PS 3: Ventilation - Properties of Gases and Mechanics of Breathing; Transport of Gases by the Blood

nose, nasal cavity, pharynx, larynx, trachea, bronchi, lungs

What are the seven major components of the Respiratory system?

alveoli

Lungs are make up of small air sacs, ____.

alveoli

The ____ are clusters of thin-walled sacs at the terminal branches of the conducting airways

one cell

The walls of the dense network of pulmonary capillaries surrounding each alveolus are ____ ____ thick.

squamous pulmonary epithelial cells (type 1), septal cells (type 2)

What are the two types of epithelial cells found in the walls of each alveolar?

surfactant (type of phospholipid), facilitating lung expansion

What do the septal cells produce?

alveolar macrophages

Also associated with the alveolar wall are ____ ____ (phagocytic cells), which remove particles of dust and debris from alveolar spaces

respiration

The exchange of gases between the atmosphere, blood, and cells is called ____.

inspiration, expiration, and external respiration

What are the 3 processes involved in respiration?

diaphragm and external intercostal muscles

What are the muscles involved in quiet breathing?

increases

The volume of the thoracic cavity ____ due to contraction of the diaphragm (descends), and by contraction of the external intercostal muscles (raises the ribs)

lungs expand to fill the increases space

What happens as the thoracic cavity enlarges that causes the intro-alveolar pressure to fall slightly?

tidal volume

The amount of air that enters the lungs (500 mL of air)

scalene muscles; sternomastoids

For deeper inspirations, the accessory inspiratory muscles, ____ and ____ further enlarge the thoracic cavity

sternomastoids

These accessory inspiratory muscles raises the sternum

scalene muscles

These accessory inspiratory muscles elevate the first two ribs

passive; it is accomplished by elastic recoil of the lungs following relaxation of the inspiratory muscles

Expiration is normally ____ during quiet breathing, because ____.

intra-alveolar; equal

Outward flow of air during expiration ceases when ____ pressure becomes ____ to atmospheric pressure

active; abdominal wall; diaphragm; internal intercostal muscles

During exercise and voluntary hyperventilation, expiration becomes ____; muscles of the ____ ____ contract and push up the ____, and the ____ ____ ____ contract, pulling the ribs downward and inward, thus decreasing the thoracic volume

compliance

____ refers to how much effort is required to stretch or distend the lungs.

pulmonary surfactant

____ ____, which is mixed with water in the fluid lining the alveoli, increases pulmonary compliance and reduces the work of inflating the lungs

stabilizes them by preventing them from collapsing

What does pulmonary surfactant do for the alveoli?

newborn respiratory distress syndrome

A deficiency of pulmonary surfactant is responsible for ____ ____ ____ ____.

Developing fetal lungs do not synthesize pulmonary surfactant until late in pregnancy, so premature babies require strenuous inspiration to inflate poorly compliant lungs

What is the reasoning behind newborn respiratory distress syndrome?

use of “positive” pressure or surfactant replacement

What is the treatment for newborn respiratory distress syndrome?

5.7L; 4.2L

Total lung capacity in males and females is about ____ and ____, respectively.

moderately

The lungs remain ____ inflated throughout the respiratory cycle.

spirometer

A ____ is used to measure changes in lung volume that occur with different respiratory efforts.

consists of an air-filled drum floating in a water-filled container; as a person breathes air in and out of the drum through a connecting tube, the resultant rise and fall of the drum are recorded as a spirogram. inspiration = upward deflection, expiration = downward deflection

How does a spirometer work?

1. inspiratory reserve volume

2. tidal volume

3. functional residual capacity

4. inspiratory capacity

5. vital capacity

6. expiratory reserve volume

7. residual volume

8. total lung capacity

What are the respective labels in order?

obstructive lung disease

A disease that affects the airway, such as bronchial asthma, or the lung itself, such as emphysema is called ____.

airway obstruction due to construction of the smaller airways, bronchi and bronchioles; caused by allergy-induced spasm of the smooth muscle in the walls of these airways

What is asthma and what it is caused by?

emptying; filling

A patient with asthma has more difficultly ____ the lungs than ____ them.

normal; functional residual capacity; residual volume; additional air

A person with asthma’s total lung capacity is ____, but the ____ ____ ____ (FRC) and ____ ____ (RV) are elevated due to ____ ____ remaining in the lungs after expiration

wheezing; breathing

Asthma attacks are characterized by ____ (as air is forced through narrowed airways) and difficult ____.

the breakdown of alveolar walls and loss of elasticity due to release of destructive enzymes from alveolar macrophages following chronic exposure to cigarette smoke or other irritants

What is emphysema?

barrel chest

When the lungs remain inflated due to loss of elasticity, the size of chest cage increases leading to a condition called ____ ____.

less; more

Expired air contains ____ oxygen and ____ carbon dioxide compared to inspired air.

partial pressure

The pressure exerted by a gas in a mixture of other gases is called ____ ____.

thin alveolar capillary

Oxygen enters and carbon dioxide leaves the blood in the lungs passively across the ____ ____ ____ membrane.

three

When hemoglobin returns to the lungs, it typically has ____ molecules of O2.

four

The heme portion of hemoglobin contained in red blood cells contains ____ atoms of iron that each binds to a molecule of oxygen

oxyhemoglobin

Oxygen and hemoglobin combine in a readily reversible reaction forming ____.

oxygen

The partial pressure of ____ is the primary factor determining how much oxygen is bound to hemoglobin.

higher; capillaries; cells; blood

The pO2 of blood pumped to the tissues is ____ than the pO2 in the cells, so oxygen diffuses from the ____ to the ____, causing a drop in ____ pO2.

bicarbonate (HCO3-)

70% of carbon dioxide is transported in plasma as ____ ions

plasma; carbaminohemoglobin

7% of carbon dioxide is dissolved in ____ and 23% combines with the globin portion of hemoglobin forming ____.

carbonic anhydrase

The enzyme responsible for conversion of CO2 to carbonic acid intermediate to HCO3- is ____ ____

carbon monoxide

____ ____ binds more tightly to hemoglobin than oxygen.

50

0.1% CO will combine with ____% of hemoglobin in the body

decreases the oxygen-carrying capability of the blood, leading to hypoxia, and resulting in CO poisoning which can be fatal

What does CO do to the human body?

medulla; brain stem

Breathing is an autonomic function generate by neurons in the ____ of the ____ ____ and modulated by higher brain centers.

Respiratory control centers; rhythmic pattern of breathing

____ ____ ____ in the brain stem are responsible for the ____.

phrenic nerve; intercostal nerves

The diaphragm and external intercostal muscles are innervated by the ____ ____ and ____ ____, respectively.

in the spinal cord

The cell bodies for the phrenic nerve and intercostal nerves are located ____.

impulses from the respiratory center terminating on motor neurons

Inspiratory muscles are stimulated by ____

an increase in H+, which is sensed by chemoreceptors located in the medulla leading to reflex increase in ventilation

An increase in arterial blood pCO2 causes ____

hyperventilation

When the diaphragm and external intercostal muscles contract more forcefully and frequently, this phenomenon is called ____

negative

Hyperventilation is a ____ feedback mechanism

chemoreceptors; breathing rhythm

____ on the ventral surface of the brain stem and in the carotid and aortic bodies on large vessel leaving heart give sensitive feedback for ____ ____.