Download HERE - hrsbstaff.ednet.ns.ca

Breathing Answer Key
1.
2.
3.
4.
5.
6.
The hairs of the nasal passage prevent large foreign particles from entering.
The mucus of the nasal passage keep the cells which line the nasal cavity moist.
The structures of the respiratory system through which air must travel are:
mouth( nasal cavity), pharynx, trachea(cilia), epiglottis, larynx, bronchi, 
bronchioles, alveoli
Cough medicines are sedatives and decrease the cough reflex of cilia. Only
recommended doses should be taken sot he cough reflex does not get completely
inhibited.
The lipoprotein of the alveoli provide lubrication so that the alveoli can “pop open”
during inhalation.
Some newborn babies have difficulty breathing because they don’t produce enough
lipoprotein and they need to use extreme force to overcome the surface friction to open
their alveoli during breathing.
BREATHING MOVEMENTS
1.
2.
3.
4.
5.
6.
7.
The diaphragm regulates the pressure in the lung cavity.
As the diaphragm contracts the air pressure in the lungs decreases so the air rushes into
the lungs. The shape of the diaphragm when it contracts is dome shaped.
As the diaphragm relaxes, the air pressure is greater in the lung so it is forced out of the
lungs. The shape of the diaphragm is flat when it is relaxed.
When the intercostal muscles contract, the ribs are pulled up and out; the lungs now have
lower air pressure and air is drawn into the lungs.
During exhalation, the fluids inside the pleura push against the lungs with greater pressure
forcing air out.
The internal intercostal muscles pull the ribcage down during extreme exercise ( not in
normal breathing.)
A puncture to the lung causes it to be impossible to establish pressure differences which is
needed for inhalation and exhalation.
REGULATION OF BREATHING MOVEMENTS
1.
2.
3.
4.
5.
6.
The medulla oblongata ( in the brain) controls breathing movements .
High levels of carbon dioxide are detected first in the brain by chemoreceptors.
Some drugs cause carbon dioxide sensors to be less sensitive.
The oxygen receptors are found in the carotid and aortic arteries.
The oxygen receptors are primarily a back-up system because carbon dioxide receptors
are more sensitive to changes in blood chemistry ( levels of gases).
Oxygen receptors would detect low oxygen before the carbon dioxide receptors detected
low CO2 in two cases:
1) at high altitude where fewer oxygen molecules isn’t accompanied by higher levels of
CO2
2)CO poisoning