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Black- Physio I > Respiratory Objectives > Flashcards

Respiratory Objectives Flashcards

1
Q

What are the anatomical structures of the conducting system?

A

Nose, larynx, nasolarynx, trachea, bronchi, bronchioles, and terminal bronchioles.

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2
Q

Why are these conducting zone structures important?

A

They are important in humidifying, filtering, and warming air before it reaches the respiratory zone.

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3
Q

What is the function of the conducting zone?

A

To bring air into and out of the respiratory zone for gas exchange.

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4
Q

What is another name for the conducting zone and why?

A

It is known as anatomic dead space because gas exchange does not occur here.

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5
Q

What are the conducting airways lined with and what is their function?

A

Mucus-secreting and ciliated cells that function to remove inhaled particles.

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6
Q

How is the conducting zone innervated?

A

The walls of the conducting system contain smooth muscle with sympathetic and parasympathetic innervation.

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7
Q

How do the parasympathetic and sympathetic innervations affect the conducting zone?

A

Parasympathetic muscarinic receptors are activated to constrict the airways. Sympathetic beta 2 receptors are activated by epinephrine to dilate the airways. Changes in diameter of the airways changes the airflow.

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8
Q

What are the anatomical structures of the respiratory zone?

A

Bronchioles, alveolar ducts, and alveolar sacs

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9
Q

Describe the differences between the structures of the respiratory zone.

A

Respiratory bronchioles are transitional structures that have cilia and smooth muscle. Alveolar ducts are completely lined with alveoli, contain NO CILIA and LITTLE smooth muscle, and terminate into alveolar sacs which are also lined with alveoli. Alveoli are pouchlike invaginations of the walls of the respiratory bronchioles, alveolar ducts, and alveolar sacs that are thin-walled with large surface for diffusion of gases. Alveoli that are poorly perfused with blood are also called dead space.

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10
Q

What is the function of the respiratory zone?

A

Site of gas exchange.

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11
Q

What are the alveolar walls lined with?

A

Elastic fibers and epithelial alveolar cells called type 1 and type 2 pneumocytes.

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12
Q

What is the function of type 1 pneumocytes?

A

Type 1 pneumocytes cover 95% of the alveolar surface, keep alveoli dry, are extremely thin and designed for efficient gas exchange between alveolus and pulmonary capillaries.

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13
Q

What is the function of type 2 pneumocytes?

A

Type 2 pneumocytes cover 5% of the alveolar surface and synthesize pulmonary surfactants, secrete cytokines, and have a regenerative capacity for type 1 and 2 pneumocytes.

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14
Q

What is the function of pulmonary surfactants?

A

To reduce the surface tension of alveoli and prevent alveoli from collapsing at the end of expiration.

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15
Q

What are the two phases of the respiratory cycle?

A

Expiration and inspiration.

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16
Q

Describe how inspiration occurs.

A

The thorax and lungs are enlarged by the contraction of the external intercostal muscles and the diaphragm.

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17
Q

Describe how expiration occurs.

A

Internal intercostal muscles contract to assist expiration and are aided by abdominal muscles. This is a passive process in a resting state.

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18
Q

Which phase requires more effort (with the exception of horses)?

A

Inspiration

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19
Q

What are the two types of breathing and how are they characterized?

A

Abdominal and costal breathing. Abdominal breathing is characterized by visible movement of the abdomen. Costal breathing is characterized by pronounced rib movements.

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20
Q

What is the functional residual capacity (FRC) and what is its purpose?

A

It is the air that remains in the lungs at the end of normal exhalation and serves as a reservoir for air and helps provide constancy to the blood concentrations of the respired gases.

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21
Q

What is pulmonary ventilation?

A

The process of exchanging the gas in the airways and alveoli with gas from the environment

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22
Q

How are respiratory pressures expressed?

A

In relation to atmospheric pressure, which is set at zero.

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23
Q

What must be true in relation to barometric pressure for air to flow in the lungs?

A

The pressure in the lungs must be higher or lower than barometric pressure (PB) which is relatively constant.

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24
Q

What three pressures effect pulmonary ventilation?

A

Pleural pressure, alveolar pressure, and transpulmonary pressure

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25
What is pleural pressure and how does it influence pulmonary ventilation?
It is the pressure exerted outside the lungs within the thoracic cavity (pleural cavity) and is usually less than atmospheric pressure. If the volume of the lungs are increases, the pressure decreases. The pressure is always negative or the lung with collapse. Also known as intra-pleural pressure.
26
What is alveolar pressure and how does it influence pulmonary ventilation?
Also known as intra-pulmonary pressure and is the pressure within the alveoli that increases and decreases with each breath. It is always equal to atmospheric pressure at the end of the inspiration and expiration phases.
27
What is transpulmonary pressure and how does it influence ventilation?
This is the pressure difference between the alveolar pressure and pleural pressure in the lungs. It is equal and opposite to the elastic reoil pressure of the lung. If transpulmonary pressure is equal to zero (alveolar pressure = pleural pressure), the lung collapses. The pressure is positive under normal conditions.
28
What is recoil pressure?
The mean of the elastic forces in the lungs that tend to collapse the lungs at each instant of respiration
29
What is Boyle’s Law?
“The pressure exerted by a constant number of gas molecules in a container is inversely proportional to the volume of the container.” Pressure decreases, volume increases = inspiration. Pressure increases, volume decreases = expiration.
30
List the two major functions of pulmonary surfactants.
Pulmonary surfactants displace water molecules and decrease the surface tension which (1) prevents the collapse of the lungs at the end of expiration and (2) increase pulmonary compliance.
31
What is pulmonary compliance?
Lung compliance (distensibility) is the extent to which the lungs will expand for each unit increase in transpulmonary pressure
32
What factors affect compliance?
Those conditions that destroy lung tissue or cause it to be fibrotic or that in any way impedes lung expansion. A lack of surfactant is associated with decreased compliance.
33
What is elasticity and how does it apply to the lungs?
Elasticity is the tendency to return to its initial size after being distended. Lungs must be able to get smaller when the stretching force is released for expiration to occur. The elastic tension increases during inspiration when lungs are stretched and is reduced by elastic recoil during expiration.
34
What is minute ventilation (VE)?
Also called minute respiratory volume. It is the total volume of air breathed per minute. It is the sum of alveolar ventilation and dead space ventilation.
35
What is minute ventilation determined by?
It is determined by the tidal volume and the number of breaths per minute.
36
What is tidal volume and what does it ventilate?
It is the amount of air breathed in or out during a respiratory cycle. Tidal volume ventilates not only the alveoli, but also the airways leading to the alveoli.
37
What is total ventilation?
It is the volume of gas moved in or out of the airways and alveoli over a certain period of time.
38
What is the importance of pulmonary ventilation?
To continually renew the air in the as exchange areas of the lungs.
39
What is alveolar ventilation?
The rate at which new air reaches gas exchange areas
40
What are the dead spaces?
When there is little or no diffusion of oxygen and carbon dioxide through the membranes of most of the airways (anatomic dead space) AND where there is no exchange of gases in nonperfused alveoli (alveolar dead space). Alveolar dead space is not present under normal conditions.
41
Why is dead space necessary?
It assists in tempering and humidifying inhaled air.
42
What defines the physiological dead space?
It is the sum of both the anatomic and alveolar dead space.
43
How is resistance to airflow determined?
By the radius and length of the airways
44
When is resistance greater?
During expiration. As lung volume increase during inspiration, airways dilate and reduce resistance for expiration.
45
What is the major factor determining airway caliber?
Contraction of bronchial smooth muscle.
46
What structures cause the majority of airway resistance?
60% of airway resistance is in the nasal cavity, pharynx, and larynx. These are areas that humidify and warm the air.
47
How can nasal resistance be lowered or avoided?
Nasal resistance can be decreased during exercise by dilation of external and by vasoconstriction of vascular tissue. Breathing through the mouth is another way to bypass the high-resistance, not possible in horses.
48
How does the velocity of airflow change in the respiratory system?
The velocity of airway flow diminishes progressively from the trachea toward the bronchioles.
49
What is alveolar hypoxia and what does it result in?
It is when the air in a poorly ventilated alveoli has a low partial pressure of oxygen and it is of limited benefit to keep sending blood to such alveoli. It results in vasoconstriction of the pulmonary arteries.
50
What is hypoxic vasoconstriction?
The consequence of generalized alveolar hypoxia.
51
Give an example of vasoconstriction.
Cattle grazing at a high altitude (low O2)  generalized hypoxic vasoconstriction  increase in pulmonary arterial pressure  increase in the workload of the right ventricle  right-sided heart failure “brisket disease”  edematous fluid accumulates in the briskets
52
What is cor pulmonale and what is it associated with?
It is the manifestation of severely elevated pulmonary vascular pressure (pulmonary hypertension). It is associated with heartworm disease and obesity.
53
What factors affect the rate of gas movement between the alveolus and the blood?
(1)The physical properties of gas, which is determined by several factors like solubility. (2) The surface area available for diffusion, which is the surface are of perfused capillaries. (3) The thickness of the air-blood barrier (respiratory membrane), less than 1 um in the lungs. (4) The driving pressure gradient of the gas between the alveolus, and the capillary blood which causes rapid diffusion of oxygen from alveolus into the capillary.
54
How is gas exchange facilitated in the alveoli?
The exchange between alveoli and the capillaries occurs by diffusion. A capillary network covers the surface of the alveolus to facilitate O2 and CO2 exchange.
55
What is diffusion?
The passive movement of gases down a concentration gradient.
56
What is the driving pressure for gas diffusion?
The difference between the alveolus and the capillary blood pressure.
57
What is mixed venous blood and why is that its name?
Blood entering the alveolar capillary from the small pulmonary arteries. It is known as mixed venous blood because it has returned to the right side of the heart in veins from all parts of the systemic circulation.
58
What is the driving pressure gradient?
60 mmHg
59
What does gas exchange refer to?
The diffusion of O2 and CO2 in the lungs and in the peripheral tissues. O2 is transferred from alveolar gas into pulmonary capillary blood, where it travels to the tissues and diffuses from systemic capillary blood into the cells. CO2 is delivered from the tissues to the venous blood, to pulmonary capillary blood, and is transferred to alveolar gas to be expired.
60
How does gas exchange occur between the tissues and the capillaries?
By diffusion, as a result of the partial pressure differences between the tissues and capillaries, oxygen diffuses into the tissues and carbon dioxide into the blood until the partial pressures of the blood and tissues are equal.
61
How is oxygen carried in the blood and why?
It is carried in two forms – dissolved (2%) and bound to hemoglobin (98%) because it is poorly soluble in water / plasma.
62
Which form of O2 produces partial pressure?
Dissolved O2 in solution, O2 in hemoglobin does not contribute to partial pressure at all
63
How is carbon dioxide carried in the blood?
Three forms – (1) as dissolved CO2 in solution (7%), (2) as carbaminohemoglobin (bound to hemoglobin- 23%), and (3) as bicarbonate (HCO3-) which is the chemically modified form (70%)
64
Describe the structure of hemoglobin.
Hemoglobin is a globular protein consisting of FOUR subunits. Each subunit contains a heme molecule and a globin chain.
65
How many molecules of hemoglobin are found in a single red blood cell?
270 million
66
How many molecules of oxygen can hemoglobin bind with? Are these reactions reversible?
Hemoglobin can reversibly bind with 4 molecules of oxygen.
67
What is oxygenated hemoglobin called?
Oxyhemoglobin
68
What is deoxygenated hemoglobin called?
Deoxyhemoglobin
69
What is hemoglobin S?
An abnormal variant of the hemoglobin that causes sickle cell disease. The affinity for oxygen is decreased in these molecules.
70
What are the factors affecting the amount of oxygen carried by the red blood cells?
(1) The hemoglobin (Hb) content of the blood and (2) the partial pressure of oxygen in the plasma (OXYHENOGLOBIN DISSOCIATION CURVE).
71
What is a decrease in Hb associated with?
Anemia
72
Do 4 molecules of oxygen bind to hemoglobin at the same time?
The binding of oxygen to the heme group of Hb is a four step process. The oxygen affinity of a particular heme is influences by the oxygenation of the others. When the first heme unit is oxygenated, O2 affinity if the second heme unit is increased and so on.
73
What is responsible for the sigmoid shape of the Oxyhemoglobin dissociation curve?
Heme-heme interactions. The percent saturation of heme sites does not increase linearly as PO2 increases.
74
What is the partial pressure of venous blood?
40 mmHg
75
What is the partial pressure of arterial blood?
100 mmHg
76
What factors affect the loading and unloading of oxygen by the red blood cells?
Affinity DECREASES in the TISSUES due to local increase in CO2 concentration, local increase in hydrogen ions, local increase in temperature. Affinity INCREASES in the LUNGS because of local decreases in CO2 concentration, local decreases in hydrogen ions, and local decreases in temperature.
77
What are the 4 components of breathing control?
Breathing is controlled by centers in the brain stem. The four components are (1) control centers for breathing in the brain stem, (2) chemoreceptors for O2 and CO2, (3) mechanoreceptors in the lungs and joints, and (4) respiratory muscles whose activity is directed by the brain stem centers.
78
What are the 3 major respiratory centers?
Dorsal respiratory group (medullary), ventral respiratory group (medullary), and the pneumotaxic center (pons)
79
What is the major role of the dorsal respiratory group? Where are most of its neurons located?
The basic rhythm of respiration is generated mainly in the dorsal respiratory group. The nervous signal that is transmitted to the inspiratory muscles, is not an instantaneous burst of action potentials. The signal begins weakly and increases in a “ramp” manner resulting in steady volume increase in the lungs during inspiration. Nucleus of the tractus solitaries (NTS)
80
What are two qualities of the inspiratory ramp are controlled?
(1) Control of the rate of increase of the ramp signal (heavy respiration) and (2) control the limiting point at which the ramp suddenly ceases (normal respiration).
81
What is the major role of the pneumotaxic center? | Where is the pneumotaxic center located?
To transmit signals to the inspiratory area. The primary effect of this center is to control the “switch-off” point of the inspiratory ramp to limit respiration and control the duration of the filling phase of the lung cycle. The pons
82
What happens if you have a strong pneumotaxic signal?
Increase the rate of breathing.
83
What is the major role of the ventral respiratory group?
This area operates as an overdrive mechanism when high levels of pulmonary ventilation are required like during heavy exercise.
84
What are the neurons of the ventral respiratory group inactive?
During normal quiet respiration
85
How does the brain stem control the breathing process?
The brain stem controls breathing by processing sensory information and sending motor information to the diaphragm.
86
How do central chemoreceptors help in the control of breathing?
They control minute to minute breathing by communicating directly with the inspiratory center (DORSAL RESP GROUP). THEY ARE VERY SENSITIVE TO INCREASES IN PCO2, caused by decreases in partial pressure and affinity of O2 AND decrease in pH. When CO2 increases, O2 decreases, and pH decreases becoming more acidic, this stimulates hyperventilation. The chemoreceptors are located in the brain.
87
How do the peripheral chemoreceptors help control breathing?
THEY ARE VERY SENSITIVE TO DECREASES IN PO2 caused by an increase in CO2 and decrease in pH. When O2 decreases, CO2 increases, and pH decreases becoming more acidic and stimulates hyperventilation. The chemoreceptors are located in the vascular system.
88
List the non-respiratory functions of the lungs.
Defense mechanism of the respiratory system Pulmonary Fluid Exchange Metabolic Functions
89
List the 3 ways particles and aerosols can be deposited in airways.
Impaction (larger particles) Sedimentation Diffusion
90
List how irritant receptors can be stimulated
``` Mechanical deformation (Ex: foreign body) Excessive amounts of material on the epithelial surface (Ex: mucus) ```
91
Describe how particles deposited on the epithelial surface are transported on the mucociliary system
The mucocillary system consists of mucus and water layers overlying epithelial cells. The watery layer (SOL) is a low-viscosity layer that bathes the surface of the epithelial cells in which the cilia beat. The mucus layer (GEL) entrap inhaled particles. Extended cilium propel particles to the tracheobronchial system or through the nasal cavity.

Black- Physio I (6 decks)

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