Lab 6 - Respiratory Physiology Flashcards
is lung volume the same for all students?
NO depends on many factors, height, age, size, health, fitness, gender, smoking…..
did exercise influence the time it takes for each breathing cycle
yes it decreased the time of a breath cycle (faster rate of breathing) bc body needs more O2
Did exercise influence the tidal volume
Yes, # lung vol receptors increase during exercise = increased ventilation rate = increased tidal vol and reaching rate
What were the 2 demonstrations of the interactions of surface tension and pressure in the lungs?
- “Two balloon demonstration”. Shows the Law of LaPlace where tension of the walls depends on the pressure and radius of a container (P=2T/r).
- “Squirt bottle”: shows how low pressure btw the abdominal wall and the outer surface of the lungs allows the expansion of the chest cavity to fill the lung with air. Also why loss of this pressure results in a collapsed lung.
What is a surfactant? What does it do in the body?
A substance added to a liquid that reduces the surface tension. It lines the alveoli to decrease surface tension from 50 dynes/cm2 to about 2. More is used for smaller alveoli (smaller radius).
What motions are responsible for filling the lungs
-lowering floor of the chest cavity via diaphragm
-increasing diameter of the chest cavity by expanding the ribcage via external intercontinental muscle contraction btw adjacent ribs
What is used to determine vital capacity and forced expiration volumes of men and women
Nonogram. Place a line intercecting the age and height of a person, continue the line to intercect with FEV and VC
Define Tidal Volume (TV). How do u measure on iworx?
Vol of air inhaled/exhaled during normal breathing cycle.
Place cursors on in the trough before inhalation and the second at the adjacent peak during inhalation. Record (V2-V)
What is the maximum inspiratory flow rate?
Maximum rate of air movement during inhalation. Same as TV (trough and peak) but record max_dv/dt
What is the maximum expiration flow rate?
Themax movement of air during exhalation. Opposite of TV and max insp fr (peak then trough). Record min_dv/dt value
What is the breath period and how do u measure it
Duration of each breath cycle. Place cursors on peak of two adjacent cycles. Record the T2-T1 value
Describe how humans regulate ventilation
- regulate level of CO2 in the arteries
- in the blood the following reaction takes place:
CO2 +H20 = H2CO3 = H + HCO3 - if the rate of CO2 production > rate of CO2 explosion: equilibrium shifts RIGHT, producing more H+
- drop in the pH of blood sensed by cental chemo receptors (medulla) and some peripheral chemo receptors in the aorta and carotid.
- chemo receptors send signal to increase breathing rate nd depth = more CO2 elimination
What is the Valsalva maneuver?
Forced expiration against a closed glottis. Creates a higher pressure in the ribcage causing veins there to collapse. =decrease in cardiac input by 30% and therefore decrease cardiac output = reflex tachycardia (increased H beat)
- blood stagnation (reduced o2 delivery) may induce cerebral hypoxia (cause fainting) and cyanosis (bluing of the skin due to reduced venous return)
Describe neural control of respiration
-respiratory centre responsible for rhythmic breathing
-centre sends excititory impulses to motor neurons controlling inspiration , and inhibitory impulses to opposing muscles (opp for exhalation)
- sensory input from stretch/compression receptors on the chest wall, limbs, higher brain can influence breathing rate
- allows coughing, sneezing, speech
What is the Hering-Breuer Deflation reflex?
Reduced (unstretched) receptor activity removes the inhibitory influence on the inspiratory centre therefore allowing the inspiration to begin again.
- after exhalation, there is an urge to inhale
