07- respiration in humans

Question 1

definition of aerobic respiration

Answer 1

• the release of energy by the breakdown of glucose in the presence of oxygen
• Carbon dioxide and water are released as waste products
• Releases a large amount of energy

Question 2

definition of anaerobic respiration

Answer 2

• the release of energy by the breakdown of glucose in the absence of oxygen
• Releases a relatively small amount of energy
• Carried out to meet the increased energy demand (lactic acid is formed in the process) → helps the muscles to keep contracting (during vigorous activity)
• Since there is insufficient oxygen to meet the demands of the vigorous muscular contractions, the muscles are in an oxygen debt

Question 3

How to remove lactic acid/oxygen debt after a race?

Answer 3

1. continuation of fast heart rate
2. continuation of deeper and faster breathing

Question 4

the “organs” involved in the gas exchange system (in order)

Answer 4

Nasal passages
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Alveoli

Question 5

describe inspiration/inhalation

Answer 5

*Diaphragm muscle contracts, diaphragm flattens
*External intercostal musclescontract while internal intercostal muscles relax (antagonistic)
*Ribs and sternum move upwards and outwards →increase volume of thorax
*The volume of thoracic cavity (chest cavity) increases
*Lungs expand, air pressure decreases, volume increases
*Pressure of the atmosphere is now higher than pressure in our lungs
*Air moves into the lungs

Question 6

describe expiration/exhalation

Answer 6

*Diaphragm muscle relaxes and the diaphragm **arches upwards **
* Internal intercostal muscles contract while external intercostal muscles relax
* Ribs and sternum move downwards and inwards **
* Volume of thoracic cavity decreases **
Lungs are compressed, air pressure increases, volume decreases
* Pressure in the lungs is now higher than the pressure in the atmosphere **
* Air is forced out **of your lungs to the exterior environment

Question 7

3 main tobacco drugs

Answer 7

nicotine, carbon monoxide, tar

Question 8

effects of nicotine on humans

Answer 8

• increase heartbeat rate and blood pressure
• increase the risk of blood clots in the arteries (leads to coronary heart disease
• risk of arteries to narrow (miscarriage)

Question 9

effects of carbon monoxide on humans

Answer 9

• Reduced the ability of blood to transport oxygen as carbon monoxide binds permanently with haemoglobin, less haemoglobin available to transport oxygen
• Increase risk of coronary heart disease

Question 10

effects of tar on humans

Answer 10

• Increases the risk of cancer in the lungs as tar can cause uncontrolled cell division
• Increases the risks of chronic bronchitis and emphysema
  (tar paralyses the cilia lining the air passages, dust particles trapped in the mucus lining cannot be removed)

Question 11

diseases caused by tobacco smoke

Answer 11

chronic bronchitis, emphysema, lung cancer

Question 12

causes of chronic bronchitis

Answer 12

• Prolonged exposure of the lungs to irritants
• Inflamed linings of bronchus secrete excessive mucus
• Cillia on cells of linings become paralysed
• Dust-trapped mucus cannot be removed
• Blocked airways
• Persistent coughing
• Lung infections

Question 13

causes of emphysema

Answer 13

• Breakdown of partition walls of alveoli
• Reduced surface area for gaseous exchange
• Reduced elasticity of lungs
• Lungs becomes inflated
• Wheezing and severe breathlessness

Question 14

causes of lung cancer

Answer 14

• Lumpy tissue due to uncontrolled growth of cells