Physiology Of Respiration

Front 1

epinephrine

Back 1

used to treat life threatening bronchioconstrtiction such as during asthma ana anaphylactic shock (carried by people susceptible to sudden constriction) because it is a sympathetic aganist

Front 2

alveolar surface tension

Back 2

liquid on surface of alveoli causes them to collapse to smallest size

Front 3

surfacant

Back 3

lipoproteins that reduce surface tension on alveoli, allowing them to expand more easily

Front 4

infant respiratory distress syndrome

Back 4

premature babies that do not yet produce enough surfacant; must be ventilated for respiration

Front 5

factors influencing pulmonary ventilation

Back 5

A. lung compliance and elasticity-
1. lung compliance- the ease with which lungs can be expanded by muscle contraction of thorax
1a. fibrosis- decreases compliance
1b. blocked bronchi- decreases compliance
1c. surface tension- alveoli difficult to expand, surfacant eases pressure
1d. thorax inflexibility- decreases compliance
2. lung elasticity- the ease with which lungs can contract to their normal resting size (exhalation)
2a. emphysema- decreases elasticity (no cure)
3. alveolar surface tension- liquid on surface of alveoli causes them to colapse to smallest size.
3a. surfacant- lipoproteins that reduce surface tension on alveoli, allowing them to expand more easily.
3b. infant respiratory distress syndrome- premature babies that do not yet produce enough surfacant; must be ventilated for respiration

Front 6

lung elasticity

Back 6

the ease with which lungs can contract to their normal resting size (exhalation)

Front 7

volumes, capacities, and function test

Back 7

A. respiratory volumes (20 year old healthy male, 155 lbs)
1. tidal volume (TV)- normal volume of air moving in/out (0.5 L)
2. inspiratory reserve volume (IRV)- volume inhaled AFTER normal tidal volume when asked to take deepest possible breath (2.1 - 3.2 L)
3. expiratory reserve volume (ERV)- volume exhaled AFTER normal tidal volume when asked to force out all air possible (1 - 2.0 L)
4. residual volume (RV)- air that remains in lungs even after totally forced exhalation (1.2 L)

Front 8

forced expiration

Back 8

contraction of abdominal wall muscles (i.e. obliques & transversus abdominus) further DECREASES volume beyond relaxed point = further INCREASE in pulmonary pressure = more air moves out

Front 9

factors facilitating lung movement AWAY from thorax wall

Back 9

1. elasticity of lungs allows them to assume smallest shape for given pressure conditions.
2. fluid film on alveoli allows them to assume smallest shape for given pressure conditions

Front 10

volume/pressure & inspiration/expiration-

Back 10

A. boyle's law on volume/pressure relationships-
1. volume is INVERSELY proportional to pressure
1a. increase in volume = decrease in pressure
1b. decrease in volume = increase in pressure
1c. volume change = pressure change, gas flows to equalize the pressure
2. simple example of boyle's law =
plastic bag with tube in the top, as bag expands by pulling, gas moves IN, as bag shrinks by squashing, gas moves OUT

Front 11

inspiration

Back 11

1. diaphragm muscle contracts, increasing thorasic cavity size in the superior-inferior dimension
2. external intercostal muscles contract, expanding lateral & anterior-posterior dimension
3. INCREASED volume (about 0.5 liter)
DECREASED pulmonary pressure (-1 mm Hg) air rushes into lungs to fill alveoli
4. deep/forced inspirations- as during exercise and pulmonary disease, scalenes, sternocleidomastoid, pectorals are used for more volume expansion of thorax

Front 12

expiration

Back 12

1. quiet expiration (exhalation)- simple elasticity of the lungs DECREASES volume. INCREASED pulmonary pressure = movement of air out of the lungs
2. forced expiration- contraction of abdominal wall muscles (i.e. obliques & transversus abdominus) further DECREASES volume beyond relaxed point = further INCREASE in pulmonary pressure = more air moves out

Front 13

quiet expiration (exhalation)

Back 13

simple elasticity of the lungs DECREASES volume. INCREASED pulmonary pressure = movement of air out of the lungs

Front 14

Factors holding lungs against the thorax wall

Back 14

1. surface tension holding the "visceral" and "parietal" pleura together
2. intrapulmonary pressure Always slightly greater than intrapleural pressure by 4 mm Hg
3. atmospheric pressure acting on the lungs
3a. atelectasis (collapsed lung)- hole in pleural "balloon" causes equalization of pressure and collapse of the lung
3b. pneumothorax- abnormal air in the intrapleural space, can lead to collapsed lung

Front 15

The mechanics of breathing- Relationships of pressure

Back 15

1. atmospheric air pressure 760 mm Hg (st sea level)
2. negative air pressure- less than 760 nn Hg
3. possitive air pressure- more than 760 mm Hg
4. intrapleural pressure- pressure within the pleural "ballon" which surrounds the lung
5. intrapulmonary pressure- pressure within the alveloi (tiny sacs) of the lung itself

Front 16

atmospheric air pressure

Back 16

760 mm Hg (at sea level)

Front 17

negative air pressure

Back 17

LESS than 760 mm Hg

Front 18

positive air pressure

Back 18

more than 760 mm Hg

Front 19

intrapleural pressure

Back 19

pressure within the pleural "balloon" which surrounds the lung

Front 20

intrapulmonary pressure

Back 20

pressure within the alveloi (tiny sacs) of the lung itself

Front 21

atelectasis (collapsed lung)

Back 21

hole in pleural "balloon" causes equalization of pressure and collapse of the lung

Front 22

pneumothorax

Back 22

abnormal air in the intrapleural space, can lead to collapsed lung