A&P - Physiology of Respiration (Quiz 4)

measurements of respiration

1) respiratory flow rate - in and out of the lungs, how rapidly we are moving air; 2) volumes - the amount of air each compartment can hold, the quantities involved in the gas exchagne; 3) lung capacities - combinations of volumes that represent or demonstrate physiological limits, 4) pressure.

volumes

1) tidal volume, 2) inspiratory reserve volume, 3) expiratory reserve volume, 4) residual volume.

vital capacity (VC)

Represents the capacity available for speech (IRV + ERV + TV). VC increases steadily with body growth up to about 20 years, holds to age 25, then begins to decline. Females have smaller VC.

One cycle of respiration

one inhalation and one exhalation

posture

posture effects efficiency of respiration. the most efficient posture for respiration is erect.

inspiratory capacity (IC)

the maximum inspiratory volume possible after tidal expiration.

total lung capacity (TLC)

the sum of all volumes (TV + IRV + ERV + RV)

residual volume (RV)

the volume remianing in the lungs after a maximum exhalation - can't be forcefully exhaled (1.1. liters).

tidal volume (TV)

volume of air exchanged in one cycle of respiration. tidal volume varies as a function of physical exertion, body size, and age.

minute volume

volume of air involved in one minute of respiration

functional residual capacity (FRC)

volume of air remaining in the body after a passive exhalation (ERV + RV)

inspiratory reserve volume (IRV)

volume of air that can be inhaled after a tidal inspiration

expiratory muscles

when actions decrease the dimensions of the thorax and push air out of the lungs

Goal of respiration

The goal of respiration is the oxygenation of blood and the elimination of carbon dioxide.

Respiration (stages)

1) ventilation (The actual movement of air in the conducting respiratory pathway), 2) distribution (to 300 million alveoli), 3) perfusion (migration of fluid through a barrier - oxygen poor blood from right pulmonary artery is perfused to the capillaries in these alveoli), 4) diffusion (the actual gas exchange across the alveolar-capillary membrane).

capacities

1) vital capacity, 2) functional residual capacity, 3) total lung capacity, 4) inspiratory capacity

Forced expiration

During forced exhalation, as when blowing out a candle, muscles reduce the size of the thorax by compressing the abdomen (abdominal muscles) or pulling the rib cage down (intercostals), thus forcing additional air out of the lungs beyond what is expired in passive expiration.

Forced inspiration

During forced inhalation, as when taking a deep breath, the external intercostal muscles and accessory muscles aid in further expanding the thoracic cavity.

torque

During inhalation, the cartilaginous portion of the rib cage twists, storing a restoring force that causes the rib cage to return to rest upon relaxation. Only after 60% of vital capacity does torque assist in expiration. Since the ribs are under negative torque when relaxed, inspiration moves the ribs from negative to normal torque (rather then from normal to positive torque).

abdominal elastic recoil

During inspiration, the diaphragm flattens and lowers the floor of the thorax leading to increased vertical dimension. Contraction of the diaphragm forces viscera against anterior abdominal wall, causing it to bulge outward. When contraction ceases, elastic recoil pushes the viscera back into normal position, exerting enough force against the diaphragm to return it to its original position. Rib muscles are relaxed (?).

passive expiration

During passive expiration, there is little or no muscle contraction involved in expiration. Instead, the forces inherent to the tissues (elasticity, gravity, and, if over 60% vital capacity, torque) restore the system to a resting position after relaxation of inspiration muscles.

Quiet (tidal) respiration

During quiet tidal respiration, inhalation is active (but limited to only about 1/2 liter of air, 6-8 liters each minute) while respiration is passive.

Speech breathing (lung volumes)

During speech breathing, greater lung volumes are used. This provides more air to speak with and enables the speaker to take advantage of higher expiratory recoil forces to drive the respiratory pump. Speech occurs under varying lung volumes depending upon content, context, etc. Pressure during speaking tasks are typically greater than during resting breathing (depends on loudness, stress, and length of utterance).

speech breathing (vs vegetative)

During speech breathing, the respiratory system must provide adequate ventilation for the body as well as sufficient aerodynamic forces for speech. Inspiration is shorter & faster, expiration is longer, lung volumes are greater, and breathing occurs less frequently. Respiratory muscles also help control airflow by countering elastic recoil.

active respiration

Expiration is active when we use muscular effort to compress the abdomen or pull the rib cage down, thus decreasing the size of the thorax and increasing expiration further than during passive exhalation.

elasticity in early childhood development

Lungs completely fill the thorax in early development - infants must breathe 2-3 times more than adults (40-70 BPM). During development the rib cage grows faster than the lungs and the pleural linings (and increased negative intrapleural pressure) cause the lungs to stretch out to fill the space. By 15 years old, people are down to 20 BPM.

inspiratory muscles

Inspiratory muscles increase thoracic dimensions and facilitate air flow into the lungs. The principal inspiratory muscle is the diaphragm

vegetative breathing

Involuntary breathing for life purposes. inspiration takes up 40% of respiration cycle, expiration 60% of respiration cycle.

elasticity

Lungs are highly elastic tissue; when the rib cage muscles relax after inspiration, the lungs tend to return to their original shape and size. In addition, when you relax the inspiratory process, the muscles of abdomen will return to their original length, pushing your abdominal viscera back in and forcing the diaphragm up.

ventilation

The actual movement of air in the conducting respiratory pathway. A direct function of the action of the diaphragm and muscles of respiration. Contraction of muscles of inspiration causes expansions of alveoli that leads to negative alveolar pressure and air being drawn into the lungs.

gravity

When standing or sitting up, gravity acts to pull the ribs back after expansion; it also pulls the abdominal viscera (guts) down leaving more room for the lungs. Gravity's effect depends upon posture, erect is the most efficient posture.

dead space air

air in the conducting passageways that can't be involved in gas exchange, either because 1) it is in the conducting airways, or 2) it reaches alveoli that are not perfused.

expiratory reserve volume (ERV)

also called resting lung volume; the amount of air that can be expired following passive, tidal expiration.