Exam 3 Flashcards
ventilatory anatomy
Nose/nostrils
nasal cavity OR oral cavity
pharynx (throat)
larynx (voice box)
trachea (windpipe)
bronchi (large airways)
bronchioles (small airways)
alveoli
Alveoli function/ anatomy
Function: site of exchange of oxygen & carbon dioxide during breathing in and out; tremendous surface area where diffusion can take place.
Anatomy: saclike structures surrounded by capillaries in lungs; balloon shaped.
Conducting zones
trachea and terminal bronchioles; anatomic dead space
function in air transport, humidification, warming, particle filtration, vocalization, immunoglobulin secretion.
Transitional and Respiratory zones
bronchioles, alveolar ducts, and alveoli.
Function in gas exchange, surfactant production, molecule activation and inactivation, blood clotting regulation, and endocrine function.
MVV, what is it? Why is it useful?
Maximum Voluntary Ventilation.
Evaluates ventilatory capacity with rapid and deep breathing for 15s.
phases of inspiration
- diaphragm contracts, flattens, and moves downward toward the abdominal cavity
- elongation & enlargement of the chest cavity expands air in the lungs, causing its intrapulmonic pressure to decrease slightly below atmospheric pressure
- lungs inflate as nose and mouth suck air inward
- completed when thoracic cavity expansion ceases; this causes equality between intrapulmonic and ambient atmospheric pressures
phases of expiration
- sternum and ribs drop, diaphragm rises (decreasing chest cavity volume & compressing alveolar gas), moving air from respiratory tract to the environment
- completes when compressive force of expiratory muscles cease and intrapulmonic pressure decreases to atmospheric pressure
Atmospheric pressure
allows the inhalation of air into the lungs as gases move down their concentration gradient from high to low concentration.
Intrapulmonary pressure
during expiration, diaphragm applies pressure to thoracic cavity and compresses the lungs, which increases intrapulmonary pressure more than atmospheric pressure causing air to expel from lungs.
What is the role of surfactant?
Lubricates surface and decreases surface tension.
FVC
stroke volume of the lungs.
FEV
FEV – Forced Expiratory Volume, maximal airflow measured over one sec (FEV1.0)
IRV
Inspiratory Reserve Volume, amount of air that can be forcibly inhaled after a normal tidal volume.
how can FVC, FEV, IRV FVC be used in the determination of disease?
Can be used to measure stages of COPD (Chronic Obstructive Pulmonary Disease).
Know how males and females vary anatomically and physiologically in regards to lung(s) function.
MVV ranges between 140 – 180L/min in healthy college-age men, and 80 – 120 L/min in healthy, college-age women
Anatomical Dead space
air-filled in conducting airways and does not participate in gas exchange, conducting zone.
Physiological Dead space
sum of all parts of the tidal volume that does not participate in gas exchange; collapsed alveoli, blocked capillary
Pulmonary ventilation
movement of air into and out of the lungs or breathing
Pulmonary diffusion
movement of gases between the air in the lungs and the blood; oxygen into blood and carbon dioxide out of the blood
Gas transport
movement of blood containing gases; oxygen traveling in blood from lungs to tissues, carbon dioxide traveling in blood from tissues to lungs
Capillary gas exchange
exchange of gases between the blood and the body’s tissues at the periphery; oxygen to tissues and carbon dioxide away from tissues
Pulmonary respiration
pulmonary ventilation and pulmonary diffusion
Cellular respiration
use of oxygen in aerobic metabolism and production of carbon dioxide (within tissues)
functions of the respiratory system
- conducts air into & out of lungs
- exchanges gases between air & blood
- humidifies air (prevents damage to membranes due to drying out)
- warms air (helps maintain temperature)
- filters air
functions of the respiratory system: filters air
Mucus traps airborne particles
Cilia move mucus toward oral cavity to be expelled
Particles not caught by mucus is engulfed by macrophages
Goblet cell creates mucus
lungs
Provide the gas exchange surface that separates blood from surrounding gaseous environment
O2 transfers from alveolar air into alveolar capillary blood while the blood’s CO2 moves into the alveolar the alveoli and then into ambient air
alveoli
Saclike structures surrounded by capillaries in lungs
Attached to respiratory bronchioles
Site of exchange of oxygen & carbon dioxide
respiratory membrane
2 cell membranes that aid diffusion
- membrane of alveolar cells
- membrane of cells of capillary wall
Increase in volume of intrathoracic cavity
Increases lung volume
Decreases intrapulmonic pressure
Causes air to rush into lungs (inspiration)
Decrease in volume of intrathoracic cavity:
Decreases lung volume
Increases intrapulmonic pressure
Causes air to rush out of lungs (expiration)
ventilatory pump
must create negative pressure within thorax
must provide system for distribution of inhaled air to alveoli
Pulmonic pressure
pressure inside lungs (760 mm/Hg)
Atmospheric pressure
pressure in your surroundings (760 mm/Hg)
Boyles Law
inverse relationship between space/volume and pressure
What determines the partial pressure of gases?
Portion of pressure due to a particular gas in a mixture of gases.
Why is there a decrease in partial pressure from the ambient air to the alveoli?
As air enters the lungs, it’s humidified by the upper airway, the water vapor reduces the O2 partial pressure. Rest is due to continual uptake of oxygen by the pulmonary capillaries, and continual diffusion of CO2 out of the capillaries into the alveoli.
Know the driving force of gases into and out of the blood, tissues.
The change in partial pressure from the alveoli to the capillaries drives oxygen into the tissues and CO2 into the blood from the tissues.
Know how oxygen is transported and what can affect this (Bohr effect).
RBCs containing hemoglobin transports 98% of oxygen.
Bohr effect
a decrease in the amount of oxygen associated with hemoglobin and other respiratory compounds in response to a lowered blood pH resulting from an increased concentration of carbon dioxide in the blood.
Be familiar with 2,3 DPG and its effects on oxygen transport.
Increased levels of RBC 2,3-DPG occur in cardiopulmonary disorders and in those who live at high altitudes to facilitate O2 release
What is the arterial-venous VO2 difference?
Describes the difference between oxygen content of arterial blood and mixed-venous blood.
Know the role of myoglobin and what it is.
Oxygen transport molecule similar to hemoglobin; reversibly binds with oxygen. Makes muscle appear red; is high in type I fibers.
How is CO2 transported and the importance of its transport.
7% - 10% is dissolved in plasma, 20% is bound to hemoglobin.
Oxygen and low PCO2 lungs cause CO2 to be released from hemoglobin.
Carbaminohemoglobin
CO2 bound to the globin portion of hemoglobin.
factors promoting diffusion
Large surface area of alveoli
Thinness of respiratory membrane (2 cells thick)
Pressure differences of oxygen & carbon dioxide between air in alveoli & blood
Partial pressure
portion of pressure due to a particular gas in a mixture of gases
Dalton’s law
total pressure of gas mixture = sum of partial pressures of each gas. Each gas moves according to its own individual pressure gradient.
Fick’s law
Volume of gas that diffuses is proportional to surface area available for diffusion, diffusion coefficient of gas, and the difference in partial pressure of gases
Henry’s law
amount of gas dissolved in any fluid depends on temperature, partial pressure of gas, & solubility of gas
oxygen depends on:
- concentration of gases in ambient air
- partial pressure of gases in ambient air
tracheal air
Air completely saturates with water vapor as it enters nasal cavities and mouth and passes down the respiratory tract (conducting zone)
As a result of humidification, the effective Po2 in tracheal air decreases by 10 mm Hg from ambient value of 159 mm Hg to 149 mm Hg
alveolar air
Average pressures exerted by O2 and CO2 against alveolar (respiratory zone) side of alveolar–capillary membrane:
Po2 = 103 mm Hg
Pco2 = 39 mm Hg
henrys law - two determining factors
Pressure difference between gas and fluid
Solubility of gas into the fluid (low in O2, high with CO2)
lung blood flow
Determines velocity at which blood passes through pulmonary capillaries
Increased blood flow during exercise results in increased gas diffusion
Blood pressure in pulmonary circulation is low compared with systemic
oxygen transport: in physical solution dissolved in the fluid portion of blood
Oxygen’s relative insolubility in water keeps its concentration low within body fluids
hemoglobin
Carries 65 to 70 times more O2 than dissolved in plasma
Each of the four iron atoms in hemoglobin molecule can loosely bind one oxygen molecule
heme
iron molecule that binds 4 oxygens per hemoglobin; globin: protein
Oxyhemoglobin
oxygen bound to hemoglobin
Deoxyhemoglobin
hemoglobin not bound to oxygen
Concentration of hemoglobin determines amount of oxygen that can be transported
anemia
causes significant decreases in iron availability to decrease hemoglobin concentration, which reduces content of RBCs that reduce the blood’s O2-carrying capacity
ph & oxyhemoglobin: increase in acidity (e.g. exercise)
Shifts curve to right
Decreases affinity of hemoglobin for oxygen
Increases oxygen delivery to tissue
decrease in acidity
Shifts curve to left
Increases affinity of hemoglobin for oxygen
Decreases oxygen delivery to tissue
increase in 2,3 DPG
Shifts curve to right
Decreases affinity of hemoglobin for oxygen
decrease in 2,3 DPG
Shifts curve to left
Increases affinity of hemoglobin for oxygen
gas exchange at the muscle
occurs due to partial pressure differences between oxygen & carbon dioxide between tissue & blood
carbon dioxide transport
7% to 10% is dissolved in plasma
20% is bound to hemoglobin
70% is transported as bicarbonate
Regulation of ventilation
Complex mechanisms adjust breathing rate and depth to the body’s metabolic needs.
What is the respiratory control center?
Located in the medulla, involved in the minute-to-minute control of breathing.
Chemoreceptor
receptor that responds to chemical changes.
Central Chemoreceptors
located in medulla, separate from respiratory control center. Responds to changes within CSF (cerebrospinal fluid), esp. In H+ concentration.
Peripheral Chemoreceptors
located in carotid and aorta. Collectively guard against alterations to hypoxia and hypercapnia.
What role does the blood play in the regulation of ventilation?
At rest, the blood’s chemical state exerts the greatest control on pulmonary ventilation.
mechanoreceptors
Sensory receptors that provide the organism w/ info about such mechanical changes in the environment as movement, tension, and pressure.
How does the onset and end of exercise alter ventilation (what is happening in the “three phases”?)
- at start or slightly before exercise, abrupt increase in pulmonary ventilation due to motor cortical activity feedback on respiratory centers as well as feedback from proprioceptors in active muscles.
- 20 second plateau, then exponential increase to reach steady-state-level due to previous factors as well as peripheral chemoreceptors.
- fine tuning of ventilation due to inputs from central and peripheral chemoreceptors to match demands of exercise. Temperature may also impact this.
Ventilatory Threshold
workload at which there is an increase in VE/VO2 and no change in VE/VCO2; used to estimate lactate threshold.
-What is OBLA?
Onset of Blood Lactate Accumulation
Be familiar with detrimental health effects of smoking.
Lower dynamic lung function that can manifest into COPD
obstructs airways and slows normal lung development
greater deficits in girls than boys (in adolescents),
children will have a higher rate of asthma and wheezing and reduced dynamic lung function.
regulation of ventilation controlled/mediated by:
Respiratory control center
Central chemoreceptors
Peripheral chemoreceptors
Pulmonary mechanoreceptors
respiratory control center - two main nuclei:
Dorsal respiratory group
Ventral respiratory group
near maximal exercise & pulmonary ventilation
If exercise exceeds 50-60% of peak oxygen consumption, Phases 1-3 have already been surpassed.
Body’s increase in pulmonary ventilation at this point becomes disproportionate to the exercise intensity
This is due to increased acidity/decreased pH (e.g. increased H+ concentrations) above lactate threshold
Stimulates peripheral chemoreceptors and increases pulmonary ventilation
Allows body to exhale excess CO2, thereby decreasing acidity; thus increase in ventilation is not to obtain more oxygen, but to expel CO2
Increase in ventilation may also be due to increases in norepinephrine (fight-or-flight), increased potassium, increased body temperature
ventilatory equivalents
Amount of air ventilated needed to obtain 1 L of oxygen or expire 1 L of carbon dioxide
Ventilatory equivalent of oxygen
ratio of pulmonary ventilation (VE) to oxygen (VO2): VE/VO2
Ventilatory equivalent of carbon dioxide
ratio of pulmonary ventilation (VE) to carbon dioxide (VCO2): VE/VCO2
ventilation limits
Increases in ventilation frequency also increases the respiratory muscles and the diaphragm itself for oxygen (shown by increased a-v O2 difference in venous blood from respiratory muscles)
Diaphragm is oxidative and fatigue resistant, but can fatigue in obstructive lung disease or at high exercise intensities
Diaphragm force output decreases at exercise above 80-85% of VO2peak to exhaustion. Other muscles can compensate and diaphragm likely still meets demands.
Oxidative capacity of respiratory muscles increase with endurance training or COPD, glycolytic does not
Diaphragm can also hypertrophy in response to heavy physical labor and weight lifting
