Chapter 22, Lesson 2: Pulmonary Ventilation

Flashcards from Chapter 22, Lesson 2 of McGraw Hill Anatomy and Physiology, Tenth Edition, by Kenneth S. Saladin.

Inspiration

The act of inhalation

Expiration

The act of exhalation

Respiratory cycle

One complete breath measuring the cycle of inhalation and expiration; relies on pressure differences

Quiet respiration

Effortless and automatic breathing while at rest

Forced respiration

Deep or rapid breathing during an activity

Diaphragm

The prime mover of respiration; contraction flattens this muscle to enlarge the thoracic cavity and pull air in

Intercostal muscles

Muscles located between the ribs (costals) that contribute to thoracic contraction and enlargement

Accessory muscles

Muscle like the erector spinae, sternocleidomastoid, scalenes, pectoralis, and serratus that act during forced respiration, deep inspiration

Valsava maneuver

Breathing technique used to help expel contents of the abdomen

Central chemoreceptors

Brainstem neurons that respond to cerebrospinal fluid pH changes which reflect CO₂ levels for respiration stability

Peripheral chemoreceptors

Receptors in the carotid and aortic bodies that respond to pH, gas content of blood

Stretch receptors

Receptors in the bronchi, bronchioles, and visceral pleura that regulate and respond to inflation

Inflation reflex (Hering-Breuer reflex)

Reflex triggered by excessive inflation that inhibits inspiratory neurons and stops inspiration

Irritant receptors

Nerves that respond to external irritants such as smoke or dust to cause reflexes like bronchoconstriction, shallow berathing, apnea, or coughing

Atmospheric pressure

The weight of the air on Earth; lower at higher elevations

Intrapulmonary pressure

Air pressure within the lungs

Boyle’s law

At a constant temperature, the pressure of a gas is inversely proportional to volume

More lung volume results in lower pressure; less lung volume results in higher pressure

Intrapleural pressure

The slightly negative pressure between the two pleural layers to allow for expansion

Charles’s law

At a constant pressure, the volume of a gas is directly proportional to temperature

Higher air temperatures expand the lungs further as it is warmed

Pneumothorax

The presence of air in the pleural cavity where the thoracic wall is punctured and negative intrapleural pressure is loss, allowing lung collapse

Atelectasis

The collapse of part or all of a lung that can also result from airway obstruction or clots

Bronchodilation

The increase in diameter of a bronchus or bronchiole for increased airflow; can be caused by epinephrine or sympathetic stimulation

Bronchoconstriction

The decrease in diameter of a bronchus or bronchiole for decreased airflow; caused by histamine, cold air, chemicals, or parasympathetic nerves

Pulmonary compliance

The ease with which the lungs can expand given a change in pressure for lung volume

Alveolar ventilation rate

The amount of air ventilating alveoli per minute

Spirometry

Measuing pulmonary ventilation to assess disease severity

Spirometer

Device used to make spirometry measurements to recapture breath and record breathing variables

Tidal volume (TV)

The volume of air inhaled and exhaled in one cycle of breathing

Inspiratory reserve volume (IRV)

Air in excess of tidal volume that can be inhaled with maximum effort

Expiratory reserve volume (ERV)

Air in excess of tidal volume that can be exhaled with maximum effort

Residual volume

Air remaining in lungs that cannot be exhaled even with maximum effort; allows some gas exchange before next breath of fresh air arrives

Vital capacity

Total amount of air that can be inhaled then exhaled with maximum effort

Inspiratory capacity

Maximum amount of air that can be inhaled after a normal tidal expiration

Functional residual capacity

Amount of air remaining in lungs after a normal tidal expiration

Total lung capacity

Maximum amount of air the lungs can contain

Restrictive disorders

Disorders that result in a reduction in pulmonary compliance (inflation); includes black lung disease and tuberculosis

Obstructive disorders

Disorders that interfere with airflow through airway obstruction; makes inhalation or exhalation more difficult and includes asthma and chronic bronchitis

Emphysema

Disorder commonly caused by smoking that combines elements of restrictive and obstructive disorders