Chapter 17

Question 1

Explain the term “breathing”

Answer 1

Muscular mechanism which is applied to transport air containing oxygen from air to lungs (inhalation) and carbon dioxide from lungs to air (exhalation)
- Also called ventilation

Question 2

Explain the term “gaseous exchange”

Answer 2

Diffusion of oxygen from alveoli to blood capillaries and vice versa with carbon dioxide

Question 3

Explain the term “respiration”

Answer 3

The release of energy in all body cells 24/7 (in mitochondria)

Question 4

Name the membranes by which the lungs are covered, and also name the fluid secreted and maintained by these membranes

Answer 4

• Pleural membranes

- Pleural fluid

Question 5

What is the function of pleural fluid?

Answer 5

Protects the lungs from friction during breathing movements

Question 6

Name the adaptations of the gaseous exchange system, in terms of alveoli structures and blood capillaries

Answer 6

• Alveoli are in large numbers, which provides a large surface area
• Alveoli walls are made up of one layer of epithelial cells
• Alveoli are surrounded by capillary networks
• Capillary walls also made up of one layer of epithelial cells
• A small distance exists between blood and air
• Blood is constantly flowing trough capillaries
• Moist layer keeps alveoli open and prevents cells from drying out

Question 7

Name the features of an effective gaseous exchange surface

Answer 7

• Large surface area
• Thin surface
• Efficient transport system
• Must always be moist
• Concentration gradient between air and blood

Question 8

Explain how leaves also illustrate the features of an effective gaseous exchange surface

Answer 8

• Large surface area
• Leaves are thin
• Efficient transport system (xylem and phloem)
• Air spaces for gases to diffuse into

Question 9

Inhalation: Explain. Go!

Answer 9

• Active phase
• Diaphragm contracts
• Abdominal muscles relax (to accommodate intestines)
• External intercoastal muscles contract
• Internal intercoastal muscles relax
• Ribs move up and out
• Thoracic cavity increases in volume
• Internal pressure decreases
• Elastic lungs expand
• Oxygen rich air flows into the lungs (inflation)

Question 10

Describe one test for carbon dioxide OTHER than the limewater test

Answer 10

Hydrogen carbonate indicator turns from RED to ORANGE-YELLOW in the presence of CO2

Question 11

State the typical breathing rate of an adult at rest and then ruring exercise

Answer 11

• 16-18 times per minute (at rest)

- 20-30 per minute (during exercise)

Question 12

Describe the effects of exercise on breathing and heartrate

Answer 12

• More oxygen will be exchanged
• Ensures active muscle cells are supplied with sufficient O2
• Faster respiration will occur in cells
• More energy will be released for the cells
• More carbon dioxide will be excreted at the same time

Question 13

Name the effects of nicotene on the respiratory system

Answer 13

• Stimulant which makes you feel more alert and active
• Reduces the diamted of arterioles
• Increases heartrate and blood pressure
• Very poisenous
• Increases the stickiness of platelets, leading to thrombosis

Question 14

Name the effects of tar on the respiratory system

Answer 14

• Carcinogen
• Absorbed by cells in lining of bronchi and can cause mutations in DNA (cancer)
• Irritant
• Leads to bronchitis
• Damages cilia in air passages, preventing the sweeping out of dust, bacteria, pollen and mucus
• Causes goblet cells to secrete extra mucus, ideal breeding ground for bacteria
• Coughing damages alveoli leading to emphysema

Question 15

Name the effects of carbon monoxide on the respiratory system

Answer 15

• Combines with haemoglobin to form carboxyhaemoglobin
• Less haemoglobin is available to transport oxygen
• Haemoglobin has a higher affinity for carbon monoxide than for oxygen
• One fifth of haemoglobin can be occupied by CO
• CO Damages lining of arteries, leading to atherosclerosis

Question 16

Describe an allergic reaction

Answer 16

• Immune response to harmless substances
• Occur when the body’s natural defense system overreacts and produces histamine
• Substances like pollen, animal hair, dust, sulphur dioxide
• Symptoms like runny nose, red eyes, sneezing, itching

Question 17

What substances can potentially lead to an asthma attack?

Answer 17

• Cigarette smoke
• Exhaust fumes
• Pollen
• Animal hairs
• Exercise
• PASSIVE SMOKING

Question 18

What happens during an asthma attack?

Answer 18

• Airways become narrow because smooth muscle in bronchi contract
• A lot of sticky mucus is produced
• Breathing becomes wheezy and person becomes breathless