biological science

1. Gas
exchange
in animals
GROUP #3
RESPIRATORY SYSTEM

2. It involves at least 3 distinct processes:
1. Pulmonary ventilation –
movement of air into and
out of lungs.
• Pulmonary ventilation have
process which oxygen
enters and carbon dioxide
exits the alveoli, respiration
is the process by which
oxygen and carbon dioxide
diffuse in and out of the
blood.

3. 2. External respiration – exchange of gases between the
blood and air in the alveoli
•Air from the outside environment enters the nose
or mouth during inspiration (inhalation)
3. Internal respiration – exchange of gases between the
blood and issues cells.

4. Gas exchange in animals
1. Direct diffusion –unicellular
organisms like amoeba
and paramecium resort to
direct diffusion of oxygen
and carbon dioxide
through the plasma
membrane.
2. Use of gills – large
animals use gills
for gas exchange.

5. 3. Tracheal system – tracheal
system are found in
insect. Air enters the
body through the
opening at the side of the
abdomen called spiracles
which lead to a system of
tube called tracheae.
Found in insect.
4. Book lungs – these are
found in spiders. Each
“lung” has a number of
leaf-like folds. Air enters
the book lungs through a
pair of slit- like openings
on the under surface of
the abdomen. Ex. Spiders

6. 5. Lung system –
terrestrial vertebrates
use lungs for gas
exchange. Air entered
through the nostril
which usually leads to
nasal cavity which
opens to the mouth or
pharynx

7. parts
1. NOSE
 Internal part is called the nasal
cavity large cavity superior to the
oral cavity & inferior to the brain.
 External part protruding from the
face.
 Contains cilia which is responsible
for filtering out foreign bodies.
 Internal nares - opening to exterior.
 External nares - opening to
pharynx.
 Nasal conchae - folds in the
mucous membrane that increase air.
 Contains olfactory cells which detect
smell.
1. PHARYNX
 Common space used by both the
respiratory and digestive systems.
 Commonly called the throat.
 Common pathway for both air and
food.
 Walls are lined by a mucosa and
contain skeletal muscles thatare
primarily used for swallowing.
 Flexible lateral walls are distensible in
order to force swallowed food into the
esophagus.
 Tonsil-are found in the nasopharynx,
oropharynx, & larygopharynx,

8. Three Sections of the
Pharynx
•Nasopharynx
 contains the pharyngeal
tonsils (adenoids) which aid
in thebody’s immune
defense
•Oropharynx
 back portion of the mouth
that contains the palatine
tonsils which aid in the
body’s immune defense
•Laryngopharynx
 bottom section of the
pharynx where the
respiratory tractdivides into
the esophagus and the
larynx.
3.LARYNX OR VOICE BOX
 Voice box is a short,somewhat
cylindrical airway ends in the
trachea.
 Consists of:
 Tyroid cartilage or adam’s apple.
 Epiglottis or lid cartilage.
 Cricoid or signet ring cartilag.
 Arytenoid or pyramid shaped
cartilage.
 Prevents swallowed materials from
entering the lower respiratory tract.
 Conducts air into the lower
respiratory tract.
 Produces sounds (vocal cords)
 Movement of lips, tougue and jaws
make sound to form words.

9. 4.TRACHEA
 A flexible tube also called
windpipe.
 Supported in front by rings
of unshaped cartilages
which prevent and
continuous of the tube
facilitating easy and
continuous passage of air
into the lungs.
 The walls of the
trachea & bronchi
are provide with cilia
that traps dust
particles and micro-
oragnisms.
Tube exteding from
the larynx to bronchi.

10. 5.LUNGS
 Occupy most of the thorax
bounded by the chest wall
with ribs and dome-shaped
sheet of skeletal muscle, the
diaphragm.
 Its superior region called the
apex projects superiorly to
apoint that is slightly
superior and posterior to the
clavicle.
• Both lungs are bordered
by the thoracic wall
interiorly, laterally, and
posteriorly, and
supported by the rib
cage.
• Toward the midline, the
lungs are separated from
each other by the
mediastinum.
• The relatively broad,
rounded surface in
contact with the thoracic
wall is called the costal
surface of the lung.

11. • Structures associated with lungs:
a) Bronchi – right and left formed
by branching of trachea.
b) Bronchioles – smaller brances of
bronchi .
c) Alveolar ducts – microscopic
branches of bronchioles.
d.M Alveoli – microscopic sacs /
pouch-like spaces at the ends of
the alveolar ducts provided with
a network of lung capillaries
facilitating gas exchange
between the air within it and the
blood within the capillaries
 Left lungs
• – divided into 2 lobes by
oblique fissure
• – smaller than the right lung–
cardiac notch accommodates
the heart.
 Right lungs
• – divided into 3 lobes by
oblique and horizontal fissure.
– located more superiorly in the
body due to liver on right side lungs.
 Fissure
• – located more superiorly in
the body due to liver on right
side lungs.