Zusammenfassung der Ressource
RESPIRATION
- AEROBIC
RESPIRATION
- Complete breakdown of glucose in the presence of oxygen to release a
large amount of energy in the form of ATP molecules which are used to
drive other chemical reactions in cytoplasm and nucleus Carbon dioxide
and water are waste products
- C6H12O6+6O2 --> 6CO2 + 6H2O + Energy
- Some energy released as
heat energy to keep warm
- 38 molecules of ATP built when one molecule of glucose
is completely oxidised to carbon dioxide and water
- ATP readily breaks down to adenosine
diphosphate in presence of appropriate
enzyme
- Releases energy and phosphate ion
which is used to drive other
chemical reactions
- Glycolysis in cytosol
- Krebs Cycle
- Electron Transport Chains
- Mitochondira
- Main site of ATP production in
aerobic respiration
- Cylinder/Rod Shaped
- Double Membrane
- Separated by inter membrane space
- Outer Membrane is a
smooth continuous
boundary
- Inner membrane folded
extensively to form cristae
which project into semi fluid
matrix
- Contain circular DNA and
70S ribosomes like bacteria
- Once free living bacteria that were ingested by ancestral
eukaryotic cell and stable symbiotic relationship was
established
- ANAEROBIC
RESPIRATION
- Energy Released from food by breaking it down
chemically but reactions do not use oxygen
although carbon dioxide is often produced
- C6H12O6 --> 2C2H5OH + 2CO2 + Energy
- Muscles
- During exercise, person
starts panting and heart beats
faster
- Remove carbon dioxide and take in more oxygen
at a higher rate ; oxygen brought to muscles
faster
- Limit on rate of breathing and heartbeat reached so
oxygen may not be delivered to muscle cells fast
enough to meet demands of aerobic respiration
- Pyruvic acid buildup exceeds
its oxidation to carbon dioxide
and water using oxygen
- Pyruvic acid converted to lactic acid by
enzyme called lactate dehydrogenase
- Small amount of
energy released in
the form of ATP
- 2 molecules of ATP produced for every
glucose molecule used
- After exercise, lactic acid from anaerobic respiration
removed
- Lactic acid diffuses from muscles to
bloodstream, carrying it to the liver
- Lactic acid converted to pyruvic
acid by enzyme lactate
dehydrogenase
- Some pyruvic acid oxidized to form
carbon dioxide and water
- Release energy in the form of ATP molecules
- Energy used to convert
pyruvic acid to glucose
- Creates oxygen debt
- Oxygen deficit
- Amount of oxygen needed but not supplied
from outside of body by breathing
- 3dm3 of oxygen per min must be supplied to
meet energy demands of exercise aerobically,
but not achieved until 6 min after exercise
began
- During lag time, oxygen reserves used
- Oxygen in myoglobin
in muscles
- Muscle tissues hold
ATP in the form of
creatine phosphate
- Oxygen debt
- Extra amount of oxygen after exercise,
when rate of oxygen uptake is not resting
requirement of 0.25dm3 per min yet
- Used to remove lactic acid from anaerobic respiration
- Causes muscle fatigue
- Glucose --> Pyruvic Acid/Pyruvate --> Carbon Dioxide + Water
- HUMAN GAS EXCHANGE SYSTEM
- Passage of Air
- Air enters body through tw external nostrils which lead to two
nasal passages
- Nostrils bear a fringe of hair to trap dust and
foreign particles
- Air warmed and moistened so harmful chemicals are detected by sensory cells in
mucous membrane
- Mucus on mucous membrane
also traps dust and foreign
particles
- Air passes through internal
nares into pharynx
- Air passes into larynx then into trachea through glottis
- Epiglottis at the top of trachea stops
food and drink from entering air
passages when we swallow
- Divides into two tubes called
the bronchi
- Right bronchus divides
into three bronchial
tubes
- Left bronchus divides
into two bronchial tubes
- Divide into
bronchioles
- Alveoli
- Thin, moist and well
supplied with blood
capillaries
- Blood capillaries transport oxygen
away from lungs and carbon dioxide to
lungs
- Maintains large difference in concentration of
gases between blood and alveolus
- Maintains steep diffusion gradient
for gases
- Gaseous exchange takes
place through walls of
alveoli
- Wall is made up of one layer of flattened cells and endothelium
of capillary also one cell thick so that the diffusion distance is
short
- Thousands of alveoli in
each lung
- Provides large surface area
for gaseous exchange
- Inner surface of alveoli coated with
film of moisture
- Oxygen dissolves, facilitating diffusion
- Some moisture evaporates into alveoli
and saturates air with water vapour
- Epithelial cells of alveoli
secrete surfactants
- Disrupt cohesive forces between water
molecules
- Lowers surface tension of fluid lining alveoli
- Increases resistance of lung to stretch
- Diagram
- Supported by C shaped rings of
cartilage to prevent them from
collapsing when we breathe in
- Epithelium
- Gland cells
- Secrete mucus to trap dust particles
and bacteria
- Ciliated cells
- Bear cilia to sweep particles up bronchi an
trachea into pharynx
- Pleura membrane lies
in the thoracic cavity
- Thin layer of lubricating fluid between pleura
allows membranes to glide over each other
easily
- Chest wall supported by ribs
- External and internal intercostal
muscles found between ribs
- BREATHING
- Inspiration
- External intercostal muscles contract, internal
intercostal muscles relax
- Rib cage pulled up and out
- Volume of thoracic cavity increased
- Air pressure in lungs reduced below
atmospheric pressure
- Air enters lungs, inflating alveoli till pressure in lungs is
equal of atmosphere
- Lung capacity and breathing rate
- Tidal air is the volume of air inhaled and exhaled
during resting breathing pattern
- Complemental air or inspiratory reserve volume is
additional volume of air that can be taken in when
taking a deep breath
- Supplemental air or expiratory reserve volume
is the additional volume of air that is forced
out by the most powerful expiratory effort
after normal expiration
- 1500cn3
- Vital capacity is volume of air
expelled by most vigorous
expiratory effort after deepest
inspiration
- Residual air is volume of air in
lungs after strongest expiration
- Breathing rate about 16 per
min at rest and 20 to 30
breaths per min during
exercise
- Diaphragm muscles
contract and flattens
- Expiration
- External intercoastal muscles relax, internal intercoastal
muscles contract
- Diaphragm relaxes and
becomes dome shaped
- Volume of thoracic cavity decreases
- Air pressure in lungs raised
above atmospheric pressure
- Air forced out of lungs till air pressure in lungs is equal to
that of atmosphere
- TRANSPORT OF GASES
- Transport of
oxygen
- Oxygen combines with haemoglobin in red blood cells to form
oxyhaemoglobin in lungs where oxygen concentration is high
- Oxygen released when blood passes through oxygen
poor tissues
- Oxygen diffuses through walls of blood
capillaries into cells
- Transport of carbon dioxide
- Carbon dioxide produced by tissues diffuses into bloodstream
- Passes into red blood cells
- Combines with water to form carbonic acid
- Co2 + H2O <--> H2CO3 <--> H + HCO3
- Catalysed by carbonic
anhydrase
- Carbonic acid dissociates
- Hydrogen ions
- Displace oxygen from haemoglobin
- Forms HHb
- Hydrogencarbonate ions
- Diffuse out into plasma along
concentration gradient
- Combine with sodium in plasma
- Forms sodium hydrogencarbbonate
- Loss of hydrogencarbonate ions balanced by
chloride ions diffusing into red blood cells from
plasma
- Red blood cells reach lungs and carbon dioxide is
released
- Reverse process occurs
- EFFECTS OF SMOKING
- Nicotine
- Addictive drug that stimulates and dulls the
brain and senses
- Causes vasocontriction and
release of adrenaline
- Increases heart rate and
blood pressure
- Causes blood to clot easily
- Increasing risk of blood clots blocking blood
vessels
- Carbon monoxide
- Binds with high affinity to haemoglobin
- Forms carboxyhaemoglobin
- Reduces efficiency of red
blood cells to transport
oxygen
- Increases rate of fatty substances
deposited on inner wall of artery by
damaging lining
- Increases risk of atherosclerosis
- Stimulates attachment of blood platelets
to surface of damaged endotheliium
- Causes blood clotting and blocking blood vessels
- Tar
- Sticky brown substance
that accumulates in lungs
- Contains carcinogenic chemicals
- Induce epithelial cells of lungs to divide uncontrollably
- Forms lumps of tissue that block
off air sacs
- Reduces efficiency of
gaseous exchange
- Stimulates excess mucus production
- Prevents removal of dust particles
- Blocks bronchiole
- Stops cilia from beating
- Diseases
- Chronic bronchitis
- Inflammation of lining of
air passages
- Excess mucus produced by goblet cells
- Cilia paralysed
- Mucus not swept up
air passages
- Coughed up as thick greenish
yellow sputum
- Damages epithelium and increases risk of
infection and inflammation
- Narrowed airways
- Reduced gaseous
exchange
- Breathlessness
- Caused by tar
- Emphysema
- Inflammation of lining
of air passages
- Attracts phagocytes
- Release elastase
- Destroys elastin in
alveolar walls
- Breakdown of walls of alveoli
- Air spaces become larger
- Total surface area for gaseous
exchange decreases
- Heavy coughing
- Bursts weakened alveoli
- Heart diseases
- Induces atherosclerosis
- Decreases ability to remove blood clots
that build up at atheromatous plaques
- Carbon monoxide
- Toxic to endothelium and thin lining
of blood vessels
- Damages lining
- Cholesterol
penetrates easier
- Combines with haemoglobin
- Reduces oxygen
transport by 15%
- Causes angina
- Heart attack
- Nicotine
- Lung cancer
- Tar contains chemicals
causing cancer
- Irritation causes thickening of epithelium by
extra cell division
- Uncontrolled cell division
- Cancer