Ch 7 Respiration in Humans

Question 1

What are the two types of respiration?

Answer 1

Aerobic and anaerobic.

Question 2

What is respiration?

Answer 2

The breakdown of food molecules such as glucose to release energy.

Question 3

What is aerobic respiration in terms of:
1. What does it break down
2. Does it require oxygen
3. What are the waste products
4. Amount of energy released

Answer 3

Aerobic respiration releases energy by
1. Breaking down glucose
2. In the presence of oxygen
3. Carbon dioxide and water are released in the process
4. A large amount of energy is released

Equation:
Glucose + Oxygen -> Carbon dioxide + Water

Question 4

Factors affecting the rate of aerobic respiration?

Answer 4

1. Heart rate
2. Breathing rate
3. Depth of breaths

By increasing these 3 factors, the rate of aerobic respiration is increases, increasing the amount of energy released for vigorous muscular contractions.

Question 5

Where does aerobic respiration take place?

Answer 5

Mitochondria.

Question 6

What is anaerobic respiration in terms of:
1. What does it break down
2. Does it require oxygen
3. What are the waste products
4. Amount of energy released

Answer 6

Anaerobic respiration releases energy by
1. Breaking down glucose
2. In the absence of oxygen
3. Lactic acid is produced in the process
4. A relatively small amount of energy is released

Equation:
Glucose -> Lactic acid + Relatively small amount of energy

Question 7

When does the body use anaerobic respiration?

Answer 7

When muscle contractions are so vigorous that the maximum rate of aerobic respiration is unable to release energy fast enough to meet the demand.

Question 8

Where does anaerobic respiration take place?

Answer 8

Muscles.

Question 9

How is oxygen debt incurred?

Answer 9

There is an insufficient intake of oxygen to meet the energy demand for vigorous muscular contractions. Thus an oxygen debt is incurred.

Question 10

How is oxygen debt removed?

Answer 10

1. Continuation of fast heart rate
   Results in the faster transportation of
   - Lactic acid from the muscles to the liver
   - Oxygen from the lungs to liver
2. Continuation of deeper and faster breathing
   Results in
   - Continued and fast intake of oxygen by the lungs
   - Oxygen is needed for the removal of lactic acid

Once lactic acid is removed, oxygen debt is repaid.

Question 11

Parts of the respiratory system? (In order of air flow)

Answer 11

1. Nasal passages
2. Pharynx
3. Larynx
4. Trachea
5. Bronchi
6. Bronchioles
7. Alveoli

Question 12

What is the role of cilia in the trachea?

Answer 12

Cilia sweeps dust-trapped mucus to the pharynx to be coughed out or swallowed.

Question 13

How is the lung adapted for efficient gaseous exchange?

Answer 13

1. Numerous alveoli: Large surface area

Alveoli:
2. One-cell thick wall: Short diffusion distance
3. Thin film of moisture on the walls: Allows oxygen to dissolve
4. Surrounded by numerous blood capillaries: Flow of blood maintains steep gas concentration gradient

Question 14

How does gaseous exchange occur in the lungs?

Answer 14

OXYGEN:
1. Oxygen dissolves into the thin film of moisture on the alveolar walls.
2. Dissolved oxygen diffuses through the alveolar wall and the blood capillary wall, into the blood cells.
3. Oxygen combines with haemoglobin to form oxyhaemoglobin.

CARBON DIOXIDE:
1. Carbon dioxide diffuses from the blood capillaries to the alveolar cavity.

Question 15

What happens when you inhale?

Answer 15

1. Diaphragm muscle contracts, diaphragm flattens.
2. Internal intercostal muscles relax and external intercostal muscles contract. (RICE)
3. Ribs and sternum move upward and forward.
4. Volume of the thoracic cavity increases.
5. Air pressure in the lungs drop to become lower than that of the atmosphere.
6. Air moves from the surroundings into the lungs.

Question 16

What happens when you exhale?

Answer 16

1. Diaphragm muscle relaxes, diaphragm arches upwards.
2. External intercostal muscles relax, internal intercostal muscles contract.
3. Ribs and sternum move downward and inward.
4. Volume of thoracic cavity decreases.
5. Air pressure in the lungs increase to become higher than that of the atmosphere
6. Air moves out of the lungs.

Question 17

Harmful chemicals in tobacco smoke?

Answer 17

1. Tar
2. Nicotine
3. Carbon monoxide

Question 18

What effect does nicotine have on the respiratory system?

Answer 18

1. Increases heart rate and blood pressure.
2. Increases the risk of blood clots in arteries, which increases the risk of coronary heart disease.
3. Narrows arteries (In a pregnant mother, this can cause fetal development issues due to less oxygen and nutrients reaching the fetus from the mother. Potentially results in miscarriage.)

Question 19

What effect does carbon monoxide have on the respiratory system?

Answer 19

1. Reduces the ability of oxygen to bind with haemoglobin, as carbon monoxide binds irreversibly to the haemoglobin at a higher affinity (more likely to) than oxygen does -> less absorption of oxygen -> lower rate of aerobic respiration -> less energy released -> fatigue
   - In a pregnant mother, less oxygen reaches the fetus, resulting in fetal development issues.
2. Increases the risk of coronary heart disease.

Question 20

What effect does tar have on the respiratory system?

Answer 20

1. Increases the risk of lung cancer, as tar can cause uncontrolled cell division.
2. Increases the risk of chronic bronchitis and emphysema.
   - Tar paralyses the cilia hairs, so dust-trapped mucus cannot be removed.

Question 21

Diseases caused by tobacco smoke?

Answer 21

1. Chronic bronchitis
   Prolonged exposure to irritants -> Lung epithelium lining become inflamed -> Excessive mucus produced by the epithelium lining -> Cilia become paralysed by the excessive mucus -> Dust trapped in mucus -> Air passages become blocked, difficult to breathe -> Persistent coughing to clear the air passages
   (Can lead to emphysema and increase the risk of lung infections)
2. Emphysema
   Persistent and violent coughing due to bronchitis -> Partition walls between alveoli break down -> Decreased surface area for efficient gaseous exchange -> Lungs lose their elasticity and remain inflated with air -> Wheezing, breathlessness
3. Lung cancer
   Tar in tobacco smoke can cause uncontrolled cell division.