Physiol Lab Quiz 4: Labs 10,11,12 Flashcards
Describe the following volumes: tidal volume
Tidal volume (TV): The amount of gas inspired or expired in an unforced respiratory cycle
— In other words… the normal amount of air in and out at rest
* = 500 mL
Describe the following volumes: inspiratory reserve volume
Inspiratory reserve volume (IRV): The maximum volume of gas that can be inspired during forced breathing in addition to tidal volume
— In other words… after a normal breath in, the IRV is the EXTRA air that could be breathed in
Describe the following volumes: expiratory reserve volume
Expiratory reserve volume (ERV): The maximum volume of gas that can be expired during forced breathing in addition to tidal volume
— In other words… after a normal breath out, the ERV is the EXTRA air that could be breathed out
Describe the following volumes: residual volume
Residual volume (RV): The volume of gas remaining in the lungs after a maximum expiration
— In other words.. the air that still in the airway
Describe the following capacities & name the volumes of air each capacity consists of: total lung capacity
Total lung capacity (TLC): The total amount of gas in the lungs after a maximum inspiration
TLC = TV + IRV + ERV + RV
Describe the following capacities & name the volumes of air each capacity consists of: vital capacity
Vital capacity (VC): The maximum amount of gas that can be expired after a maximum inspiration
VC = TV + IRV + ERV
Describe the following capacities & name the volumes of air each capacity consists of: inspiratory capacity
Inspiratory capacity (IC): The maximum amount of gas that can be inspired after a normal tidal expiration
IC = TV + IRV
Describe the following capacities & name the volumes of air each capacity consists of: functional residual capacity
Functional residual capacity (FRC): The amount of gas remaining in the lungs after a normal tidal expiration
FRC = ERV + RV
Calculate percentage change (percent increase or percent decrease)
% change = [ (new-old)/old ] x 100
- % increase = positive number
- % decrease = negative number
Calculate percent predicted
% predicted = (actual/expected) x 100
Distinguish hypoxemia vs. hypoxia
Hypoxemia: When oxygen partial pressure goes below 60 mmHg in the BLOOD; deficiency of O2 in blood
Hypoxia: Hypoxia is the lack of oxygen in tissues
Memorize the carbonic acid reaction
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
Describe the law of mass action
— If we have A LOT of CO2 (hypoventilation), the chemical equation (carbonic acid reaction) will be driven to the RIGHT, forming more H+ ions, which will decrease pH, making it more acidic (pH < 7); higher concentration
— But if we have TOO LITTLE CO2 (hyperventilation), it will drive the equation to the LEFT, reducing the amount of H+ ions (increasing the pH) and making it more basic (pH > 7); lower concentration
Memorize the pH range classified as acidosis vs. alkalosis
Normal blood pH is 7.4
* Acidosis: anything LOWER than 7.35
* Alkalosis: anything GREATER than 7.45
Which muscles contract during eupnea?
ONLY your diaphragm and external intercostal muscles are contracting and relaxing
Which additional muscles contract during forced respiration and during what part of forced respiration?
Forced respiration: when you are breathing deeply and rapidly
— Forced inspiration:
* Scalenes
* Sternocleidomastoid
* Pectoralis minor (elevates the ribs/widen the rib cage)
~ This increase the thoracic volume, while decreasing the pressure of the thoracic cavity
— Forced expiration:
* Internal intercostals (depress and decrease the lateral volume of the rib cage)
* Abdominal muscles (push the abdominal viscera against the diaphragm, further reducing the volume of the thoracic cavity)
~ This increases the pressure and forces air to flow out of the lungs
With the following values: TV=500ml; IRV=1.5L; ERV=2L; RV=1L ; what are the different lung capacities? (Show your work)
* L for capacities
* mL for volume
Vital Capacity (VC) = TV + IRV + ERV
→ 500ml = 0.5L
→ 0.5L + 1.5L + 2L = 4L
Functional Residual Capacity (FRC) = ERV + RV
→ 2L + 1L = 3L
Inspiratory Capacity (IC) = TV + IRV
→ 500ml = 0.5L
→ 0.5L + 1.5L = 2L
Total Lung Capacity (TLC) = TV + IRV + ERV + RV
→ 500ml = 0.5L
→ 0.5L + 1.5L + 2L + 1L = 5L
What are the differences between restrictive vs obstructive disorders?
- Restrictive disorders: a decrease in vital capacity since the lungs cannot fully fill with air or there is damage that decreases the vital capacity. Even though the vital capacity is decreased, the rate of forced exhalation is normal
- Obstructive disorders: a slower rate of forced exhalation because of bronchoconstriction but can have a normal vital capacity
What test will you perform to test each type of disorder?
a. Restrictive disorder:
b. Obstructive disorder:
a. Restrictive disorder - Spirometry (vital capacity)
b. Obstructive disorder - By measuring the patient’s forced expiratory volume (FEV1), which is the percent of vital capacity that is exhaled within the first second
What is the chemical equation to form carbonic acid?
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
What happens to the chemical equation when you hold your breath?
Holding our breath = LOTS of CO2; the chemical equation will be driven to the RIGHT, forming more H+ ions, which will decrease pH, making it more acidic
H2O + ↑CO2 → (↑) H2CO3 → (↑)H+ + (↑)HCO3-
Distinguid hypocapnia vs hypercapnia
Hypocapnia - not enough CO2; less than 37 mmHg
Hypercapnia - too much CO2; greater than 43 mmHg
What condition(s) might occur if you hold your breath for too long in regards to:
a. pH
b. CO2
c. O2
a. pH - ↓ pH ; Respiratory acidosis
b. CO2 - ↑ ; Hypercapnia
c. O2 - ↓ ; Hypoxemia
What are the normal values for pH, CO2, and O2? What is normal saturation of oxygen in hemoglobin in arterial blood?
- pH - 7.4
- CO2 - 37-43 mmHg in arterial blood
- O2 - 95 mmHg in arterial blood; around 40 mmHg in venous blood
— The hemoglobin of erythrocytes is typically at 97% or 98% saturation of oxygen in arterial blood
Name the enzyme that catalyzes the reaction to form carbonic acid
Carbonic anhydrase
How does breathing deeply and quickly affect the chemical equation for carbonic acid when we breathe deeply and quickly?
Decrease in CO2 concentration, decreases carbonic acid concentration, which decreases concentration of H+ & HCO3- , which increases pH.
H2O + ↓CO2 ← H2CO3 ← (↓)H+ + (↓)HCO3-