Chapter 21 - Respiratory System Flashcards
Rising CO2 levels are the most powerful respiratory stimulant.
As CO2 is hydrated in the brain tissue, liberated H+ acts directly on the central chemoreceptors causing a reflexive increase in breathing rate and depth. Low PCO2 levels depress respiration.
______ involves the intermittent realse of expired air as the glottis opens and closes.
Speech
As the length and tension of the voval folds change, the pitch of the sound varies. Generally, the tenser the vocal folds the farster they vibrate and the higher the pitch.
Under normal resting conditions (PO2 = 100 mm Hg), arterial blood is _____ % saturated, and 100 ml of systemic arterial blood contains about _____ ml of O2.
98; 20
The oxygen content is written as 20% (volume percent).
At sea level, the atmosphic pressure is
760 mm Hg (the pressure exerted by a column of mercury 760 mm high)
760 mm Hg = 1 atm
The lungs are perfused by two circulations:
The pulmonary circulation
The bronchial circulation
Differ in size, origin and function.
Submucosa
Connective tissue layer dep tot he mucosa.
Contains seromucus glands that help rooudce mucus “sheets” within the trachea.
Supported by 16-20 C-shaped rings of hyaline cartilage encaded by the adverntitia, the outermost later of connective tissue.
Internal and External Respiration are driven by ______ diffusion. They are also driven by partial pressure gradients of O2 and CO2 that exist on the opposite sides of the exchange membranes.
Simple
During forced or deep inspiration, accessory muscles further increase the thoracic volume. Several muscles, including the ______ and ______ muscles of the neck and the _______ ________ of the chest, rasie the ribs even more than during quiet inspirations.
The back extends as the the _____ ______ muscles straighten the throacic curvature.
Scalenes; Sternocleidomastoid
Pectoralis Minor
Erector Spinae
Dorsal Respiratory Group (DRG)
Integrates input from peripheral stretch and chemoreceptors and communicates this information to the VRG.

The tissue composition of the walls of th main bronci mimics that of the trachea, however, the conducting tubes become smaller, the following structural chagnes occur:
1. Support structures change - Irrecgular patches of cartilage replace the cartilage ringes, and by the time the broncioles are reached, the tube walls no longer contain supportive cartialge.
The tube walls throughout the broncial tree contain elastic fibers.
2. Epithelium changes - Tthe mucosal epithelium thins as it changes from pseudostratified columnar to simple columnar and then to simple cuboidinal in the terminal bronchioles. Most airborne debris found at or below the level of the broncioles must be removed by macrophages in the alveoli.
3. Amount of smooth muscle increases - A complete layer of circular smooth muscle in the bronchioles and the lack of supporting catilage allows the bronchioles to provide substantial resistnace to air passage under certin conditions.
Chronic inflammation, or infections such as tuberculosis, can cause _____ _____ tissue to replace normal lung tissue.
Nonelastic Scar
Decreased produciton of surfactant can also decrease lung compliance, the more energy is needed to breath.
Increased ventilation in response to metabolic needs is called ______.
Hyperpnea
The lungs are innervated by ________ and ________ motero fibers and visceral sensory fibers.
Nerve fibers enter each lung through the _____ _____ on the lung root and run along the broncial tubes and blood vessesl in the lungs.
Parasympathetic fibers cause the air tubes to ______, whereas sympathetic fibers _____ them.
Parasympathetic; Sympathetic
Pulmonary Plexus
Constrict; Dilate
Once inside the lungs, each main broncus subdivides into _____ (secondary) bronchi - _____ on the right and ____ on the left - each supplying one lung lobe.
Lobar
Three; Two
Spirometer
A cumbersome instrument utilizing a hollow bell inverted over water, now patients blow into a small electronic measuring device.
Declining blood pH (acidosis) and increasing PCO2 weaken the Hb-O2 bond, a phenomenom called the ______ ______.
Bohr Effect
This enhances oxygen unloading where it is needed the most.
When you move on a long-term basis from sea level to the mountains your body makes respiratory hematopoietic adjustments via an adaptive response called _________.
Acclimatization
Vital Capacity (VC)
The total amount of exchangeable air.
VC = TV + IRV + ERV
The trachea’s _____ ______ make it flexible enough to stretch and move inferiorly during inspiration and recoil during expiration, but the cartilage rings prevent it from collapsing and keep the airway patent despite the pressure changes that occur during breathing.
Elastic Elements
Distinguised by permanent enlargement of the alveoli, acccompanied by destruction of the alveolar walls.
Invariably the lungs lose their elasticity.
Emphysema
The respiratory changes in ________ do not alter blood O2 and CO2 levels significantly.
Hyperventilation is excessive ventilation, and is characterized by low ____ and alkalosis.
hyperpnea
PCO2
Cellular Respiration
The actual use of oxygen and production of carbon dioxide by tissue cells and the cornerstone of all energy-producing chemical reactions in the body.
Quiet expiration depends more on lung ______ than on muscle _______.
Elasticity; Contraction
Reduced Hemoglobin or Deoxyhemoglobin (HHb)
Hemoglobin that has released oxygen.

























