respiration Flashcards
aerobic respiration
The chemical breakdown of food substances in the presence of oxygen with the release of a large amount of energy. Carbon dioxide and water are released as waste products
Word equation: glucose+oxygen → carbon dioxide+water+large amount of energy released
Chemical equation: c6h12o6+6o2=6H2O+energy+6CO2
Glucose is oxidised
Enzymes are present
anaerobic respiration
Chemical breakdown of food substances in the absence of oxygen, with the release of small amount of energy, compared to aerobic respiration
Word equation: glucose → lactic acid + small amounts of energy released
Insufficient oxygen to meet demands of vigorous contractions of muscle
Muscles incur oxygen debt
Lactic acid builds up
Mscle pain and fatigue
During period of rest after exercise
Breathig rate continues to be fast for some time to repay oxygen debt
Lactic acid removed from muscles
Lactic acid transported to liver
Oxidised to release energy
energy released is used to convert the remaining lactic acid into glucose
How muscle cells incur oxygen debt during exercise:
vigorous exercise
body needs a lot more O2
deeper and faster breathing rushes O2to the muscles
this extra O2 is used to release (NOT PRODUCE!!) more energy
a point is reached when the body cannot breathe any faster or harder
aerobic respiration alone cannot meet the enhanced energy demands
muscle cells get the extra energy needed by anaerobic respiration
(Note: Aerobic respiration still continues)
accumulation of lactic acid causes muscle fatigue and muscle pain
immediately after exercise, lactic acid converted to glucose
process requires O2 and this extra O2 needed to remove lactic acid
is called an oxygen debt
in order to get the extra O2 needed, the body continues to breathe
deeply for some time after vigorous activity has ceased
how alveoli works
Gas exchange takes place through the walls of alveoli
Alveoli provides large surface area for gaseous exchange
Gas exchange occurs by diffusion
Blood entering lungs has lower conc of oxygen and higher conc of CO2
Atmospheric ar enytering alveoli has higher conc of oxygen and lower conc of CO2
Conc gradient is set up for O2 and CO2
Between blood and alveolar air
Oxygen diffuses from alveolar air into blood capillaries
Carbon dioxide diffuses from blood capillaries into alveolar air
How is diffusion gradient of gases maintained:
- Continuous flow of blood throguh capillary
Blood w high conc of O2 is moved away
Blood w high conc of CO2 is transpoted to alveolus - Moevment of air in and out of alveolus
Brings in more O2
Removed CO2 from alveolus
Adaptations of lung for gaseous exchange:
Numerous alveoli in lungs -> provides large total surface area
One cell thick alveoli wall -> provides shorter diffusion distance for gases, ROD of gases is faster
Thin film of moisture covers the surface of alveolus -> allows oxygen to dissolve in it
Walls of alveoli are richly supplied with blood capillaries -> flow of blood mainatians steep concentration gradient of gases betwene blood and air in alveoli + increase surface area available for diffusion of gases
How carbon dioxide is removed from the tissue cells:
Tissue cells produce a large amount of CO2 during aerobic respiration
As blodo oasses through these tissues via blood capillaries, carbon dioxide diffuses into the blood from tissues then enters RBC
Carboj dioxide reacts with water in RBC to form carbonic acid, catalysed by carbonic ahnydrase
Carbonic acid is converted into hydrogencarbonate ions
Hydrogecn carbonate ions diffuse out of RBC into plasma
How carbon dioxide enters lungs:
Hydrogen carbonate ions diffuse back into RBC
In RBC: hydrogen carbonate ions combine with hydrogen ions to form carbonic acid, then into water and CO2
CO2 diffuses out of blood capillaries into the alveolar space where it is expelled during exhalation
Epithelium cells in trachea consists of:
Gland cells
Secrete mucus to trap dust particles and bacteria in the air channelled to the lungs
Cilated cells
Cilia sweeps the trapped particles and bacteria up the trachea into the pharynx
inhalation
diaphragm muscles contracts and flattens down
External intercostal muscles contract
Internal intercostal muscles relax
Ribs move upwards and outwards
Thoracic cavity increases in volume
Lungs expand
Air pressure lungs falls below atm pressure
Air forced into lungs
exhalation
Diaphragm muscles relaxes and arches upwards
External intercostal muscles relax
Internal intercostal muscles contract
Ribs move downwards and inwards
Thoracic cavity decreases in volume
Lungs are compressed
Air pressure of lungs in higher than atm pressure
Air exits lungs
Inhalation air path
nostril -> nasal passage -> pharynx -> larynx -> trachea -> bronchi -> bronchioles -> alveoli -> blooc capillary
Effects of Tobacco smoke on Human Health:
- Nicotine
Addictive
Causes release of adrenaline
Makes blood clot more easily
Increases heart rate and blood pressure
Increases risk of blood clots in arteries, leading to increased risk of heart diseases - Carbon monoxide
Binds irreversibly with haemoglobin to form carboxyhaemoglobin which decreases ability of red blood cell to transport oxygen
Increases rate of fatty deposits on inner arterial walls
Increases the risk of atherosclerosis
Narrows lumen of arteries, leads to increased blood pressure - Tar
Causes uncontrolled cell division, increasing risk of lung cancer
Paralysis cilia lining air passages
Dust trapped in mucus lining the air passages cannot be removed, increasing the risk of chronic bronchitis and emphysema
Absorption of oxygen:
Oxygen taken in by lungs diffuses from alveolar air into blood capillaries then into RBC
In rbc, oxygen combines with haemoglobin to form oxyhaemoglobin this is a reversible reaction
In oxygen poor tissues, the oxyhaemoglobin will release oxygen which will then diffuse into the tissue cells through walls of capillaries
