Pulmonary Part 2 Flashcards
The normal automatic process of breathing from the __________
The ________can override these centers if voluntary control is needed
from the brainstem; cortex
Neurons in medulla oblongata and pons control ______
Unconscious breathing
The automatic rhythmic is controlled by neurons located in the ___________
medullary rhythmicity center
•Respiratory nuclei in medulla -rhythm –
2 respiratory and what are they involved in ?
inspiratory center (dorsal respiratory group)
- frequent signals, you inhale deeply
- signals of longer duration, breath is prolonged –
expiratory center (ventral respiratory group) •involved in forced respiration
*****Medullary respiratory center is in the
*****Medullary respiratory center is in the reticular formation of the medulla beneath the floor of the fourth ventricle
***Pre-BotzingerComplex (partof VentralGroup) =
essential for generation of the respiratory rhythm
***Dorsal Respiratory Group:
sets the basic respiratory
Ventral Respiratory Group = associated with forced respiration •
These groups of cells have intrinsic periodic firing abilities and are responsible for basic rhythm of ventilation –Even when all afferent stimuli is abolished, these cells generate repetitive action potentials that send impulses to the diaphragm and other respiratory muscles
The expiratory area is normally quiet during normal breathing, but will _______
become activated with forceful breathing
Pneumotaxic center in the _______pons –
UPPER
Inhibits inspiration –Limits the burst of action potentials in the phrenic nerve, effectively decrease the tidal volume and regulating the respiratory rate –“Fine tuning” of respiratory rhythm because a normal rhythm can exist in the absence of this center
•Apneustic center in the _______ pons –
LOWER
Impulses have an excitatory effect on the Dorsal Respiratory Group in the medulla –Promotes inspiration –Sends signals to the Dorsal Respiratory Group in the medulla to delay the “switch off” signal provided by the pneumotaxic center
Impulses from the _____ and ___________ do what?
Vagus (X); Glossopharyngeal (IX); nerves
modulate the output of inspiratory cells
The cycle of inspiration: –Latent period of several seconds
Crescendo of action potentials leading to a ramp of strengthening inspiratory muscles
–Inspiration action potentials cease and inspiratory muscle tone falls
–Expiration occurs due to elastic recoil of lung tissues and chest wall
From limbic system & hypothalamus –•
respiratory effects of pain& emotion
From airways and lungs
–irritant receptors in respiratory mucosa •stimulate vagal signals to medulla results in_______and_______
stretch receptors in airways:_________reflex •excessive inflation triggers_______ of ______
J-receptors are ______ ______Receptors - what do they do?
bronchoconstriction and coughing
inflation; stop of inspiration
Juxtapulmonary capillary receptors. They increase rapid, shallow breathing
Stimulate vagal signals to medulla results in
bronchoconstriction/ coughing
From chemoreceptors –
monitor blood pH, CO2and O2 levels
stretch receptors in airways -inflation reflex
•excessive inflation triggers stop of inspiration
Rate and depth of breathing adjusted to maintain levels of:
–pH
–pH –PCO2
–PO2
Rate and depth of breathing adjusted to maintain levels of:
–pH
–PCO2
–PO2
______primary stimulus for central chemoreceptors) •–
pH of CSF
Respiratory acidosis (pH < 7.4)
caused by ↓ ↓↓ ↓ pulmonary ventilation –hypercapnia: PCO> 45 mmHg –hypercapnia: PCO 2 > 45 mmHg •CO2 easily crosses blood-brain barrier •in CSF the CO2 reacts with water and releases H+ •central chemo receptors strongly stimulate inspiratory center
“blowing off ” CO2pushes reaction to the left
CO2(expired) + H2O ← ←← ←H2CO3 ← ←← ←HCO3-+ H+ –so hyperventilation reduces H+
•Respiratory alkalosis (pH > 7.4)
–hypocapnia: PCO 2 < 35 mmHg –Hypoventilation (↑ ↑↑ ↑CO2), pushes reaction to the right ↑ ↑↑ ↑CO+ HO → →→ →HCO→ →→ →HCO-+ H+
↑ ↑↑ ↑CO2+ H2O → →→ →H2CO3 → →→ →HCO3-+ H+ –↑ ↑↑ ↑H+lowers pHto normal
•pH imbalances can have metabolic causes –
Ex: uncontrolled diabetes mellitus •ketoacidosis, may be compensated for by Kussmaul respirations
Where are peripheral found?
Peripheral –found in major blood vessels •aortic bodies –signals medulla via C.N. X
Where are carotid bodies
carotid bodies –signals medulla by C.N. IX
Central –in medulla •
primarily monitor pHof CSF •↑ ↑↑ ↑[H+] stimulates ventilation •↓ ↓↓ ↓[H+] inhibits it
Ventilatory responses what percentage is mediated by central chemoreceptors?
80% mediated by central chemoreceptors
Ventilatory responses what percentage is mediated by peripheraL chemoreceptors?
20% mediated by peripheral chemoreceptors.
Central receptors monitor
CSF
The normal pH of CSF is ______ and it has much _______buffering capacity compared to blood, resulting in greater change in pH with changes in PCO2
•Changes can be compensated by –Example:
7.33,less
active transport of HCO3-into the CSF HCO3-into the CSF
A patient with chronic lung disease will have CO2 retention, but may have a near normal CSF pH and a resulting low ventilation for his or her PCO2 level
With severe lung disease, the hypoxic drive to ventilation becomes very important –Chronic CO2 retention results in the __________
What become the chief stimulus of ventilation?
compensation of CSF pH to nearly normal range
These patients have lost most of their increase in the stimulus for ventilation from CO2 –By this point, the kidney should have already metabolically compensated for the respiratory acidosis, so the peripheral chemoreceptors have no pH stimulus to increase ventilation
-Under these conditions, arterial hypoxemia (PaO2) becomes the chief stimulus of ventilation •If a high O2 mixture is given to relieve the hypoxemia, the ventilation may be grossly depressed.
The cortex can _________these centers if _______Control is needed
Can override; voluntary
Medullary Rhythmicity area : dorsal group is the ______ group and the Ventral group is the _______Group
Inspiratory Group; expiratory
Inspiratory group is the
Expiratory group is the
Dorsal group
Ventral group
Respiratory Center in pons :
pneumotaxic area
Apneustic area
The pons regulate
rate and depth
What does the pneumotaxic center of the pons do?
Pneumotaxic center: Sends continual inhibitory impulses to inspiratory center, as impulse frequency rises, breaths shorter, faster and shallower.
What does the Apneustic Center of the pons do
Apneustic center: Promotes maximal lung inflation and long deep breaths
Inspiration & expiration
Vagus nerve : type of receptors (3)
Stretch
Irritant
J receptors
Central control impulses from the_______and ________
VAGUS; GLOSSOPHARYNGEAL nerves modulate the output of inspiratory cells
The cycle of inspiration
- latent period of several seconds
- Crescendo of action potentials leading to a ramp of strengthening inspiratory muscle
- Inspiration action potential cease and inspiratory muscle tone falls
Expiration occurs due to elastic recoil of lung tissues and chest wall
Central Control
Medullary respiratory center is in the reticular formation of the medulla beneath the floor of the fourth ventricle.
Pre-Botzinger Complex
Part of the ventral group= essential for generation of the respiratory rhythm
Dorsal respiratory Group sets what?
sets the basic respiratory rhythm
Ventral respiratory Group
associated with forced respiration
Ventral resp group, These groups of cells have i
- intrinsic period firing abilities and are responsible for basic rhythm of ventilation.
- Event when all afferent stimuli is abolished, these cells generate repetitive action potentials that send impulses to the diaphragm and other respiratory muscles.
Central control; The expiratory area is normally quiet during normal breathing but
will become activated with forceful breathing
PNEUMOTAXIC CENTER:located where ? does what? what mechanism
in the upper pons
-inhibits inspiration
- Limits the burst of action potentials in the phrenic nerve, effectively decrease the tidal volume and regulating the respiratory rate
Fine tuning of respiratory rhythm because a normal rhythm can exist in the absence of this center.
Apneustic center
in the lower pons
Impulses have an excitatory effect on the DORSAL RESPIRATORY group in the medulla
Promotes inspiration
sends signals to the respiratory group in the medulla to delay the “switch off” signal provided by the pneumotaxic center.
INPUT to RESPIRATORY CENTERS
From limbic system & hypothalamus
respiratory effects of pain & emotion
INPUT from airways to lungs
From airways & lungs
Irritant receptors in respiratory mucosa
stimulate vagal signals to medulla, result in bronchoconstriction / coughing
INPUT to stretch receptors in airways
irritation reflex
excessive inflation triggers stop of inspiration
J-receptors - Juxtapulmonary capillary receptors. - increase rapid, shallow breathing
Input to respiratory from chemoreceptors
monitor blood pH, CO2 and O2 levels.
Blood chemistry and respiratory rhythm : Rate and depth breathing adjusted to maintain levels of
pH
PCO2
PO2
****Effects of Hydrogen IONS’
primary stimulus for what kind of chemoreceptors?
Respiratory________caused by a_________pulmonary ventilation
***pH of CSF (primary stimulus for central chemoreceptors) Respiratory acidosis (ph<7.40 ) caused by decreased pulmonary ventilation
Respiratory Acidosis (ph is ________) caused by Decreased pulmonary ________
Hypercapnia –>
CO2 easily crosses______
In CSF, the ________reacts with _____and releases____
Central chemoreceptors strongly stimulates _______Center
______CO2 pushes reaction to the left
What does HYPERVENTILATION do?
PCO2 >45 mmHg
CO2 easily crosses BBB
In CSF, the CO2 reacts with water and releases H+
Central chemoreceptors strongly stimulate inspiratory center
Blowing off CO2 pushes reaction to the left
CO2 (expired ) + H2O
Reduces H+
Respiratory alkalosis (ph\_\_\_\_\_\_\_-) Hypo\_\_\_\_\_\_\_\_\_\_: PCO2\_\_\_\_\_\_ Hypo\_\_\_\_\_\_\_\_Increased\_\_\_\_\_\_pushes reaction to the right \_\_\_\_\_\_H+lowers pH to normal pH imbalances can have metabolic causes
>7.4 PCO<35mmHg Hyperventilation--> Increased CO2 ↑CO2+H20-->H2CO3 --> HCO3- + H+ ↑ ph \_\_\_\_\_\_\_\_\_to normal
Ph imbalances can have metabolic causes ex
uncontrolled DM
Ketaacidosis ,compensated by Kussmaul Respirations.
What is the normal ph of the CSF? between blood and CSF which one possess LESS buffering capacity? what does that mean?
7.33, CSF ; Greater change in pH with changes in PCO2
**Which monitor CSF
Central receptors
How is change in the CSF compenesated
Active transport of HCO3- into the CSF
A patient with chronic lung disease will have
CO2 retnetion , but may have a normal CSF ph and a resulting low ventilatio for his or her PCO2 level.
***Chemoreceptors types
Peripheral and Central.
**Chemoreceptors Peripheral
Found where?
2 Types? and does what ?
**Found in major blood vessels
Aortic bodies - Signals medulla via CN X
Carotid bodies - Signals medulla by CN XI
****Chemoreceptors Central Found where? 2 Types? and does what ? What inhibits ventilation? What stimulates ventilation?
In medulla
Primarily monitor pH of CSF
↑ [H+] stimulates ventilation
↓ [H+] inhibits it
*****Ventilator responses 80% mediated by ______
central chemoreceptors
*****Ventilator responses 20% mediated by _
Peripheral chemoreceptors
**if a high O2 mixture is given the relieve the hypoxemia, the ventilation may be
**Grossly depressed
Chronic O2 retention results in the compensation of CSF ph to _______
These patients have lost most of their __________
nearly normal range
Increase in the stimulus for ventilation from CO2
BY THIS POINT, THE KIDNEYS ALREADY METABOLICALLY COMPENSATED FOR THE respiratory acidosis, so the peripheral chemoreceptors have no pH stimulus to increase ventilation.
Under these conditions, arterial HYPOXEMIA (PaO2) becomes the chief stimulus or ventilation
**Peripheral chemoreceptors located in the _________ at the __________ of the ________ arteries and in the __________above the _______
Located in the carotid bodies at the bifurcation of the
common carotid arteries, and in the aortic bodies
above the aortic arch
***Which of the bodies are more important?
Afferent nerve is the ___________ (CN__).Contain glomus cells –sites of ___________ -modulate ___________ ___________ by physiological and chemical stiumuli
Carotid bodies;
GLOSSOPHARYNGEAL XI;
site of CHEMORECEPTION
neurotransmitter release by
***Peripheral CHEMORECEPTORS respond to :
- The response of the peripheral chemoreceptors to arterial PCO2 is _________ than that of the _______chemoreceptors even though peripheral responses are __________ but ________
- ****Decrease in arterial PO2 and pH, and increases in arterial PCO2
- LESS IMPORTANT; CENTRAL; FASTER but Weaker
CAROTID receptors respond to drop in
pH (IX)
AORTIC receptors response to
PCO2 (X)
Conditions that affect ventilation
Receptors can be_______or _______
What are factors that enhanced ventilation?
enhanced or suppressed MLE Metabolic acidosis Low PO2(<60mmHg) Elevated temperature
Conditions that affect ventilation
What are factors that SUPPRESSED ventilation?
MANC MA (Metabolic alkalosis) A (any cns depressant) N (cold) N (Narcotics)
Integrated responses
- Decreasing arterial PCO2 is ________ in reducing the __________ to Ventilation
very effective
stimulus
The main stimulus to increase ventilation when arterial _________ rises comes from the ______receptors which respond to the increases _____ in CSF , and also from peripheral receptors responding to both the rise in _______ and decrease in ______
PCO2; Central ; {H+}; pCO2 , pH
1.Just review: Drug effects on ventilation
Amnestics : _______CNS leading to a decrease ____
Affect _______ and _______
At high doses may cause _______
OPIODs Affect\_\_\_\_\_\_\_\_\_\_\_Center Decrease \_\_\_\_\_\_\_ Mildly increase \_\_\_\_\_\_\_\_\_\_ Decrease \_\_\_\_\_\_\_\_\_over all
Suppress; RR
Muscle tone and upper airway
Apnea
Respiratory drive center
Respiratory Rate
Tidal Volume
minute ventilation
2.Just review: Drugs effects on Ventilation
Volatile Anesthetics :
Suppresses _______ ______relaxes _________ including leading to what kind of breathing?
Nitrous Oxide:
Supportive of _______
resulting in an ______in RR
-suppresses neural activation
all muscles including the diaphragm, leading to fast and shallow breathing
Suppresses response to PCO2 (abolishes response to PO2)
- Ventilation; increase
Pressure and flow: What drives respiration? _______Pressur
Atmospheric pressure
What 2 things are inversely proportional?
Intrapulmonary pressure and LUNG volume
Just review :Physical Pressure drive_____
Partial Pressure drive _____
Conduction
Gas exchange
Flow governed by
Poiseuilles’ s Law
Turbulent flow occurs with increased velocity, tube diameter, and gas density.
Describe transitional flow
A mixture of laminar and turbulent , occurs at branch point of the airways,
In Trachea and larger airways either turbulent or transitional
Found in smallest airway is________Flow
laminar
REVIEW Pressure in the potential space between the parietal and visceral pleura is___________
• Pressures are generated by the movement between the lung and chest wall
– The lung tends to________ its volume due to inward elastic recoil
– The chest wall tends to________its volume due to outward elastic recoil
normally subatmospheric around -3 to -5 cm H2O
decrease; increase
**difference in volume & compliance leads to a
**Difference in ventilation
***** Difference in ventilation can be due to
difference in volume and compliance
Are all alveoli in the lower lung ventilated equally?
which alveoli receive more ventilation per breath?
NO
Base receive more ventilation than the alveoli in the upper regions of the lungs.
The influence of gravity on a supported structure is called
Dependency
Dependency accounts for
Regional differences in alveolar ventilation (dependent vs nondependent)
Effective gas exchange depends on what
Approximately even distribution of gas (ventilation) and blood (perfusion) in all portions of the lungs (V/Q)
Ventilation and perfusion depend on
body position.
If a standing individual assumes a supine or side lying position–> which are best ventilated?
The areas of the lungs that are the most dependent becomes the best ventilated and perfused?
If a standing individual assumes a supine or side lying position–> which are best ventilated?
The areas of the lungs that are the most dependent becomes the best ventilated and perfused
Distribution of perfusion in the pulmonary circulaton also is affected by
ALVEOLAR PRESSURE (gas pressure in the alveoli)
how does the pulmonary capillary bed differs from systemic capillary bed?
It is surrounded by gas containing alveoli.
what happens when the gas pressure in the alveoli exceeds the blood pressure in the capillary
the capillary collapses and flow ceases.
Zone I
PA>Pa>Pv
Zone II
Pa>PA>Pv
Zone III
Pa>Pv>PA
PA
Alveolar pressure
Pa
arterial pressure
Pv
venous pressure
Zone 1 =
Increased Pa, compressed arterioles = V without Q deadspace.
__________Determine rate of diffusion of each gas and
gas exchange between blood and alveolus
Partial pressures (as well as solubility of gas)
****What is elasticity
When lungs are inflated, there is a tendency to _________
Tendency of the lung tissue to return to its original position after an applied force has been removed
- When inflated, there is a tendency to recoil to a smaller unstressed volume
*****To keep the lungs inflated
an opposing pressure difference is required, provided by chest wall and respiratory muscles,
The difference between the two curves is called
hysteresis
The lung always retains some residual air, and even in forced expiration, ________would prevent further air loss
small airway closure and trapping
Accentuates collapse Airway
Bernouilli effect
When air enters a constriction, the linear velocity _____and pressure _______
increases; decreases
**COMPLIANCE : opposite of _______
It is a measure of __________ of the lung
Mathematically it is the change in _________divided by the change in ______Pressure . Volume in ____and pressure is in _______
Chest wall compliance is the opposite of elasticity, it is a measure of the distensibility of the lung. Mathematically it is the change in lung volume divided by the change in recoil pressure, where change
in volume is in liters and change in pressure is in cm H20
1 cm H2O
98.07 Pa= 0.735559 mmHg
Factors reducing compliance
Low volume
Fibrous tissue
Atelectasis and
Increases in surface tension
Factors affecting Airway resistance
Diameter
Flow
Density
Poseuilles Law
______or ______That affect recoil include _______
Age, pathologies (pulmonary fibrosis)
How do you calculate MINUTE VENTILATION (Ve)?
Ve = Vt x f Ve = minute ventilation Vt= Tidal volume f = frequency or RR
Calculatons - Alveolar minute ventilation (VA) formula
V(A) = (Vt - VDs) x RR
V(A)= alveolar ventilation
Vt =Tidal volume
V ds = Physiologic dead space 1ml per POUND of IDEAL body weight
anatomic ds =__________
mechanical ds =_________
alveolar ds =________
physiologic ds =________
conducting airway
ventilator machine circuit, ET tube, etc
nonperfused alveoli (usually nominal)
the sum of anatomic & alveolar ds
If you want to increase alveolar ventilation, should you
increase respiratory rate or tidal volume?
Which is more affective at increasing alveolar ventilation? increasing TV or increasing frequency? why?
Increasing frequency while maintaining a constant volume results in proportional increase of both alveolar ventilation and dead space
Increasing tidal volume while maintaining constant frequency results in no change to dead space but an increase in alveolar ventilation
Answer: increasing tidal volume is more effective to increase VA than increasing breathing frequency
Age effects
Decreased alveolar elasticity/ lung compliance
higher residual volume
Loss of alveolar surface area
Decreased pulmonary perfusion.
Pathological Disorders : RESTRICTIVE (PISAM)
Decrease compliance and vital capacity PISAM Pulmonary fibrosis sarcoidosis Interstitial lung disease Myasthenia Gravis ALS
Pathological Disorders : OBSTRUCTIVE
interfere with airflow, expiration requires more effort o ris less complete ACE Asthma COPD Emphysema
REVIEW Composition of air is a mixture of gases and
At sea level?
each contributes to its partial pressure
At sea level 1 atm of pressure = 760 mmHg
Nitrogen constitutes 78.6% at the atmophere
REVIEW Partial pressures as well as _____________ determine ____________of each gas and __________between blood and alveolus
solubility of gas
Rate of diffusion
Gas exchange.
Henry’s law: amount of gas that dissolve in _______is determined by its _________in water and its __________
– amount of gas that dissolves in water is
determined by its solubility in water and its
partial pressure in air
Factors affecting gas exchange
Concentration gradient Gas solubility Membrane thickness Surface area Ventilation perfusion coupling --> are O2 has increased conc. gradient CO2 has increased solubility
Ventilation perfusion coupling
Areas of good ventilation need good perfusion
Oxygen transport: Concentration in arterial blood
- 5% bound to hemoglobin
1. 5% dissolved
Explain binding to hemoglobin
each heme group of 4 globin chains my bind O2
Oxyhemoglobin (HbO2)
Deoxyhemoglobin (HHb)
Oxygen Transport : Oxyhemoglobin Dissociation curve
Relationship between hemoglobin saturation and PO2 is not a simple linear one
after binding with O2, the shape of hemoglobin change to make it easier for further UPTAKE (which is a positive feedback cycle)
Factors decreasing affinity (RIGHT SHIFT)
CADET face Right C increased PCO2 A Acidosis (decreases pH) D 2,3 DPG high E Exercise T Temperature, High
Curve: x axis and y-axis is
PaO2; SaO2
Factors increasing affinity (left shift)
Alkalosis Decreased PCO2 Low level 2,3 DPG Carboxyhemoglobin Methemoglobin Abnormal hemoglfon
CO2 transport
Carbonic acid - 70%
Carbaminohemoglobin - 23%
Dissolved gas 7%
Review CO2 loading GAS exchange at tisses systemic
Carbonic anhydralase in RBC catalyzes • CO2 + H2O →H2CO3 → HCO3- + H+ Chloride shift: Keep reaction proceeding O2 unloading : H+ binding to HbO2, decreased affinity for O2 (hb arrives 97% saturated, leaves 75% saturates, venous reserve Amount of O2 released in 22%
Review Gas Exchange at lung (alveolar)
– as Hb loads O2 its affinity for H+ decreases,
H+ dissociates from Hb and bind with HCO3-
• CO2 + H2O ←H2CO3 ← HCO3- + H
-Reverse Chloride shift
• HCO3- diffuses back into RBC in exchange
for Cl-, free CO2 generated diffuses into
alveolus to be exhaled
What is essential for the generation of the respiratory rhtynm? it is part of what respiratory group?
Pre Botzinger complexv
ventral respiratory group
FRC (functional residual capacity)
is the volume remaining in the lungs at the end of a normal tidal expiration.
Compliance
Change in V / Change in P
What affects recoil
Age and pathologies
