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Sec 3 Pure Bio > Respiration In Humans > Flashcards

Respiration In Humans Flashcards

1
Q

Why do we respire?

A
  • need energy to live (move, grow, excrete, reproduce)
  • oxidation is the process where food molecules as broken down to use energy available in food
  • oxidation of food molecules to produce energy is called respiration
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2
Q

Aerobic respiration

A
  • breakdown of food molecules in presence of oxygen
  • produces large amts energy
  • waste products: CO2, H2O
  • chemical eqn: C6H1206 +602 to 6C02+6H2O+energy
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3
Q

ATP

A
  • energy released during respiration is stored in a small molecule called adenosine triphosphate (ATP)
  • main energy currency used in all cells
  • energy released when a phosphate bond is broken
  • ATP converted to ADP (Adenosine diphosphate)
  • aerobic respiration occurs in mitochondria of cells
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4
Q

Anaerobic respiration

A
  • breakdown of food molecules is absence of oxygen
  • also know as incomplete oxidation of oxygen
  • release less energy, produce lactic acid
  • C6H12O6 to 2C3H6O3 (lactic acid) +energy
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5
Q

Anaerobic respiration in humans

A
  • formation of lactic acid/ lactic acid fermentation
  • glucose partially broken down
  • lactic acid produced still contains energy, only small amt of energy is released
  • energy released helps muscles to keep contracting
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6
Q

What happens during exercise and why?

A
  • muscles contract vigorously to enable movement
  • respiratory and heart rate increase to allow more oxygen to reach the muscles
  • if increased oxygen intake is unable to meet oxygen demand, resulted in oxygen debt and anaerobic respiration to provide the energy required
  • oxygen debt is the vol of oxygen required to remove lactic acid that has built up
  • anaerobic respiration results in the accumulation of lactic acid
  • accumulation of lactic acid can result in muscle fatigue
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7
Q

Recovery

A
  • during period of rest, breathing rate remains fast to provide sufficient oxygen to muscle cells and repay oxygen debt
  • lactic acid gradually removed from muscles and transported to liver
  • in liver, some of the lactic acid is oxidized to release energy, energy used to convert rest of lactic acid to glucose
  • once all lactic acid has been converted, oxygen debt is repaid
  • glucose then transported back to muscles
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8
Q

Anaerobic respiration in plants

A
  • yeast releases ethanol (alcohol) and carbon dioxide as waste products (irreversible)
  • called alcoholic fermentation
  • chemical eqn: C6H12O6 to C2H5OH +CO2+ small amts of energy
  • glucose only partially broken down
  • ethanol produced contains energy, small amt of energy released
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9
Q

Differences between alcoholic and lactic acid fermentation (where it occurs)

A

Alcoholic fermentation: plants and yeast

Lactic acid fermentation: mammals

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10
Q

Differences between alcoholic and lactic acid fermentation (Waste products)

A

Alcoholic fermentation: ethanol and carbon dioxide

Lactic acid fermentation: lactic acid, no carbon dioxide

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11
Q

Differences between alcoholic and lactic acid fermentation (oxidation/conversion to glucose)

A

Alcoholic fermentation: ethanol cannot be further oxidized or converted back to glucose
Lactic acid fermentation: can be oxidized and converted back to glucose

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12
Q

Difference between respiration and photosynthesis

energy

A

Respiration: energy released
Photosynthesis: energy stored in carbohydrate molecules

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13
Q

Difference between respiration and photosynthesis

uses and products

A

Respiration: oxygen used, CO2 and water given off
Photosynthesis: CO2 and water used, O2 given off

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14
Q

Difference between respiration and photosynthesis

catabolic/anabolic process

A

Respiration: catabolic process, breakdown of carbohydrate molecules
Photosynthesis: anabolic process, building up of carbohydrate molecules

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15
Q

Difference between respiration and photosynthesis

where it occurs

A

Respiration: occurs at all times in all cells, independent of chlorophyll and sunlight
Photosynthesis: occurs only in cells containing chlorophyll and in presence of sunlight

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16
Q

Difference between respiration and photosynthesis

dry mass

A

Respiration: results in loss of dry mass
photosynthesis: results in gain of dry mass

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17
Q

Why do we need a respiratory system?

A
  • humans are large organisms, made up of millions of cells, small SA:V unlike unicellular organisms
  • need a special system of organs for gaseous exchange between cells in body and environment
  • mechanism of exchange is called external respiration, involves a process called breathing
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18
Q

Nasal passage

A
  • fringe of hairs and mucous layer on walls of nasal passage
  • trap dust, microorganisms
  • as air passes thru the air passages it is warmed and moistened
19
Q

Trachea

A
  • supported by c-shaped rings of cartilage

- ensures trachea is always open and does not collapse

20
Q

Gland cells

A
  • in inner walls of trachea and bronchi

- gland cells secrete mucus, trap dust particles and bacteria in air that enters lungs

21
Q

Ciliated cells

A
  • in inner walls of trachea and bronchi

- have cilia that sweep trapped particles and bacteria up the bronchi and trachea, into pharynx

22
Q

Bronchus and alveoli

A
  • lungs lie in pleural cavity
  • bronchial tubes divide repeatedly to form bronchioles
  • bronchioles end in cluster of air sacs aka alveoli
23
Q

Flow of air entering body

A
  1. nostrils
  2. nasal passages
  3. pharynx
  4. larynx
  5. trachea
  6. bronchi
  7. bronchioles
  8. alveoli
24
Q

The alveoli

A
  • site of gaseous exchange
  • numerous alveoli increase SA:V for gaseous exchange
  • rate of diffusion between alveoli and capillaries increase
25
Q

Alveoli features and their uses

A
  • well-supplied with blood capillaries, enable efficient gaseous exchange, maintains conc gradient
  • alveolar surface coated with thin film of water, allow gases to dissolve in it (for diffusion)
  • wall of each alveolus is 1 cell thick, supplied by 1 cell thick capillaries (decreases distance for diffusion)
26
Q

Gaseous exchange in the alveolus

A
  1. blood entering lungs has lower conc of oxygen and high conc of CO2 than inhaled air in the alveolus
  2. CO2 from blood diffuses into the alveolus and is channeled out of lungs via expiration
  3. air in alveolus high conc of O2, lower conc of CO2 than blood entering lungs
  4. O2 in alveolus diffuses into blood in capillary vessels, transported to heart where it is pumped throughout the body
27
Q

How oxygen is transported

A

-oxygen molecules bind to haemoglobin (Hb) in rbc to form oxyhaemoglobin

28
Q

How O2 is absorbed in the lungs

A
  • 1 cell thick alveolar wall that separates blood capillaries from alveolar air is permeable to O2 and CO2
  • alveoli air contains high conc of O2 than blood, O2 dissolves in the moisture lining of the alveolar walls, diffuses into blood capillaries
  • O2 combine with Hb to form oxyhaemog-lobin (reversible)
  • direction depends on amt of O2 in surroundings
  • lungs where O2 conc is high, O2 combine with Hb to form oxyhaemoglobin
  • blood pass thru oxygen-poor tissues, oxyhaemoglobin releases oxygen which diffuses thru wall of blood capillaries into cell of tissues
29
Q

How carbon dioxide is transported

A
  • CO2 react with water to form carbonic acid
  • reaction catalysed by carbonic anhydrase
  • carbonic acid then converted into hydrogencarbonate ions which will diffuse out of rbc and into blood plasma
  • in lungs, hydrogen carbonate ions are converted back into carbonic acid and then to carbon dioxide
  • diffuses out of blood capillaries in cavity of the alveolus, expelled when breathe out
30
Q

Diaphragm

A

-a dome-shaped sheet of muscle and elastic tissue that contracts and relaxes to change the vol of thoracic cavity

31
Q

Inspiration (RICE)

A
  • internal intercostal muscles relax, external contract)
  • rib cage raised upwards and outwards
  • thoracic vol increases
  • diaphragm contracts and flattens down
32
Q

Expiration (ERIC)

A
  • external intercostal relax, internal contract
  • rib cage downwards and inwards
  • thoracic vol decreases
  • diaphragm relaxes and arches upwards
33
Q

Stimulus for breathing

A
  • caused by high conc of CO2 in blood or alveolar air, not lack of O2
  • when there is too little CO2 in lungs, breathing does not occur
34
Q

Stimulus for breathing experiment

A
  • number of breaths per minute taken by human subjects breathing in:
    (i) Atmospheric air 21% O2, 0.03 CO2 (stable breathing)
    (ii) 100% pure O2 (breathing decreases)
    (iii) air with 90% O2, 10% CO2 (breathing increases)
35
Q

Nicotine

A
  • addictive drug that causes the release of adrenaline
  • makes blood clot easily
  • increases heartbeat rate and blood pressure
  • increases risk of blood clots in the arteries, leads to increased risk of coronary heart disease
36
Q

Carbon monoxide

A
  • combines with haemoglobin to form carboxyhaemoglobin
  • increase the rate of fatty deposits on inner arterial wall, lead to increased risk of coronary heart disease
  • reduces ability of blood to carry oxygen
  • narrows lumen of arteries, increase blood pressure
37
Q

Tar

A
  • cause uncontrolled cell division
  • paralyses cilia lining in the air passages
  • increases risk of cancer in lungs
  • dust particles trapped in mucus lining air passages cannot be removed , increase risk chronic bronchitis and emphysema
38
Q

Irritants (e.g. hydrogen cyanide, acrolein, formaldehyde)

A
  • paralyses cilia lining air passages
  • dust particles trapped in mucus lining air passages cannot be removed
  • increased risk chronic bronchitis and emphysama
39
Q

Chronic bronchitis

A
  • the epithelium lining the airways is inflamed
  • excessive mucus secretion
  • cilia lining the airways are paralyzed
  • air passages become blocked, difficult to breathe
  • persistent coughing to clear air passages
  • increase risk of lung infection
40
Q

Symptoms of chronic bronchitis

A
  • breathing difficulties due to blocked airways

- persistent cough (body’s response to clear blocked airways)

41
Q

Emphysema

A
  • partition walls of alveoli breaks down due to violent coughs
  • reduces SA:V available for gaseous exchange
  • lungs lose their elasticity, become inflated with air
42
Q

Emphysema symptoms

A
  • breathing difficulties (lungs no longer elastic)

- wheezing

43
Q

Chronic obstructive lung disease

A
  • a persons that suffers from both chronic bronchitis and emphysema
  • chronic (recurrent, persistent)
  • obstructive (due to blockage in airways)
44
Q

Lung cancer

A
  • risk of lung cancer increases when a person smokes tobacco
  • cancer is the uncontrolled division of cells producing outgrowths or lumps of tissue
  • also increases risk of cancers of mouth, throat, pancreas,, kidney, urinary bladder

Sec 3 Pure Bio (16 decks)

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