CHAP 7 RESPIRATION IN HUMANS Flashcards
define ‘ aerobic respiration’
the release of energy by breaking down glucose in the presence of oxygen
- carbon dioxide & water are released as waste products
- takes place when enough O2
- takes place continuously in both plants & animals [ mitochondria]
what is the word equation for aerobic respiration?
glucose + oxygen -> carbon dioxide + water
which part of the cell plays a vital role in aerobic respiration?
mitochondria
- respiration is carried out in a series of steps that are catalysed by enzymes -> mitochondria contains these enzymes-> mitochondria plays a vital role in respiration
why does our body cells respire anaerobically during vigorous exercise resulting in an oxygen debt that is removed by rapid, deep breathing after exercise?
vigorous exercise-> requires muscles to move more than usual -> body need carry out more cellular respiration-> muscle contraction need LOTS of energy -> respiration ( to provide energy to the body) requires LOTS of O2 -> need more O2 to muscles -> rate of breathing & volume of each breath increases for O2 to be transported to muscles at a faster rate to continue aerobic respiration-> however there is a limit to increase heartbeat & rate of breathing -> when vigorous activity continues , maximum aerobic respiration is unable to produce energy fast enough to meet demand -> IF vigorous muscle contraction continues -> energy demand increases -> muscle cells must carry out anaerobic respiration to make up for the increases energy demand ( lactic acid formed in the process ) -> small amounts of energy released in anaerobic respiration + energy released in aerobic respiration -> helps keep muscle contracting -> since insufficient amount of O2 to meet the demands of vigorous muscle contractions -> muscles incur an oxygen debt ( amt of oxygen needed to remove lactic acid ) -> more lactic acid built up -> more oxygen debt
how can oxygen debt be removed?
- continuation of fast heart rate -> continued & fast transport of lactic acid from muscles to liver and oxygen from lungs to liver.
- continuation of deeper & faster breathing -> continued & fast intake of O2 by lungs -> sufficient O2 required to remove lactic acid from blood -> lactic acid removed -> oxygen debt repaid
what are the adaptations of nose? [3]
- as air passes through the nasal passages, it is warmed & moistened
- dusts & foreign particles ( including bacteria in the air ) are trapped by the hairs in the nostrils as well as mucus on the mucous membrane
- harmful chemicals may be detected by small sensory cells in the mucous membrane.
what are the adaptations of trachea? [2]
GLAND CELLS - secrete mucus to trap dust particles & bacteria
CILIATED CELLS - hair-like structures called cilia on the surfaces. The cilia sweep the dust-trapped mucus up the trachea
what are the adaptations of lungs? [4]
NUMEROUS ALVEOLI - provide a large surface area for gas exchange
WALL OF ALVEOLI - one cell thick -> provides a short diffusion distance for gases, ensuring a higher rate of diffusion
THIN FILM OF MOISTURE - covers the inner wall of alveolus -> allows oxygen to dissolve in it.
WALLS OF ALVEOLI RICHLY SUPPLIED WITH BLOOD CAPILLARIES -> flow of blood maintains the concentration gradient of gases.
where does gas exchange occur in humans?
alveoli - the walls of alveoli -> walls thin , moist and richly supplied with blood capillaries
by what process does gas exchange occur in the lungs?
diffusion
what causes diffusion of oxygen between alveoli & capillaries?
blood entering the lungs from heart has a LOWER CONCENTRATION OF OXYGEN & HIGHER CONCENTRATION OF CARBON DIOXIDE than the ATMOSPHERIC AIR entering the alveoli in the lungs. a CONCENTRATION GRADIENT for OXYGEN & CARBON DIOXIDE is SET UP between BLOOD & ALVEOLI
how does gas exchange between blood & alveoli occur ?
oxygen from alveoli dissolves into the thin film of moisture on the wall of the alveolus -> dissolved oxygen then diffuses through the wall of alveolus and the wall of blood capillary into the red blood cells -> oxygen combined with haemoglobin to form oxyhemoglobin-> carbon dioxide diffuses from the blood into the alveolar air
how is the concentration gradient between oxygen & carbon dioxide between the alveolar air and the blood maintained ? [2]
- a continuous flow of blood through the blood capillaries
- continuous breathing -> cause air in the lungs to be constantly refreshed
how is oxygenated blood formed?
oxygen binds with haemoglobin to form oxyhaemoglobin
how is oxygen transported around the body?
in lungs ( O2 concentration high) -> oxygen binds with haemoglobin-> oxyhaemoglobin-> oxygenated blood transported from lungs to other parts of body -> when blood passes through organ/ tissue ( O2 concentration low) -> oxyhaemoglobin release oxygen to respiring cells
