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Secondary 3 Biology > respiration in humans > Flashcards

respiration in humans Flashcards

1
Q

what is respiration?

A

oxidation of food substances with the release of energy in living cells

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2
Q

what is aerobic respiration?

A
  • breakdown of food molecules in the presence of O2 with the release of a large amount of energy, CO2 and water are released as waste products
  • occurs in mitochondria of all cells
  • energy consuming processes : cell division, synthesis of proteins from amino acids
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3
Q

what is the word equation for aerobic respiration?

A

glucose + oxygen –> carbon dioxide + water + large amount of energy released

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4
Q

what is anaerobic respiration?

A

breakdown of food substances in absence of oxygen. Releases less energy than aerobic respiration

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5
Q

what is the word equation for fermentation (plants and yeasts)

A

glucose –> ethanol + carbon dioxide + small amount of energy released

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6
Q

what is the energy conversion in muscle cells?

A
  • during exercise, muscles contract vigoursly to enable movement
  • respiratory rate and heart rate increases to enable more O2 to reach muscles for faster rate of respiration to release more energy
  • if increased oxygen intake is not able to meet the oxygen demand, an oxygen debt results and anaerobic respiration takes place to provide energy required
  • anaerobic respiration results in accumulation of lactic acid in muscle cells
  • lactic acid accumulation can cause fatigue and muscular pains
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7
Q

what is the word equation of anaerobic respiration for human muscles?

A

glucose –> lactic acid + small amount of energy released

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8
Q

what is oxygen debt?

A
  • since there is insufficient O2 to meet the demands of vigorous muscular contractions, oxygen debt incurrs
  • during periods of rest, breathing rate continues to be fast for some time. Provide sufficient O2 to muscle cells to repay O2 debt
  • lactic acid is gradually removed from muscles and transported to the liver
  • in liver, some lactic acid is oxidised to release energy
  • this energy is used to convert remaining lactic acid to glucose
  • when all lactic acid is converted, O2 debt is repaid
  • glucose transported back to muscles
    note: sprint –> anaerobic
  • bc within short period of time, O2 supply to muscles is insufficient for aerobic respiration to meet energy needs
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9
Q

what are the similarities between aerobic and anaerobic respiration?

A
  • both release energy for cellular activities

- both involves breakdown of glucose

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10
Q

what are the characteristics of aerobic respiration?

A
  • requires O2 to be present
  • releases large amount of energy
  • breakdown glucose to water and carbon dioxide
  • occurs in mitochondria
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11
Q

what are the characteristics of anaerobic respiration?

A
  • does not require O2 to be present
  • releases small amount of energy
  • breaks down glucose to lactic acid in humans, breaks down glucose to ethanol and carbon dioxide in plants
  • occurs in cytoplasm
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12
Q

what is the function of nasal passage?

A
  • air usually enters from external nostrils
  • walls of nostrils bear a fringe of hairs
  • nostrils lead to two nasal passages which are lined with moist mucous membrane
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13
Q

what are the advantages of breathing through the nose?

A
  • dust, foreign particles and some bacteria are trapped by hair in the nostrils and mucus on mucous membrane
  • air can be warmed and moistened
  • harmful chemicals may be detected by sensory cells in the mucous membrane
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14
Q

what happens from the nose to trachea?

A
  • air in nasal passage enters the pharynx. From there, air passes into larynx and into trachea through glottis
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15
Q

what is the function of trachea?

A
  • supported by C-shaped rings of cartilage
  • keeps lumen of trachea open
  • membrane next to lumen is epithelium which consists of:
  • gland cells that secrete mucus to trap dust particles and bacteria
  • ciliated cells that have hair-like structures called cilia on their surface. The cilia sweep the dust-trapped mucus up the trachea
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16
Q

what is the function of the bronchi and bronchioles?

A
  • trachea divides into two tubes called bronchi
  • each bronchus carries air into lungs
  • similar in structrues to trachea
  • each bronchus branches repeatedly, giving rise to numerous bronchioles
  • v fine tubes
  • each bronciole ends in cluster of air sacs or alveoli
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17
Q

what is the function of the alveoli (air sacs)?

A
  • gas exchange takes place through the walls of alveoli

- numerous alveoli in lungs increase surface area to volume ratio for faster gaseous exchange

18
Q

how are lungs adapted?

A
  • numerous alveoli in the lungs
  • walls of alveoli are richly supplied with blood capillaries
  • wall of alveolus is one cell thick
  • surface of the alveolus is covered with thin film of moisture
19
Q

why are there numerous alveoli in the lungs?

A

increase surface area to volume ratio for faster gaseous exchange

20
Q

why are the walls of alveoli richly supplied with blood capillaries?

A

constant flow of blood maintains concentration gradient of gases

21
Q

why is the wall of alveolus one cell thick?

A

shorter diffusion distance increases rate of diffusion of gases through it

22
Q

why is the surface of the alveolus covered with thin film of moisture?

A

allows oxygen to dissolve in it

23
Q

what happens during gaseous exchange in the lungs?

A
  • gas exchange in lungs occur by diffusion
  • blood entering lungs has a lower concentration of O2 and higher concentration of CO2 than atmospheric air entering alveoli in the lungs
  • concentration gradient for O2 and CO2 is set up between blood and alveolar air
  • O2 diffuses from alveolar air into blood capillaries
  • CO2 diffuses in opp. direction
  • O2 and CO2 concentration maintained by:
    # continuous flow of blood through blood capillaries
    # movement of air in and out of alveoli, caused by breathing
24
Q

how is oxygen absorbed in your lungs?

A
  1. the one cell thick alveolar wall that separates blood capillaries from the alveolar air is permeable to O2 and CO2
  2. since the alveolar air contains a higher conc. of O2 than the blood, O2 dissolves in the moisture lining the alveolar walls and diffuses into blood capillaries
  3. oxygen combines with haemoglobin in rbc to form oxyhaemoglobin. This reaction is reversible
  4. in lungs where O2 conc is high, oxygen combines with haemoglobin to form oxyhaemoglobin
  5. when blood passes through oxygen-poor tissues, the oxyhaemoglobin releases O2, which then diffuses through walls of blood capillaries into the cells of the tissues
25
Q

how is carbon dioxide from lungs?

A
  1. tissue cells produce a large amount of CO2 as a result of aerobic respiration
  2. as blood passes through these tissues via blood capillaries, CO2 diffuses into the blood and enters rbc
  3. CO2 reacts with water in rbc to form carbonic acid. This reaction is catalysed by carbonic anhydrase in rbc
  4. carbonic acid is converted into hydrogencarbonate ions which diffuse out of rbc
    small amount of CO2 is transported and dissolved in rbc
  5. in lungs, hydrogencarbonate ions diffuse back into rbc where they are converted into carbonic acid and then into water and carbon dioxide by carbonic anhydrase
  6. CO2 then diffuses out of the blood capillaries and into alveoli, where it is expelled when you breathe out
26
Q

what is the chest cavity?

A
  • support by ribs
  • two sets of muscles - internal and external intercoastal muscles
  • antagonistic (one relax, one contract)
27
Q

what does the diaphragm do?

A
  • dome shape sheet of muscle and elastic tissue that contracts and relaxes to change volume of thoracic cavity
28
Q

what happens during inhalation?

A
  • Relax
  • Internal intercoastal muscles
  • Contract
  • External intercoastal muscles
29
Q

what happens during exhalation?

A
  • External
  • Relax
  • Internal
  • Contract
30
Q

how to explain inspiration and expiration?

A
  1. external intercoastal muscles contract/relax, internal intercoastal muscles relax/contract
  2. ribs move upwards/downwards and outwards/inwards
    3/ diaphragm muscles contract/relax and flattens/arches upwards
    4.
30
Q

how to explain inspiration and expiration?

A
  1. external intercoastal muscles contract/relax, internal intercoastal muscles relax/contract
  2. ribs move upwards/downwards and outwards/inwards
  3. diaphragm muscles contract/relax and flattens/arches upwards
  4. volume of thoracic cavity increases/decreases
  5. lungs expand/compress and pressure decreases/increases
  6. atmospheric pressure higher/lower than lungs, thus forces atmospheric air into lungs/air is force out of lungs to exterior environment
  7. sternum moves up and forward/down to original position
31
Q

what is the properties of nicotine?

A
  • addictive and causes the release of adrenaline

- makes blood clot easily

32
Q

what are the effects of nicotine?

A
  • increases heart rate and blood pressure

- increases risk of blood clot in arteries –> lead to increased risk of coronary heart disease

33
Q

what are the properties of carbon monoxide?

A
  • combines with haemoglobin to form oxyhaemoglobin

- increases rate of fatty deposits on the inner arterial wall, which leads to increased risk of coronary heart disease

34
Q

what are the effects of carbon monoxide?

A
  • reduces ability of blood to carry oxygen

- narrows lumen of arteries and leads to increase in blood pressure

35
Q

what are the properties of tar?

A
  • causes uncontrolled cell division

- paralyses cilia lining in the air passages

36
Q

what is the effect of tar?

A
  • increases risk of cancer in lungs
  • dust particles trapped in mucus lining the air passages cannot be removed, increasing risk of chronic bronchities and emphysema
37
Q

what are the properties of irritants (hydrogen cyanide)?

A
  • paralyse ciliar lining in the air passages
38
Q

what is the effect of irritants?

A

dust particles trapped in mucus lining air passages cannot be removed, increasing risk of chronic bronchities and emphysema

39
Q

what is chronic bronchitis?

A
  • epithelium lining of air passages becomes inflames
  • excessive mucus is secreted by epithelium
  • cilia on epithelium is paralysed
  • muscus and dust particles cannot be removed
  • air passages become blocked
  • makes breathing difficult
  • persistent coughing to clear air passages
  • increased risk of lung infection
40
Q

what is emphysema?

A
  • persistent and violent coughing due to bronchities can lead to emphysema
  • partition walls between alveoli break down
  • results in decreased surface area for gaseous exchange
  • lungs lose elasticity and become inflated with air
  • breathing becomes difficult
  • wheezing and sever breathlessness result in chronic obstructive lung disease

Secondary 3 Biology (13 decks)

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