Flashcards in Bergdahl- Chapter 12 Deck (73):
what is the relationship between velocity of blood, blood flow, and cross sectional area ? what does this imply ?
velocity of blood= blood flow / CSA
meaning that it's faster in the aorta than in the capillaries because the capillaries have a huge CSA. This means there is more time for gas exchange in the capillaries, which is what we want
what is blood flow
Blood flow is the quantity of blood that passes a given point in the circulation in a given period of time
what is mean arterial pressure ? how is it calculated ?
pressure that propels blood to tissues
MAP = diastolic pressure + 1/3 pulse pressure
what is pulse pressure ? how is it calculated ?
Pulse pressure = difference between systolic and diastolic pressure
what is resistance ?
Resistance is the impediment to blood flow in a vessel.
Measure of amount of friction blood encounters with vessel walls, generally in peripheral (systemic) circulation
what is conductance ? how is it calculated ?
Conductance is a measure of the blood flow through a vessel for a given pressure difference.
Conductance = 1/Resistance
what is compliance ? how is it calculated ?
change in volume / change in pressure
how is cardiac output calculated ?
CO= HR x SV
how is (arterial) blood pressure calculated ?
BP= CO x TPR
what is total peripheral resistance ?
same as resistance
at what level does respiration occur (and not ventilation)
at the alveolar level. before that- pulmonary ventilation
what is external respiration
the gas exchange between lungs and blood
what is internal respiration
the gas exchange at cellular level
what is cellular respiration
utilization of oxygen by the cells to produce energy
what is pulmonary ventilation ?
process of moving and exchanging ambient air with lung air
between what two anatomical structures is the air filtered and humidified in pulmonary ventilation ?
between nose and mouth and bronchi (so in trachea and other dead spaces)
what are the pecularities of size and weight of lungs
they weigh 1 kg and have a volume of 4-6 L, meaning they are large in space but not in mass (lung tissue is only 10% solid)
what is gas transport due to ?
what is the number of alveoli we have in our bodies ? how does this number change ?
number grows, then plateau, then decrease
what do pore of Kohn within alveoli do?
disperse surfactant to reduce surface tension
what is surface tension ?
for a given volume, reducing the surface area as much as possible to enhance the "tightness" between water molecules
what does surfactant do ?
decreases surface tension
what does surfactant contain ?
lipoprotein mixture of phosholipids, proteins, and calcium ions produced by alveolar epithelial cells
the ventilatory system is divided in two parts, what are they ?
- conducting zones (anatomical dead space) trachea and terminal bronchioles
- transitional and respiratory zones: bronchioles, alveolar ducts, alveoli
what are the functions of conducting zones ? (6)
air transport, humidification, warming, particle filtration, vocalization, immunoglobulin secretion
what are the functions of transitional/respiratory zones ? (5)
gas exchange, surfactant production, molecule activation/inactivation, blood clotting regulation, endocrine function
what temperature will alveolar air be ?
the same in any weather condition due to warming in conducting zones
at what zone/ generation of bronchi does human lung tissue become a respiratory zone ? what happens to the CSA ?
16 to 17
CSA dramatically increases
what is Fick's law of diffusion ?
A gas diffusing through a tissue will have a rate
1) directly proportional to the tissue area, a diffusion constant, and the pressure differential of gas on each side of membrane
2) inversely proportional to tissue thickness
what does elasticity depend on ?
Q= F = change in P / R
formula for flow / cardiac output
what is Boyle's law ?
P1V1= P2V2 (pressure of gas inversely related to volume if temperature is constant)
inspiration during exercise, which muscles contract ?
scaleni and external intercostal muscles
ribs rotate and lift up and away
diaphragm lowers 10 cm
in exercise, inspiratory action will make the diaphragm, ribs, and sternum move in which manner ?
why do athletes bend forward from waist to facilitate breathing following exercise ?
promotes blood flow back to heart
minimizes antagonistic effects of gravity on the usual upward direction of inspiratory movements
expiration at rest- which muscle action ?
PASSIVE PROCESS from natural recoil of stretched lung tissue and relaxation of inspiratory muscles
when does expiration at rest end ?
when compressive force of expiratory muscles ceases, and intrapulmonary pressure decreases to athmospheric pressure
what muscles contract during expiration (exercise)?
internal intercostals and abdominal muscles act on ribs to push them down
what is tidal volume ?
air moved during inspiratory or expiratory phase of each breathing cycle
0.4-1.0 L / air per breath
inspiratory reserve volume
inspiring as deeply as possible following normal inspiration
2.5-3.5 L above inspired tidal air
expiratory reserve volume:
after normal exhalation, continuing to exhale 1- 1.5 L
forced vital capacity
total volume of air voluntarily moved in one breath
TV+ IRV+ ERV
4-5 L men
3-4 L women
residual lung volume
air volume in lungs remaining after exhaling as deeply as possible
0.8-1.2 L women 0.9-1.4 men
increases with age
what is the function of RV ?
prevents lungs from collapsing
allows uninterrupted gas exchange between blood and alveoli to prevent fluctuations
when does RV temporarily increase in exercise ? (2 reasons)
-closure of small peripheral airways
- increase in thoracic blood volume
what is stroke volume in exercise ?
150 mL (very small compared to total lung surface area)
what does dynamic lung volume depend on ?
1) maximum FVC of lungs
2) speed of moving a volume of air (breathing rate)
what does breathing rate depend on ?
lung compliance/ resistance of respiratory passages to air
what is forced expiratory volume ?
FEV (1.0) / FVC
measured over 1 second
reflects pulmonary expiratory power and overall resistance to air movement upstream in lungs
normative values for FEV1/ FVC
obstructive disease like asthma : delineation at 70 % or less
restrictive disease like fibrosis: over 85%
maximum voluntary ventilation
ventilatory capacity with rapid and deep breathing for 15 sec
usually 25% more than ventilation in maximal exercise
140-180 L/min men
80-120 L/min women
gender differences in lung measure
women have :
reduced lung size and airway diameter
smaller diffusion surface
smaller static and dynamic lung measures
what are the consequences of gender differences in lung measure ?
greater respiratory muscle work and use of reserve for women
smaller lung volume + high expiratory flow rate places demand on system affecting oxygen exchange
what are the limitations of dynamic lung function tests ?
they indicate severity for obstructive and restrictive diseases but dont provide a lot of info for those in normal range about aerobic fitnesss
would regular endurance exercise stimulate large increases in functional capacity of pulmonary system ?
nope not really
what two variables can predict expected avg lung function ?
age and stature
what is minute ventilation ?
volume of air breathed each minute
what is the formula for minute ventilation ?
Ve= breathing rate (12 bpm) x tidal volume (0.5 L)
how can minute ventilation be increased ?
Ve= breathing rate x tidal volume, so with one or the other
breathing rate can increase to 35-45 bpm or 60-70 (elite)
tidal volumes rarely exceed what % of vital capacity ?
in the tidal volume inspired, what volume is anatomical dead space ? what happens to the rest ?
150-200 mL anatomical dead space
350 mL enters and mixes with alveolar air
what is alveolar ventilation ?
portion of inspired air reaching alveoli and doing gas exchange
what is ventilation perfusion ratio
ratio of alveolar ventilation to pulmonary blood flow
usually 0.84 meaning 4.2 L alveolar ventilation / 5 L pulmonary blood flow
what is physiological dead space
usually = anatomical
portion of alveolar volume with v/p ratio approaching 0
at what % dead space of lung does adequate gas exchange become impossible ?
in exercise, how do you maintain alveolar ventilation ? which variables change ?
Ve = breathing rate x tidal volume
they'll increase significantly tidal volume with only small increase in breathing rate
basically, they breathe deeper instead of panting
does modifying breathing style benefit exericise performance ?
what is hyperventilation ?
increase in pulmonary ventilation that exceeds O2 consumption and Co2 elimination needs of metabolism
what is dyspnea ?
shortness of breath
(fig 12.9) in exercise, at the expense of what static lung volume will the athlete increase tidal volume to increase minute ventilation ?
decreasing IRV + a little ERV will augment VT
RV will stay the same.
what is the valsalva maneuver ?
moderately forceful attempted exhalation against a closed airway, usually done by closing one's mouth, pinching one's nose shut while pressing out as if blowing up a balloon.
for short application of force
what are the physiologic consequences of the Valsalva maneuver ?
dramatically reduces venous return and arterial blood pressure
-> diminishes brain blood supply (dizzy)
-> once glottis reopens, blood flow will re-establish by an overshoot in arterial BP