the tube feet as
the carbon dioxide exits the body
Respiratory System of Birds
`
Respiratory System of Birds
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Respiration in birds is much different than in humans
and in other mammals.
These differences are adaptations for flight. Due to
their high metabolic rate required for flight, birds have
a high oxygen demand.
The bird has 2 sets of air sacs:
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The caudal air sacs include the abdominal air sacs
and the caudal thoracic air sacs.
The cranial air sacs include the cervical air sac,
clavicular air sac, and the cranial thoracic air sacs.
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Air enters via trachea. Half of the inhaled air
enters posterior sacs, the other half passes thru
the lungs and into anterior sacs. Air from
anterior sacs emptied directly into trachea and
out of the mouth/nares. Posterior sacs empty
their air into the lungs. Air passing thru the
lungs as the bird exhales is expelled via the
trachea.
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A mammal's lungs are made up of millions of
tiny ballons, called alveoli, which expand and
contract as the animal breathes.
A bird's lungs, on the other hand, are not elastic
– they do not change size when bird breathes.
A bird's lungs are composed of air chambers
whose walls are made of a thin layer of
squamous epithelium surrounded by capillaries.
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Specialized elastic structures called air sacs
are connected to the lungs and act like furnace
bellows to draw air through the lungs – very
much like a furnace forces air through the
ductwork of a house.
As air passes through the ductwork of the
lungs, O2 in the air is exchanged for CO2 in the
blood of capillaries within the chamber walls.
Respiratory System of Amphibians
Respiratory System of Amphibians
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The lungs in amphibians are primitive:
possessing a few internal septa and large
alveoli, so having slow diffusion rate for oxygen
entering the blood.
Ventilation is accomplished by buccal pumping
(breathing with one's cheeks).
Most amphibians are able to exchange gases
with the water or air via their skin.
Respiratory System of Amphibians
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To enable sufficient cutaneous respiration, the
surface of their highly vascularized skin must
remain moist to allow the oxygen to diffuse at a
sufficient high rate.
Because oxygen concentration in the water
increases at both low temperatures and high
flow rates, aquatic amphibians in these
situations can rely primarily on cutaneous
respiration, as in the Titicaca water frog and the
hellbender salamander.
Respiratory System of Amphibians
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In air, where oxygen is more concentrated,
some small species can rely solely on
cutaneous gas exchange, most famously the
plethodontid salamanders, which have neither
lungs nor gills.
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Many aquatic salamanders and all tadpoles
have gills in their larval stage, with some (such
as the axolotl) retaining gills as aquatic adults.