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.
9. 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
10. 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
11. 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.
12. 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
13. 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.
14. 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