This document discusses various respiratory organs in animals, including gills, book lungs, lungs, and skin. It provides details on lung structure and function in various vertebrates. Gas exchange occurs primarily through gills in fish, book lungs in spiders, and highly vascularized skin in amphibians. Advanced vertebrate lungs contain alveoli that increase surface area for gas exchange. Respiratory regulation involves centers in the medulla oblongata and pons. Locomotion and respiration are often synchronized across species.

1. ANIMAL PHYSIOLOGY
r e s p i r a t o r y o r g a n s
Dr. NAGABHUSHAN C M Ph.D
ASSISTANT PROFESSOR
DEPT OF STUDIES IN ZOOLOGY,
VSK UNIVERSITY, BALLARI
91-9880-121-090
nagabhushancm@vskub.ac.in

2. Gills
Book lungs
Tracheae
Skin
Lungs
r e s p i r a t o r y o r g a n s

3. gills/ book lungs / lungs / tracheae/ skin
Coconut crab
Cardiosoma crab
Isopods (wood lice)
Anguilla vulgaris

4. gills/ book lungs / lungs / tracheae/ skin
Spiders and scorpions

5. gills/ book lungs / lungs / tracheae/ skin
insects

6. gills/ book lungs / lungs / tracheae/ skin
vertebrate

7. Vertebrate lungs
 Complex LUNGS across the higher classes of vertebrates
 Increased surface area is created by ALVEOLI
 In FROGS – 20 cm2 / cm3 lung tissues
 In MOUSE – 800 cm2 / cm3
 the HUMAN LUNGS – 100 m3 strong enough to tolerate being stretched
more than 20,000 times a day.
 Thickness of the respiratory membrane is 0.2 µm (paper thickness – 50 µm)

8. Lung volumes of mammals against body
mass
0
0.2
Shrew
Mouse
Rat
Guinea pig
Rabbit
Dog
Monkey
Goat
Man
Horse
Camel/ porpoise
From
BOTTOM
- TOP
0.001 0.01 0.1 1 10 100 1000 BODY MASS (kg)
LUNG
VOL (l)
100
10
1.0
0.1
0.01
0.001
0.0001
Slope: 1.06
VL = 0.046ml . Mb
1.06

9. Breathing (inhalation and exhalation)
 Alveoli
 Tidal volume (500 cm3 OR 500 ml) –
Dead space.
 Anatomical dead space(150 cm3)
 IRV , ERV, VITAL CAPACITY,
residual volume.
 The composition of alveolar air is
Always = 15 % O2 + 05 % O2
 surface tension
(like soap bubbles)
(phospholipids and their effect
on surface tension =
SURFACTANTS)
 the amt of surfactant present in all
vertebrates is JUST ABOVE
MINIMUM required to cover the
pulmonary surface.
 Cost of breathing: 1.2 % of total
Oxygen consumption at rest ; 3%
during exercise; 5% in fishes.

10. Breathing (sync with locomotion)
 1:1 ratio in KANGAROO during
hopping.
 1:1 in birds using sternum and wings.
 2:1 in dogs during each stride.
 1:1 in other mammals as well.
 Regulation of respiration: ventilation
is adjusted to the O2 need,
CO2 LEADS TO ventilation
O2 RESULTS IN No change .
 Respiratory centers: MO &
Pons Varoli

11. gills/ book lungs / lungs / tracheae/ skin
amphibian
Mucous gland (M),
Stratum Compactum (C),
Stratum Spongiosum (S),
Skin arteries (A),
Branching arterioles (SA),
Subepidermal or respiratory capillary network (RC),
Arteriolar branches (PA),
Venules (DV),
Subcutaneous veins (V),
Subcutaneous venular plexus (SV),
Epidermis (E),
Lymph endothelium (LE).

12.  Highly vascularised AMPHIBIAN SKIN
 Plethodont salamanders have NEITHER
GILLS NOR LUNGS.
 FROGS: RELATIVE ROLES OF SKIN AND
LUNGS CHANGE OVER THE YEAR
 SALAMANDERS: 15 % THROUGH ORAL
MUCOSA, 85 % BY SKIN.
 O2 BLOOD MIXES WITH VENOUS
CIRCULATION.
gills/ book lungs / lungs / tracheae/ skin
TEMP AT 5, 15 AND 25 DEGREES
C
LUNGS
CO2
SKIN
CO2
SKIN
O2
LUNGS
O2

13. AIR BREATHING FISH
(accessory organ)
 Fish respond to decrease in oxygen content in the water by
SURFACING AND GULPING AIR.
 180 times gulps air per hour (Gold fish)
 2 reasons for using accessory organs:
 Depleted O2 content in water
 Periodic draughts

14. AIR BREATHING FISH
(accessory organ)
GILLS:
SYNBHRANCHUS
MOUTH / OP CAVITY:
ANABAS
STOMACH: PLECOSTOMUS
INTESTINE: HOPLOSTERNUM
SWIM BLADDER: AMIA
LUNGS: LEPIDOSIREN

15. Transport of solutes and water.

16. Transport of gases: RESPIRATION