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Biology 12 - Respiration

+ Part A: Definitions: Define the following terms, IN YOUR OWN WORDS, IN AS FEW WORDS AS CLARITY ALLOWS.

1. breathing see p. 270
2. external respiration see p. 270
3. internal respiration see p. 270
4. cellular respiration see p. 270
5. inspiration see p. 270
6. expiration see p. 270
7. vocal cords see p. 272
8. trachea see p. 273
9. bronchi see p. 274
10. bronchioles see p. 274
11. alveoli see p. 274
12. ventilation see p. 275
13. diaphragm see p. 276
14. pleural membranes see p. 276
15. hemoglobin see p. 276
16. negative pressure see p. 277
17. breathing center see p. 277
18. dead air see p. 278
19. residual air see p. 278
20. influenza see p. 283
21. bronchitis see p. 283
22. strep throat see p. 283
23. emphysema see p. 284
24. tuberculosis see p. 284
25. pneumonia see p. 284

Part B - Short Answers

1. Inspiration and expiration are involved in the process of breathing.
2. During inspiration, the rib cage moves up and out; the diaphragm moves down.
3. The primary stimulus for breathing is the amount of carbon dioxide in the blood.
4. Oxygen moves from the alveoli to the capillaries by means of diffusion.
5. Carbon dioxide is carried in the plasma as the bicarbonate ion.
6. Hemoglobin readily takes up oxygen in the lungs, where the pH is neutral and the temperature is cool.
7. At the tissues, oxygen diffuses out of the blood and carbon dioxide diffuses into the blood.
8. In which structures does gas exchange actually occur? alveoli
9. When food is swallowed, the respiratory passage is closed off. How are the nasal passages closed off? soft palate moves back
10. How is the trachea (larynx) closed off? epiglottis covers the glottis
11. Make a sketch that includes the following parts. Be sure to label all the parts:
a. sinus
b. nasal cavity
c. hard palate
d. opening to eustachian tube
e. soft palate
f. epiglottis
g. glottis
h. larynx
i. trachea
12. Indicate whether the following phrases describe INSPIRATION or EXPIRATION: i) lungs expanded INSPIRATION ii) muscles (diaphragm and ribs) relaxed EXPIRATION iii) diaphragm dome-shaped EXPIRATION iv) chest enlarged INSPIRATION v) less air pressure in lungs than environment INSPIRATION
13. Put these statements in the proper sequence:

Event a Respiratory center stops sending messages to diaphragm and rib muscles b Respiratory center sends excitatory message to diaphragm and rib muscles c Diaphragm becomes dome-shaped and rib muscles relax d Chest expands as diaphragm goes down and rib cage goes out. e Air goes rushing out as lungs recoil. f Air comes rushing in as lungs expand g Expanded lungs send message to respiratory system Correct sequence: B,D,F,G,A,C,E
14. Where does oxygen enter the blood? lungs. Where does oxygen leave the blood? tissues
15. Where does carbon dioxide enter the blood? tissues Where does it exit from the blood? lungs
16. Give the equation that describes how oxygen is transported in the blood. Label one arrow lungs and the reverse arrow tissues.

lungs

Hb + O2

HbO2

tissues

17. Give the equation that describes how most carbon dioxide is transported in the blood. Label one arrow lungs and the reverse arrow tissues.

tissues

tissues

CO2 + H2O

H2CO3

H+ + HCO3-

lungs

lungs

18. What is the name of the enzyme that speeds up the above reaction? carbonic anhydrase
19. Carbon dioxide combining with water produces hydrogen ions. Why does the blood not become acidic? Hemoglobin combines with excess hydrogen ions
20. Hemoglobin is remarkably suited to the transport of oxygen. Why? It easily combines with oxygen in the lungs and easily gives it up in the tissues
21. Why does a person die from carbon monoxide poisoning? Hemoglobin combines with carbon monoxide preferentially to oxygen
22. How does hemoglobin help with the transport of carbon dioxide? It combines with carbon dioxide, to a degree, to form carbaminohemoglobin, and picks up hydrogen ions produce in the reaction of CO2 and water.
23. Rewrite these false statements to make true statements:
i. Diffusion of gases occurs in the lungs but not in the tissues diffusion of gases occurs in both the lungs and the tissue ii. The trachea is held open by cartilaginous rings so that food can pass down more easily. the trachea is held open by cartilaginous rings so that air can always pass down it iii. The glottis opens wide during swallowing. the epiglottis covers the glottis during swallowing. iv. An alveolus is a thin-walled air sac surrounded by a layer of poorly vascularized tissue.
An alveolus is a thin-walled air sac surrounded by a layer of highly vascularized tissue.
v. The respiratory center is sensitive to low oxygen content in the blood.
The respiratory center is sensitive to high carbon dioxide content in the blood. vi. A person can commit suicide by holding his or her breath.
A person cannot commit suicide by holding his or her breath. vii. The direction in which gases move between the lungs and the blood is determined by temperature.
The direction in which gases move between the lungs and the blood is determined by the law of diffusion.
24. List the four steps that lead to bronchiogenic carcinoma.
There is a thickening of cells (callousing)
Cilia disappear
Cells with atypical nuclei appear (cancer in situ)
Atypical cells break loose and penetrate other tissues (metastasis)
25. Smoking cigarettes a) cause tuberculosis b) leads to emphysema and cancer c) increases the vital capacity of the lungs d) leads to super health and a long, happy life b
Scholarship Exam Questions - Total = 16 MARKS

1. The following table shows the relative amount of oxygen consumed by the major organs in an adult human:

Oxygen Consumption

Rest
Heavy Work
Skeletal Muscles
0.30
6.95
Digestive organs
0.25
0.20
Heart
0.11
0.40
Kidneys
0.07
0.07
Brain
0.20
0.20
Skin
0.02
0.08
Other
0.05
0.06
Explain the change in the uptake of oxygen between rest and heavy work by each of the following: a) Skeletal Muscles: (5)
· increased ATP demands in muscles will require more ATP, and therefore greater rates of aerobic respiration, and therefore greater oxygen uptake. (1 mark) b) Skin
· skin will help cool the body during heavy work by producing sweat. Extra ATP, and therefore extra oxygen, is required for this to occur. (1 mark) c) Heart
· The heart will be pumping faster and harder, and therefore require more ATP, so it too will need more oxygen. (1 mark) d) Digestive organs
· During heavy work, energy is diverted away from the digestive system to the muscles. Thus, the digestive organs will require less energy, and less oxygen, during heavy work. (1 mark) e) Brain
· The brain needs to function regardless of whether work is being done, so its energy needs, and thus oxygen consumption will remain constant. (1 mark)
2. A person was brought to the emergency room unconscious. Breathing was shallow and irregular. A blood sample showed the blood pH to be 7.18 (normal = 7.4). A mechanical respirator, which increased breathing rate, was inserted and sodium bicarbonate was administered intravenously. (3)
a) Explain why the lowered breath rate lowers the blood pH
· The lowered breathing rate increases the amount of carbon dioxide in the blood. Carbon dioxide, when it combines with water, forms carbonic acid. The carbonic acid lowers the pH. (1 mark)
b) How does the respirator help return the blood pH to normal?
· By increasing the breathing rate with the respirator, more carbon dioxide is removed from the blood, which helps to decrease blood acidity. (1 mark)
c) What was the reason for administering the sodium bicarbonate?
· Sodium bicarbonate is a base, and will neutralize acid in the blood. Its purpose is to raise the pH. (1 mark)
3. Explain how the structure of alveoli is related to its function. (3)
· One cell wall thick, so that gases can diffuse across to and from the blood. (1 mark)
· Sacs are kept open by lipoproteins, so they don't collapse between breaths. (1 mark)
· Sac wall have mechanoreceptors to signal expiration to occur after inspiration. (1 mark)
4. Explain how the nervous system controls the rate of breathing (inspiration and expiration). (2)
· Inspriration: detectors in carotid and aortic bodies detect increased CO2 levels, and send a signal to the breathing center in the medulla oblangata, which in turn sends a signal to the diaphragm and rib muscle to contract. (1 mark)
· Expiration: mechanoreceptors in alveoli walls detect stretching of walls, indicating that inspiration has occured. Receptors send a signal to medulla oblangata to stop the previous signal sent that had caused the muscles to contract. Diaphragm and rib muscles relax, and the person exhales. This is an example of negative feedback. (1 mark)
5. Explain how the partial pressures of O2 and CO2 influence their transport at the alveolus-capillary level and at the capillary-tissue (non-lung) level. (2)
· Oxygen is present in higher concentrations in the air (alveoli) than its surrounding capillaries. Thus, oxygen will diffuse from the air into the blood. Carbon dioxide will diffuse out of the blood into the alveoli as it is more concentrated in the blood than in the surroundng air. (1 mark)
· At the arterial side of a capillary bed, oxygen is present in higher concentrations than in the surrounding tissue fluid, so it will diffuse from the blood to the tissues. At the venous side of a capillary bed, osmotic pressure is greater than blood pressure, and carbon dioxide concentrations are higher than oxygen concentrations. Carbon dioxide will therefore diffuse into the blood from the tissue fluid. (1 mark)
6. What is the role of hemoglobin in maintaining blood pH? (1)
· Hemoglobin will pick up excess hydrogen ions formed from the reaction of carbon dioxide with water, and transport it back to the lungs, where the reverse reaction occurs and CO2 leaves the blood. This prevents H+ from building up in the blood, so that blood pH remains constant. (1 mark)