resp 3

Question 1

What would it mean if alveolar pressure becomes more positive

Answer 1

expiration
-all the CV muscles relax
-as alveolar volume decreases, the pressure inside increases above atmospheric pressure causing air to flow out

Question 2

what are the muscles of forced inspiration (3)

Answer 2

1. sternocleidomastoids
   -lifts sternum upward & contributes to water pump handle effect
2. neck and back muscles
   -elevates pectoral girdle increasing volume
3. upper respiratory tract muscles
   -decreases airway resistance

*external intercostal muscles - contract to lower the rib more than it depresses the upper rib

Question 3

what are the muscles of forced expiration?

Answer 3

1.abdominal
2.internal intercostals
3.neck and back muscles

*internal intercostal muscles - depress the upper rib more than raising the lower rib

Question 4

is the lung directly attatched to the diaphram or thoracic wall?

Answer 4

No. not as simple as diaphram pulls lungs down and ribs out. there is an intrapleural pressure present at the top of the lung (-3mmHg)

Question 5

why is there a subatmospheric pressure in the pleura?

Answer 5

because the viseral pluera wants to shrink slighty

and the parietal pluera wants to expand slightly

Question 6

What happens to the intrapleura fluid during inspiration?

Answer 6

the inspiratory muscles pull the parietal layer of pluera aways from the visceral layer. This motion creates an increase in volume which means pressure becomes stronger (more negative)

Question 7

What is pheumothorax?

Answer 7

its when the closed system of the pluera has been broken. Thus the pressure within is able to escape. Meaning you cannot expand the lungs

-stabbing
-lung collapses because of the pressure gradient (-3pluera & 0 ATM)

Question 8

what is lung compliance?
what is lung elastance?

Answer 8

lung compliance is how easy it is to fill the lungs (more compliant = easier to fill)

lung elastance is how easy it is to expel the air (more elastic = harder to fill)

Question 9

give an example of decresed compliance (elastic)

Answer 9

pulmonary fibrosis

-excess fibrous connective tissue in lungs
-from inhaling several pollutants, metals, gases

Question 10

give an example of increased compliance

Answer 10

Emphysema

-enzymes break down alveolar tissue
-alveoli merge: loss of capillaries and reduced surface area
-loss of lung recoil
-CAUSE: smoking

Question 11

what is surfactant

Answer 11

detergent molecule
90% phospholipids 10% protein
reduces surface tension by decreasing the desity of water molecules

Question 12

what are the 2 functions of surfactant

Answer 12

1. increases compliance
   -with less surface area, we see increased compliance
   -smaller alveioli also have higher concentration of surfactant
2. ensures alveoli of all size infalte

Question 13

what is Infant Respiratory Distress Syndrome?

Answer 13

infants develope insuffecient production of surfactant.