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Chapter 23: Respiratory System

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The primary functions of the respiratory system are
to move air to and from the exchange surfaces of the lungs, to provide an area for gas exchange between air and circulating blood, to protect respiratory surfaces from dehydration and environmental variations
The conversion of angiotensin I to angiotensin II in the lung capillaries indirectly assists int the regulation of
blood volume and blood pressure
Pulmonary surfactant is a phospholipid secretion produced by alveolar cells to
reduce the cohesive force of H2O molecules and lower surface tension
The "patrol force" of the alveolar epithelium involved with phagocytosis consist primarily of
alveolar macrophages
The respiratory system consists of structures that
provide an extensive surface area for gas exchange between air and circulating blood, permit vocalization and production of sound, move air to and from the exchange surfaces of the lungs along the respiratory passageways
The air-filled pockets within the lungs where all gas exchange between air and blood occurs are the
alveoli
Structures in the trachea that prevent its collapse or overexpansion as pressures change in the respiratory system are the
C-shaped tracheal cartilages
The entry of liquids of solid food into the respiratory passageways during swallowing is prevents by the
epiglottis folding down over the glottis
A single respiratory contraction consists of
inspiration & expiration
The trachea allows for the passage of large masses of food through the esophagus due to
distortion of the posterior tracheal wall
The function of the hilus along the medial surface of the lung is to
provide access to pulmonary vessels and nerves
Dilation and relaxation of the bronchioles is possible because the walls of bronchioles contain
smooth muscle tissue regulated by the ANS
Structural features that make the lungs highly pliable and capable of tolerating great changes in volume are
the elastic fibers in the trabeculae, septa, and the pleurae
After passing through the trachea, the pathway a molecule of inspired air would take to reach an alveolus is
primary bronchus -> secondary bronchus -> bronchioles -> terminal bronchioles -> respiratory bronchioles -> alveolus
The serous membrane in contact with the lung is the
visceral pleura
The diffusion of gases between interstitial fluid and cytoplasm is
internal respiration
Breaching, which involves the physical movement of air into and out of the lungs is
pulmonary ventillation
The process which prevents the buildup of carbon dioxide in the alveoli and ensures a continuous supply of oxygen that keeps pace with absorption by the bloodstream is
alveolar ventillation
The absorption of oxygen and release of carbon dioxide by cells is
internal respiration
Air enters the respiratory passageways when the pressure inside the lungs is lower than then
atmospheric pressure
The movement of air into and out of the lungs is primarily dependent on
pressure differences between the air in the atmosphere and air in the lungs
During inspiration there will be an increase in the volume of the thoracic cavity and an
increasing lung volume, decreasing intrapulmonary pressure
During expiration the diaphragm
relaxes and the dome rises into the thoracic cage
Stiffening and reduction in chest movement effectively limit the
respiratory minute volume
During expiration there is an
increase in pulmonary pressure
A lack of surfactant secretion onto alveolar surfaces causes the
alveoli to collapse
If there is a PO2 of 104mm Hg in the alveoli, and a PO2 of 40 mm Hg and a PCO2 of 45 mm Hg within the pulmonary blood, there will be a net diffusion of
O2 into the blood from the alveoli; CO2 from the blood into the alveoli
When the partial pressure difference is greater across the respiratory membrane, the rate of gas diffusion is
faster
The arrangement that improves the efficiency of pulmonary ventilation and pulmonary circulation occurs when
blood flow and air flow are coordinated
If the partial pressure of oxygen is lower in the puolmonary capillaries than in the alveolus, then
O2 will diffuse out of the alveolus into the pulmonary capillary
Blood entering the system circuit normally has a PCO2 of 40mm Hg, while peripheral tissues have a PCO2 of 45mm Hg; therefore
CO2 diffues into the blood
Each molecule of hemoglobin has the capacity to carry ______ molecules of oxygen (O2)
4
What percentage of total oxygen (O2) is carried within red blood cells chemically bound to hemoglobin
98%
Factors that cause a decrease in hemoglobin saturation at a given PO2 are
increasing diphsphoglycerate (DPG), increasing temperature, decreasing pH
Each hemoglobin molecule consists of
four globular protein subunits, each containing four heme units
When each hemoglobin molecule binds with four molecules of oxygen, the end product is
oxyhemoglobin
Carbon dioxide is transported in the blood by
conversion to a molecule of carbonic acid, binding to the protein part of the hemoglobin molecule, dissolving in plasma
If the rate and depth of respiration exceed the demands for oxygen delivery and carbon dioxide removal, the condition is called
hyperventillation
Under normal conditions the greatest effect on the respiratory centers is initiated by
increases and decreases in PCO2
Emotional states which initiate sympathetic activation in the ANS cause
bronchodilation and increase the respiratory rate
The initiation of inspiration originates with discharge of inspiratory neurons in the
medulla
Examples of protective reflexes which operate when you are exposed to toxic vapors, chemical irritants, or mechanical stimulation of the respiratory tract include
sneezing, coughing, pharyngeal spasms
As volume of the lungs increases, the
inspiratory center is inhibited, the expiratory center stimulated
With increasing age, elastic tissue deterioration and stiffening and reduction in chest movement effectively limit the
respiratory minute volume
The nervous system interacts with the respiratory system by
monitoring respiratory volume and blood gas levels
In the chronic, progressive condition of emphysema
respiratory bronchioles and alveoli are functionally eliminated
A respiratory disorder characterized by fluid leakage into the alveoli or swelling and constriction of the respiratory bronchioles is
pneumonia
Intracellular bicarbonate ions are exchanged for extracellular chloride ions resulting in a mass movement of chloride ions into the
red blood cells
The paranasal sinuses include
frontal, sphenoid, ethmoid, and maxillary
A rise in arteriole PCO2 elevates cerebrospinal fluid (CSF) carbon dioxide levels and stimulates the chemoreceptive neurons of the medulla to produce
hyperventillation
The primary function of pulmonary ventilation is to maintain adequate
alveolar ventilation
The purpose of the fluid in the pleural cavity is to
reduce friction between the parietal and visceral pleura
When the diaphragm and external intercostal muscles contract
intrapleural pressure decreases
If a person is stabbed in the chest and the thoracic wall is punctured but the lung is not penetrated
the lung will probably collapse
The most important factor determining airway resistance is
airway radius
The sympathetic division of the ANS causes _______ of airway smooth muscle; therefore, resistance is _________
relaxation; decreased
The substance often administered during an asthmatic attack to decrease resistance via airway dilation is
epinephrine
Decreased amounts of CO2 concentrations in the bronchioles cause
an increase in bronchiolar constriction
The air flow and blood flow in the right proportion at each alveolus improves
efficient external respiration
If a person is breathing 15 times a minute and has a tidal volume of 500ml, the total minute respiratory volume is
7,500 ml
The residual volume is the volume of air
that remains in lungs after maximal expiration
The maximum amount of air moved in and out during a single breath is
vital capacity
If a person is breathing 12 times per minute, the tidal volume is 350ml, and the volume in the anatomic dead space is 150ml, what is the alveolar ventilation rate
4,200ml/min
The most effective means of increasing alveolar ventilation is
breathe slowly and deeply
When a person does not produce enough surfactant and becomes exhausted by the effort required to keep inflating and deflating the lungs, the condition is called
respiratory distress syndrome
The partial pressure of O2 in the atmosphere at sea level is
160mm Hg
The process of internal respiration involves each of the follow except that
hemoglobin binds more oxygen
Movement of air into and out of the lungs is accomplished by the process of _______, while all movement of gases across membranes is by ________
bulk flow; passive diffusion
The correct sequential transport of O2 from the tissue capillaries to O2 consumption in cells is
erythrocytes, plasma, interstitial fluid, cells
It is important that free H+ resulting from dissociation of H2CO3 combine with hemoglobin to reduce the possibility of
an acidic condition within the blood