Chapter 6: The Respiratory System Flashcards
Air enters the respiratory tract through the external ________ of the nose and then passes through the nasal cavity, where it is filtered by mucous membranes and nasal hairs (____________).
nare; vibrissae
After the nares, air passes into the ________ and the ________.
pharynx, larynx
The ____________ resides behind the nasal cavity and at the back of the mouth. It is a common pathway for both air destined for the lungs and food destined for the esophagus.
pharynx
The ________ lies below the pharynx and is only a pathway for air.
larynx
To keep food out of the respiratory tract, the opening of the larynx, the ________, is covered by the ____________ during swallowing.
glottis, epiglottis
The larynx contains 2 ________ ________ that are maneuvered using skeletal muscle and cartilage.
vocal cords
From the larynx, air passes into the cartilaginous ________ and then into 1 of 2 mainstem ________.
The bronchi and trachea contain ciliated epithelial cells - why?
trachea; bronchi
To catch any material that has made it past the mucous membranes in the nose and mouth
In the lungs, the bronchi divide into smaller structures known as ____________, which divide further until they end in the tiny balloon-like structures in which gas exchange occurs, these are ____________.
bronchioles; alveoli
Each alveolus is coated with ____________, a detergent that lowers surface tension and prevents the alveolus from collapsing on itself.
surfactant
Each alveolus is surrounded by a network of ____________ to carry oxygen and carbon dioxide.
capillaries
The lungs themselves are contained in the thoracic cavity, which also contains the heart. The chest ________ forms outside the thoracic cavity.
wall
Membranes known as ____________ surround each lung. It forms a closed sac against which the lung expands. The surface adjacent to the lung is the ____________ ________, and the outer part is the ____________ ________.
pleurae; visceral pleura, parietal pleura
The lungs do not fill passively, they require ____________ ________ to generate the negative pressure for expansion.
skeletal muscle
The ____________ is a thin, muscular structure that divides the thoracic (chest) cavity from the abdominal cavity.
diaphragm
The diaphragm is under ________ control, although breathing itself is under ________ control.
somatic; autonomic
The space within the sac that surrounds the lung is referred to as ________________ ________, which contains a thin layer of fluid, which helps lubricate the 2 pleural surfaces.
intrapleural space
The pressure ________________ that can be created across the pleura ultimately drive breathing.
differentials
Inhalation is an active process. We use our diaphragm as well as the ____________ ____________ muscles (one of the layers of muscles between the ribs) to expand the thoracic cavity.
external intercostal
As the diaphragm flattens and the chest wall expands outward, the ________________ ____________ (the volume of the chest cavity) increases.
intrathoracic volume
Because the intrapleural space most closely abuts the chest wall, its volume increases (first/last?).
first
When you inhale, the diaphragm flattens and chest wall expands outward, which creates low pressure in the intrapleural space. The gas in the lungs is initially at atmospheric pressure, but is now (lower/higher?) than the pressure in the intrapleural space.
What happens then? WHat is this called?
higher; the lungs will expand into the intrapleural space and the pressure in the lungs will drop, causing air to be sucked in from a higher-pressure environment (from the outside world)
This is known as negative-pressure breathing, because the driving force is lower (negative) pressure in the intrapleural space compared with the lungs
Exhalation does not have to be an active process. Simple relaxation of the ____________ ____________ muscles will reverse inhalation processes. This causes chest cavity to decrease in volume.
external intercostals
As the diaphragm and external intercostals relax, the intrapleural space is (lower/higher?) than in the lungs, which is still at atmospheric pressure. This causes air to be pushed out.
higher
During active tasks, we can speed up the process of inhalation by using the ____________ ________________ muscles and abdominal muscles, which oppose the external intercostals and pull the rib cage down.
internal intercostal
A ____________ is used to measure lung capacities and volumes.
spirometer
____________________ is the max volume of air in the lungs when one inhales completely? Usually 6 to 7 liters.
Total lung capacity
TLC
____________ is the volume of air remaining in the lungs when one exhales completely.
residual volume
RV
________ ____________ is the difference between the min and max volume of air in the lungs.
vital capacity
TLC- RV
________ ____________ is the volume of air inhaled or exhaled in a normal breath.
tidal volume
TV
____________ ________ ________ is the volume of additional air that can be forcibly exhaled after a normal exhalation.
expiratory reserve volume
ERV
________________ ____________ ____________ is the volume of additional air that can be forcibly inhaled after a normal inhalation
inspiratory reserve volume
IRV
Ventilation is primarily regulated by a collection of neurons in the medulla oblongata called the ____________ ________ that fire rhythmically to regular contract of respiratory muscles.
ventilation center
In the ventilation center, neurons contain ________________ that are primarily sensitive to carbon dioxide concentration.
chemoreceptors
As the partial pressure of carbon dioxide in the blood rises (hypercarbia or hypercapnia), the ________________ ________ will increase so that more carbon dioxide is exhaled, causing CO2 levels in the blood to fall.
respiratory rate
The ventilation center neurons also respond to changes in oxygen concentration, although this tends to have significance only during period of significant ____________ (low O2 concentrations in the blood).
hypoxemia
Each alveolus is surrounded by a network of capillaries, which bring deoxygenated blood from the pulmonary ____________, which originate from the right ____________ of the heart.
arteries; ventricle
Where do pulmonary arteries originate from?
right ventricle
The walls of the alveoli are only one cell thick, which facilitiates the diffusion of ____ from the blood into the lungs, and ____ into the blood.
CO2, O2
The oxygenated blood returns to the left ____________ of the heart via the pulmonary ________.
atrium; veins
What drives gas exchange in the alveoli?
pressure differential
WHen blood arrives at the alveoli, it intially has a relatively low partial pressure of ____ and a relatively high partial pressure of ____, facilitating transfer of each down its respective concentration gradient.
O2, CO2
Because the gradient between the blood and air in the lungs is already present as the blood enters the lungs, how much energy is required for gas transfer?
None
At higher altitudes, we would have to breathe (quicker/slower).
quicker
The natural response of hemoglobin to the decreased CO2 concentration would be to (increase/decrease?) the unloading of oxygen to tissues.
decrease
In the short term, the body can do what to in order to ensure O2 delivery in high altitudes?
make more red blood cells
In the long term, what can the body do to ensure O2 delivery in high altitudes?
facilitate the distribution of oxygen to tissues
The respiratory tract can also be used for ____________ because it is highly vascular.
thermoregulation
Heat is regulated via the body surfaces by ____________ and ________________.
vasodilation and vasoconstriction
As capillaries expand, more blood can pass through these vessels and a larger amount of thermal energy can be dissipated. What happens when they contract?
Less blood passes through, conserving thermal energy
Which capillaries are used for thermoregulation?
nasal and tracheal
The first line of defense in the respiratory system is ?
the nasal cavity’s vibrissae
what enzyme in the nasal cavity attacks the peptidoglycan walls of gram-positive bacteria?
lysozyme
The internal airways are lined with ____________, which traps particulat matter and larger invaders. Underlying cilia then propel the mucus up the respiratory tract to the oral cavity, where it can be expelled or swallowed; this is called the ________________ ____________.
mucus; mucociliary escalator
____________ can engulf and digest pathogens and signal to the rest of the immune system that there is an invader.
macrophages
Mucosal surfaces also contain ____ antibodies that help to protect against pathogens that contact the mucous membranes.
IgA
________ cells also populate the lungs; they have preformed antibodies on their surfaces. When the right substance attaches to the antibody, this cell releases inflammatory chemicals to promote an immune response.
mast
Mast cell antibodies are also usually reactive to substances like ________ and ________, so they provide inflammatory chemicals that mediate allergic reactions.
pollen and mold
What is the bicarbonate buffer system?
reference p236-237
