docsity-respiratory-system-of-animal.pptx

Respiratory system of animal
Biology
Universiti Teknologi Mara
62 pag.
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CHAPTER 2
RESPIRATORYSYSTEM
1

Respiratory System
CONTENTS
 2.1 Characteristics of respiratory surfaces
 2.2 Respiration in fish - gills, countercurrent exchange
 2.3 Respiration in insect - tracheal system
 2.4 Respiration in amphibians - skin and lungs
 2.5 Respiration in birds - lungs
 2.6 Respiration in mammals - lungs, breathing mechanism,
tidal volume, vital capacity, residual volume
2

 Your respiratory system is made up of the organs in your body that
help you to breathe.
 Remember, that Respiration = Breathing.
 The goal of breathing is to deliver oxygen to the body and to take
away carbon dioxide.
 The feathery gills projecting from a salmon
⚫ are an example of a specialized exchange system (respiration)
found in animals
3

Circulatory system
Cellular respiration ATP
Cellular level
Energy-rich
molecules
from food
Respiratory
surface
Respiratory
medium
(air of water)
Organismal
level
O2 CO2
4
Cellular respiration involves the breakdown of organic
molecules to produce ATP
.
A sufficient supply of oxygen is required for the aerobic respiratory machinery
of Kreb's Cycle and the Electron Transport System to efficiently convert
stored organic energy into energy trapped in ATP.
Gas exchange
Supplies oxygen for cellular respiration and disposes of
carbon dioxide

5
2.1 CHARACTERISTICS OF RESPIRATORY
SURFACES
The Characteristics of a Respiratory Surface are :
• - thin walls
• - a moist inner surface
• - a huge combined surface area
• - a rich blood supply- each alveolus is surrounded by
capillaries.

RESPIRATORY SYSTEM ANIMAL AND PLANT PHYSIOLOGY ENMM
Well ventilated
Rich blood
supply
Large surface
area
Thin walls
Moist inner
surface
Characteristics of
Respiratory Surfaces
For gaseous
exchange.
Ventilation
mechanisms,
such
as human
breathing
movements,
increase the
rate of gas
exchange
Each
alveolus is
surrounded
by a network
of capillary
blood
vessels
Those gases can
only cross cell
membranes when
they are dissolved
in water or an
aqueous solution,
thus respiratory
surfaces must be
moist.
For diffusion of gas

RESPIRATION
The process by which:
livingorganisms exc
hange
c
arbondioxide
and oxygen
Dependent uponthe
principleof diffusion
via respiratorysurfaces(in
respiratory organssuchas
gills,
tracheaeor lungs)
with their environment/
respiratorymedium(air or
water)

⦁No problem keeping the cell membranes of the respiratory
surface MOIST (aqueous environment)
⦁But, O2 concentrations are LOW
WATER
Respiratory Medium
8
respiratory medium, either air or water

9
AIR
• HIGH concentration of oxygen than water
• O2 and CO2 diffuse FASTER in air
• Less energy required for ventilation (air is far lighter and much easier to
pump)
• Air dries out the respiratory surface

 Small organisms such as single-celled
protozoa (Amoeba and Paramecium),
Hydra, earthworm, and jellyfish
exchange gases directly across their
cell membrane or body surface
through simple diffusion.
 Because of small body volume,
diffusion alone is sufficient to
transport oxygen and carbon dioxide
into, around , and out of their bodies.
 Simple animals that lack specialized
exchange surfaces for gas exhange
have flattened, tubular, or thin
shaped body plans, which are the
RESPIRATORY SYSTEM ANm
IMAo
L s
AN
tD e
PLfA
fN
iT
cPiH
e
YS
n
IO
tLO
fG
o
Yr
ENg
MM
as exchange.

Higher organisms such as fishes, insects,
amphibians, birds, and mammals exchange gases
at a specialized region of body called a respiratory surface.
They cannot maintain gas exchange by diffusion across their
outer surface like small organisms.
The respiratory surface is often part of an elaborate
respiratory organ (example: gills, tracheae or lungs).
Respiration in
Higher Organisms

3 Basic Processes of Respiration:
Pulmonary Ventilation /Breathing:
The inhalation and exhalation of air and involves the
exchange of air between the atmosphere and the
alveoli of the lungs.
External (pulmonary) respiration:
Exchange of gases between the alveoli of the lungs and the blood
in pulmonary capillaries across the respiratory membrane.
During this, pulmonary capillary blood gains O2 and loses CO2 .
Internal (tissue) respiration:
Exchange of gases between blood in systemic capillaries and
tissue cells. Inthis step the blood loses O2 and gains CO 2. Within
cells, the metabolic reactions that consume O2 and give off CO2
during the production of ATP are termed cellular respiration.

13
2.2 RESPIRATION IN FISH/
MARINE ANIMALS
⦁Gills are outfoldings of the body surface
• Specialized for gas exchange
⦁In some invertebrates
◦The gills have a simple shape and are distributed over much of the body

Respiration inFish
~ takes place in GILLS~
L
amellaelining
eachgill
filament
Gasexchange
takesplacein
lamellae as
water flow
through
them.
It increasesthe
surfacearea to
allow moregas
exchangeto
takeplace, just
asthe alveoli do
in the lungs.
Gills canc
ollect
dissolvedoxygen
fromthewater
and releasecarbon
dioxide.
G
ill filaments
extending from
gill arches.
G
illsarec
onsisted
of gill arches, gill
filamentsand
lamellae.

(a) Sea star. The gills of a sea
star are simple tubular
projections of the skin.
The hollow core of each gill
is an extension of the coelom
(body cavity).
(b) Gas exchange
occurs by diffusion across the
gill surfaces, and fluid in the
coelom circulates in and out of
the gills, aiding gas transport.
The surfaces of a sea star’s
tube fe
15
et also function in
gas exchange.
Gills
Tube foot
Coelom

Many segmented worms have flaplike gills
That extend from each segment of their body
(b) Marine worm. Many
polychaetes (marine
worms of the phylum
Annelida) have a pair
of flattened appendages
called parapodia on
each body segment.
The parapodia serve as gills
and also function in
crawling and swimming.

The gills of clams, crayfish, and many other animals
Are restricted to a local body region
(d) Crayfish. Crayfish
and other crustaceans
have long, feathery
gills covered by the
exoskeleton.
Specialized body
appendages drive
water over the gill
surfaces.
(c) Scallop. The gills of a
scallop are long,
flattened plates
that project from the
main body mass
inside the hard shell.
Cilia on the gills
circulate w
17
ater around
the gill surfaces. Gills
Gill
s

The effectiveness of gas exchange in fishes’ gill is increased
by :
ventilation and countercurrent flow of blood
and water
Ventilation : any method of increasing the flow of the respiratory
medium over the respiratory surface
18

Ventilation : any method of
increasing the flow of the
respiratory medium (water)
over the respiratory surface
(lamellae of gills)
Water must be flowing over the
gills to provide a continual
source of oxygen.
Several ways to keep them
ventilated:
Some fish swim with their
mouths open almost all of
the time.
Other fish have a special
flap called an operculum,
which is used to force water
across the gills.
Ventilation

20

Fish utilize a countercurrent exchange pathway:
Arteries are arranged so that blood flows in the
opposite direction of water movement against the gills.
By having respiration pathway in this orientation,
maximum gas exchange can take place.
Countercurrent Exchange
Pathway

Countercurrent Exchange
Pathway
By setting up a countercurrent
pathway, the blood isalways
passing water that still has
oxygen. The equilibrium would
not reached, diffusion/gas
exchange isconstantly taking
place.
If the blood and the water
were moving in the same
direction (concurrent) ,
the blood would reaches
equilibrium with water which
would stopsthe
diffusionor gas exchange.

• The tracheal system of insects
– Consists of tiny branching tubes that penetrate
throughout the body to deliver air (oxygen) directly
to body cells.
23
2.3 RESPIRATION IN INSECT

Spiracle
The respiratory system of an insect consists of branched internal tubes
that deliver air directly to body cells. Rings of chitin reinforce the largest
tubes, called tracheae, keeping them from collapsing.
Enlarged portions of tracheae form air sacs near organs that require a large
supply of oxygen. Air enters the tracheae through openings called
spiracles on the insect’s body surface and passes into smaller tubes
called tracheoles.
The tracheoles are closed and contain fluid (blue-gray). When the
animal is active and is using more O2, most of the fluid is withdrawn into
the body. This increases the surface area of air in contact with cells.
24
Tracheoles
Air sacs
Tracheae

25
Air
sac
cell
Trachea
Tracheole
Tracheoles Mitochondria
Myofibrils
Body wall
(b) This micrograph shows cross
sections of tracheoles in a tiny
piece of insect flight muscle (TEM).
Each of the numerous mitochondria
in the muscle cells lies within about
5 µm of a tracheole.
2.5 µm
Air
 The tracheal tubes
⚫ Supply O2 directly to body cells
Air flow: Spiracle  tracheae  tracheole  tissue cells
Body

Small
Insects
Aquatic
Insects
Must seal their spiracles
when they are under the
water to prevent flooding
their tubes.
Some aquatic insects
even have specialized
spiracles that
can puncture underwater
plants and access their
plants’ oxygen storage
centers.
Gas exchange
occurs by diffusion
only.
Passive movement
of air into the
tracheae and
diffusion brings in
enough O2 to support
cellular respiration.
Larger
Insects
Actively pump air
into the tubes.
Larger insects with
higher energy
requirement must
ventilate
air in and out of
the tracheae
through rhythmic
body
movements
produced by
muscles.

Insects breath
through spiracles
(small holes in their
abdomen).
Air enters the spiracles
allowing oxygen to
travel along a network
of tubes called
trachaea to reach the
cells in the insects
body.

28
2.4 RESPIRATION IN AMPHIBIANS
~ takes place in LUNGS, SKIN
and LINING OF MOUTH~
 An amphibian such as a frog
 Ventilates its lungs by
positive pressure breathing,
which forces air down the
trachea
 Since they have no
diaphragm, they need to
force air into their lungs

Balloon-like structures, poorly developed, not efficient
respiratory organs where gas exchange is limited.
The process that ventilates the lungs is breathing – alternate
inhalation and exhalation of air.
No diaphragm and ribs, they need to ventilate their lungs by
positive pressure breathing, which force air into the lungs.
Amphibians force the air into their lungs using throat muscles in a
process called buccal pumping:
During inhalation, muscles lower the floor of the buccal cavity, drawing
in air through the nostrils.
With the nostrils & mouth closed, the floor of the buccal cavity rises
and air is forced out of the buccal cavity and into the lungs.
During exhalation, muscles surrounding lungs contract and air is
forced back out the lungs.

30
Buccal cavity
Lung

Highly
vascularized
Lots of blood vessels
going through it. Since
the blood vessels are
close to their
permeable skin surface,
diffusion can take place
right through the skin.
Moist
Gases can only cross
cell membranes when
they are dissolved in
water or an aqueous
solution, thus
respiratory surfaces
must be moist
Thin
Allows the respiratory
gases to readily
diffuse in
and out between the
blood vessels and the
surroundings.
Credit: SF State News- San Francisco State
University

 Amphibians also have a respiratory surface on the lining of their
mouth on which gas exchange takes place readily.
 While at rest, this process is their predominate form of
breathing,
only fills the lungs occasionally.
 This is because the lungs, which only adults have, are poorly
developed.

~ takes place in LUNGS~
 The respiratory system of birds is
similar to that of mammals:
- Gases are exchanged in the
capillaries
- The major difference is the way to
breathe/ route of airflow through
the
bird.
 Besides lungs, bird have 8/9 air sacs
that
- collect air
- keep air flowing through the lungs.
2.5 RESPIRATION IN BIRDS

How a bird breathes –
Route of airflow through the lungs
and air sacs
A second inhalation will
move the air from the
lungs to the anterior air
sac.
When a bird inhales, air is
brought into the posterior
air sacs, which expand.
Upon exhalation, the air is
forced from the posterior
air sacs into the lungs. This
is where gas exchange
takes place.
A second exhalation
will push the air out of
the body.
INHALATION
Air sacs fill
Anterior
air sacs
Trachea
Lungs Lungs
Posterior
air sacs
Air Air
1 mm
Air tubes
(parabronchi)
in lung
EXHALATION
Air sacs empty; lungs fill

35
 Air passes through the lungs
⚫ In one direction only
⚫ Fresh air does not mix with air that has already carried out gas
exchange
 Every exhalation
⚫ Completely renews the air in the lungs
⚫ Direction in which air moves alternates

Characteristics of route of
airflow through the lungs
and air sacs in birds
This progression of air through the bird means that the
lungs are compressed during inhalation and expand
during exhalation.
It also takes two full inhalations and exhalations to
move one gulp of air through the bird.
The unidirectional flow of air through the lungs allows
all the air flowing through the lungs to be fresh air with
maximal oxygen to be collected.

37
2.6 RESPIRATION IN MAMMALS – LUNGS,
BREATHING MECHANISM, TIDALVOLUME,
VITALCAPACITY, RESIDUALVOLUME
The process that ventilates the lungs is breathing which
alternate inhalation and exhalation of air

Respiration in Mammals
The process that ventilates the lungs is breathing–
alternate inhalation and exhalation of air.
Breathing is dependent upon the rib muscles and the diaphragm.
Mammals ventilate their lungs by negative pressure breathing,
which pulls air into the lungs.
Breathing is done without conscious effort.

Respiration in Mammals
Respiration is regulated by medulla oblongata and pons in the brain.
They decide how fast respiration needs to take place by monitoring the
level of carbon dioxide in the blood.
In times of excitement or during exercise, the cells require more oxygen
than normal. Respiration speeds up.
Additionally, the heartbeat increases because the circulatory system is
required for the respiration system to function.

HOW A MAMMAL BREATHES
Mammals ventilate their lungs
By negative pressure breathing, which pulls air into
the lungs
Air inhaled Air exhaled
INHALATION
Diaphragm contracts
(moves down)
EXHALATION
Diaphragm relaxes
(moves up)
Diaphragm
Lung
Rib cage
expands as
rib muscles
contract
Rib cage gets
smaller as
rib muscles
relax
40

Air inhaled
INHALATION
Diaphragm contracts
(moves down)
EXHALATION
Diaphragm relaxes
(moves up)
Diaphragm
Lung
Rib cage
expands as
rib muscles
contract
Rib cage gets
smaller as Air exhale
rib muscles
relax
41
Ventilating/
Breathing Mechanism
INHALATION:
Lung volume increases as
d
the rib muscles and
diaphragm contract.
Rib cage move up and out;
the diaphragm flattens and
moves downward.
Air pressure inside the
lungs decrease and drop
below that of the air
outside their body.
Air rushes inside through
nostrils and mouth and
down the breathing
tube to the alveoli.
1
2
3
4

Air exhaled
EXHALATION
Diaphragm relaxes
(moves up)
m
Rib cage
expands as
rib muscles Air inhaled
contract
Lung
Diaphrag
INHALATION
Diaphragm contracts
(moves down)
Rib cage gets
smaller as
rib muscles
relax
EXHALATION:
The rib muscles and
diaphragm relax, this reduces
lung volume and
forces air up the breathing
tubes and out through the
nostrils.
Lung volume decreases as the
rib muscles and diaphragm
relax to their
neutral state.
Rib cage move down and in;
the diaphragm domes up
moves upward.
Air pressure inside the lungs increases and forces air up the breathing
tubes and out through the nostrils and mouth.
1
2
3
4

43
MAMMALIAN RESPIRATORY SYSTEMS:
A CLOSER LOOK
 A system of branching ducts
⚫ Conveys air to the lungs

NOSE/NOSTRILS
It gets warmed, moistened, and
filtered by cilia and
mucus membranes which can trap
dust and pathogens.
EPIGLOTTIS
The epiglottis regulates air going
into the trachea
(windpipe) and closes upon
swallowing to prevent food
from being inhaled. It is the
gatekeeper to the lungs.
TRACHEA
A long structure of soft tissue
surrounded by c-shaped rings of
cartilage (hyaline).
Source: The McGraw-Hill Companies, Inc.

BRONCHIOLES
The tiny branch of air
tubes within the lungs that
is a continuation of the
bronchus. The
bronchioles connect to
the alveoli (air sacs).
BRONCHI
Extensions of the
windpipe that shuttle air to
and from the lungs.
ALVEOLI
Tiny air sacs that
crucial in increasing the
surface area that can be
used for gas exchange.
Source: The McGraw-Hill Companies, Inc.

 In mammals, air inhaled
through the nostrils
⚫ Passes through the pharynx
into the trachea, bronchi,
bronchioles, and dead-end
alveoli, where gas exchange
occurs
⚫ O2 in the air entering the
aveoli dissolves in the moist
film lining the inner surfaces
and rapidly diffuses across
the epithelium - capillaries
⚫ CO2 diffuses in the opposite
direction, capillaries across
the epithelium of the
alveolus and into the air
space
48

 Gas exchange takes place in
the capillaries, so the alveoli
are closely aligned with the
network of capillaries.
 This brings the blood
carrying waste products into
close enough proximity with
fresh air for
diffusion to take place.
 The waste is removed and the
oxygen is taken up by the
blood.

Oxygen O2
CO2
Carbon
dioxide
From air, entering the alveoli, then dissolves
in
the moist film that lining the inner surfaces
and rapidly diffuses across the epithelium to
capillaries.
Diffuses in the opposite direction, from
capillaries across the epithelium of the
alveolus
and into the air spaces.
Gaseous Exchange in Mammalian
Air flow during inhalation:
NOSTRILS  PHARYNX  EPIGLOTTIS  LARYNX  TRACHEA  BRONCHI
BRONCHIOLES  ALVEOLI

BREATHING MEASUREMENT
Tidal volume : the volume of air an animal inhales and
exhales with each breath at rest
(the normal volume of air displaced between normal inspiration and
expiration when extra effort is not applied)
51

52
Vital capacity / inspiratory reserve volume: the amount of
air that can be taken during forced breathing over tidal
volume
Residual volume: the amount of air that remains in the
lungs after forcefully exhaling
BREATHING MEASUREMENT..

The volume of
air exhaled
and inhaled by
individuals
during each
breath at rest
(extra effort is
not applied).
The
maximum
volume of air
that can be
forced out
from the lungs
besides the
tidal volume.
The volume
of air left in
the lungs after
forcefully
exhaling.
Lung Volume and Capacities
The
maximum
volume of
air inhaled
into the lungs
besides the
tidal volume.
Expiratory
Reserve
Volume
Residual
Volume
Inspiratory
Reserve
Volume
Tidal
Volume

The total volume
of air that can be
exhaled out of
the lungs after
fully inhaling
(inspiratory
reserve volume
+ tidal volume +
expiratory
reserve
volume).
The volume of
air remaining
in the lungs
after a normal
exhalation
(expiratory
reserve
volume +
residual
volume).
The maximum
volume of air
that can fill the
lungs
(vital
capacity +
residual
volume).
The maximum
volume of air
that can be
inhaled
(inspiratory
reserve
volume +
tidal volume).
Total Lung
Capacity
Functional
Residual
Capacity
Inspiratory
Capacity
Vital
Capacity

Lung volumes can be measured using a
SPIROMETER.
Patient takes a deep
breath and blows as hard
as possible into tube.
Clip on nose
Machine records the results
of the spirometry test.

57
CONTROL OF BREATHING IN HUMANS
 The main breathing control centers
⚫ Are located in two regions of the brain, the medulla oblongata
and the pons
The centers in the medulla
Regulate the rate and depth of breathing in response to pH
changes in the cerebrospinal fluid
The medulla adjusts breathing rate and depth
To match metabolic demands
Sensors in t
3 he aorta and carotid arteries
Monitor O2 and CO2 concentrations in the blood

Pons
Breathing
control
centers Medulla
oblongata
Carotid
arteries
Aorta
Cerebrospinal
fluid
Diaphragm
Rib muscles
In a person at rest, these
nerve impulses result in
about 10 to 14 inhalations
per minute. Between
inhalations, the muscles
relax and the person exhales.
The con1trol center in the
medulla sets the basic
rhythm, and a control center
in the pons moderates it,
smoothing out the
transitions between
inhalations and exhalations.
Nerve2
impulses trigger
muscle contraction. Nerves
from a breathing control center
in the medulla oblongata of the
brain send impulses to the
diaphragm and rib muscles,
stimulating them to contract
and causing inhalation.
The medulla’s control center
also helps regulate blood CO2 level.
Sensors in the medulla detect changes
in the pH (reflecting CO2 concentratio
of the blood and cerebrospinal fluid
bathing the surface of the brain.
5 Nerve impulses relay changes in
CO2 and O2 concentrations. Other
sensors in the walls of the aorta
and carotid arteries in the neck
detect changes in blood pH and
send nerve impulses to the medulla.
In response, the medulla’s breathing
control center alters the rate and
depth of breathing, increasing both
to dispose of excess CO2 or decreasin
both if CO2 levels are depressed.
6 The sensors in the aorta and
carotid arteries also detect changes
in O2 levels in the blood and58signal
the medulla to increase the breathing
rate when levels become very low.

RESPIRATORY PIGMENTS BIND AND TRANSPORT
GASES
The metabolic demands of many organisms
Require that the blood transport large quantities of O2 and
CO2
59

• Gases diffuse down pressure gradients
– In the lungs and other organs
• Diffusion of a gas
– Depends on differences in a quantity called partial pressure
• A gas always diffuses from a region of higher partial pressure
– To a region of lower partial pressure
• In the lungs and in the tissues
– O2 and CO2 diffuse from where their partial pressures are
higher to where they are lower
The Role of Partial Pressure Gradients
60

Inhaled air Exhaled air
160 0.2
O2 CO2
40 45
O2 CO2
100 40
O2 CO2
120 27
O2 CO2
CO2
O2
Alveolar
epithelial
cells
40 45
O2 CO2
Pulmonary
arteries
Blood
entering
alveolar
capillaries
Blood
leaving
tissue
capillaries
Blood
entering
tissue
capillaries
Blood
leaving
alveolar
capillaries
CO2
O2
Heart
Tissue
Alveolar
capillaries
of lung
Tissue
cells
<40 >45
O2 CO2
104 40
O2 CO2
Pulmonary
veins
Systemic
arteries
Systemic
veins
O2
CO capillaries
2
O2
Alveolar spaces
104 40
O2 CO2
61

62

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