Description
Describe the blood–gas interface and explain why the lungs are ide-
ally suited for gas exchange
• List components and functions of the conducting airways
• Distinguish between the various types of airways in terms of epithe-
lium and cartilage
• Describe the forces and factors responsible for maintaining inflation
of the lungs
• Explain how inspiration and expiration take place
• Distinguish among atmospheric pressure, alveolar pressure, intra-
pleural pressure, and transpulmonary pressure
• Define pulmonary compliance
• Describe the role of elastic connective tissues in elastic recoil of the
lungs as well as in lung compliance
• Explain how surface tension affects the elastic behavior of the lungs
• Describe the functions of pulmonary surfactant
• Explain how interdependence promotes alveolar stability
• Describe factors that determine airway resistance
• Define tidal volume, residual volume, expiratory reserve volume,
and inspiratory reserve volume
• Define functional residual capacity, inspiratory capacity, total lung
capacity, and vital capacity
• Distinguish between total ventilation and alveolar ventilation
• Distinguish among anatomical dead space, alveolar dead space, and
physiological dead space
• Explain how each factor in Fick’s law of diffusion influences gas
exchange
• List the partial pressures of oxygen and carbon dioxide in various
regions of the respiratory and cardiovascular systems
• Explain how the PO2 and PCO2 of alveolar gas are determined
Explain the effects of airway obstruction and obstructed blood flow
on ventilation-perfusion matching
• Describe local control mechanisms that restore the V/Q ratio to one
• Explain how oxygen is transported in the blood
• Describe the physiological significance of the steep and plateau por-
tions of the oxyhemoglobin dissociation curve
• Describe the effects of carbon dioxide, pH, temperature, 2,3-bispho-
sphoglycerate, anemia, and carbon monoxide poisoning on the trans-
port of oxygen
• Explain how carbon dioxide is transported in the blood
• Compare and contrast functions of the dorsal and ventral respiratory
groups in the medullary respiratory center
• List and describe sources of input to the medullary respiratory center
• Compare and contrast the function of the peripheral and central
chemoreceptors
17.1 Introduction
The cells of the body require a continuous supply of oxygen to produce
energy and carry out their metabolic functions. Furthermore, these aerobic
metabolic processes produce carbon dioxide, which must be continuously
eliminated. The primary functions of the respiratory system include:
• Obtaining oxygen from the external environment and supplying it
to the body’s cells
• Eliminating carbon dioxide produced by cellular metabolism from
the body
The process by which oxygen is taken up by the lungs and carbon dioxide
is eliminated from the lungs is referred to as gas exchange.
17.2 Blood–gas interface
Gas exchange takes place at the blood–gas interface, which exists where the
alveoli and the pulmonary capillaries come together. The alveoli are the
smallest airways in the lungs; the pulmonary capillaries are found in the walls
of the alveoli. Inspired oxygen moves from the alveoli into the capillaries
for eventual transport to tissues. Entering the lungs by way of the pulmonary
circulation, carbon dioxide moves from the capillaries into the alveoli for
elimination by expiration. Oxygen and carbon dioxide move across the
blood–gas interface by way of simple diffusion from an area of high concen-
tration to an area of low concentration.
According to Fick’s law of diffusion, the amount of gas that moves across
the blood–gas interface is proportional to the surface area of the interface
and inversely proportional to thickness of the interface. In other words, gas
exchange in the lungs is promoted when the surface area for diffusion is
Digestive system
Anatomy of GI Tract with special reference to anatomy and functions of
stomach, ( Acid production in the stomach, regulation of acid production
through parasympathetic nervous system, pepsin role in protein
digestion) small intestine and large intestine, anatomy and functions of
salivary glands, pancreas and liver, movements of GIT, digestion and
absorption of nutrients and disorders of GIT
Energetics:
Formation and role of ATP, Creatinine Phosphate and BMR.
