Gas exchange

in animals

GROUP #3RESPIRATORY SYSTEM

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.

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.

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.

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

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

parts1. 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, 

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.

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.

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.

•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.