Section 8 Flashcards
Functions of the Ventilatory system (2)
supply and eliminate air
regulate acid-base in acute fashion (bc it’s capable of buffering lactic acid).
Terms and definitions of ventilatory system (3)
Acid-base: regulate H+ concentrations
Ventilation: mechanical process of moving air into and out of the lungs. In other words, mechanically manipulating pressures and volumes to create pressure changes to allow movement of air.
Diffusion: movement of gases from a place with high concentration to a place with low concentration
Anatomy of ventilation (8)
- Air enters nose/mouth
- Abdominal cavity
- Pharynx
- Larynx
- Trachea (wind pipe)
- R and L Bronchi (primary entry for the lungs)
- Bronchioles (after bronchi branch)
- Alveoli (gas exchange occurs)
Characteristics of the lungs (3)
Large surface area (50−100m2 (½ tennis court))
Highly vascularized
600,000,000 membranous sacs
Characteristics of the alveoli (3)
Thin-walled
Elastic sacs
Thin walled blood transporting capillaries
Mechanics of Ventilation and their defs. (2)
Conduction Zone: filters, warms, and humidifies air (trachea, bronchi, bronchioles)
Respiratory Zone: gas exchange, surfactant production (respiratory bronchioles, alveolar ducts, and alveoli)
Inspiration during REST & EXERCISE
REST: the diaphragm really only needs to flatten.
EXERCISE: scalene and external intercostal muscles between ribs contract, causing ribs to rotate and lift up and away from the body. When the diaphragm descends, the ribs swing upward, and the sternum thrusts outward to increase the lateral and anterior-posterior diameter of the thorax.
Expiration during REST and EXERCISE
Rest: represents a passive process of air movement out of the lungs and results from two factors: (1) natural recoil of the stretched lung tissue (it wants to squeeze back down bc it doesn’t want to be stretched) and (2) relaxation of the inspiratory muscles.
Exercise: internal intercostal and abdominal muscles act powerfully on the ribs and abdominal cavity to reduce thoracic dimensions. This makes expiration rapid and more extensive.
Components of Static Lung Volumes and Capacities (6)
Tidal Volume (TV) Inspiratory Reserve Volume (IRV) Expiratory Reserve (ERV) Residual Volume (RV) Forced Vital Capacity (FVC) Total Lung Capacity
Tidal Volume (TV)
volume of air inspired and expired per breath
Inspiratory Reserve Volume (IRV)
volume of additional air you can inspire above the normal TV.
Expiratory Reserve (ERV)
volume of additional air you can expire below the normal TV
Residual Volume (RV)
volume of air left in lungs after max expiration
Forced Vital Capacity (FVC)
FVC = TV + IRV + ERV; max volume expired after max inspiration (forced inspire and expire; we live off this).
Total Lung Capacity
TV + IRV + ERV + RV, volume in lungs after max inspiration; how much air can go in the lungs at one time.
Describe mathematically/verbally how breathing rate/depth (shallow, normal, deep) influence alveolar ventilation
Equation: TV x breathing rate (breaths/min) = total minute ventilation – dead space minute ventilation (150mL) = alveolar minute ventilation
Shallow breathing: no gas exchange occurs; new air mixes with old stale air, and the alveoli can’t do anything with old air. 150 x 40 = 6000 – (150x40) = 0 alveolar vent.
Normal Breathing: slightly deeper, quiet breathings at rest. Breathing rate decrease, TV increases. 500 x 12 = 6000 – (150x12) = 4200 alveolar vent.
Deep breathing: deep, slow breaths; doubling TV and halving breathing rate. 1000 x 6 = 6000 – (150x6) = 5100 alveolar vent.
Ventilation during exercise
Low to moderate: ventilation increases linearly with O2 uptake and CO2 production, averaging 20-25L of air per L of O2 consumed. Mainly increases through increased TV.
High: point where Ventilatory Equivalent breaks linearity; minute ventilation increases sharply and increases disproportionately relative to increases in O2 consumption (sharp increase in Ve/VO2 ratio).
Cost of breathing during rest and exercise
Rest and light exercise: cost of breathing is small. Blood is better distributed to inactive areas. Of majority of the 84% of the blood that goes to muscles during exercise, at rest goes to muscles that help us breathe.
Maximal Exercise: relatively high; blood is diverted away from respiratory muscles to skeletal muscles being used. Respiratory muscles require a significant portion of total blood flow (up to 15% of 84%).
More well trained you become (better oxidative abilities involved in accessory muscles), less amount of blood needed for the accessory muscle, thus decreasing how hard you need to breath during exercise.
Force Expiratory Volume (FEV)
how much volume of air you can get out of your lungs in 1 second (FEV1).
FEV and FVC relationship
can tell us if breathing is normal, obstructed, or restricted. FEV1/FVC indicates pulmonary airflow capacity. It reflects pulmonary expiratory power and overall resistance to air movement stream in the lungs. Healthy individuals normally expel 85% of vital capacity in 1s.
Normal Example: you have inspired 5L of air. In 1s, I expire 4 L of the 5L (4/5 = 0.8 > 80%).
Abnormal Example (asthma): struggle to breathe and inspire only 3.1L of air. In 1s, I expire 1.3 or the 3.1L (1.3/3.1 = 0.419 > 42%)
Restrictive Example: Inspired 2.8L. In 1s, I expire 3.1L (2.8/3.1 = 90%
Partial pressure of gases equation
Partial pressure = % gas × total pressure of all gases
Concentration of respired gases
O2 = 20.93% (or 0.2093) = ~ 159 mm Hg PO2 CO2 = 0.03% (or 0.0003) = ~ 0.23 mm Hg PCO2 N2 = 79.04% (or 0.7903) = ~ 600 mm Hg PN2
Solubility of CO2 and O2 and how that impacts transport of the gases
CO2 solubility: most soluble (~25x more soluble than O2); ~10% is carried dissolved in blood.
Transport: 60% as bicarbonate (HCO3-), 30% as
carbaminohemoglobin, 10% dissolved in blood.
O2 solubility: more soluble than N2; ~1.5% O2 is carried dissolved in blood (majority of O2 is carried by hemoglobin.
Transport: 98.5% bound to hemoglobin (Hgb), 1.5%
dissolved in blood.
O2 Transport
98.5% of O2 chemically bound to Hgb (protein in RBC’s that transports 4 oxygen molecule).
O2 Carrying Capacity
Each gram of Hgb combines with 1.34LmL O2.
Amount of O2 transported depends on concentration of Hgb.
With normal Hgb levels, each dL of blood contains about 20 mL O2. Oxygen + Hgb = oxyhemoglobin; No oxygen bound = deoxyhemoglobin.
The main points about RBC’s at the tissues and lungs
PP 9, slides 10 and 12
Ventilation-Perfusion mismatch
Mismatch: occurs when ventilation and perfusion are distributed unevenly into each lung
Normal: 5L blood (2.5L goes into both the L and R lung) 5L of air (2.5L goes into both the L and R lung)
Mismatch: 5L of blood (1L goes into the L lung and 4L goes into the R lung) 5L air (4L goes into the L lung and 1L goes into the R lung)
Accounts for many gas exchange problems occurring in pulmonary disease and possibly during intense activity among highly trained endurance athletes.
Oxyhemoglobin dissociation curve describes what relationship
between the pressure of O2 and the binding to Hgb; or why Hgb would bind (load) with O2 and let go (unload) of O2 at tissue level.
*The O2 “loaded” in the lungs and “unloaded” in the tissues.
Increased temperature, decreased pH shift the curve which way? What is the negative and positive impact?
Increased temp., decreased pH shifts the curve DOWN and to the RIGHT
Negative: there is a decrease in saturation of Hgb with O2
Positive: the Hgb and O2 are not bound as tightly and the O2 is released to the skeletal muscle more easily.
Why does endurance performance suffer at altitude?
Altitude has little effect on events that last more than 2 minutes.
Events longer than 2 minutes see reduced performance.
Short-term altitude training decreases Vo2max.
When returned to sea-level, aerobic capacity remains slightly lower than pre-altitude aerobic capacity.
Describe acclimatization to altitude
refer to SG
Effects of training on minute ventilation
Exercise does not alter lung structure, it just makes the lungs and musculature stronger (like working out); thus, we become a more effective breather.
By becoming a stronger, more effective breather and strengthening respiratory muscles, at any given work period (rest to near maximal exercise), minute ventilation is decreased.
