1.
7. Respiratory system

2.
7. Respiratory system
 The function of respiratory system includes
 Gas exchange
 Filtration of inspired air
 Production of sound
 Elimination of some water and heat via expired air
 The primary function of respiratory system is the intake of oxygen
and the elimination of CO2 from the body
 Oxygen is required by tissues for oxidative metabolism
 CO2 is end product of metabolism & must be eliminated from body

3.
 Mammalian respiratory apparatus consists of:
 the lungs & airways leading to them
 the thorax & its pleural sacs
 diaphragm & muscles of the thorax
 afferent & efferent nerves connected with these structures.
 Airways are nasal cavity, pharynx, larynx, trachea & its branches
bronchi & bronchioles.
 The respiratory system can be divided in to
The upper respiratory system
 including nose, pharynx and associated structures
The lower respiratory systems
 including larynx, trachea, and lungs

4.
Nose and Pharynx
 Nose: is externally visible portion of the respiratory system
 Nose divided in to external and internal position
External position
 Consists of bone, hyaline cartilage, muscle, skin, and mucous
membrane.
Interna position
 It is nasal cavity
 Pharynx: connects the nasal cavity and the mouth to the larynx and
esophagus respectively.

5.
Larynx
 Connects the laryngopharynx with the trachea, and it contains the
vocal cords.
 Two functions of larynx
 Provide a routing mechanism for air and food
 To make sound
 Anatomically larynx formed by five mucus covered cartilages
including single epiglottis, thyroid, and cricoids cartilage and paired
arytenoids cartilage.
Trachea and Bronchi
 The trachea, or windpipe, is a cylindrical tube extending from the
larynx to right and left primary bronchi above the base of heart.

6.
 The trachea consists of four layers
 Mucosa – deepest layer
 Submucosa
 Hyaline cartilage
 Adventitia – the most superficial layer

7.
Respiratory anatomy of the lung
 The lung are paired organs located within the thorax
 The left and right lungs have two and four lobes, respectively
 The lung surrounded by a serous membrane called the pleural
membrane.
 The superficial layer lining the thoracic cavity is the parietal pleura
and the layer closely adhering to the lung is the visceral pleura.
 The mediastinum is the midline site formed where the two pleura
membrane meets.
 It contains the heart, large vessels, esophagus, and other structures,
and separates the two lungs from one another.

8.
Blood supply to the lung
 The pulmonary and bronchial arteries supply blood to the lung
 Pulmonary artery carries deoxygenated blood through the
pulmonary trunk and into the right and left pulmonary arteries.
 Oxygenated blood returns to the left atrium via the pulmonary
veins.
 Bronchial arteries arises from aorta and deliver oxygen to the
lung

9.
Pulmonary ventilation
Respiration, the process of gas exchange occur in three
steps;
1. Pulmonary ventilation/ breathing: is the mechanical
movement of air in to (inspiration) and out
(expiration) of the lung.
2. External respiration is the exchange of gas between
lungs and the pulmonary capillaries, which occurs
across the respiratory membrane.
 The blood gain O2 and loss CO2
3.Internal systematic capillaries and tissue.
 The blood gain CO2 and loss O2

10.
Internal and External respiration
External respiration
External respiration, also called pulmonary gas
exchange, is the diffusion of O2 and C02from the
alveoli pulmonary blood.
Pulmonary blood is deoxygenated blood from right
ventricle.
Internal respiration
System gas exchange occurs at the tissue level where
their is an exchange of O2 and CO2 between systemic
capillary and tissues.

11.
Transport of O2 and C02
Oxygen transport
Oxygen has a low solubility coefficient, so it
does not readily dissolved in blood. Instead
over 98% of O2 is bound to hemoglobin.
The heme portion of hemoglobin contain four
atoms of iron, each able to bind to one
molecule of O2

12.
Carbon dioxide transport
 Carbon dioxide is a waste product of metabolism.
 It is transported in the blood to the lung in three forms
1. Dissolved CO2
 Account very small amount
 7-10% is carried dissolved in the plasma
2. Carbamino compounds:
 Approximately 20% of C02 is transported in the red blood cell
attached to the amino acids of globin and forming
carboaminohemoglobin.
3. Bicarbonate ions
 Most C02 transported through blood.

13.
Chemoreceptors
The respiratory system functions to bring in O2 and
eliminate C02 from the body. This function is assisted
by specialized receptors called chemoraceptors.
Chemoreceptors monitors the level of CO2,O2 and H+,
and send such information to the respiratory center.
Chemoreceptors found in several location, but the
central chemoreceptors found on medulla oblongata