Respiratory System Normal Function Flashcards
Internal (Cellular Respiration)- The Whole Point
Intracellular Respiration: AKA _____ ______ refers to the utilization of ___ and energy substrates (____) to produce energy in the form of (2), (1) is a byproduct
IS THE PURPOSE OF _______ _______
Cellular Metabolism, O2 and Food -> energy in form of ATP and Heat, CO2 byproduct
EXTERNAL RESPIRATION
External Respiration
=
External Respiration is there to meet the needs of Internal Respiration
Delivery of O2 from external environment to the site of cellular respiration and the removal of CO2 from site of cellular respiration into external environment
General Anatomy of Thoracic Cavity
Superior Margin:
Inferior Margin:
Encased by (2)
Clavicles
Diaphragm
Rib Cage and Diaphragm on bottom
Air Tight Seal
Purpose:
- (1): lines cavity of each lung (sits against lung tissue)
- (1): Membrane that sits against thoracic cavity wall and diaphragm
- (1): Fluid that sits between these two membranes
To create a lower pressure than atomospheric and abdominal - critical in maintaining inflation of lungs and breathing
- Visceral Pleura
- Parietal Pleura
- Intrapleural Fluid
General Anatomy
- Airway Flow =
- (1): Largest main airway that’s supported by (1)
- (1): voice box
- (1): lose rings of cartilage and have smooth muscle surrounding walls
Mouth and Nose -> Pharynx -> Larynx -> Trachea -> bifurcates into right and left bronchus -> Bronchioles -> Terminal bronchiole -> Respiratory Bronchiole -> Alveoli
- Trachea, rings of cartilage
- Larynx
- Bronchioles
Bronchioles
- (1): last bronchiole before gas exchange
- (1): where gas exchange starts (have some alveoli coming out of it)
- Site of Gas Exchange:
- Terminal Bronchiole
- Respiratory Bronchiole
- Respiratory Bronchioles and Alveolar Sacs (specifically at pulmonary capillaries)
Alveolar Microanatomy
- (1): Composed of flat endothelial cells that form wall of capillary, contain ___ (around same diameter - keeping it close to cap wall to minimize ____ ____)
- Type I Alveolar Cell:
- Type II Alveolar Cell:
- Alveolar Macrophage:
- Pulmonary Capillary: RBCs - minimize diffusion distance
- Pink flat cells that form walls of alveolar sacs
- responsible for producing Pulmonary Surfactant (substance that acs as detergent: reduces surface tension of water vapor (that likes to stick together) in alveolar sacs - prevents collapse
- Phagocytizes any inhaled debris, dust, pathogenic organisms
Gas Exchange
Movement of gases (O2 and CO2) across the alveolar and capillary walls
- Accomplished via?
- The direction of diffusion determined by?
- Passive Diffusion
- Partial Pressure Gradients: measure of concentration of gas
Mixture of Gases in Atmospheric Air
Atmospheric Pressure =
79% _____
21% _____
Trace amounts of __, __, and other ____
760mmHg (total pressure at sea lvl)
Nitrogen
Oxygen
CO2, H20, gases
Partial Pressure of Gases That Make up Atmospheric Air
- Partial Pressure of N2 in Atmospheric air: PN2 = 760 x 0.79 = ____ mmHg
- Partial Pressure of O2 in Atmospheric air: PO2 = 760 x 0.21 = ____ mmHg
- PCO2 = ____ mmHg (so small bc like we said there are only trace amounts)
- 600
- 160
- 0.03
Air in Lungs is Humidified
PH2O =
PN2 =
PO2 =
- Since we are trying to get oxygen from alveolar space into the blood: partial pressure of O2 in alveolar space must be ____ than partial pressure of O2 in blood at site of gas exchange
- O2 mixes with ____ ____ after inhalation -> dilutes air that we take in -> ___ PN2 and PO2
47
563 (from 600)
150 (from 160)
- higher
- water vapor -> decreases PN2 and PO2
Partial Pressure of Air in Alveoli
PO2 in Alveoli =
Less than __% of air in alveolar space is fresh air
- Air that comes in gets ____ by air that was taken in by previous breaths -> and that air going to have higher __ concentration bc it moves from blood into alveolar space
- Advantage of 15% turnover is air in the alveoli remains at 100mmHg whether you are breathing restfully in or out so at all time periods oxygenation in alveolar sacs is ____ -> gas exchange can happening at all times
- If you hold your breath for long period of time PO2 can go ___ (won’t go down in a few secs)
- If your exercise PO2 in alveolar sacs can go __
100
15%
- diluted, high CO2
- stable
- down
- up
Partial Pressure Gradient for Oxygen
Alveolar PO2 constant from inhalation to exhalation bc (2)
Partial Pressure Gradient = __ mmHg
- PO2: ____ (outside) -> ____ (in airways) -> _____ (in alveoli)
- PO2 of deoxygenated blood in pulmonary capillary space = __
- PO2 of oxygenated blood going back to heart through pulmonary vein = __
- only 15% “Fresh air”
- O2 diffusing into blood
60 mmHg
- 160 -> 150 -> 100
- 40
- 100
Partial Pressure Gradient for Carbon Dioxide
- PCO2 in deoxygenated blood = ___
- PCO2 in alveolar space = ___
- PCO2 of oxygenated blood going back to the heart = ___
- Partial Pressure Gradient = ___
So why does our body hold onto more CO2 then the amount in the environment?
- 46
- 40
- 40
- 6
To maintain healthy pH balance
Aspects of the Diffusion Barrier
Diffusion during gas exchange is governed by the following relationship:
Amount of gas transported = _____/_____ x _____
- 3 aspects of ficks law
- increased SA -> _____ diffusion
- increased Partial Pressure -> _____ diffusion
- increased thickness of barrier -> _____ diffusion
- Lungs are highly _____ to maximize diffusion based on these factors
Surface Area/Thickness of Diffusion Barrier X (partial pressure gadient)
- Fick’s Law
- increased
- increased
- decreased
- adapted
Surface Area Available for Gas Exchange
Total SA of lungs = ___ m2
Compared to SA of ___ m2 if lungs were just hollow sacs of air
- So big due to ______/anatomy of lungs: ____ pattern of airway branches into smaller and smaller branches then alveolar sacs
75m2 (size of tennis court)
- 01m2
* arrangement: branch pattern
Thickness of Diffusion Barrier
- Thickness of diffusion barrier is very ____ in pulmonary system
- Total thickness of this barrier = ___ micrometers (50x thinner than paper)
- List of everything that stands between blood and alveoli (6)
- small
- 0.5
- Layer of surfactant
- Alveolar epithelial cell
- Interstitial space
- Capillary endothelial cell
- Plasma
- RBC membrane
Alteration Diffusion
- Examples of Altered
- Surface Area (1)
- Thickness of Diffusion Barrier (1)
- Partial Pressure Gradient
- Decreased Atmospheric PO2 (_____)
- Decreased ____ of O2 to alveoli
- Reduced # of functional alveoli
- Thickening from Scar Tissue
- Altitude
- Delivery of O2
Oxygen Carriage by Blood - Gas Transport
Oxygen is carried by blood in one of two ways + what percentage?
(2)
- 1.5% Physically Dissolved in Plasma (O2 is very poorly soluble in plasma)
- 98% Chemically Bound to Hemoglobin
Hemoglobin
- Hemoglobin (Hb) is a large intracellular ____ - RBCs
- ____ subunits each with a ____ containing ____-group
- Each heme-group can _____ bind one O2 molecule
- One hemoglobin can carry up to ___ O2 molecules
- ______ = when unbound to oxygen
- _____ = when bound to oxygen
- protein
- 4 subunits, iron containing Heme-group
- reversibly
- 4
- Deoxyhemoglobin
- Oxyhemoglobin
Structure of Hemoglobin Protein
- (1): Upper Chains
- (1): Lower Chains
- (1): that contains iron: in center of each unit that acts as ____ sites of oxygen
- 4xO2 = _____ Hgb
- And once one O2 binds to Hgb it alters the ____ of Hb to ____ bind to last 3 so you ____ find unsaturated Hb -> and vice versa if one comes off then the rest easily come off too
- Beta Chains
- Alpha Chains
- Heme Group - iron -> binding sites of oxygen
-
Saturated Hb
- structure, easily, rarely find unsaturated
Hemoglobin Oxygen Binding
The main factor that determines the binding of O2 to Hb is the ___
- When all 4 O2 binding sites on Hb are occupied, Hb is ____ _____
The % of Hb saturation is determined by the ___ of blood
- This relationship is simply a matter of ___ ____
- Hb + O2 <-> HbO2
The relationship between PO2 and %Hb saturation is NOT _____
PO2
- fully saturated
PO2
- Mass Action
NOT LINEAR
PO2 (partial pressure of O2 in plasma) is the main factor that determines binding of O2 to hemoglobin - bc determines the amount of O2 actually available to actually bind to Hgb
Is a reversible reaction: when there is low O2, oxyhemoglobin tends to unbind from O2
Hemoglobin Dissociation Curve
- At _____ levels of blood PO2, relationship is much more steep
- Upper levels of blood PO2, relationship is more ____
This difference is highly adapted for Hb’s Job
- Hb job in the lungs is to bind to O2, so under conditions of high PO2 in ____ capillaries it binds to O2 very tightly and doesn’t let go as it leaves the lungs, when it gets to tissues it readily ____ of O2
- Pulmonary Cap PO2 __-__
- Systemic Cap PO2 ~__
- lower
- flat
- pulm cap tightly, in tissues lets go
- 95-100
- ~40
Local Metabolic Changes also affect %Hb Saturation
-
Right Shift Curve when ____ Metabolic Activity
- CO2 =
- Acidity =
- Temperature =
- Result:
-
Left Shift Curve when _____ Metabolic Activity
- CO2 =
- Acidity =
- Temperature
- Result:
- Conclusion:
-
Higher Metabolic Activity
- Higher (more metabolically active tissue)
- Higher (production of lactic acid)
- Higher
- Lower Hgb saturation bc Hb lets go of even more O2 to metabolically active tissues
-
Lower Metabolic Activity
- Lower
- Lower
- Cooler
- Higher Hgb saturation bc tissue doesn’t need it right now
- Hb delivers more O2 to tissues that need it the most and less O2 to tissues that need it the least
Carbon Dioxide Carriage by Blood
(3)
And percentages
- 10% Physically dissolved in blood (CO2 is higher in plasma bc more polar-again depending on PCO2 of plasma)
- 30% Bound to Hemoglobin (binds to actual protein not the heme groups - doesn’t compete with O2)
- 60% in the form of Bicarbonate (HCO3-)
Haldane vs. Bohr Effect
Haldane Effect:
Bohr Effect:
- Describes how oxygen concentrations determines hemoglobins affinity for carbon dioxide
- When CO2 does bind to hemoglobin it reduces its affinity for O2, part of the mechanism above that as CO2 lvls rise, Hgb tends to let go of O2
Carbon Dioxide in the Form of Bicarbonate
- CO2 diffuses across RBC membrane and in the presence of (1) has to interact with (1) to form (1) -> which ionizes into 3H and (1) - all happening in the RBC
- HCO3 exits and enters plasma through a?
- H20 -> Carbonic Anhydrase -> Carbonic Acid -> Bicarbonate HCO3-
- Secondary Active Transport Exchanger with Cl
Carbon Dioxide in form of Bicarbonate (Notes)
- In Deoxygenated blood, CO2 ____ in plasma and you get ____ reaction
- In Oxygenated blood, CO2 is getting _____ you get ____ reaction forming CO2 and leaving the cell
- Chloride shift:
- climbs, forward reaction
- removed, reverse reaction
- CL is pushed back and forth in and out of the cell
Mechanics of Ventilation and Breathing
Air moves down a pressure gradient
- Negative gradient = ______
- Positive gradient = _______
Natural state of lungs is to be in a _____ position
But in a healthy individual, they are in _____ position bc of unique ______ arrangement of thoracic cavity
- Inhalation
- Exhalation
collapsed
inflated, anatomical
Anatomical Arrangement of Thoracic Cavity
-
(1): Serous membranes (sheets of connective tissue that produces fluid) line each lung
- (1): lines the lungs
- (1): lines the interior of the thoracic cavity (
-
(1): fluid that fills intrapleural space in between these two membranes
- There should not be air in this space, only this water based fluid - and water has a special property known as
- (1): water molecules in solution are attracted to each other and sticks to itself -> if you were to pull water molecules aparty they would resist that like ____ -> Keeps lungs ____ by causing lungs to stuck to cavity _____
-
Pleural Membranes
- Visceral Pleura
- Parietal Pleura
- Pleural Fluid
- Surface Tension -> GLUE, INFLATED, WALL
Any break in plueral membranes -> lung collapses (pneumothorax)
Three Different Pressures
- Atmospheric Pressure =
- Intra-Aleolar Pressure =
- Intrapleural Pressure =
- Which way is air flowing?
- 760
- 760
- 756
Nowhere, pressures in atmosphere and alveoli are equal right now
Intrapleural Fluid Cohesiveness
=
Keeps Lungs ____
- Pressure in pleural space is 756
- Volume Pressure Relationship
- Greater volume (thoracic cavity expands) -> ___ pressure (inhalation)
- Less volume (thoracic cavity shrinks) -> ___ pressure (exhalation)
Water based intrapleural fluid sticks together like glue to
Keep Lungs Inflated
- Volume Pressure Relationship
- Less pressure (more volume)
- More pressure (less volume)
Transmural Pressure
Keeps lungs ____ and chest _____
Transmural pressure gradient across lung wall = (1) - (1)
Transmural pressure gradient across thoracic wall = (1) - (1)
lungs inflated, chest compressed
Intraalveolar pressure - Intrapleural pressure
Atmospheric pressure - Intrapleural pressure
Major Muscles of Inhalation
(2)
Which are innervated by which nerves?
External Intercostal Muscles - Intercostal nerves
Diaphragm - Phrenic nerve
Muscles of Inhalation (Notes)
- The way we expand the thoracic cavity is by _____ muscles that increase thoracic cavity volume
-
(1): big flat muscle that represents boundary between abdominal and thoracic cavity
- When contracting, becomes ____ and increases _____ dimension of cavity
-
(1): muscles that sit between ribs, oriented in a crisscross pattern where internal intercostal muscle moves one way and this one moves the opposite way
- When contracting, external muscles ____ the rib cage and increases _____ circumference
-
(1): big flat muscle that represents boundary between abdominal and thoracic cavity
- During rest, we have mild contraction of these movements (subtle movements of chest when we sleep)
-
contracting
-
Diaphragm
- flat, vertical
-
External intercostal muscles
- lift, transverse
-
Diaphragm
Before Inspiration
External intercostal and diaphragm muscles are _______
Net movement of air =
Relaxed
No net movement
During Inspiration
What happens to both intraalveolar and intrapleural pressure?
Both pressures drop
Accessory Inspiratory Muscles Involved in Forceful Inhalation
(2)
Both muscles help expand thoracic cavity by?
Sternocleidomastoid
Scalenus
By lifting the clavicle and sternum (skin sucks in the middle of neck and sides of clavicles - is very apparent when in use)
Passive Expiration
Muscles are just ______
Pressure goes ___ in lungs as they recoil (get smaller) to push air out
Relaxing
up
Muscles Involved in Forceful Exhalation
(2)
And how do these muscles function to forcefully exhale?
Internal Intercostal Muscles: pulls down on rib cage (trying to shrink it)
Abdominal Muscles: push viscera and diaphragm up and into thoracic cavity
Breathing is Rhythmic
What muscle drives this rhythmic activity?
Diaphragm that is innervated by the phrenic nerve
The Phrenic and Intercostal Nerves Terminate in the Spinal Cord
- Intercostal Nerves - ______ Spinal Cord
- Phrenic Nerve - _____ Spinal Cord (3)
- Thoracic
- Cervical C3, 4, 5
Cell bodies of phrenic nerve sit high in C3, 4, 5 - so spinal cord injuries that are high above C3, 4, 5 that person will lose voluntary and involuntary contraction of diaphgram and rely on mechanical ventilation
Respiratory Control Centers in Brain Stem
(2) (3) (2)
Where ______ control of respiration originates
Which Center is MOST IMPORTANT?
-
Medullary Respiratory Center
- Pre-Botzinger Complex
- Dorsal Respiratory Group
- Ventral Respiratory Group
-
Pons Respiratory Centers
- Pneumotaxic Center
- Apneustic Center
Involuntary
Medullary Respiratory Center
Medullary Respiratory Center
- Pre-Botzinger Complex:
- Dorsal Respiratory Group:
- Ventral Respiratory
- Restful breathing flow:
- Forceful breathing flow:
- Maintains the rhythmicity of breathing, controls the rate
- Controls muscles involved in restful breathing (diaphragm, external intercostal muscles)
- Controls accessory muscles
- Pre-Botzinger complex -> DRG -> muscles
- Pre-Botzinger complex -> VRG -> accessory muscles
Pons Respiratory Center
-
Pneumotaxic and Apneustic Center:
- Pneumotaxic center _____ inbreath
- Apneustic center _____ inbreath
- Both are usually active at the same time to fine tune breathing and adjust breathing based on _____ demands (exercise increases rate and depth of breathing)
-
Regulates and Fine tunes breathing by adjusting rate and depth of breathing by controlling duration of inhalation
- shortens
- lengthens
- metabolic
Pontine Control of Breath
- ___ ___ control of breathing + adjustment based on ____ information coming back from body about metabolic demands
- Normal RR =
- Normal Tidal Volume =
- When we exercise you need more oxygen -> metabolic demands change -> respiratory ___ and ____ also change
Control of Breathing
- Efferent control: originates at the ____ group being fine tuned by ___
- Feedback of metaboli demands coming into the brain from (3) pieces of info your brain gets to adjust breathing
- Top down, sensory
- 10-12
- ~500ml
- rate and depth
- medullary, pons
- PO2, PCO2, pH
Apneusis
A respiratory pattern that tends to occur after? characterized by?
Brain injury is doing 2 things
- Diminishing input from _______ center which ends up ____ of _____ center
- Interference in brains ability to ____ sensory input from the body (bc usually should be enough to maintain a normal RR)
severe brain trauma, long gasps followed by short exhalation
- pneumotaxic, increasing apneustic
- interpret
Pulmonary Receptors, Negative Feedback
(2)
Pulmonary Irritant Receptors (PIR)
Pulmonary Stretch Receptors (PSR)
All respond to both stretch and irritation but mainly respond to one more (day job + side job)
Pulmonary Stretch Receptors
=
- Found where?
- Minimally sensitive to?
- Hering-Bruer Reflex =
When lungs inflate too rapidly -> overinflation of lungs and injury of lung tissue
- bronchiole smooth muscle
- irritation
- Causes shallow rapid breathing when trying to exercise from 0-100 too quickly
Pulmonary Irritant Receptors (PIR)
=
- Located in ____ of airway - dispersed among _____ cells that line the airway (____ ____ epithelial cells)
- Less sensitive to?
- Response: Reflexive ________ and breathing pattern that looks like a ____ - designed to minimize exposure to irritant
-
(1): (not pictured) are irritant receptors and trigger the same reflex just located within (1) - juxta means next to capillary
- same function just more concerned with preventing damage to site of exchange and preventing absorption of harmful substance into bloodstream
Protects lungs from chemical injury such as ammonia (smoke)
- lumen, epithelial, ciliated columnar
- stretch
- Bronchoconstriction, gasp
- J “Juxtacapillary” Receptors- alveolar sacs
Like when someone smokes for first time, their chest tightens up and start to cough and can’t catch breath bc their activating these irritant receptors like crazy
Metabolic Changes that Adjust Breathing
(3)
- CO2 vs. O2, which one does our body care about more and why?
- pH: as ___ lvls rise, pH changes, also has a separate effect on breathing more related tot he contribution that the respiratory stem has in the body’s control of pH
PO2, PCO2, pH
- CO2 because directly reflects metabolic consumption and fluctuates more easily -> so by using CO2 to control breathing you’re allowing for the adjustment of breathing before you see a change in O2
- CO2
Chemoreceptors
(2)
=
Central Chemoreceptors
Peripheral Chemoreceptors
Receptors in the body that sense changes in PO2, CO2, pH
Central Chemoreceptors
Located within _____ in the respiratory center
- Don’t have direct access to blood so ____ measures composition of blood by using ___
Sensitivity to
- PO2 =
- PCO2 =
- pH =
Brainstem
- indirectly, CSF
- Weakly sensitive
- Highly sensitive
- No sensitivity at all to plasma pH (bc hydrogen ions cannot cross BBB)
Peripheral Chemoreceptors
Located at (2)
- (1): sensory endings measuring composition of blood in aorta
- (1): assessing composition of blood destined for brain
Sensitivity to
- PO2 =
- PCO2 =
- pH =
Aortic Arch, Carotid Sinus
- Aortic bodies
-
Carotid bodies
- Moderate sensitivity
- Weak sensitivity
- High sensitivity
Sensitivity Analysis of Peripheral Chemoreceptors
Peripheral chemo-receptors are the primary way our body senses ___ but arterial PO2 has to get to about __mmHg aka 92% to even respond or care
At this point, the _____ center stimulates increase in rate and depth -> this is a (1) mechanism
Does not contribute to ____ to ____ regulation of respiration
PO2, ,60mmHg
Medullary -> EMERGENCY, LIFE-SAVING
x moment to moment
Sensitivity Analysis of Central Chemoreceptors
Responsible for (1) regulation
- PCO2 represents what’s physically dissolved in _____
- Reason why its so important is bc it has to be dissolved in plasma before using it in the other (2) ways
- Only the CO2 that’s in the _____ can cross the ___ -> once CO2 crosses, it can form bicarb in the CSF and effect CSF’s __ which _____ chemoreceptors can sense
Moment to Moment*
- plasma
- Bound to Hgb, Make Bicarb
- plasma, BBB, pH, central
How Central Chemoreceptors Really do the Moment to Moment Regulation
Central chemo receptors indirectly measure blood (1) by directly measuring (1)
Which are ____ sensitive to changes in ____
Response: sense changes and stimulate ____ respiratory center, if increased PCO2 -> ____ rate and depth of breathing to blow ___ CO2
- Chronically High PCO2 (ie emphysema) effects:
- Rapid, Acute Increase in PCO2 effects:
indirectly measure PCO2 by directly measure pH of CSF
highly, PCO2
medullary, increased, blow off CO2
- central chemo receptors decrease in their sensitivity and stop responding
- represents injury to brain -> impaired function/suppression of respiratory function
Control of Arterial (H+)
2 sources of H+ concentration in circulation
- (1)
- (1)
- Peripheral Chemoreceptors are sensitive to __ and do not _____ between these two (any acidosis stimulates breathing) however
- Central Chemoreceptors are sensitive to ___ and will sense changes and respond before there is even a change in pH bc of multiple ____ systems
- CO2 derived acid in form of carbonic acid
- Non-CO2 Metabolically derived acid
- pH, differentiate
- PCO2, buffer
Example of Metabolically Derived Acid
(1)
- Uncontrolled and cannot get glucose into cells -> body breaks down fat as an energy source and byproduct of fatty acid metabolism in ____: results in ______ breathing (___ventilation) aka _____ compensation for metabolic acidosis
- This is sensed by the _____ chemoreceptors and is not doing it for the sake of respiratory control but of pH control
Type 1 DM
- ketones, Kussmaul’s (hyperventilation), respiratory
- Peripheral
Voluntary Control of Respiration
Breathing under both involuntary and voluntary control
- Which can override the other? What part of the brain?
- Non respiratory acts such as?
- Voluntary pathway can override the involuntary system, cerebral cortex
- Speaking, singing, whistling, coughing, sniffling, clearing throat
