During exercise, there are higher requirement for oxygen delivery to the blood and carbon dioxide removal. This is acheived through:
C. decreased tidal voluume coupled with increased ventilation frequency
nasal passages and structures prior to the respiratory bronchioles:
B. protect the alveoli from damage
select the option that is NOT true:
airflows between the two areas of the ventilator pathway depends on:
D. the oxygen content of the blood
the peripheral chemoreceptors that help regulate ventilation:
C. are especially responsive to carbon dioxide
why is carbond dioxide able to diffuse across respiratory and cellular membranes with smaller partial pressure difference than oxygen?
C. the membrane are more permeable to carbon dioxide than oxygen
at the end of exhalation:
C. exchanges of gases continues at the alveoli
during transitition to exercise, the first ventilator response is to increase:
D. tidal volume
under normal conditions, ventilation is controlled:
A. primarily by the partial pressure of carbond dioxide
what is the primary fxn of the lungs:
to exchange gases between the air and the blood
list the structures of the respiratory system:
nose/nostrils
nasal cavity
pharynx, larynx, trachea
bronchi: 2 (one leading to each lung)
bronchioles
alveoli: sac like structures surrounded by capillaries where gas exchage takes place
list and describe the 3 processes necessary to protect the bronchioles and alveoli:
humidifying air: prevents the membranes from damage due to drying out or desiccation
warming the air: helps to maintain the temperature of teh lungs, and temp. of structures where gas exchange takes place
filtering the air: mucus traps airborne particles, cilia move mucus twoard oral cavity to be expelled
what are the characteristics of alveoli:
what are the 2 fxn/benefits of the alveoli:
characteristicssaclike structures surrounded by capillaries in lungs
attached to respiratory bronchioles
300 million in the lungs
fxns/benefitssite of exchange of oxygen & carbon dioxide
provide tremendous surface area where diffusion can take place
further aiding pulmonary diffusion are two cell membranes that compose the:
where are the 2 membranes found:
further aiding pulmonary diffusion are two membranes that compose the respiratory membranes
-the membrane of the alveolar cells
-the membrane of the cells of the capillary wall
each lung is encased by a double layer _____ sac.
list each layer, and what it surrounds:
pleural sacs
visceral (pulmonary) pleura: surrounds outer surface of the lungs
parietal pleura: surrounds the inner surface of the throacic cavity & digaphragm
pleural fluid: lubriacting fluid bewteen the 2 membranes
intrapleural pressure: pressure in pleural cavity between 2 membranes; less atmosphereic pressure
describe the changes during ventilaiton when there is an increase in volume of intrathoracic cavity:
an increase in lung volume
intrapulmonic pressure decreases
air rushes into the lungs (inspiration)
describe the changes durin ventilation when there is a decrease in volume of intrathoracic cavity:
a decrease in lung volume
the volume of the intrathoracic caivity increases
air rushes out of the lungs (expiration)
the most important inspriatory muscle is the:
explain how the contraction of this muscle affects volume and pressure:
-diaphragm is the most important inspiratory muscle
-as the diaphragm contracts, it flattens out, resulting in an increase in intrathroacic volume and putting into motion the intrathoracic pressure changes that cause inspiration
contraction moves the abdominal contents foward & downward
other accessory inspiratory muscles are: external intercostals, scalenes, sternoclediomastoid, pectoralis minor
at rest, no muscluar effort is needed to cause expiration, explain how the elastic properties of the diaphragm aid in expiration:
upon relaxation of the diaphragm intrathoracic volume decreases and results in the motion of changes in intrapulmonic presssure that cause expiration
list the muscles that aid voluntary, forced expiration during exercise:
internal intercostals
rectus abdominis
internal oblique muscles of abdominal wall
- accessory muscles of expiration contract, pulling the ribs downward
express the equation for the relationship bewteen pressure and resistance in regards to airflow
what are the 3 main factors that affect airflow:
what decreases reistance to airflow during exercise:
the pressure difference between the 2 areas
resistance to airflow
diameter of the airway
bronchodilation decreases resistance to airflow during exercise
the amount of air moved in and out of the lungs during a practicular timeframe (1 minute) is called:
pulmonary ventilation
the amount of air moved per breath is called:
tidal volume
what is the equation used to express pulmonary ventilation:
VE= VT x f
VE= volume of air expired per minute
VT= tidal volume ( amount of air moved per breath)
f= frequency per minute
-or-
VE= VA + VD
VA= anatomical dead space: air that never reaches the alveoli
VD= alveolar ventilation: air that does reach the alveoli
describe how lung capacities and volume affect the mehanics of ventilation:
determied using spirometry equipment
reserve of tidal volume at rest allows tidal volume to increase during exercise
residula volume: the amount of air left in the lungs after max exhalation
residual volume is important bc it meas lungs do not empty or collapse, becuase air remains with the lungs.....ALLOWS FOR CONTINUEOUS EXCHANGE OF GASSES AT THE ALVEOLIE BETWEEN BREATHS
describe how the frequency and depth of breathing affect the mehcanics of ventiliation:
-from rest to exercise, an increase in the depth of breathing (vT= tidal volume)-if an increase in depth is not sufficent, an increase in breathing frequency will occur
list the 2 factors that aid gas diffusion at the lungs/capillary:
what is the driving force of gas diffusion:
the large surface area of the alveoli
thinness of the respiratory membrane (only 2 cells thick)
driving force: the pressure difference of oxygen and cabon dioxide between air in the alveoli and the blood
the driving pressure of oxygen and carbond dioxide between air in the alveoli and the blood is determined by which 3 concepts:
partial pressure: the portion of pressures due a particular gas in a mixture of gasses in both the blood and the alveoli
Dalton's law:
Henery's Law
the total pressure of a gas mixture is equivalnet to teh sum of all the pressures of all the gases that compose the mixtures is stated as:
Dalton's Law
the law that states that the amount of gas dissolved in any fluid depends on the temperature, partial pressures of gas, and the solubility of the gas is called:
Henery's Law
temperature of blood is constant
solubility of oxygen and carbon dioxide wihin the blood is constant
the amount of gases dissolved in the blood is directly dependent on the partial pressure
describe how oxygen diffusion into the blood is directed by Henery's Law:
Parital pressure of oxygen (PO2) must be greater alveoli than in the blood
Partial pressure of oxygen (PO2) must be greater in the blood than in the tissues
the differences betwee PO2 in the alveoli & blood and between the blood and the tissue provide the driving force for diffusion of oxygen
describe how carbon dioxide diffusion in the blood is directed by Henery's Law:
Partial pressure of carbon dioxide (PCO2) must be greater tissues than in the blood
Partial pressure of (PCO2) must be greater in the blood than the alveoli
Partial pressure of PCO2 must be greater in the alveoli than in the atmospheric air
**Expiration**
differeces between PCO2 tissue & blood, and difffereces between PCO2 in blood & alveoli provide the driving force for diffusion of caron dioxide
pulmonary blood flow deteremines the velocity at which blood passes thru the __________.
as blood flow increases, as in during exercise, the more total ________ can take place.
pulmonary blood flow deteremines the velocity at which blood passes thru the pulmonary capillariesas blood flow increases, as in during exercise, the more total gas diffusion can take place
BP in the pulmonary circulation is very low (25/10); this help to protect thin respiratory membrane from damgae due to high BP
increased capillary blood volume slows blood transit time thru capillaries; allows for more time for gas equilibration and maintain low BP
describe the effiency of transporting oxygen carried in the blood to the body thru:
plasma:
RBC:
plasma: only 9 to 15 mL of oxygen can be dissoloved in plasma, which is insuffficent to meet the needs of the body
RBC: red blood cells containing hemoglobin ( an iron-containing pigment capable of reversibly binding to oxygen) transports 98% of oxygen
when oxygen is bound to hemoglobin, _________ is formed.
hemoglobin not bound to oxygen is termed:
oxyhemoglobin
deoxyhemoglobin
becuase majority of oxygen is transported bound to hemoglobin, its concentration determins the amount of oxygen that can be transported by the blood
the ability of hemoglobin to bind and release oxygen at correct site is explained by oxyhemoglobin disassociation curve:
in the lungs, 100% saturation occurs, even if PO2 drops here, little change in oxygen saturation would occur, so the curve is flat, why is this physiologically important:
ensures that close to 100% saturation takes place at the lungs even if PO2 at the lungs decrease due to factors suc as an assent to moderate altitude
the ability of hemoglobin to bind and release oxygen at correct site is explained by oxyhemoglobin disassociation curve:
the curve has a very steep slope, at the location of active tissues where PO2 is low, this ensures that a small change in PO2, a very large change in oxygen saturation will take place. why is this important:
oxygen will be more readily released and available to the tissues, critical for supply of oxygen to tissues during exercise when PO2 at the tissue level decreases
describe how an increase or decrease in temperature shifts the oxyhemoglobin curve:
-an increase in temperature shifts the curve to the right
-this means that an increase in temp. decreases affinity of hemoglobin for oxygen resulting in lower % oxygen saturation at any given PO2
-aids the delivery of oxygen to muscle tissue, more oxygen to muscle
-a decrease in temperature shifts the curve to the left
-a decrease in temp. increases the affinity of hemoglobin for oxygen
describe how an increase or decrease in pH effect (Bohr effect) shifts the oxyhemoglobin curve:
-an increse in pH shifts the curve to the right-an increase in pH decreases affinity of hemoglobin for oxygen (H+ increases and reversibly binds to hemoglobin) **same as temperature**aids in delivery of oxygen to tissues**
-a decrease in pH shifts the curve to the left
- a decrease in pH increases affinity of hemoglobin for oxygen
describe how 2,3 Diphosphoglycerate (2,3 DPG), a byproduct of anaerobic rxns from glycolysis, shifts the oxyhemoglobine curve:
-an increase in 2,3 DPG shifts the curve to the right
- 2,3 DPG can loosely bind to hemoglobin reducing its affinity for oxygen, and increasing oxygen delivery to the tissue
- a decrease in 2,3 DPG shifts the curve to the left
-increases affinity of hemoglobin for oxygen
list the 3 methods for carbon dioxide transport in the blood:
plasma: 7-10% dissoloved CO2
hemoglobin: 20% hemoglobin bound
bicarbonate: 70%
gas exchange at the muscle or any tissue occurs due to:
partial pressure differences between oxygen & carbon dioxide between tissue & blood
an oxygen transport molecule similar to hemoglobin except that it is found within skeletal and cardiac muscle is called:
myoglobin
-reversibly binds with oxygen from the cell membrane to the mitochondria
-assists in passive diffusion of oxygen from cell membrane to mitochondria (speeds up diffusion of oxygen)
-fnx as oxygen reserve at the start of exercise (oxygen bound to myglobin maintains O2 requirements of muscle that is becoming active, lag from ventilation)
describe the characteristics of muscles fibers with myglobin:
high in Type I fibers
high aerobic capacity ( slowtwitch)
appears reddish
high mitochondria content
how is the disassociation curves different for hemoglobin and myoglobin:
myoglobin has a much steeper curve
approches 100% oxygen saturation at a much lower PO2
within mitochondria active muscles, PO2 is low
allows myoglobin to transport oxygen at the lower levels of PO2 found within skeletal muscle
which 2 structures of the brain make up the respiratory control center, serving as the "pacemaker":
medulla oblongata
pons
capable of generating a rhythmical breathing pattern
pulmonary ventilation is generally involuntary, but it can be changed voluntarily
the rate & depth of breathing can be modified by:
higher brain centers
chemoreceptors in the medulla
other peripheral inputs
chemoreceptors that respond to changes within the cerebral spinal fluid and are especially sensitive to changes of H+ concentration of pH are called:
central chemoreceptors
chemoreceptors located within the carotid arteries and the arotic arch that repsond to changes in blood PCO2 and H+ concentration are called:
peripheral chemorecptos
-carotid bodies also repsond to changes in PO2, montior changes within head/brain
aortic monitos pulmonayr/systemic circulation
how do the lungs contribute neural imput for control of ventilation
the lungs contain stretch receptors, mainly in bronchioles
diaphragm/abdominal muscles contain stretch receports and sense metabolic changes
how do the muscles contribute neural imput for control of ventiliation:
proprioceptors (muscle spindles, golgi tendon bodies) are sensitive to changes in body position
chemoreceptors are sensitive to potassium concentrations, and H+ concentration
describe the 3 phase of submaximal exercise and pulmonary ventilation:
phase 1-ventilation increase due to motor cortex activity and propoceptors in active muscles
-short plateau last 20 sec. tthen exponentially rise to reach steady-state leve
phase 2-continued effect of motor cortex, feedback from active muscles, feedback from peripheral chemoreceptors
-steady-state level
phase 3-fine-tuning of pulmonary ventilation during steady-state
-feedback from pheripheral chemoreceptors, central chemoreceptors so ventilation is matched to meet demands of submaximal exercise
exercise stops-quick drop in ventilation
-removal of feedback from motor cortex, proprioceptors in active muscles
the amount of air ventilated needed to obtain 1 L of oxygen or expire 1 L of carbon dioxide are called:
ventialtory equivalents
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
the technique of using ventilatory equivalents to estimate lactate threshold is called:
ventilatory threshold
the work intensity at which both VE/VO2 & VE/VCO2 increase is called:
respiratory conpenstion point (RCP)
-characterized by a decrease in end-trial partial pressure of O2
-indicates end of control of VE by PCO2
VT & RCP can be used to create 3 training zones of exercise intensity, based on heart rate:
