Chapter 22 Flashcards
Functions of Respiratory System
-Gas exchange
-Communication
-Olfaction
-Acid-Base Balance
-Blood Pressure Regulation
-Blood and lymph flow
-Platelet production-Blood filtration
-expulsion of abdominal contents
Conducting zone
Air movement
Respiratory zone
Gas exchange
4 processes required for oxygen to reach the tissues and CO2 to leave the body
1) Pulmonary Ventilation
2)External respiration
3) Transport of gases in bloodstream
4)Internal respiration
Dalton’s law
Total atmospheric pressure is the sum of the contributions of the individual gases
Role of diaphragm in respiratory system
-main breathing muscle
-contracts to flatten and increase thoracic volume during inspiration and relaxes during expiration
Role of external intercostals in respiratory system
-elevates ribs during inspiration which expands the chest
What muscles are part of forced inspiration
-sternocleidomastoid
-scalene
-pectoralis
What muscles are part of forced exhalation
-internal intercostals
-abdominal muscles
Role of sternocleidomastoid in respiratory system
Lifts the sternum
Role of scalene in respiratory system
Elevates the first two ribs
Role of pectoralis in respiratory system
Helps expand rib cage
Role of internal intercostals in respiratory system
Depress the ribs, reducing chest volume
Role of abdominal muscles in respiratory system
Pushes abdominal contents up against the diaphragm to force air out
Respiratory controls of dorsal medulla oblongata
Modifies respiratory rates due to external stimuli (chemoreceptors, irritant receptors, stretch receptors)
Respiratory control of ventral medulla oblongata
1st generator of respiratory; signals to specific diaphragm and external and inter coastals; 12-15 breaths per minute
Role of Central chemoreceptors in respiratory system
-brain stem neurons that respond to changes in pH of cerebrospinal fluid
—> pH reflects the CO2 level in the blood -regulates respiration to maintain pH
-Ensures stable CO2 in blood
Role of peripheral chemoreceptors in respiratory system
-Cartoid and aortic bodies
—> Responds to the O2 nd CO2 content and the pH of blood
Does increasing resistance decrease airflow?
Yes!
2 factors that influence airway resistance
-bronchiole diameter
-pulmonary compliance
Bronchodilation
Increase in diameter, increases airflow
Bronchoconstriction
Decrease in diameter, decreases airflow
Pulmonary compliance
Ease with which lungs can expand
Change in lung volume relative to given pressure change
How is compliance reduced?
By degenerative lung diseases
(Lungs are stiffened by scar tissue)
How is compliance limited?
Limited by the surface tension of the water film inside alveoli
Surfactant
Secreted by great cells of alveoli disrupts H bonds between water molecules and reduces surface tension
IRD
When premature babies lack surfactant and are treated with artificial surfactant until they can make their own
What is the composition of air
-78.6% nitrogen
-20.9% oxygen
-0.04% CO2
0%-4% water vapour (depends on temperature and humidity)
What is Dalton’s law of partial pressure
The separate contribution of each gas in a mixture
-P(element) = (% of it) x760mm Hg =___Hg (should all add up to 760mmHg
What are the 3 layers of respiratory membrane
- Alveolar endothehelium
- Thin basement membrane
- Capillary endothelium
Type 2 cells
-Secrete surfactant which prevents alveoli from collapsing by providing surface tension
-goes betweeen water molecules which allows alveoli to expand more easily
Alveolar macrophages
-a phagocytic cell of the immune system
-increases additional immunity
Henry’s law
The amount of gas that dissolves in a liquid is directly proportional to its parietal pressure above the liquid, provide the temperature remains constant
What’s the membrane thickness
0.5um thick
Why does alveolar gas exchange present little obstacle to diffusion
When membrane is thicker gases have further to travel between blood and air and cannot equilibriate fast enough to keep up with blood flow
