Respiratory System in Animals Flashcards
What is the Respiratory Cycle?
One complete breath, including inspiration and expiration. It represents the process of air moving into and out of the lungs.
What is Respiratory Frequency?
number of breaths/ minute, (AKA breathing rate) and measured in breaths per minute (bpm).
What are the different types of Respiratory Pressures?
- Atmospheric Pressure.
- Intrapulmonary (Alveolar) Pressure
- Intrapleural Pressure
- Transpulmonary Pressure
What is Lung Compliance?
How easy the lungs expand during inspiration which is determined by the elasticity of lung tissue and surface tension within the alveoli
What is Airflow Resistance?
The opposition to airflow within the respiratory passages, dependent on airway diameter, obstructions, or constrictions.
What is the Principle of Surface Tension?
The force exerted by liquid molecules at the surface of the alveoli, which tends to collapse them.
What is tidal volume (TV or Vt) ?
The amount of air inhaled or exhaled in a normal breath.
What is Pulmonary Ventilation? How is it callculated?
Dr. Aka defines…“physical act and attributes of the animal that support efficient oxygen delivery to the lungs and removal of carbon dioxide from the lungs…”
The process of moving air in and out of the lungs, (measured as the total volume of air exchanged per minute), calculated as tidal volume multiplied by respiratory rate.
TV x RR
What is Dead Space in the respiratory system? 3 types are:
The portion of the respiratory system where gas exchange does not occur.
1. Anatomical Dead Space
2. Alveolar Dead Space
3. Physiological Dead Space
What is the Ventilation/Perfusion (V/Q) Relationship?
The ratio of ventilation to perfusion. (air reaching the alveoli : blood flow to the alveoli.
What is Atmospheric Pressure (Patm)?
The pressure exerted by the air outside the body.
What is Intrapulmonary (Alveolar) Pressure (Palv)?
The pressure within the alveoli of the lungs.
What is Intrapleural Pressure (Pip)?
The pressure within the pleural cavity, usually negative relative to atmospheric pressure.
What is Transpulmonary Pressure?
The difference between alveolar pressure and intrapleural pressure, which keeps the lungs inflated.
What are respiratory surfactants?
Respiratory surfactants reduce surface tension and prevent alveolar collapse.
What is Inspiratory Reserve Volume (IRV)?
The additional air that can be inhaled after a normal inhalation when the subject is at rest.
What is Expiratory Reserve Volume (ERV)?
The extra air that can be exhaled by forceful expiration after a normal tidal exhalation.
What is Residual Volume (RV)?
The air remaining in the lungs after the most forceful exhalation.
What is Vital Capacity (VC)?
The total amount of air that can be exhaled after a maximal inhalation (TV + IRV + ERV).
What is Total Lung Capacity (TLC)?
The total volume of the lungs after maximum inhalation (VC + RV).
What is anatomical dead space?
Anatomical Dead Space: The airways that do not participate in gas exchange.
What is alveolar dead space?
Alveolar Dead Space: Alveoli that are ventilated but not perfused with blood.
What is physiological dead space?
Physiological Dead Space: The sum of anatomical and alveolar dead space.
What is crucial for efficient gas exchange?
A balanced V/Q ratio
What are the 4 basic respiratory structures in mammals? (humans, dogs, etc.)
lungs, trachea, bronchi, and alveoli:
Describe the alveoli:
Tiny air sacs in the lungs where oxygen and carbon dioxide exchange occurs.
What are the 3 basic respiratory structures in birds?
Lungs, air sacs, and parabronchi
What is the function of the respiratory system?
Respiratory systems allow animals to move oxygen (needed for cellular respiration) into body tissues and remove carbon dioxide (waste product of cellular respiration) from cells.
What is cellular respiration?
- Cellular respiration is the aerobic breakdown of glucose in the mitochondria to make ATP.
The respiratory system is responsible for exchange of gases by ____________ and _______________ into the microscopic alveoli where gases are exchanged.
filtering air ; transporting it
Why do we need to filter gasses?
It provides the energy needed by cells of the body to function according the task they are assigned to do in the body.
The transport of oxygen (O₂) and carbon dioxide (CO₂) in animals occurs through the ______ system
circulatory system (blood)
The efficiency of transporting gasses in blood is crucial for _____________ and maintaining _________.
cellular respiration ; homeostasis
Oxygen is transported in 2 primary ways:
- Bound to Hemoglobin (Majority Transport)
- Dissolved in Plasma (Minority Transport)
How is oxygen bound to hemoglobin?
About 98-99% of oxygen is transported by hemoglobin (Hb), a protein found in red blood cells (RBCs).
Hemoglobin + Oxygen → Oxyhemoglobin (HbO₂)
Oxygen binds to hemoglobin in the lungs (or gills) and is released to tissues where it’s needed.
The binding and release of oxygen depend on oxygen partial pressure (PO₂), pH, and temperature (Bohr effect).
How is oxygen dissolved in blood plasma?
Only about 1-2% of oxygen is dissolved directly in the blood plasma, as oxygen has low solubility in water.
This dissolved oxygen contributes to the partial pressure of O₂ in the blood and influences hemoglobin saturation.
What are the 3 ways carbon dioxide is transported?
- As Bicarbonate Ions (Majority Transport – ~70%)
- Bound to Hemoglobin (Carbaminohemoglobin – ~20-23%)
- Dissolved in Plasma (Minority Transport – ~7-10%)
How is gas exchanged at the lungs and tissues?
In the Lungs (External Respiration)
- O₂ diffuses from alveoli (or gills) into blood and binds to hemoglobin.
- CO₂ diffuses from blood into the alveoli and is exhaled.
In the Tissues (Internal Respiration)
- O₂ is released from hemoglobin and diffuses into cells for cellular respiration.
- CO₂ diffuses from cells into the blood for transport back to the lungs.
Regulation of gas transport is done through The ______ Effect and ______ Effect.
Bohr Effect ; Haldane Effect
https://www.khanacademy.org/test-prep/mcat/organ-systems/hematologic-system/v/bohr-effect-vs-haldane-effect
What is the Bohr Effect?
enhancing O₂ release in tissues.
the more acidic a solution, the more O2 dissociates with Hb. O2 free flows into tissue cells.
Increased or decreased CO₂ and H⁺ lower blood pH, reducing hemoglobin’s affinity for O₂,
(other definition in slide 103?? - the effect of increased or decreased release of carbon dioxide [concentration] in blood on the O2/Hb curve)
What is the Haldane Effect?
Deoxygenated blood has a higher capacity to carry CO₂, facilitating CO₂ uptake in tissues and release in the lungs.
(other definition in slide 105? - the effect of oxygen on the property of hemoglobin to release carbon dioxide at the alveolar level)
The more CO2 binds to Hb, the more O2 is kicked off
What is the Oxygen/Hemoglobin Dissociation Curve?
video: https://www.youtube.com/watch?v=XcupwWwfsz8
The oxygen-hemoglobin dissociation curve is a sigmoidal (S-shaped) graph that represents the relationship between the partial pressure of oxygen (PO₂) and the percentage saturation of hemoglobin (Hb) with oxygen. It shows how readily hemoglobin binds to or releases oxygen under different conditions.
Key Features of the Curve:
At high PO₂ (e.g., in the lungs), hemoglobin is almost fully saturated with oxygen.
At low PO₂ (e.g., in tissues), hemoglobin releases oxygen to the cells.
The sigmoid shape results from the principle of cooperativity (explained below).
What is the Principle of Cooperativity?
The principle of cooperativity refers to how hemoglobin’s ability to bind oxygen changes as more oxygen molecules attach:
Positive Cooperativity: When one O₂ molecule binds to hemoglobin, it increases the affinity of hemoglobin for additional O₂ molecules.
As more O₂ binds, hemoglobin’s shape changes (allosteric modulation), making it easier for subsequent O₂ molecules to attach.
This results in the sigmoidal shape of the oxygen dissociation curve.
Similarly, when O₂ is released, hemoglobin’s affinity for O₂ decreases, making it easier to unload the remaining oxygen.
What is the summary of the Oxygen Dissociation Curve shifts?
Right Shift (O₂ unloading): High CO₂, low pH, high temperature, high 2,3-BPG
Left Shift (O₂ binding): Low CO₂, high pH, low temperature, low 2,3-BPG
The respiratory system provides the _______needed by cells of the body to function according the_____ they are assigned to do in the body.
energy ; task
O2 should move through the blood in the right
_______________ to the cells..
concentration
What does the respiratory system involve?
involves the organs in animals that exchange gases with the
environment.
What is respiration usually referred to?
“Respiration” is an everyday term that is often used to mean “breathing”.
What are the structural components of the respiratory system divided into?
upper and lower tracts
What is the upper respiratory tract made of?
Nose, Nasal cavity, sinuses, and
pharynx.
What is the lower respiratory tract made of?
Larynx, trachea, bronchial tree,
and lungs
What is the functional component of the respiratory system divided into?
conducting portion and the respiratory portion
What are the components of the conducting portion of the respiratory system?
Pharynx, larynx, trachea and
bronchi
What are the components of the respiratory portion of the respiratory system?
Respiratory bronchioles, alveolar
ducts and alveoli
What are the intercostal muscles?
The muscles that run between the ribs
How are gasses moved through membranes? NOT active transport
bulk transport and exocytotic mechanism (primarily through diffusion)
What are the 3 laws for gas behavior in the respiratory system?
Henry’s Law
Boyle’s Law
Charles’s Law
ham burger with cheese
What does Boyle’s Law discuss?
pressure and volume are related inversely under constant mass and temperature
What does Charles’ Law discuss?
Under constant pressure, volume of gas and temperature are directly related.
(one increases = the other increases)
What does Henry’s Law discuss?
Volume of gasses that dissolve in water is directly proportional to the pressure of the gasses and solubility coefficient.
Where does diffusion of respiratory gasses take place?
Across the respiratory membrane
What does Fick’s Law discuss
Fick’s first law: Movement of particles from high to low concentration (diffusive flux) is directly proportional to the particle’s concentration gradient.
Fick’s second law: Prediction of change in concentration gradient with time due to diffusion
See Slide 12
Why does gas diffusion occur?
Oxygen is consumed by the tissues which lowers its partial pressure.
Carbon dioxide is produced by tissues which increases its partial pressure.
How do water respires circulate oxygen?
gills
*highly vascularized
*not part of the integumentary system
Do fish have a higher metabolic rate than mammals?
Yes
How do fish use gills to breathe?
- Fish draw in water by closing the gill lid over the gill and opening its mouth
- When the fish closes its mouth and opens the gill lid the water is forced out and over the respiratory surface of the gill filament .
- Gills have high supply of blood vessels in order to act as a respiratory membrane
Describe how fish breathe by a counter-current mechanism?
The flow of water over the gills is in the opposite direction to the flow of blood of the gills. This creates a concentration gradient.
What type of animals diffuse gasses through their skin?
aquatic animals with a low metabolic rate.
What are the different specialized structures used for gas exchange?
- gills - (aquatic animals)
- spiracles (tubes in terrestrial insects)
- lungs - (most terrestrial vertebrates)
[avian uses lungs, air sacs, & pneumatic bones]
Why is equilibrium never fully met in a counter-current exchange?
To increase efficiency by constantly having a gas exchange. The diffusion gradient is maintained.
Describe the lung:
Paired, soft, spongy, cone-shaped and honey-combed with
epithelium having a much larger surface area in total than the outer surface area of the lung itself
What makes the inner lung surface area larger than the outer total surface area?
alveoli
What is the major structural function unit of the lungs?
alveoli
Describe the alveoli:
Moist, thin-walled pockets that are the site of gas exchange.
Each one is closely associated with the pulmonary cavity
What are the 2 major factors that keep the lungs expandable?
elastin and surfactant
What keeps the lungs from collapsing and sticking together?
slightly oily surfactant prevents the alveolar walls from collapsing and sticking together.
What is the disease called from a lack of surfactant in the lungs?
hyaline membrane disease affecting premature babies (usually develops in the last 2-4 weeks of pregnancy)
What are surfactants?
The primary compound that lowers the surface tension of fluid in the lungs
What is surfactant made of?
(may delete)
It is a complex mixture of phospholipids and proteins secreted by alveolar type II cells, which lines the alveoli and significantly reduces surface tension, preventing lung collapse during exhalation
What organ do ALL reptiles use for respiration?
lungs
What do aquatic turtles use to breathe?
lungs / permeable skin
What is the cloaca?
end of the digestive system associated with the respiratory tract that some aquatic species use to increase area of gas exchange
What ventilates squmate (scaled reptiles) lungs?
axial muscles
What do crocodiles have that is similar to mammals and helps them breathe?
diaphragm that is pulled down by the liver to create a space for the lungs to breathe
Do snakes have both an upper and lower respiratory system?
yes ; they have a hollow tube (glottis) that allows air into their lungs (the one closest to the head is the only one for gas exchange, the other one is an air storage sac)
Describe avian (Birds (e.g., Pigeons, Eagles) respiration system:
Lungs: Compact and rigid with a unidirectional airflow system.
Air Sacs: Additional structures that store and move air through the lungs, allowing continuous oxygen exchange.
Parabronchi: Small tubes where gas exchange occurs instead of alveoli.
What are the major 4 phases of respiration?
- pulmonary ventilation
- diffusion of oxygen
- transport of oxygen and carbon dioxide
- regulation of ventilation
What 4 sets of muscles raise the rib cage and how?
- external intercostals
- sternocleidomastoid m. (lift upward on the sternum)
- anterior serrati (which lift many of the ribs)
- scaleni (which lift the first two ribs)
What are 2 methods for expanding and contracting the lungs?
- downward & upward movement of the diaphragm (regular)
- elevation & depression of the ribs (accessory muscles)
What are elevators of the chest cage called?
muscles of inspiration
What are the depressors of the chest cage called?
muscles of expiration
What is the respiratory rate (RR) of the cat and dog?
cat : 20-40/min
dog: 20-34/min
Damage to which cranial nerve affects respiration?
vagus nerve, cranial nerve X (10)
Damage to which cervical vertebrae affects respiration?
3
C5, C6, C7
What are the 6 anatomical barriers of the respiratory membrane?
- alveolar epithelium (type 1 cell)
- epithelial basal membrane
- lung interstitial space
- capillary endothelium basement membrane
- capillary epithelium, simple squamous
- alveolar fluid (surfactant layer)
In the alveolus, the respiratory surface is made up of the ______and _____________.
alveoli and capillary walls
The walls of the capillaries
and the alveoli are so close together that they may share the same _________.
membrane
What does the surfactant layer line?
fluid lining the inner angular space
What is the respiratory surface made up of?
the alveoli and capillary walls
What influences the diffusion coefficient of the gas?
- molecular size (constant)
- temperature
- fluid viscosity/ chemical properties of the membrane
- density of gas (constant)
What influences the partial pressure gradient between the capillary and the alveolus?
- Alveolar gas mixture
- solubility of the gas
- mixed venous blood gas content
What influences the blood-gas barrier thickness?
Age and diseases
What is Syngamus trachea?
A gapeworm, (AKA red worm and forked worm), is a parasitic nematode worm that infects the tracheas of certain birds. The resulting disease, known as “gape”, occurs when the worms clog and obstruct the airway.
What are the 2 pulmonary gas exchange surface areas?
alveolar membrane and capillary membrane
The maximum available alveolar surface area is around _______? It is influenced by age and disease.
140m^2
The maximum available capillary surface area is around _______. 3 Factors that influence this are:
125m 2;
1. degree of pulmonary capillary recruitment
2. pulmonary blood flow
3. blood volume
What describes the interplay between the surface area factors, as both shunt and dead space resulting in a reduced gas exchange surface area?
V/Q matching (ventilation/perfusion)
What is capillary transit time?
how much time for efficient gas exchange that oxygen can be transferred from the blood to the tissues.
the time it takes for blood to travel through a capillary bed, and it’s a key factor in the efficiency of oxygen and nutrient exchange between blood and tissues.
What are the normal and minimum capillary trasnsfer times? What is a cause for delay?
normal ~0.75-1.0 seconds
minimum 0.25 seconds
delay - disease affecting the blood-gas barrier
What is the normal capillary transit time for dogs?
0.45 seconds
Once oxygen reaches the capillary, it rapidly binds to hemoglobin molecules within red blood cells, this is called the _________ rate?
reaction rate
true/false? Diffusion alone is enough t to account for the rate of oxygen uptake in the pulmonary capillaries.
false ; diffusion is not fast enough, it is insufficient
What other gases also bind to serum proteins and triglycerides at the capillary level?
volatile anesthetics
What is the fluid layer that lubricates and surrounds the lung providing movement within the cavity?
pleural fluid layer
What is pleural pressure?
the pressure of the fluid in the thin space between the lung pleura and the chest wall pleura
At the beginning of respiration, what kind of pleural pressure inside is the lungs? How does this change with more inspiration?
slightly negative ;
It becomes more positive and pressure increases as inspiration increases.
What is pneumothorax?
a condition where air enters the space between the lung and the chest wall (pleural space). This causes the lung to partially or completely collapse.
If the pleural pressure is higher than the alveolar pressure, what happens?
it collapses the lung
What are possible causes of pneumothorax?
traumatic injury and (rarely) spontaneous pneumothorax
At the beginning of expiration what kind of pleural pressure is inside the lungs? How does this change with more expiration?
slightly positive;
the pressure decreases further and becomes more negative with expiration
What is hydrothorax?
a condition where excess fluid accumulates in the pleural space, the area between the lungs and the chest wall.
also called pleural effusion
To cause inspiration, the pressure in the alveoli must fall to a value ______ ______ atmospheric pressure.
slightly below
During inspiration, the alveolar pressure decreases to about ____ cm of water.
-1 cm of water
During expiration, the alveolar pressure increases to about ____ cm of water.
+1 cm of water
To initiate expiration, alveolar pressure must be ___________ atmospheric pressure.
slightly above
How much air is forced out of the lung in 2-3 seconds of expiration?
0.5 liters of inspired air
During recoil, ________ pressure is higher than ________ pressure.
alveolar ; pleural
What is recoil pressure?
the elastic forces in the lungs that tend to collapse the lungs at each instant of respiration.
What is compliance of the lung?
The change in volume that occurs per unit change in the system’s pressure.
It is a measure of the lung’s ability to stretch and expand.
Lung compliance (C) = Change in lung volume (V)/Change in transpulmonary
What is the principle of surface tension?
When water forms a surface with air, the water molecules on the surface of the water have an especially strong attraction for one another.
The water surface is always ____ as a result of surface tension.
attempting to contract
the water molecules on the surface have a strong affinity to one another
What holds a raindrop together?
A tight contractile membrane of water molecules around the entire surfaceof the raindrop.
surface tension
The water surface on alveoli are always attempting to _________.
contract
as a result, the alveoli try to collapse
an elastic contractile force of the entire lungs is caused (surface tesion elastic force)
Surface tension in the alveoli results in:
Air attempting to be forced out of the alveoli, which causes the alveoli to collapse.
What is surfactant and what does it do?
It is a surface active agent in water which greatly reduces its surface tension.
What secretes surfactant?
Type 2 alveolar epithelial cells, (10% surface area of the alveoli)
What are some features of type 2 alveolar epithelial cells?
- granular, containing lipids that are secreted into the surfactant into the alveoli.
- They have hydrophobic/ hydrophilic ends which form bonds to each other.
What is surfactant made of?
- several phospholipids (dipalmitoyl phosphatidylcholine or lecithin)
- proteins (surfactant apoproteins)
- Ions (calcium ions)
What is pleurisy?
an inflammation of the pleura, (the thin membranes that line the lungs and chest cavity) caused by bacteria/virus, trauma, pulmonary embolism (PE), or cancer
What reduces the surface tension in the surfactants? Why?
dipalmitoyl phosphatidylcholine ; because it does not fully dissolve and the remainder spreads over the water surface of the alveoli
What happens to the alveoli if the air passage is blocked [due to choking, infection, pulmonary embolism (PE), cancer tumor]?
it creates a positive (+) pressure and surface tension increase causing the alveoli to collapse
What is the formula for the pressure generated from surface tension and pressure inside the alveoli (Laplace’s Law)
Pressure = 2x surface tension/Radius of alveolus
P=2T/r
Why is it important for surfactants to reduce the collapsing pressure alveolar surface?
reduces the effort required by the respiratory muscles to expand the lung
The smaller the alveolus, the _________the alveolar pressure caused by the surface tension.
greater
Surface tension alveolar pressure is especially significant in small premature babies and animals (piglets and foals), many of whom have alveoli with radii less than _____% than that of an adult person.
less than 25%
What is Barker’s Syndrome?
a genetic disorder affecting newborn piglets where their lungs have a greater tendency to collapse due to little or no surfactant in the alveoli upon birth
acute respiratory distress
Another name for hyaline membrane disease is _______?
(ARDS) acute respiratory distress syndrome or (RDS) respiratory distress syndrome
Synthetic Surfactants? Slide 58/59 Do you really need to know this?
Synthetic surfactants
* Colfosceril palmitate (Exosurf) - a mixture of
Dipalmitoylphosphatidylcholine (DPPC) with hexadecanol and
tyloxapol added as spreading agents
* Pumactant (Artificial Lung Expanding Compound or ALEC) - a mixture
of DPPC and PG
* KL-4 - composed of DPPC, palmitoyl-oleoyl phosphatidylglycerol, and
palmitic acid, combined with a 21 amino acid synthetic peptide that
mimics the structural characteristics of SP-B.
* Venticute - DPPC, PG, palmitic acid and recombinant SP-C
* Lucinactant - DPPC, POPG, and palmitic acid.
The simple method for studying pulmonary ventilation is to record the volume movement of air into and out of the lungs, a process called ________.
spirometry
What are pulmonary capacities?
When 2 or more pulmonary volumes are combined.
What is the inspiratory capacity (IC)?
This is the amount of air an animal can breathe in, beginning at the normal expiratory level and distending the lungs to the maximum amount .
the tidal volume + inspiratory reserve
IC = TV + IRV
What is the functional residual capacity (FRC)?
The amount of air that remains in the lungs at the end of normal expiration.
The functional residual capacity equals the expiratory reserve
volume plus the residual volume.
FRC = ERV + RV
What is vital capacity (VC)?
This is the maximum amount of air a subject can expel from the lungs after first filling the lungs to their maximum extent.
The vital capacity equals the inspiratory reserve volume plus the tidal volume plus the expiratory reserve volume .
VC= IRV + Vt + ERV
What is the minute reserve volume (MRV)?
The minute respiratory volume is the total amount of new air moved into the respiratory passages each minute.
Minute Respiratory Volume : Respiratory Rate (RR) x Tidal Volume
(TV): MRV = RR x TV
What is the ultimate importance of pulmonary ventilation?
Continually renew the air in the gas exchange areas of the lungs, where air is in proximity to the pulmonary blood.
The rate at which new air reaches the gas exchange areas of the lung is called?
alveolar ventilation
What are the 4 components of the gas exchange areas?
1) alveoli
2) alveolar sacs
3) alveolar ducts
4) respiratory
bronchioles.
When air does not reach the gas exchange because it is filling the nose, pharynx, and trachea, this is called the ____ _____.
dead space
On expiration, the dead space is expelled ____. Does it go to gas exchange?
first ; no
What comprises the anatomical dead space?
nose, pharynx, trachea, bronchi
What is the alveolar dead space?
the volume of gas that fills the alveoli that is under perfused / not perfused / not participating in gas exchange
What is the physiologic dead space?
Total volume of gas that is inspired but takes no part in gas exchange in the airway and alveoli
It is both anatomical and alveolar dead spaces.
The physiological dead space takes into consideration ____________ in airflow characteristics.
differences
Physiological dead space is determined by the volume of gas that may enter the alveoli and does not have diffusional interchange with the blood because of inadequate ____ ______ ______.
pulmonary capillary perfusion
Anatomical dead space is relatively a fixed volume in a given animal, although it may change during a given respiratory cycle because of:
the lengthening and dilation of bronchi and bronchioles during inspiration and their shortening and constriction during expiration
What is dead space volume, and how is it calculated?
The dead space volume is equal to the partial pressure of CO2 in the alveoli air minus the partial pressure of CO2 in the expired air divided by the partial pressure of CO2 in the alveoli.
Vd = PaCO2 – PeCO2 x Vt ÷ PaCO2
What is a ratio that compares the dead space (Vd) to the tidal volume (Vt) in the lungs? Why is it useful?
Vd /Vt x 100 %
It’s used to assess lung function and can indicate the severity of lung injury.
Name 4 important reasons for dead space in the lungs?
- Acts as conduit (channel) for air on its way to the diffusible spaces
- Warms the inspired air
- Saturates inspired air with water vapor at body temperature
- Clears inspired air of suspended particles
What is the process of exchanging gas in the airways and alveoli with atmospheric air?
ventilation
What is the volume of gas moved into or out of the airways and alveoli over a certain period of time?
total ventilation
What is the total volume of gas moved into or out of the
airways and alveoli in one minute? It is also known as minute respiratory volume
(Ve = fVt). f = breathing frequency, Vt = tidal volume
minute ventilation
What is the volume of air that does not take part in gas exchange over a certain period of time?
dead space ventilation
What is alveolar ventilation (AV)?
It is determined by subtracting dead space
volume from tidal volume: AV = TV - DsV
The relationship between the partial pressures of oxygen and carbon dioxide in the alveoli and blood as well as the amount of blood that is supplied to the alveoli is known as the _____ _____ _____.
ventilation-perfusion ratio (Va/Q)
A normal ventilation/perfusion ratio implies there is balance between ventilation and perfusion of the ______, so that exchange of oxygen and carbon dioxide between the alveoli and blood is optimal.
alveoli
A low ventilation -perfusion ratio (low Va/Q) means?
ventilation has declined but perfusion remains adequate
A high ventilation -perfusion ratio (high Va/Q) means?
ventilation is exceeding perfusion
Mismatches of ventilation and perfusion are probably the most common cause of ________.
hypoxemia
What is hypoxemia?
a low level of oxygen in the blood. O2 sats under 90%
It is not an illness or condition, state of being. Correction with supplemental oxygen
The trachea and bronchi not occupied by the cartilage plates are made of ______ muscle.
smooth
The walls of the bronchioles are made of ______ muscle.
smooth
The terminal bronchiole, called the respiratory bronchiole is made of?
pulmonary epithelium + fibrous tissue + few smooth muscle fibers
Many obstructive diseases of the lung are from narrowing of the smaller bronchi and larger bronchioles due to:
excessive contraction of the smooth muscle
Where does the greatest amount of resistance to airflow occur?
larger bronchioles and bronchi near the trachea
In some disease conditions, smaller bronchioles often play a far greater role in determining airflow resistance because:
of their small size
What are 3 causes of airway resistance?
1) Muscle contraction in their walls
2) Edema occurring in the walls
3) Mucus collecting in the lumens of the bronchioles.
What is the condition when fluid builds up in the lungs, including in the alveolar walls. This can lead to breathing difficulties and poor oxygenation of the blood.
pulmonary edema?
What is mucus collecting in the lumens of the bronchioles called?
bronchiolitis , causes by a virus
What is another name for mucus in the lungs?
phlegm or sputum
What occurs when all or a part of the lungs shrinks by losing air. It can occur in one lobe of the lung, or it can happen suddenly in both lobes.
atelectasis
What is an abnormal contraction of the smooth muscle of the bronchi, resulting in an acute narrowing and obstruction of the respiratory airway?
bronchospasm
Which nerve fibers innervate smooth muscle within the walls of bronchi and small pulmonary vessels? Activation causes bronchodilation and vasodilation.
sympathetic
(The lung is innervated by sympathetic nerves derived from the upper thoracic and cervical ganglia.)
In the respiratory system, _______ & ______________ dilate bronchioles and improve airflow.
epinephrine & norepinephrine
(in the blood *think fight or flight, it helps breathing)
Which bronchodilator has a greater effect on respiratory function? Why?
Epinephrine because of its greater stimulation of beta-adrenergic receptors—which cause dilation of the bronchial
tree
There are a few parasympathetic nerve fibers derived from the _________ nerve penetrate the lung parenchyma.
vagus
(Cranial nerve X)
10
The parasympathetic nervous system, specifically when the vagus nerve is stimulated, releases ____________, which causes mild to moderate constriction of the bronchioles.
acetylcholine
The bronchoconstrictive effect of acetylcholine is relevant in conditions like ______ & ________, where airway hyperresponsiveness and inflammation are key features.
asthma and chronic obstructive pulmonary disease (COPD)
Drugs that block the effect of acetylcholine, such as _______, can sometimes relax the respiratory passages enough to relieve the obstruction.
atropine
What causes the parasympathetic nervous system to become activated?
1) reflex responses of the lungs due to irritants and allergies
2) irritation of the epithelial membrane, like noxious gases, dust, or bronchial infection
3) small pulmonary emboli
What are the 3 lung reflex responses?
1) coughing
2) sneezing
3) airway constriction
What reflex often occurs when micro-emboli
occlude small pulmonary arteries?
bronchiolar constricton reflex
What 3 local sensory factors often cause bronchiolar constrictor reflex?
1) Histamine
2) Slow reactive substance of anaphylaxis.
3) Mast cells during allergic reactions, especially those caused by pollen in the air
What are the 2 roles of mucus in respiratory passageways?
1) keeps membranes moist
2) traps small particles out of the inspired air and keeps most of
these from ever reaching the alveoli
What is the role of cilia in respiratory
passageways?
Cilia causes the mucus and its entrapped particles to be
either swallowed or coughed to the exterior.
The mucus is secreted partly by individual ______ ______ cells in the _________lining of the passages and partly by small submucosal
glands.
mucous goblet cells ; epithelial lining
Where is the carina landmark?
the point where the trachea divides into the right and left main bronchi
The larynx, carina, the terminal bronchioles, and even the alveoli are especially sensitive to corrosive _______ _______.
chemical stimuli
2 examples of chemical stimuli are:
sulfur dioxide gas or chlorine gas
(Afferent or Efferent) nerve impulses pass from the respiratory passages mainly through the vagus nerves to the ________ of the brain.
afferent ; medulla
A cough is an automatic sequence of events that is triggered by the _______ ________ of the medulla.
neuronal circuits
What are the 6 stages of a cough reflex?
- Rapid inspiration of air.
2 Closure of the epiglottis
3 Shutting of the vocal cords entraps the air within the lungs.
4 Forceful contraction of the abdominal and intercostal
muscles pushing the stomach against the diaphragm.
5 Consequently, the pressure in the lungs rises rapidly
6 Finally, the vocal cords and the epiglottis suddenly open
widely, so that air under this high pressure in the lungs explodes outward.
What will initiate a sneeze reflex?
irritation of the nasal passages (mediated by the 5th cranial nerve)
trigeminal nerve
The (afferent or efferent) impulses pass in the _____ _____ nerve to the medulla, where the sneeze reflex is triggered.
Afferent;
fifth cranial nerve
Cranial nerve V is the
Trigeminal nerve
What is depressed, so that large amounts of air pass rapidly
through the nose, thus helping to clear the nasal passages of foreign matter, creating a sneeze.
uvula
What happens when the alveolar volume is excessive relative to rate of metabolism and accumulation of carbon dioxide?
hyperventilation
During hyperventilation, partial pressure of _____is reduced.
partial pressure of carbon dioxide
Does hyperventilation always cause tachycardia (increased heart rate)?
No
What occurs when the alveolar volume is small relative to the metabolic rate?
hypoventilation
When there is a rise in partial pressure of ______ _____, hypoventilation occurs.
carbon dioxide
Hypoventilation is most often seen with _______ (slow heart rate) but can also occur with normal and rapid heart rate (tachycardia).
bradycardia
A lowered partial pressure of carbon dioxide during hyperventilation is called ___________.
hypocapnia
An elevated level of carbon dioxide during
hypoventilation is referred to as ________.
hypercapnia
Normal partial pressure is called ________.
eucapnia
Does hypercapnia involve respiratory acidosis or respiratory alkalosis?
respiratory acidosis
Does hypocapnia involve respiratory acidosis or respiratory alkalosis?
respiratory alkalosis
In respiratory acidosis, what is the plasma concentration of CO2 (high or low)? Why?
CO2 is elevated
- the body is not effectively removing it through breathing, leading to a lowered blood pH (acidic).
Acidosis: High CO2, low pH
Alkalosis: Low CO2, high pH
What is hemiplegia?
Hemiplegia is a condition that causes paralysis or weakness on one side of the body.
What is the most prevalent lung disease seen in horses?
Heaves (ROA)
What is heaves? What is its length, and how is it treated?
An allergic-base disease in horses that compromises the horse’s ability to breathe. It is chronic and can threaten long-term health and performance.
The allergy is usually towards something in that horse’s environment, and a reaction can be avoided by relocating the horse.
What is nasopharyngeal collapse in horses?
The movement or collapse of any/all of the “walls” of the nasopharynx that causes disruption to the flow of air from the nasal cavities to the larynx and trachea.
Condition in horses that causes “roaring” that affects the vocal cords and causes a characteristic roaring sound during exercise.
laryngeal hemiplegia
What is the most prevalent lung disease seen in horses?
heaves or RAO (recurrent airway obstruction) similar to asthma in humans
See pg. 13 in Cunningham Physiology Respiratory Printout for Case Study
What is nasopharynx collapse in horses? How is it treated?
the movement or collapse of any or all of the “walls” of the nasopharynx that causes disruption of the flow of air from the nasal cavities to the larynx and trachea
Use of a flair strip helps with this problem
Upper respiratory dysfunction is common in horses. Any condition impeding the flow of air from the nares to the trachea can result in ____________and exercise ___________.
respiratory noise ; intolerance
What is Epiglottic entrapment in Horses?
The epiglottis isn’t allowed to close. The condition occurs when the apex and lateral margins of the epiglottis are completely enveloped within the arytenoepiglottic fold. While the epiglottis remains dorsal to the soft palate as normal, its function is (usually) inhibited when entrapped.
What are the 3 ways carbon dioxide is transported?
- 7% is dissolved in plasma as simple forms
- 23% as carbamino compounds such as carbaminohemoglobin (Hgb.CO2)
- 70% as bicarbonate ion (HCO3)
What % of CO2 travels by dissolving in plasma as simple forms?
7%
What % of CO2 travels as carbamino compounds? (carbaminohemoglobin (HgbCO2)
23%
What % of CO2 travels as a bicarbonate ion? (HCO3)
70%
What % of CO2 enters RBC?
93%
What % of CO2 that enters the RBC undergoes a hydration reaction?
70%
What enzyme catalyzes the hydration reaction of CO2?
carbonic anhydrase
What is the importance of the hydration reaction?
- It prevents the accumulation of hydrogen ions
- It facilitates the release of oxygen at the tissue level
What are the 2 ways oxygen is transported?
- 3% is dissolved in plasma
- 97% is transported in chemical combination with hemoglobin and oxyhemoglobin
What are some advantages of using hemoglobin to transport oxygen?
What determines the oxygen dissociation curve?
oxygen partial pressure. The more partial pressure, the more (___) hemoglobin
slide 110
What is the hemoglobin concentration of RBCs in dogs?
228
2 cubed
What is the hemoglobin concentration of RBCs in cats?
130-150
What is cooperativity?
The phenomenon of increased oxygen binding to all the binding site of reduced hemoglobin due to the initial binding of one oxygen molecule.
It is responsible for the sigmoid shape of the Hb/P2 dissociation curve
What does it mean when the O2/Hg dissociation curve shifts to the left?
Hemoglobin combines with more oxygen (loading)
What does it mean when the O2/Hg dissociation curve shifts to the right (wanted shift)?
hemoglobin tends to release its oxygen content (unloading)
What 4 factors support a shift to the right of the O2/Hg dissociation curve?
- Increased hydrogen ions
- increased CO2 (Bohr effect)
- Increased temperature (increased cell metabolism)
- Increased DPG (diphosphoglycerate: normal produce of RBCs)
What are the 4 major factors involved in the displacement of the O2/Hb curve?
- carbon dioxide
- pH
- Temperature
- 2,3- Diphosphoglycerate (DPG)
Low pH moves the O2/Hg curve to the ____.
right (Bohr effect)
High pH moves the O2/Hg curve to the ____.
left
A rise in temperature moves the O2/Hg curve to the ____.
right
A normal DPG concentration usually moves the O2/Hg curve slightly to the ____.
right
117
What is the Herring-Breur reflex?
A reflex triggered to prevent over-inflation of the lung (protects the alveoli from bursting)
What receptors in the smooth muscle of the airways respond to excessive stretching of the lung during large inspirations?
Pulmonary stretch receptors
What happens when pulmonary stretch receptors are activated?
They send action potentials through large myelinated fibers of the vagus nerve to the inspiratory area in the medulla and apneustic center of the pons (Trigger)
What response occurs after the trigger is enacted by the vagus nerve?
The inspiratory area is inhibited directly and the apneustic center is excited by the pneumotaxic center to prevent it from activating the inspiratory area (Response)
What part of the pons is the Pneumotaxic center?
The rostral portion
What part of the pons is the Apneustic center?
The caudal portion
What is the function of the dorsal respiratory group in the medulla?
Initiate the rhythm of respiration and retain respiration
What is the function of the ventral respiratory group in the medulla?
controlling forced exhalation and increasing the force of inspiration by stimulating accessory respiratory muscles, while also contributing to the basic respiratory rhythm
The rhythmic pattern of breathing and the adjustments that occur therein are integrated within portions of the brain stem known as the _______ _____:
respiratory center
How many air sacs do birds have, and how many are paired?
- 9 air sacs
- 8 are paired
Which air sacs in birds are paired?
- cervical air sacs
- anterior thoracic air sacs
- posterior thoracic air sacs
- abdominal air sacs
Which air sac in the bird is not paired?
interclavicular air sac
What part of the airway in birds is known as the bronchus in mammals?
the mesobronchus
organization of respiratory system in birds (he said we don’t reallllyyyy have to know everything since we don’t know avian anatomy, but idk if we should know basic stuff just in case because I do NOT trust him)
125-143
How many respiratory cycles does it take to move one ‘packet’ of air in birds?
What is the advantage of this?
2
- air, which has a high oxygen content, always moves unidirectionally through the lungs
What is Eupnea?
normal respiration
What is dyspnea?
difficult or laboured breathing
What is hyperpnea?
excessive breathing
- the rate and/or depth of breathing is increased
- does not necissarily cause change in blood gas level
can lead to hyperventilation
the patient may be unaware of any change in breathing
What is polypnea?
rapid and shallow breathing
NOT THE SAME as tachypnea = faster than normal respiratory rate
What is apnea?
no breathing/ longer pauses between breaths
What is cheyne-stokes respiration (CSR)?
rhythmic waxing and waning of the depth of respiration
the patient breathes deeply and rapidly (hyperpnea) for a short period, then breathes very slightly (hypopnea) or stops breathing altogether (apnea). The pattern occurs over and over again every 45 seconds to 3 minutes.
* Disease affecting the respiratory center
What is biot’s respirations?
sequences of gasps, apnea, and several
deep gasps
irregular breathing changes
cheyne-stokes = consistant cycle of breathing types
What is Kussmaul’s respiration?
https://www.youtube.com/watch?v=raEKXVfuWTo
rapid, deep labored breathing without pause
air hunger
metabolic acidosis, particularly diabetic keto acidosis (DKA)
What is apneustic respiration?
https://www.youtube.com/watch?v=10zMXm2h8rM
animal holds an inspired breath at the end of inhalation for short period before exhaling (Dr. Aka)
Sustained, gasping inspiration followed by short, inefficient expiration. Mechanical ventilator is usually needed.
Causes:
1. Brain Injury: Damage to the upper pons (brainstem) typically due to stroke or trauma.
2. Lesions in the respiratory center of the brain.
3. Drug overdoses (less common)
4. After certain types of anesthesia. (less common)
https://www.dvm360.com/view/respiratoryventilatory-monitoring-proceedings
Is carbonic acid a major contributor to the extracellular blood pool?
No
