Physiology Flashcards
When the diaphragm is relaxed what happens to air?
it rushes out
When the diaphragm is contracted what happens to air?
air rushes in
In quiet respiration how much does the diaphragm drop?
1.5 cm or about 500 mL
In forced respiration how much does the diaphragm drop?
7 cm or 4.7 L
What controls 2/3rds of airflow?
diaphragm
intercostal muscles
stiffens thoracic cage and prevents caving inward; enlarges the thoracic cage
controls 1/3rd of pulmonary airflow
What holds ribs in place during quiet respiration?
scalenes
During quiet respiration what pulls the rest of the ribs up and helps the sternum thrust forward?
external intercostals
What elevates the upper ribs during forced respiration?
scalenes
During forced respiration what arches the back and increases the diameter of thoracic cavity?
erector spinae
During quiet respiration what recoils?
bronchial tree and tendons of diaphragm
What ensures that recoil does not occur too quickly during respiration?
musculature
During forced expiration what pulls the ribs down?
internal intercostals
What pulls down the sternum during forced expiration?
rectus abdominis
Can the thoracic cavity exert pressure on the abdominal cavity?
yes
Do lungs have pacemaker cells?
no
What sets the resting rhythm of breathing?
neural control
Can skeletal muscles contract without neural stimulation?
no
What are the 3 pairs of respiratory centers in the medulla oblongata and the pons?
VRG
DRG
PRG
Ventral Respiratory Group
made of inspiratory and expiratory neurons
reverberating circuit produces a repetitive effect until inhibitory signal is receive, oscillates in electrical activity, sets basal rate of 12 breaths per minute
Dorsal Respiratory Group
influences VRG
integrates input from pontine respiratory group, central chemoreceptors, peripheral chemoreceptors, and irritant chemoreceptors
What are chemoreceptors responsive to?
pH, CO2, and O2
Pontine Respiratory Group
influences DRG
integrates input from hypothalamus, limbic system, and cortex
Central chemoreceptors
attempts to maintain a stable pH/ CO2 level in the CSF