Download Workbook Unit 6 ANSWERS File

Section 2 Workbook (units 4, 5 & 6) KeyANANSWERAN__AN_________ Name: Key C8. Analyze the functional inter-relationships of the structures of the respiratory system
35. Give functions for each of the following:
Structure
Function
Filter, moisten and warms the inhaled air
nasal cavity
Drains tear ducts, cranial sinuses, and ears
Passageway for air (and food)
pharynx
epiglottis
larynx
trachea
bronchi
bronchioles
alveoli
Prevents food and drink from entering trachea
Produces sound
Conducts air to bronchi during inhalation
Conducts air to bronchioles during inhalation
Conducts air to alveoli during inhalation
Gas exchange
Diaphragm – creates sealed cavity and pulls open the lungs to decrease the pressure for
inhalation
Ribs – protect the lungs and heart
Filled with fluid to cushion and protect the lungs and reduce friction.
pleural membranes Create a sealed cavity so that a negative air pressure can be created for inhalation.
Air tight space surrounded by the ribcage. Sealed cavity so that a negative pressure can
thoracic cavity
be created for inhalation
diaphragm and ribs
36. Label the structures listed above on the diagrams below:
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37. Explain the roles of cilia and mucus in the respiratory tract.
The mucus traps pollen, dust and other debris that gets into the lungs and the cilia sweep the mucus out of
the lungs to the pharynx where it is swallowed to get rid of it and keep the lungs clean
C9. Analyze the processes of breathing
38. Describe the interactions of the following structures in the breathing process: respiratory center in
the medulla oblongata, lungs, pleural membranes, diaphragm, intercostal (rib) muscles, stretch
receptors.
•
•
•
•
The medulla oblongata is sensitive to CO2 and H+ to trigger inhalation by sending a message to the
intercostal muscles which contract (to move the ribcage up and out so the lungs can expand) and to
the diaphragm with contracts and flattens (to pull open the lungs.
The lungs expand which decreases the air pressure in the lungs so air rushes into the lungs to fill the
space.
Stretch receptors in the alveoli detect when the alveoli are full and send a message to the medulla
oblongata to stop the signal so that the intercostal muscles relax (ribs move down and in to original
position) and the diaphragm relaxes so that the lungs recoil and air is moved out of the lungs.
The pleural membranes create a sealed thoracic cavity for negative pressure can be created for
inhalation
39. Compare the processes of inhalation and exhalation.
Inhalation: The ribcage is moved up and out of the way so that the lungs can expand when the diaphragm
pulls them open to create a negative air pressure in the lungs so air moves into the lungs.
Exhalation: The ribcage moves down and in when the lungs recoil due to relaxation of the diaphragm.
This increases the air pressure inside the lungs so that air leaves the lungs
40. Explain the roles of carbon dioxide and hydrogen ions in stimulating the respiratory center in the
medulla oblongata.
CO2 and H+ influence the pH of the blood.
Chemoreceptors detect and increase in CO2 and H+ levels (not O2) or in other words a drop in blood pH
(more acidic). When this drop in pH is sufficient, a message is sent to the intercostal muscles and
diaphragm from the medulla oblongata to stimulate contraction of these muscles – causing inhalation
41. Explain the roles of hydrogen ions in stimulating carotid and aortic bodies.
CO2 and H+ influence the pH of the blood.
Chemoreceptors detect and increase in CO2 and H+ levels (not O2) or in other words a drop in blood pH
(more acidic). The carotid and aortic bodies detect this drop and when this drop in pH is sufficient, a
message is sent to the medulla oblongata to stimulate contraction of the intercostal muscles and diaphragm
– causing inhalation
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C10. Analyze internal and external respiration.
42. Describe the exchange of carbon dioxide and oxygen during internal respiration. Mention where it
occurs, and the conditions that favour the exchange at that location (e.g. pH, temperature).
Internal respiration = gas exchange between the body tissues and the blood
Conditions = pH 7.3; 38º C; high pressure
•
Water and O2 are forced out of the capillary into the ECF at the arteriole end of the capillary bed
due to BP being greater than OP
•
At the venule end, water and CO2 is drawn into the capillary because of BP being less than OP and
the blood is hypertonic to the ECF causing (osmosis)
•
CO2 is carried as dissolved
gas in the blood plasma, carbaminohemoglobin (HbCO2), and
bicarbonate ions (HCO3-).
43. Describe the exchange of carbon dioxide and oxygen during external respiration.
Mention where it occurs, and the conditions that favour the exchange at that location (e.g. pH,
temperature).
External respiration = gas exchange between the alveoli and the blood
Conditions = pH 7.4 ; 37º C; low pressure
•
CO2 is released by the hemoglobin and the bicarbonate ion is converted into CO2 and water by
carbonic anhydrase so that the CO2 can diffuse into the alveoli to be exhaled from the body
•
O2 diffuses from the alveoli into the blood and is picked up by hemoglobin to form oxyhemoglobin
(HbO2) to be carried to the tissues.
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44. Explain the roles of each of the following in the transport of carbon dioxide and oxygen in the blood:
Substance
Role in Transport of Blood Gases
Transport O2
oxyhemoglobin
carbaminohemoglobin
Transport CO2
Transport H+
reduced hemoglobin
Transport CO2
bicarbonate ions
carbonic anhydrase
Catalyzes the reaction so that CO2 can be transported as bicarbonate
ion (buffering the blood in the process)
45. Write the chemical equations for internal respiration.
HbO2 → Hb + O2
H+ + Hb → HHb
CO2 + Hb → HbCO2
carbonic anhydrase
carbonic anhydrase
CO2 + H2O
→
H2CO3
→
HCO3- + H+
46. Write the chemical equations for external respiration.
Hb + O2 → HbO2
HHb → H+ + Hb
HbCO2 → Hb + CO2
carbonic anhydrase
carbonic anhydrase
HCO3- + H+
→
H2CO3
→
CO2 + H2O
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