Respiration Flashcards
what is respiration
breaking down of food molecules such as glucose to release energy
what is aerobic respiration
breaking down of glucose in the presence of oxygen
*glucose + oxygen → carbon dioxide + water
*generates/releases a large amount of energy
*occurs at all times
what is anaerobic respiration
breaking down of glucose in the absence of oxygen
*glucose → lactic acid
*occurs in muscle cells (mitochondria) during vigorous activities
*generates/releases a relatively small amount of energy
*takes place alongside aerobic respiration
why is anaerobic respiration needed
- during vigorous activity, muscle cells need more energy for muscles to contract
- aerobic respiration alone is not fast enough to supply the increase in energy demand
- anaerobic respiration takes place to meet increased energy demand
what is oxygen debt
amount of oxygen needed to remove lactic acid
*occurs when the supply of oxygen to muscle cells is insufficient during vigorous activity
how is oxygen debt repaid
1) continued increased heart rate
- transports lactic acid to liver via blood for removal
- transports oxygen to the liver
2) continued deeper and faster breathing
- obtains oxygen for supply to liver
what are the 2 differences between breathing and respiration
breathing:
- movement of air in and out of lungs (naturally flows in and out due to pressure difference)
- physical process
respiration:
- refers to cellular respiration
- chemical process (series of chemical reactions)
what are the 7 components of the human respiratory system
1) nasal passages
2) pharynx
3) larynx (voice box)
4) trachea
5) bronchus
6) bronchioles
7) alveoli
describe the use of nasal passages
- nostrils through which air is breathed in
- nasal hairs and mucus on nasal passage walls trap dust and foreign particles
describe the use of the trachea
- gland (goblet) cells secrete mucus which traps dust particles and bacteria channelled to the lungs
- ciliated cells have cilia that sweep dust-trapped mucus up into the pharynx to be coughed out or swallowed
*C-shaped cartilage rings ensure that trachea is always open
what are bronchi
bronchial tubes dividing repeatedly to form bronchioles
what are bronchioles
tubes that end in clusters of air sacs (alveoli)
what are 4 adaptations of alveoli
1) numerous alveoli
- larger surface area for exchange of gases
2) one-cell thick alveolar walls
- shorter diffusion distance
3) thin film of moisture on inner walls of alveoli
- allows oxygen to dissolve
4) walls of alveoli surrounded by numerous blood capillaries and continuous blood flow in these capillaries
- maintains concentration gradient
how does gaseous exchange occur at the alveoli
- oxygen dissolves in thin film of moisture
- oxygen diffuses through thin alveolar and capillary walls into blood capillaries
- oxygen binds to haemoglobin in RBCs to form oxyhaemoglobin
- carbon dioxide diffuses from blood into alveolar cavity
what is the diaphragm
dome-shaped muscular elastic tissue separating the thorax from the abdomen
describe the process of inspiration
1) diaphragm contracts and flattens
2) external intercostal muscles contract, internal intercostal muscles relax
3) ribs and sternum move up and outwards
4) volume of thoracic cavity increases
5) lungs expand, air pressure decreases as volume increases
6) atmospheric pressure higher than pressure in lungs
7) air moves into lungs
describe the process of expiration
1) diaphragm muscle relaxes and arches upwards
2) external intercostal muscles relax, internal intercostal muscles contract
3) ribs and sternum move down and inwards
4) volume of thoracic cavity decreases
5) lungs compress, air pressure increases as volume decreases
6) air pressure in lungs higher than atmospheric pressure
7) air forced out of lungs
what are the comparisons of the components in inspired and expired air? (oxygen, carbon dioxide, nitrogen, water vapour, dust particles, temperature)
inspired:
oxygen - higher
carbon dioxide - lower
nitrogen - about the same
water vapour - variable (rarely saturated)
dust particles - variable (usually present)
temperature - variable
expired:
oxygen - lower
carbon dioxide - higher
nitrogen - about the same
water vapour - saturated
dust particles - little, if any
temperature - body temperature (37°C)
what is tidal air
normal volume of air displaced between normal inhalation and exhalation
what is complemental air
additional volume of air during forced inhalation
what is supplemental air
additional volume of air during forced exhalation
what is vital capacity
maximum volume of air a person can exhale after maximum inhalation
what is residual air
volume of air in lungs that cannot be expelled after maximum exhalation
*ensures that alveoli remain open
what are 3 components of cigarettes
1) nicotine
2) carbon monoxide
3) tar
what are the effects of nicotine (2 points)
- increased heart rate and blood pressure
- increased risk of blood clotting in and narrowing of arteries, leading to increased risk of coronary heart disease
*in pregnant mothers, it can decrease the amount of food substances reaching the fetus, affecting fetal development and may result in miscarriages
what are the effects of carbon monoxide (2 points)
- reduces ability of blood to transport oxygen as it binds permanently to haemoglobin; less haemoglobin available to transport oxygen
- increased risk of coronary heart disease
*in pregnant mothers, less oxygen reaches the fetus through the placenta, affecting fetal development
what are the effects of tar (2 points)
- increases risk of lung cancer (uncontrolled cell division, potentially of cancer cells)
- increased risk of chronic bronchitis and emphysema (can cause paralysis of cilia lining air passages; dust-trapped mucus cannot be removed)
what is chronic bronchitis
- inflamed linings of bronchus lead to secretion of excessive mucus
- cilia on cells of linings become paralysed, dust-trapped mucus cannot be removed
*causes blocked airways, persistent coughing, lung infections
what is emphysema
- partition walls of alveoli are broken down, reducing surface area for gaseous exchange and elasticity of the lungs
- lungs become inflated
*causes wheezing and severe breathlessness
