7 — respiration in humans Flashcards

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1
Q

Respiration

A
  • the breaking down of food molecules such as glucose to release energy.
  • Glucose + 6O2 -> 6CO2 + 6H2O + energy (converted to heat)
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2
Q

Aerobic respiration

A

Is the release of large amount of energy by the oxidation of glucose in the presence of oxygen. Carbon dioxide and water are released as waste products.

Glucose + Oxygen -> carbon dioxide + water + large amount of energy
C6H12O6 + 6O2 -> 6CO2 +. 6H2O + large amount of energy

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3
Q

Anaerobic respiration

A

Is the release of energy by the oxidation of glucose in absence of oxygen. Anaerobic respiration releases relatively lesser amount of energy as compared to aerobic respiration and releases lactic acid as waste product.

Glucose -> lactic acid + small amount of energy

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4
Q

Test for aerobic respiration

A

Test CO2 as one of by products:
- Hydrogencarbonate indicator setup
- Limewater

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5
Q

Test for anaerobic respiration

A

CO2 given off during fermentation in yeast:
- Glucose solution boiled n cooled to remove dissolved O2 from solution
- Limited O2 available to yeast -> anaerobic respiration occurs
- Limewater will form white precipitate in presence of CO2 from anaerobic respiration of yeast

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6
Q

Process of respiration

A
  1. Exercise – Increases muscle contractions →energy requirement increases
  2. Heartbeat rate and breathing ^ to increase blood supply rich in O2 and glucose to muscles + ^gaseous exchange to obtain ^ oxygen, remove CO2 faster
  3. Continuous muscle contractions occur
  4. Energy from maximum rate of aerobic respiration is insufficient to supply increased demand, oxygen deficit occurs
  5. Anaerobic respiration occurs to meet high energy demand
  6. Production of lactic acid -> oxygen debt + definition (Glucose -> lactic acid) →Accumulation
  7. High heart n breathing rate continues to repay oxygen debt n remove lactic acid from muscles
  8. Lactic acid transported to liver is oxidised to release energy to convert remaining lactic acid to glucose
  9. Transported back to liver to store as glycogen
  10. Fatigue, muscular pains, cramps occurs
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7
Q

Oxygen debt

A

the volume of oxygen required to break down the lactic acid produced in muscles during anaerobic respiration

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8
Q

Oxygen deficit

A

The difference between the oxygen the body needs during the activity and what it actually managed to take in is called oxygen deficit.

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9
Q

How oxygen debt is paid

A
  • Continued fast heart rate
    • to transport lactic acid from muscles to liver via blood for removal
    • transport oxygen from lungs to liver
  • Continued deeper and faster breathing
    • to obtain oxygen for supply to liver for removal of lactic acid to pay oxygen debt
  • In the liver, oxygen is used to oxidise some lactic acid to release energy -> used to convert the remaining lactic acid back to glucose to store inside liver as glycogen.

Oxygen debt is paid when lactic acid is removed.

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10
Q

Nose’s adaptations and functions

A

A fringe of hairs on walls of nostrils
- Dust & foreign particles, including bacteria r trapped by the hairs in the nostrils and the mucus on the mucous membrane.

2 nasal passages lined with a moist mucous membrane
- Air is warmed & moistened
- Harmful chemicals can be detected by small sensory cells in mucous membrane

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11
Q

Trachea

A

Contains thin epithelium membrane next to lumen
- Epithelium consists of :
Gland/goblet cells -> secrete mucus to trap dust particles & bacteria

Cartilage keeps lumen of trachea open
- Ciliated cells -> hv cilia (hair-like structures) on their surfaces to sweep dust trapped mucus up trachea

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12
Q

Gas exchange in alveoli

A
  • Blood entering lungs hv lower conc of O2, ^CO2 than atmospheric air entering alveoli in lungs -> steep conc gradient for O2 and CO2 betw blood n alveolar air maintained by continuous blood flow thru capillaries & breathing -> faster rate of diffusion of gases
  • O2 dissolves into thin film of moisture on alveolar wall
  • Dissolved O2 diffuses thru wall of alveolus n wall of blood capillary into RBCs
  • O2 combines with haemoglobin to form oxyhaemoglobin
  • CO2 diffuses from blood into alveolar air
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13
Q

Inhalation/inspiration

A
  1. Diaphragm muscle contracts & flattens.
  2. External intercostal muscles contract while internal intercostal muscles relax
  3. Rib cage swings upwards and outwards. Sternum moves up and forward.
  4. Volume of thoracic cavity increases, lungs expand and air pressure inside decreases.
  5. Atmospheric pressure is higher than pressure in lungs Thus air is forced into the lungs.
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14
Q

Exhalation/ expiration

A
  1. Diaphragm muscle relaxes & arches upwards.
  2. External intercostal muscles relaxes while internal intercostal muscles contracts
  3. Ribs swings downwards and inwards. Sternum moves down to original position
  4. Volume of thoracic cavity decreases, lungs compressed and air pressure inside increases.
  5. Atmospheric pressure is lower than pressure in lungs -> air is forced out of lungs into exterior env
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15
Q

Lung cancer cause n effects

A

C: Tobacco smoking ^risk
E: Lumpy tissue due to uncontrolled growth of cells

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16
Q

Chronic bronchitis Cause and effect

A

C: Prolonged exposure to irritant particles that are found in tobacco smoke

E:
- Epithelium lining of air passages becomes inflamed.
- Excessive mucus secreted by epithelium.
- Cilia on the epithelium paralyzed. Mucus and dust particles cannot be removed.
- Air passages blocked, breathing becomes difficult.
- Persistent cough to clear air passages, in order to breathe. This increases the risk of getting lung infections.

17
Q

Emphysema Cause n effect

A

C: Persistent and violent coughing due to bronchitis may lead to emphysema.

E: - Partition walls between alveoli break down due to persistent and violent coughing.
- This results in a decreased surface area for gaseous exchange.
- Lungs lose their elasticity and become inflated with air.
- Breathing becomes difficult. Wheezing and severe breathlessness.

18
Q

For strenuous exercises, 20% of energy comes from aerobic respiration whereas 80% of energy comes from anaerobic respirations.
For less strenuous exercises, 80% of energy comes from aerobic respiration whereas 20% of energy comes from anaerobic respirations. Explain the statements. [6]

A
  1. The energy demand for more strenuous is higher than the energy demand for less strenuous exercises [1]
  2. There is insufficient transport of oxygen / supply of oxygen to the muscle tissues for aerobic respiration [1]
  3. Therefore athletes doing strenuous exercises obtain the remaining large proportion of energy required to meet energy demand by anaerobic respiration [1]
  4. In less strenuous exercises, the energy demand is lower than the energy demand for more strenuous exercises [1]
  5. There is sufficient transport of oxygen / supply of oxygen to the muscle tissues for aerobic respiration in releasing large amount of energy [1]
  6. Therefore athletes doing less strenuous exercises obtain the remaining small proportion of energy required to meet energy demand by anaerobic respiration [1]
19
Q

Explain why oxygen uptake remains high during post-exercise. [4]

A
  • To repay oxygen debt [1]
  • Lactic acid is removed from muscles and transported to liver for detoxification [1]
  • Some of the lactic acid is oxidised to carbon dioxide and water, releasing energy. [1]
  • Energy is used to convert the remaining lactic acid to glucose, which is then transported back to the muscles. [1]
  • Excess glucose to convert into glycogen to be stored in the liver or muscles [1]
20
Q

Compare and contrast between aerobic and anaerobic respirations in humans. [5]

A

Similarities:
- Both aerobic and anaerobic respiration release energy for cellular activities. [1]
- Both aerobic and anaerobic respiration involves the oxidation of glucose as substrate. [1]
- Both aerobic and anaerobic respiration involve enzymatic reactions.

Differences:
-Aerobic respiration involves the use of oxygen while anaerobic respiration does not involve oxygen. [1]
- Aerobic respiration releases large amount of energy but anaerobic respiration releases small amount of energy. [1]
- Aerobic respiration involves the breakdown of glucose to water and carbon dioxide but anaerobic respiration involves the breakdown of glucose to lactic acid (in humans) and to ethanol and carbon dioxide (in plants). [1]
- Aerobic respiration occurs in the mitochondria but anaerobic respiration occurs in the cytoplasm. [1]

21
Q

Describe the adaptations of the alveoli / alveolus in gaseous exchange. [4]

A
  1. Numerous alveoli in the lungs; to Increase surface area to volume ratio of faster rate of diffusion and exchange of gases. [1]
  2. Walls of alveoli are richly supplied with blood capillaries; constant flow of blood to maintain steep concentration gradient of O2 and Co2 between blood and air in the alveoli for more efficient diffusion. [1]
  3. Wall of each alveolus is one cell thick; shorter diffusion distance to increase rate of diffusion of gases through it. [1]
  4. Surface of alveolus is covered with a thin film of moisture; to allow oxygen to dissolve in it. [1]
22
Q

Describe the mechanism of inhalation and the impact of a punctured lung on the breathing process. [6]

A

Mechanism
- Diaphragm muscle contracts and flattens down.
- External intercostal muscles contract and internal intercostal muscles relax, rib cage is raised upwards and outwards
- Thoracic volume increases, pressure in the lung decreases, pressure difference cause air to be forced into the lungs
Impact
- Free exchange of air between external environment and inside thoracic cavity
- No pressure difference can be generated
- No air will be forced into the lung, no gaseous exchange

23
Q

Describe and explain the effects of smoking on pregnant mothers. [4]

A
  • Tobacco smoke contains carbon monoxide [1]
  • Carbon monoxide binds strongly/more readily and irreversibly to haemoglobin in red blood cells to form carboxyhaemoglobin [1]
  • hence decreasing the oxygen carrying capacity of the red blood cells. [1] Carbon monoxide also increases the risk of atherosclerosis and blood clotting in the arteries.
  • Developing fetus will have insufficient oxygen, glucose and nutrient supply to release less energy during reduced rate of aerobic respiration for normal development hence has lower growth rate. [1]

Effects of foetus:
Harmful substances such as nicotine, alcohol and drug molecules are able to diffuse across the placenta from the mother to the fetus and cause severe damage to the fetus’s development.

24
Q

Name the structure most similar to a plunger in syringe (a model) in the respiratory system. Explain how these two structures are similar. [2]

A

Diaphragm. [1] Muscles in the diaphragm contract and causing the diaphragm to
flatten downwards to increase the volume of the thoracic cavity during inspiration.
[1]

25
Q

Suggest why the number of deaths from lung cancer in smokers is much greater than in non-smokers [1]

A

Cigarette smoke contains carcinogenic substances such
as tar which increases the risk of lung cancer.

26
Q

Explain why smoking can cause coronary heart disease which can result in death. [4]

A

Smoke contains carbon monoxide/nicotine which creases the rate of fatty deposits on the wall of coronary arteries/atherosclerosis [1]
narrows lumen + increase blood pressure [1]
blood rich in O2 and glucose r insufficiently supplied to heart muscles [1]
heart muscle cells cannot release enough energy via oxidation of glucose during aerobic respiration + leading to heart attack and death [1]

27
Q

Describe and explain the effect of emphysema on gaseous exchange. [2] / Effect of smoking on alveolus

A

Partition walls between alveolus is damaged
decreased surface area for gaseous eexchange
leading to slower rate of gaseous exchange

28
Q

Explain why the oxygen used increases as the level of exercise increases. [4]

A
  • Increased exercise increases muscular contractions which increases energy demand [1];
  • resulting in an increased rate of respiration [1]
    to release more energy [1];
  • which increases oxygen demand to fuel an increased rate of aerobic respiration. [1]
29
Q

Define breathing

A

involves movement of air in n out of lungs

30
Q

State the circumstances which anaerobic respiration occurs in humans and the effects of the process on muscle cels. [5]

A

When humans perform vigorous exercises like a sprint. [1]
The maximum rate of aerobic respiration in the muscle cells is unable to release enough energy to meet the high energy demand. [1]
There is also insufficient oxygen and as a result, muscle cells will carry out anaerobic respiration to release and supplement the energy needed to meet the high energy demand. [1]
Lactic acid is produced by anaerobic respiration in the muscles cells. [1]
The built up of lactic acid concentration in the muscle cells results in fatigue in the muscle and muscle pain. [1]

31
Q

State and explain what effect an oxygen saturation of 91% will have when the person is walking up the stairs. [3]

A

Heart rate and breathing rate of the person increases, as the
person will have lesser oxygen transported to his tissue cells / muscles for aerobic respiration. [1]
Lesser energy will be released which is insufficient to meet the high energy demand due to increased muscular contractions when the person climbed up the stairs. [1]
Tissue cells/ muscles will need to undergo anaerobic respiration to release energy to meet the increased energy demand, producing lactic acid and this will cause muscle fatigue/ pain/ tiredness. [1]

32
Q

State which blood vessel in human will have the highest oxygen saturation and give a reason. [2]

A

Pulmonary vein [1]
Blood in the blood capillaries surrounding the alveoli in the lungs are fully oxygenated before transported to the pulmonary vein. [1]

33
Q

Suggest and explain how high altitudes affect the uptake of oxygen from the alveoli into the blood of a person climbing a mountain. [2]

A

High altitude has lower air pressure and lower
concentration of oxygen. The concentration gradient between the air and the blood in the lungs is less steep [1], thus rate of diffusion of oxygen from air/ atmosphere into the blood in the lung will decrease. [1]
Less oxygen will bind to haemoglobin in red blood cells thus less oxygen is transported in body tissues.

34
Q

State the form in which water is lost from the lungs. [1]

A

Water vapour

35
Q

Suggest how insulin taken by breathing it in enters the blood. [2]

A

Insulin enters the alveoli and dissolves in the layer of moisture on the inner walls of the alveoli. Higher concentration of insulin in alveoli than in the blood, [1] hence it diffuses down a concentration gradient from the alveoli into the blood capillaries and dissolve in the blood plasma. [1]