What is the track of the Conducting Zone?
Nose > Nasal Cavity > Pharynx > Larynx > Trachea > Bronchi > Central Bronchioles > Terminal Bronchioles
What is the function of the conducting zone?
To Warm, humidify and purify air
What is the track of the Respiratory zone?
Respiratory Bronchioles > Alveolar Ducts, Surrounded by alveolar sacs, made of alveoli
What is the function of the respiratory zone?
This is where gas exchange occurs
What are the 3 parts of the pharynx?
- Nasopharynx- behind nose
- Oralpharynx- behind mouth
- Laryngopharynx- behind the larynx
What structures are located in the nasopharynx? And where does it start and stop?
- Pharyngeal tonsils
- Eustachian Tube
- Tubal Tonsils
- Start- internal nares, end uvula
What structure are located in the Oral pharynx, and where does it begin and stop?
- Palatine Tonsils (MALT)
- Starts- Uvula, Ends-Epiglottis
Where is the laryngopharynx? Where does it start and stop?
- Behind the Larynx
- Start-Epiglottis, end- Cardiac sphincter
Name the 9 pieces of cartilage found in the larynx
Epiglottis (1), Thyroid Cart. (1), Cricoid Cart. (1), Arytenoid (2), Corniculate (2), Cuneiform ( 2)
What is the type of cartilage found in the larynx?
Hyaline, except for the epiglottis which is elastic cartilage
What is the epiglottis also known as, and why?
- "the Guaridan of the Airways"
- Because it folds over the top of the larynx in order to make sure no food enters the larynx
What is "Adam's Apple"?
Laryngeal Prominence on the Thyroid Cartilage
Name the cartilage and the muscle on the trachea
- C-Rings: Hyaline cartilage
- Trachealis Muscle is on the posterior portion
What does the trachea divide into and where does this occur?
The Trachea divides into the Primary Bronchi at T4
What is the difference between the Right and Left Primary Bronchi?
- The Right has 3 secondary Bronchi and is wider,
- The Left has 2 secondary Bronchi and is narrow
- Particles are more likely to enter the Right
What are other names for the Primary Bronchi?
What are other names for the secondary bronchi?
What are names for the tertiary bronchi?
How many segmented bronchi are in each lung?
What does a Bronchi become a bronchiole?
When it's diameter= 1mm
What is the purpose of the trachealis?
When it contracts the trachea's diameter decreases therefore inreasing air velocity from the lungs
What are the 3 types of bronchioles?
- Central Bronchioles
- Terminal Bronchioles
- Respiratory Bronchioles
What is the function of the fissures in the lungs, and how many lobes are in each lung?
Fissures separate the lungs into lobes, The Right side has 3 and the left side has 2
Which lung has a cardiac notch?
What are the 2 types of cells found in the respiratory membrane?
- Type I Pneumocytes ( Simple Squamous)
- Type II Pneumocyte ( Cuboidal
What is the function of Type I Pneumocytes?
- Secretes Glycoproteins forming Basal Lamina
- Allows for gas exchange
What is the function of Type II Pneumocytes?
Secretes Surfactan, which reduces the surface tension on the alveoli to keep it expanded
What is the ratio of Type I and Type II penumocytes?
What is the pulmonary Capillary membrane made of?
Simple Squamous epithelium that ecretes basal lamina
What occurs between the Pulmonary Capillary membrane and the respiratory membrane?
Each secretes Basal Lamina which fuse together, connecting the two membranes
Where is the greatest resistance of airflow?
The Subsegmental Bronchi
What are the 4 types of respiratory Physiology Processes?
- Pulmonary Ventilation
- Internal Respiration
- External Respiration
- Gas Transport
What is Pulmonary Ventilation?
Breathing, movement of air in and out of the lungs
What is external respiration?
The exchange of gases between the pulmonary capillaries and the alveoli, O2 comes in, CO2 goes out
What is internal respiration?
The exchange of gases between the systemic capillaries and surrounding tissue. O2 goes out, CO2 comes in
What is the transport of gases?
The use of blood as a transporting device for gases between the alveoli and tissues
What is the Intrapulmonary/Intraaveolar Pressure?
- Pressure in the alveoli of the lungs
- Equals the ATM
What is the Intraplural Pressure?
- The pressure within the pulmonary cavity
- 4< Intrapulmonary Pressure
Why is Intraplural Pressure less than Intrapulmonary Pressure?
Because if the lung would collapse if the pressure was equalized or higher in the intraplura
What are the 2 types of lung collapse?
- Atelectasis- when the pressure in the iraplural and intrapulmonary equalizes
- Pneumothorax- when air penetrates the intraplural cavity
What are the accessory muscles for inhalation?
Scalenes, intercostals, sternocleidomastoid
What does Boyle's Law explain about Pulmonary Ventilation?
- Boyle's Law: +V, -P
- Diaphragm moves down, which creates more volume, which decreases pressure which allows for P gradient for airflow
What is the equation for gas flow?
Change in Pressure / Resistance
How does the Parasympathetic system affect airflow?
Constricts Bronchi, which increases resistance of airflow, which decreases Gas flow
How does the Sympathetic system affect airflow?
Dialates Bronchi, which decreases resistance of airflow, which increases gas flow
What is lung compliance?
Ability of the lung to stretch
What two factors influence lung compliance?
- Distensibility of the lung tissue
- Alveolar surface tenstion (levels of surfactan)
When would lung compliance decrease?
Fibrosis ( Scar tissue) or lack of surfactan
When would lung compliance increase?
What could increase surface tenstion in the lungs?
Less surfactan levels, high water molecule concentration
What is the equation for Internal Pressure of the alveoli?
2x Surface Tension / radius of alveolus
Is a large alveoli more likely to collapse than a smaller alveoli?
When is surfactan produced and why?
At the end of pregnancy, because there is no need for the lungs to be inflated while the baby is still in the womb
What are the different respiratory volumes you need to know?
- Breaths per min-12
- Tidal Volume (TV)- 500mL
- Expiratory Reserve Volume (ERV)- 1200mL
- Inspiratory Reserve Volume (IRV)- 3100mL
What are the different respiratory capacities you need to know?
- Total Lung Capacity(TLC)- 6000mL
- Vital Capacity (VC)- 4800mL
- Inspiratory Capacity(IC)- 4800mL
- Functional Residual Capacity (FRC)- 2400mL
What is Tidal Volume?
- Amount of air inhaled/exhaled with each breath under resting conditions
What is Inspiratory Reserve Volume (IRV)
- Amount of Air that can be forcefully inhaled beyond the Tidal Volume
What is Expiratory Reserve Volume (ERV)
- Amount of air that can be forecully exhaled beyond a normal tidal volume exhalation
What is Residual Volume (RV)
- Amount of air remaining in the lungs after a forced exhalation
What is the Total Lung Capacity (TLC)
- Sum of all Respiratory Volumes
- TV +IRV+ERV+RV
What is Vital Capacity (VC)
- Amount of air that can be expired after a maximum inspiratory effort
- TV + IRV + ERV
What is the inspiratory capacity (IC)
- Maximum amount of air that can be inspired after a normal expiration
- TV + IRV
What is the Functional Residual Capacity (FRC)
- Volume of air remaining in the lungs after a normal tidal volume expiration
What is the Minute Respiratory Volume?
- TV x Breaths per min
- (500mL) x 12 = 6000 mL/Breaths per min
What is the alveolar ventilation rate?
- (TV-Anatomical Dead Space) x Breaths per minute
- (500mL - 150mL) x 12 = 4200mL
What is anatomical dead space?
Volume of air trapped in Conducting Zone
What is Alveolar Dead Space?
A certain volume of air that has been removed from gas exchange, ex. Lung Collapse
What is Total Dead Space?
Anatomical Dead Space + Alveolar Dead Space
What does Henry's Law state?
When a mixture of gases comes into contact with a liquid, each gas will dissolve in proportion with it's partial pressure.
What determines the dissolvability of a gas into a liquid?
- Henry's Law
- Solubility coefficient
What determines the composition of Alveolar Gases?
- Exchanges going on between respiratory gases and pulmonary capillaries
- Humidification of air by conducting zone
- mixing of new and old gases
What is the difference between Nitrogen and Oxygen in terms of Henry's Law?
- Nitrogen dissolves the least in liquid
- Oxygen dissolves much better than Nitrogen
What determine's Alveolar gas composition?
- New gas mixing with old gas
- Humidification of air by conducting zone
- Exchanges going on in external respiration
What is external respiration?
Gas exchange between the alveoli and the pulmonary capillaries
What are the four factors influencing external respiration?
- Total Surface Area of the lung
- Thickness of the respiratory membrane
- Perfusion rates
- Partial pressure gradient of gases and gas solubilities
How does the Total Surface Area of the Lung affect External Respiration?
- The greater the surface area the greater the rate of external respiration
- The total surface area is around 90m2
How does Membrane Thickness affect External Respiration?
- The membrane is usually between .5um-1.0um.
- If the membrane is thicker gas exchange is more difficult
How does the Partial Pressure gradient of gases affect External Respiration?
- Po2 in the Venous blood is 40mmHG
- Po2 in the alveoli is 104mmHG
- Pco2 in Venous blood is 45mmHG
- Pco2 in alveoli is 40mmHG
- Gases flow doewn the partial pressure gradient
How does gas solubility affect external respiration?
Since the partial pressure gradient is CO2 is so small, CO2's high solubility allows for it to pass through the respiratory membrane into the alveoli
How does Ventilation Perfusion Matching affect External Respiration?
- The pulmonary capillaries constrict/dialate to redirect bloodflow to areas with high Po2.
- The Bronchioles constrict/dialate to redirect CO2 out of the lungs.
How long does it take for gas exchange to occur and how long is blood in the pulmonary capillaries?
Where does the biggest change in the Hemoglobin Saturation Curve occur?
Between 10%-70% O2 saturation
What is Po2 leaving the lung?
What is Arterial Blood's Oxygen content?
20mL of O2 per 100mL of Blood
How much oxygen is absorbed into the plasma?
How much oxygen is bound to the hemoglobin?
What is Hemoglobin's saturation at 104mmHG
How much O2 is given to the surround tissue per 100mL?
What is venous blood's saturation at 40mmHG
What happens if the hemoglobin saturation curve shifts to the right?
- -pH, +Pco2, +T, +DPG
- Hemoglobin's affinity for O2 decreases
What happens if the hemoglobi saturation curve shifts to the left?
- +pH, -Pco2, -T, -DPG
- Hemoglobin's affinity for O2 increases
What is the definition of affinity?
A natural liking for something
What is DPG
- Binds to deoxygenated blood, decreasing hemoglobins affinity for O2
What is the definition of Hypoxia?
Lack of Oxygen going to the tissues
What are the causes of Anemic Hypoxia?
- Abnormal Hemoglobin
- Abnormal Hemoglobin content
- Decreased Red Blood Cells
What are the different types of Hypoxia?
- Anemica Hypoxia
What are the causes of Ischemic Hypoxia
- Decreased Blood Flow to the tissues
- eg. Congestive Heart Failure-Inadequate Blood being pumped out of the heart
What are causes of Histotoxic Hypoxia?
- Adequate O2 content in the blood, but not enough O2 getting to the tissues
- eg. Metal Poisoning, Cyanide
What are the causes of Hypoxemic Hypoxia?
- Low O2 in the blood
- eg. Pulmonary Disease, problems with gas exchange
- CO poisoning
What are the three ways that CO2 is transported in the blood?
- Dissolved in the Plasma
- Attached to the globin
- Transported as Bicarbonate in the plasma
How much CO2 is dissolved into the plasma?
How much CO2 is attached to the globin?
How much CO2 is transported as Bicarbonate?
How does CO2 become HCO3-?
CO2 + H2O --> H2CO3 --> H+ + HCO3-
What is Carbonic Anhydrase?
An enzyme in the RBC that acts as a catalyst for CO2 to become HCO3-
What is the Bohr Effect?
H+ and CO2 bind to the hemoglobin causing the release of O2 ino the tissue, which allows for more CO2 to bind to the Hb
What is the Haldane Effect?
he ability for more CO2 to enter the hemoglboin to buffer H+ as more O2 leaves the hemoglobin
What occurs after HCO3- is created in the RBC?
HCO3- moves into the plasma, and to counteract the anion shift, CL- is moved in the RBC
What is the Chloride Shift?
When HCO3- moves in the plasma, and to counteract this anion change, Cl- moves into the RBC
What occurs first, the Bohr effect or the Haldane effect?
- Bohr Effect, so CO2 binds to the Globin
- Then Haldane, CO2 buffers the H+ as O2 leaves the body
Where are the two respiratory Centers located?
in the Brain Stem: Medulla Oblongata and Pons
What groups are present in the Medulla Oblongata?
- Dorsal Respiratory Group (DRG)
- Ventral Respiratory Group (VRG)
What is the Dorsal Respiratory Center in charge of?
What does the Dorsal Respiratory Center do in terms of inspiration?
- Stimulates Phrenic Nerve, which stimulates the Diaphragm
- Stimulates the Intercostal nerves which stimulate the External Intercostals
- Both of which cause inspiration
What does the Dorsal Respiratory Group do in terms of Pace setting?
Sets Eupnea (normal respiration rate)
What is Eupnea?
- Normal Respiratory Rate of 12 breaths per minute
- 3 sec- Expire, 2 sec-Inspire
When is the Dorsal Respiratory Group active/inactive?
- Active during Inspiration
- Inactive during expiration
What is the Ventral Respiratory Group responsible for?
- Inactive during normal respiration
- Active during Forced Expiration
What are the centers located in the pons?
- Pneumotaxic Center
- Apneustic Center
Where is the pneumotaxic center and what does it do?
- In Superior Pons
- Controls Smooth Breathing, inhibits DRG to allow for expiration
Where is the Apneustic Center and what does it do?
- Located in Caudal Pons
- Stimulates DRG to allow for inspiration
What are the Factors influencing Rate and Depth of Breathing?
- Pulmonary Irritant Reflexes
- Hering-Breuer Reflex
- Higher Brain Centers
- Chemical Composition of Blood
What occurs during Pulmonary Irritant Reflex?
Inhaled Debris/Toxins stimulate receptors in Bronchioles which send nerve impulses along Afferent nerve Fibers which cause Bronchiole constriction to prevent the debris from entering the lung, coughing
What occurs during a Hering-Breuer reflex?
- Protects against overexpansion of the lungs
- Visceral Pleura and conducting pathways have stretch receptors, when they are stimulated they inhibit Medulla and cause expiration
What occurs in the higher brain centers in terms of Rate and depth of breathing?
- Hypothalamus- Pain/Emotions > excites/inhibits resp. centers
- Cortex-Voluntary Control of Respiration
What occurs with Chemical Composition in terms of Rate and Depth of Breathing?
- Affected by Pco2, Po2, pH in arterial blood
- Central chemoreceptors and Peripheral Chemoreceptors
Describe the Central Chemoreceptors in terms of Rate and Depth of breathing
- In the Medulla
- Respond strongly to CO2 levels and pH
- Respond weakly to O2 levels
Describe the peripheral chemoreceptors in terms of the Rate and Depth of breathing
- Respond strongly to O2 levels
- Respond weakly to CO2 levels and pH
What is the main stimuli of breathing?
What is the average pH of blood?
What occurs in Cerebral Spinal Fluid in terms of increased CO2 levels?
CO2 in CSF + H2O > HCO3- + H+, there's no buffer in H+ so pH decreases, stimulating Central Chemoreceptors, stimulates respiratory Center, causes hyperventilation, decreases CO2 and increases pH
What is Hypercapnia?
What is Hypocapnia?
What is hyperventilation?
Increased rate of Breathing
What is hypoventilation?
Decreased rate of breathing