Respiratory System III

Lungs

An organ in the body; Cannot move by itself

Pleural Sac

2 types = visceral and parietal; Negative pressure in the ____ space; Elastic fibers in lung recoil (push out); All keep the lung inflated

Viseral Pleura

Located in the pleural sac; Attached to the lung

Parietal Pleura

Located in the pleural sac; Attached to the thoracic cavity

Intrapleural Pressure

Involved in pulmonary ventilation; Pressure in space between parietal and visceral pleura; Averages about 4 mm Hg; Maximum of 18 mm Hg; Remains Below Patm throughout respiration cycle

Pneumothorax

Aire (atmospheric) enters pleural space - between your lungs and chest wall - pressure changes; Basically if disrupt the negative pressure in the pleural sac, this condition results; Lung collapses; Symptoms = sudden sharp chest pain (1 side or other, but

Mechanics of Breathing

Inhalation (always active) and exhalation (passive or active); 2 types of inhalation = quet and forced; 2 types of exhalation = quiet and forced

The Respiratory Muscles

Most important are the diaphragm, the external intercostal muscles of the ribs, and the accessory respiratory muscles (activated when respiration increases significantly)

Quiet Inhalation

Involved in the mechanics of breathing; Active--diaphragm and external intercostal muscles

Quiet Exhalation

Involved in the mechanics of breathing; Passive

Forced Inhalation

Involved in the mechanics of breathing; The muscles involved in this type of breathing are the diaphragm, the external intercostal muscles, and the accessory respiratory muscles (activated when respiration increases significantly)

Forced Exhalation

Involved in the mechanics of breathing; Active breathing; Muscles involved in this type of breathing are the accessory respiratory muscles (activated when respiration increases significantly)

Diaphragm

Involved in breathing; Contraction draws air into the lungs; 75% of normal air movement

External Intercostal Muscles

Involved in breathing; Assist in inhalation; 25% of normal air movement

Accessory Muscles

Involved in breathing; Assist in elevating ribs; Muscles include the sternocleidomastoid, scalene muscles, the pectoralis minor, and the serratus anterior; All these muscles needed in forced inhalation

Muscles of Active Exhalation

A type of breathing and ___ involved = internal intercostal and transversus thoracis muscles (depress the ribs), the abdominal muslces (compress the abdomen and force diaphragm upward)

Abdominal Muscles

Some of the muscles involved in active exhalation; Compress the abdomen and force the diaphragm upward

Internal Intercostal and Transversus Thoracis Muscles

Two of the muscles involved in active exhalation; Depress the ribs

Inhalation

One part of the breathing cycle; Increase size of pleural cavities (so increases the volume of the rib cage and lungs); Decrease pressure in the lungs (versus outside); Expansion of pleural cavity and lungs = volume increasess; Decreases pressure within t

Exhalation

One part of the breathing cycle; Decrease size of pleural cavities (so decreases volume of rib cage and lungs); Increase pressure in lungs (versus outside); Decrease of pleural cavity and lungs = volume decreases; Increases pressure within lungs; Air exit

Three Processes of External Respiration

Pulmonary ventilation (breathing); Gas diffusion; Transport of O2 and CO2

Gas Diffusion

One of the three processes of external respiration; ___ across membranes and capillaries

Transport of O2 and CO2

One of the three processes of external respiration; Into and out of the alveolar capillaries; To and from the capillary beds in other tissues

Pulmonary Ventilation

One of the three processes of external respiration; Is the physical movement of air in and out of the respiratory tract; Provides alveolar ventilation; Muscle movement alone does not allow one to breath (lifting weights, running, etc.); Contraction and re

Boyle's Law

Predicts the result of introducing a change in volume or pressure to the initial state of a fixed quantity of gase (commony wirtten PV=K); Defines the relationship between gas pressure and volume (p1V1 = p2V2); The man who created this recognized the rela

Atmospheric Pressure

The weight of air at sea level; 760 mm Hg

Respiratory Cycle

Consists of one inspiration (inhalation) and one expiration (exhalation)

Pressure and Airflow to the Lungs

From are of higher pressure to area of lower pressure; Changes in the volume of pleural cavity (with expansion or contraction of diaphragm & rib cage); Causes changes in volume that create changes in pressure

Compliance

An indicator of expandability; How easily the lungs expand and contract--depends mostly on elastic fibers; Low ___ requires greater force; High ___ requires less force; Factors that affect it = connective tissue structor of the lungs (fibrosis, emphysema)

Elastic Rebound

When inhalation muscles relax, ___ components of lungs recoil; Returning lungs and alveoli to original position

Millimeters of Mercury (mm Hg)

This is the most common method of reporting blood pressure and gas pressures; Normal atmospheric pressure is approximately 760 mm Hg

Intrapulmonary Pressure

Also called intra-alveolar pressure; Pressure within the alveoli; Is relative to Patm (Patomospheric); In relaxed breathing, the difference between Pat and ___ ___ is small (about -1 mm Hg on inhalation or +1 mm Hg on exhalation)

Intra-alveolar Pressure

Also called intrapulmonary pressure; Pressure within the alveoli; Is relative to Patm (Patomospheric); In relaxed breathing, the difference between Pat and ___ ___ is small (about -1 mm Hg on inhalation or +1 mm Hg on exhalation)

Modes of Breathing

Respiratory movements are classified by pattern of muscle activity into Quiet breathing (eupnea) and Forced breathing (hyperpnea)

Quiet Breathing (Eupnea)

One of the modes of breathing; Involes active inhalation and passive exhalation; Diaphragmatic breathing or deep breathing; Costal breathing or shallow breathing

Forced Breathing (Hyperpnea)

One of the modes of breathing; Involves active inhalation and exhalation; Assisted by accessory muscles; Maximum levels occur in exhaustion

Respiratory System

Adapts to changing oxygen demands by varying the number of breaths per minute (respiratory rate = f; 12-16) and the volume of air moved per breath (tidal volume; 500ml, Vt)

Respiratory Minute Volume

Ve; Amount of air moved per minute; Is calculated by respiratory rate (per minute) x tidal volume (f x Vt = Vd)

Anatomic Dead Space

Vd; Only a part of respiratory minute volume reaches alveolar exchange surfaces; Volume of air remaining in conduction passages is this

Alveolar Ventilation

Va; Amount of air reaching alveoli each minute (remember dead space--air already in lung); Calculated as respiratory rate x (tidal volume - anatomic dead space); Va = f x (Vt - VD)

Resting tidal Volume

Amount of air one can move in or out of lungs in single respiratory cycle (resting conditions)

Expiratory Reserve Volume (ERV)

Amount of air one can voluntarily expel after completed normal respiratory cycle

Residual Volume

Amount of air remaining in lungs after maximal exhalation (1200 males, 1100 females); Minimal volume--amount air left if lungs collapsed

Inspiratory Reserve Volume (IRV)

Amount of air one can take in over and above tidal volume

Inspiratory Capacity

Tidal volume + inspiratory reserve volume

Functional Residual Capacity

Amount of air remaining in lungs after a quiet respiratory cycle

Vital Capacity

Maximum amount of air one can into or out of lungs in a single respiratory cycle

Total Lung Capacity

Total volume = vital capacity and residual capacity (average = 6000ml males, 4200ml females)