resp 4

Question 1

what is the definition of surface tension?

Answer 1

-it is a measure of the force acting to pull a liquid’s molecules together at an air-water interface

Question 2

what is the other determinant of compliance besides tissue?

Answer 2

-an equally important determinant of compliance and a major determinant of the lungs elastic recoil is surface tension at the air water interface of the airways

Question 2

what is Laplace’s equation?

Answer 2

Question 2

who proved that lung compliance and elastase was not only due to tissue?

Answer 2

-Von Neergaard in 1929

Question 3

what is the graph of how surface tension creates pressure to the alveoli wall?

Answer 3

Question 4

what is surfactant?

Answer 4

-a detergent-like molecule secreted by Type II alveolar cells
-90% phospholipids and 10% proteins
-hydrophobic and hydrophilic regions
-reduces the surface tension to 25 dynes/cm or less

Question 5

what are the functions of surfactant?

Answer 5

1. increases compliance
2. ensures alveoli of all size inflate

Question 6

what is the graph of slowly and rapidly expanding alveolus

Answer 6

Question 7

what is infant respiratory distress syndrome?

Answer 7

-in premature infants: developmental insufficiency of surfactant production and immaturity of the lungs
-prevalence decreases with gestational age (50%:26-28 weeks)(25%: 30-31 weeks) affects 1% of new born infants

Question 8

what are the treatments and prevention of infant respiratory distress syndrome?

Answer 8

-prevention: glucocorticoid injection

treatment:
-artificial surfactant
-continuous positive airway pressure (CPAP)
-intubate

Question 9

what is airway resistance based on? where is resistance in healthy individuals?

Answer 9

-Poiseuille’s equation
-in healthy individuals 90% of airway resistance occurs in trachea and bronchi and is constant (smallest total cross-sectional area)

Question 10

what is the table of factors that affect airway resistance?

Answer 10

Question 11

what is bronchoconstriction/dilation?

Answer 11

-commonly paracrine control, CO2 being the major one
-high levels=dilation
-low levels=constriction

Question 12

what is released during allergic reactions?

Answer 12

-histamine released from mast cells bronchoconstricts

Question 13

what is the parasympathetic control of resistance in airways?

Answer 13

-parasympathetic nerves innervate bronchiole smooth muscle and activate PLC-IP3 pathway via M3 muscarinic receptor (constriction)

Question 14

what is the sympathetic control of resistance in airways?

Answer 14

-circulating epinephrine binding B2 adrenergic receptors (dilation)

Question 15

what is the graph of asthma? what are the treatments?

Answer 15

infrequent attacks:
-B2-adrenergic agonist
-oppose bronchoconstriction

more frequent attacks:
-weekly inhaled corticosteroid

Question 16

how are the CVS and the respiratory system similar in efficiency of breathing?

Answer 16

-in CVS efficiency of heart is measured by cardiac output (HRxSV)
-in respiratory system effectiveness of ventilation is determined by total pulmonary ventilation: the volume of air moved into and out of the lungs each minute (minute ventilation)

Question 17

how do you calculate total pulmonary ventilation? why is this not a good indicator of the fresh air that reaches the alveoli?

Answer 17

Question 18

what is the graph of how much air makes it to alveoli?

Answer 18

Question 19

what are the tables of the efficiency of breathing?

Answer 19