22.3 The Process of Breathing

intrapleural pressure usually remains at about ____

-4 mm Hg

adhesiveness of pleural fluid

allows lungs to be pulled outward when the thoracic wall moves during inspiration.

V1=

initial volume

P1=

the initial pressure

inspiration

the process that causes air to enter the lungs

expiration

the process that causes air to leave the lungs

what causes the compression of the lungs during expiration?

the recoil of the thoracic wall

total lung capacity (TLC)

the sum of all the lung volumes (TV, ERV, IRV, and RV)

one atm= ___ mm Hg

760

quiet breathing

aka eupnea, a mode of breathing that occurs at rest and does not require the cognitive thought of the individual. the diaphragm and external intercostals must contract

forced breathing

aka hyperpnea. a mode of breathing that can occur during exercise or actions that require the active manipulation of breathing, such as singing.

muscle groups used during normal inspiration

diaphragm and external intercostal muscles

expiration aka

exhalation

how is atmospheric pressure expressed?

in terms of the unit atmosphere, abbreviated atm, or in millimeters of mercury (mm Hg).

inspiration aka

inhalation

two major steps of pulmonary ventilation

inspiration and expiration

Boyle's Law formula

P1V1=P2V2

pressure (in a gas)

a force created by the movement of gas molecules that are confined.

resistance

a force that slows motion, in the lungs, the flow of gases

muscle contractions during forced breathing

both inspiration and expiration occur during muscle contractions. Other accessory muscles of the neck, abdomen, and rib cage must also contract.

A decrease in volume leads to a(n) ________ pressure. a.decrease in b.equalization of c.increase in d.zero

c. increase in

inspiration and expiration are dependent on

the differences in pressure between the atmosphere and the lungs.

Gas flow decreases as ________ increases. a.resistance b.pressure c.airway diameter d.friction

a. resistance

thoracic wall compliance

ability of the thoracic wall to stretch while under pressure.

deep breath

aka diaphragmatic breathing requires the diaphragm to contract. as the diaphragm relaxes, air passively leaves the lungs

Contraction of the external intercostal muscles causes which of the following to occur? a.The diaphragm moves downward. b.The rib cage is compressed. c.The thoracic cavity volume decreases. d.The ribs and sternum move upward.

d. the ribs and sternum move upward

pulmonary ventilation

the act of breathing, which can be described as the movement of air into and out of the lungs.

Inspiratory capacity (IC)

the maximum amount of air that can be inhaled past a normal tidal expiration, is the sum of the tidal volume and inspiratory reserve volume.

Boyle's Law

the pressure of a gas is inversely proportional to its volume: If volume increases, pressure decreases.

intra-alveolar pressure or intrapulmonary pressure

the pressure of the air within the alveoli, which changes during the different phases of breathing

intrapleural pressure

the pressure of the air within the pleural cavity, between the visceral and parietal pleurae.

respiratory volume

the term used for various volumes of air moved by or associated with the lungs at a given point in the respiratory cycle.

four major types of respiratory volumes

tidal, residual, inspiratory reserve, expiratory reserve

The pressure difference between the intra-alveolar and intrapleural pressures is called ________. a.atmospheric pressure b.pulmonary pressure c.negative pressure d.transpulmonary pressure

D. transpulmonary pressure

Which of the following processes does atmospheric pressure play a role in? a. pulmonary ventilation b. production of pulmonary surfactant c. resistance d.surface tension

a. pulmonary ventilation

alveolar dead space

air found within alveoli that are unable to function, such as those affected by disease or abnormal blood flow.

anatomical dead space

air that is present in the airway that never reaches the alveoli and therefore never participates in gas exchange.

shallow breath

aka costal breathing. requires contraction of the intercostal muscles. As the intercostal muscles relax, air passively leaves the lungs

when does the intrapulmonary pressure of the alveoli equalize with atmospheric pressure?

always because the alveoli are connected to the atmosphere via the tubing of the airways

major mechanisms that drive pulmonary ventilation

atmospheric pressure (Patm); the air pressure within the alveoli, called intra-alveolar pressure (Palv); and the pressure within the pleural cavity, called intrapleural pressure (Pip).

what three types of pressure is pulmonary ventilation dependent on?

atmospheric, intra-alveolar, and intrapleural.

what causes the formation of the negative intrapleural pressure?

competing forces within the thorax

P2=

final pressure

V2=

final volume

is intrapleural pressure always lower than or higher than the intra-alveolar pressure?

lower.

residual volume function

makes breathing easier by preventing the alveoli from collapsing

TLC for men and women

men: 6000mL women: 4200 mL

pulmonary surfactant

mixes with water present in the lining of the alveoli and helps reduce surface tension. Without it, the alveoli would collapse during expiration

are the lungs themselves involved in creating movement?

no the lungs are passive

is energy required to push air out of the lungs?

no. expiration is passive

respiratory cycle

one sequence of inspiration and expiration

inspiratory reserve volume (IRV)

produced by a deep inhalation, past a tidal inspiration

Residual volume (RV)

the air left in the lungs if you exhale as much air as possible

Vital capacity (VC)

the amount of air a person can move into or out of his or her lungs, and is the sum of all of the volumes except residual residual volume (TV, ERV, IRV)

Tidal Volume (TV)

the amount of air that normally enters the lungs during quiet breathing, which is about 500 mL.

functional residual capacity (FRC)

the amount of air that remains in the lung after a normal tidal expiration; it is the sum of expiratory reserve volume and residual volume

Expiratory reserve volume (ERV)

the amount of air you can forcefully exhale past a normal tidal expiration, up to 1200 milliliters for men.

atmospheric pressure

the amount of force that is exerted by gases in the air surrounding any given surface, such as the body.

total dead space

the anatomical dead space and alveolar dead space together, and represents all of the air in the respiratory system that is not being used in the gas exchange process.

respiratory capacity

the combination of two or more selected volumes, which further describes the amount of air in the lungs during a given time.

Besides differences in pressure, what else is breathing dependent upon?

the contraction and relaxation of muscle fibers of both the diaphragm and thorax

transpulmonary pressure

the difference between the intrapleural and intra-alveolar pressures and determines the size of the lungs. (higher transpulmonary pressure=larger lungs)