chap7: respiration in humans Flashcards
what is aerobic respiration
aerobic respiration is the release of energy by the breakdown of glucose in the presence of oxygen.
carbon dioxide and water are released as waste products.
aerobic respiration releases a large amount of energy
what is anaerobic respiration
anaerobic respiration is the release of small amounts of energy by the breakdown of glucose in the absence of oxygen.
what is oxygen debt
oxygen debt is the amount of oxygen needed to remove lactic acid.
how can oxygen debt be removed after vigorous activity
continuation of fast heart rate to transport lactic acid to the liver and oxygen from the lungs to the liver
continuation of deeper and faster breathing to continue fast intake of oxygen by the lungs
how does oxygen in the air enter the lungs
nose -> pharynx -> larynx -> trachea -> bronchus -> bronchioles -> alveoli
how are the lungs adapted for efficient gas exchange
numerous alveoli: increases surface area to volume ratio
one cell thick alveolus wall: short diffusion distance
thin film of moisture: oxygen to dissolve
walls of alveoli are richly supplied with blood capillaries: maintain concentration gradient of gases
how does gaseous exchange occur in the alveoli
oxygen dissolves in the thin film of moisture on the wall of the alveolus
dissolved oxygen diffuses through the alveolus wall and blood capillary walls into the red blood cellls
oxygen binds with haemoglobin to form oxyhaemoglobin
carbon dioxide diffuses from the blood into the alveolar air
how is o2 and co2 conc gradients maintained between the alveolar air and blood
continuous flow of blood through the capillaries
continuous breathing causes air in the lungs to be constantly fresh
describe inhalation
diaphragm contracts and flattens
external intercostal muscles contract
internal intercostal muscles relax
ribs and sternum moves up and outwards
volume of thoracic cavity increases
lungs expands
air pressure decreases
atmospheric pressure is higher than within lungs
air moves into lungs
describe exhalation
diaphragm expands and arches upwards
external intercostal muscles relaxes
internal intercostal muscles expands
ribs moves downwards and inwards
volume of thoracic cavity decreases
lungs compressed
air pressure increases
atmospheric pressure is lower than in the lungs
air is forced out of the lungs
inhaled vs exhaled air
inhaled air: more o2, lesser co2, lesser water vapour
exhaled air: less o2, more co2, more water vapour
effect of nicotine on the human body
increased heart rate and high blood pressure
increased risk of blood clots in the arteries -> increased risk of coronary heart disease
increased risk of arteries narrowing
effects of nicotine on the human body
increased heart rate and high blood pressure
increased risk of blood clots in the arteries -> increased risk of coronary heart disease
increased risk of arteries narrowing
effects of nicotine on a fetus
narrowed arteries decreases the amount of food substances reaching the fetus hence affecting its development and may result in a miscarriage
effects of carbon monoxide on the human body
when inhaled, carbon monoxide will bind irreversibly to the haemoglobin in the RBC to form carboxyhaemoglobin. this decrease the oxygen carrying capacity of the RBC.
increases risk of coronary heart disease
