Transcript Respiration - segaran1996

Learning Outcomes
• Explain the significance of respiration in an
organism.
• Differentiate between aerobic and anaerobic
respiration.
• Describe the parts of the breathing system in
humans and explain how the exchange of gases
takes place.
• Explain the difference between breathing and
respiration.
• Describe the effect of cigarette smoke on the
respiratory system.
Understanding Respiration
• Respiration is the process by which chemical
energy present in food is released by the living cell.
• Oxygen is needed for this process and carbon
dioxide is produced as waste.
Understanding Respiration
• The whole process of respiration is controlled by
enzymes that transfer energy in food molecules, eg.
sugars and lipids, to ATP.
• ATP is compound that is able to supply on-the-spot,
instant and usable energy for cell activities.
• Mitochondria are the organelles that house the
enzymes and substrates associated with aerobic
respiration.
• Respiration takes place in all cells, in all organisms,
all of the time.
Is Breathing the same as Respiration?
• No
• Breathing is the mechanical process that supplies
oxygen to the body to drive respiration and
remove the carbon dioxide produced.
Why do living things need Energy?
• Synthesis of large organic molecules from simpler
ones, eg. synthesis of proteins from amino acids.
• Cell division
• Active transport in absorption
• Muscle contraction, eg. heartbeat, breathing
movement
• Transmission of nerve impulse
• Heat energy from respiration used to regulate body
temperature.
Differences between Respiration &
Photosynthesis
TYPES OF RESPIRATION
1. Aerobic Respiration / Cellular Respiration
• It is the oxidation of food substances in the
presence of oxygen with the release of a large
amount of energy.
• Water and carbon dioxide are released as waste
products.
glucose + oxygen  carbon dioxide + water + energy
C6H12O6 + 6O2  6CO2 + 6H20 + 36 ATP
• Green plants and most animals (including Man) undergo
aerobic respiration
TYPES OF RESPIRATION
2. Anaerobic Respiration
• Anaerobic respiration is the oxidation of food
substances in the absence of oxygen.
• Anaerobic respiration releases less energy
than aerobic respiration.
In Man, especially muscles:
Glucose  Lactic acid + Energy
TYPES OF RESPIRATION
2. Anaerobic Respiration
In yeast:
•Alcoholic fermentation by
yeasts is responsible for the
production of wine, beer
and bread.
glucose
energy + ethanol + carbon dioxide
What happens during intense physical activities?
Anaerobic Respiration
In humans:
• During muscular exercise,
blood vessels in muscles
dilate, the heart begins to
beat faster and blood flow is
increased in order to increase
the available oxygen supply.
• Up to a point, the available
oxygen is sufficient to meet
the energy needs of the body.
What happens during intense physical activities?
Anaerobic Respiration
• However, when muscular
exertion is very great,
oxygen cannot be supplied to
muscle fibers fast enough,
and the aerobic breakdown
of glucose cannot produce all
the ATP required for further
muscle contraction.
• During such periods,
additional ATP is generated
by anaerobic breakdown of
glucose. In the process, a lot
of lactic acid is produced.
Lactic acid.....so what?
• When lactic acid builds up in muscles....
It causes fatigue (weakness, tiredness) and muscular
pains.
The body needs to rest and recover.
During the rest period, the breathing rate continues to
be fast for some time. This is to provide sufficient
oxygen : to remove the lactic acid in the muscles, to
replenish depleted ATP and replenish hemoglobin with
oxygen.
The additional oxygen that must be taken into the body
after vigorous exercise to restore all systems to their
normal states is called oxygen debt
Why the skeletal muscle reach the fatigue stage
while the cardiac muscle does not reach the
fatigue stage?
How oxygen get into the body and carbon dioxide
leave our body?
• Breathing is the mechanical process that supplies
oxygen to the body to drive respiration and
remove the carbon dioxide produced.
…….so air from the surrounding is taken in and
brought to the lungs.
GAS EXCHANGE SURFACES
• Animals have different ways of
getting their oxygen supply.
Human Respiratory System
nasal
passages
external nostril
pharynx
larynx
trachea
bronchi
cluster of alveoli
(air sacs)
bronchioles
How does air get into the lungs and alveoli?
•By breathing in (inhale, inspiration)
Air enters as follows:
Nostrils nasal passages  larynx  trachea  bronchi
Bronchioles  alveoli
nasal
passages
external nostril
pharynx
larynx
trachea
bronchi
cluster of
(air sacs)
How does air get into the lungs and alveoli?
•When breathing in, the volume of the chest cavity
increases because the ribs move upwards and outwards.
•Air rushes in to fill up the extra space in the lungs. The
alveoli are filled with air from the external surrounding.
GAS EXCHANGE IN THE ALVEOLI
•Gas exchange in the lungs take place by the process
of DIFFUSION
•Blood entering the lungs has a lower concentration
of oxygen but a higher concentration of carbon
dioxide compared to fresh air in the alveoli of lungs.
GAS EXCHANGE IN THE ALVEOLI
•Therefore, oxygen from the alveoli air will first dissolve in
the moisture lining in alveoli, then diffuse into the blood
capillaries.
•Oxygen will combine with haemoglobin in the red
blood cells to form oxyhaemoglobin. The oxygen rich
blood is carried away from the lungs.
•Oxygen will be released when blood passes through
cells which have low concentration of oxygen, eg.
muscle cells
•Carbon dioxide diffuses from the blood capillaries into
the alveoli (opposite direction)
nasal
passages
nal
Nasal cavity
pharynx
larynx
trachea
cluster of
alveoli (air
sacs)
bronchiol
es
• Short stiff hairs screen large
particles from entering
• Mucus moistens the air and
traps small particles which
escape past the pharynx
• Rich vascular supply warms
incoming air
• Harmful chemicals may be
detected by the sensory
cells
nasal
passages
nal
Pharynx
pharynx
larynx
trachea
cluster of
alveoli (air
sacs)
bronchiol
es
• Muscular tube
• Lymph tissue (tonsils)
detects microorganism present in
the food, air and
water will stimulate
production of white
blood cells.
nasal
passages
nal
Larynx
• Epiglottis closes during
swallowing to prevent
food or drink from
entering the trachea.
• Vocal cords vibrate to
produce different sound
pharynx
larynx
trachea
cluster of
alveoli (air
sacs)
bronchiol
es
Trachea
C-shaped cartilage
• Cylinder tube kept open by C-shaped cartilage rings
• Lined with ciliated, mucus secreting epithelial cells.
al
sages
Trachea
• Mucus: traps particles
• Continual movement of
cilia sweeps trap particles
upwards toward the
pharynx
pharynx
larynx
trachea
cluster of
alveoli (air
sacs)
bronchiol
es
Alveolus
• There are numerous
alveoli, alveolus wall is
one cell thick, moist and
well supplied with blood
capillary
How does all these
adaptations are important for
the alveolus to carry out its
function?
Blood
capillary
alveolus
ALVEOLUS: Respiratory surface of man
• The alveolus is hollow and lobed shaped:
Provides large surface area to volume
ratio for rapid diffusion.
• The inner walls are moist.
Gases in the air must dissolve in water
before they can diffuse into the cells.
• The wall of alveolus is only one cell
thick.
The distance to be travelled across by
gases is short to ensure faster rate of
diffusion.
• The wall of alveolus supplied with a
dense network of blood capillaries.
The continuous flow of blood maintains
a concentration gradient.
6.2 The Breathing Mechanism
The Human Respiratory System
• Respiratory system and
the position of the lungs
in the chest cavity:
6.2 The Breathing Mechanism
The Human Respiratory System
• Air enters the respiratory system either by the
nostrils or mouth.
• Hairs lining the nasal passage together with
mucous secretions, filter and trap any particles
such as dust, pollen grains and even bacteria
present in the air.
• Mucous secretions moisten and warm the
incoming air.
Breathing mechanisms
Inhale
• Muscles of diaphragm
contract, it flattens
• External intercostal
muscle contract
• Internal intercostal
muscle relax
• Ribs move upward and
outward
• Volume of thoracic cavity
increases
• Low air pressure in lungs
• Air enters to fill the lungs
Breathing mechanisms
Exhale
• Muscles of diaphragm
relax and it arches
upwards
• External intercostal
muscle relax
• Internal intercostal
muscle contract
• Rib returns to original
position
• Volume of thoracic
cavity decreases
• Lungs compressed,
High air pressure in
lungs
• Air is forced out
6.2 The Breathing Mechanism
Gaseous Exchange at the Alveolus
Gaseous exchange in the lungs
• Gaseous exchange in the
lungs takes place by
diffusion
• Inspiration air in alveoli
contain more oxygen
than the blood
• Inspiration air in alveoli
contain less carbon
dioxide than the blood
• Diffusion occur because
of the diffusion gradient
Oxygen molecules
Carbon dioxide molecule
What else have you observed in the diagram?
Gaseous exchange in the lungs
• As the air in the air sacs contain more
oxygen, the oxygen will diffuse into the
blood after dissolving in the moisture
lining of alveoli.
• The oxygen will combine with
haemoglobin to form oxyhaemoglobin
• The reaction is reversible. Oxygen will be
relased when blood passes through cells
which have low concentration of oxygen.
Why oxyhaemoglobin must be
unstable?
Hb
+ O2
- O2
HbO2
Gaseous exchange in the lungs
• The carbon dioxide produced from the respiration is
dissolved in the water to form carbonic acid and
some hydrogen carbonates ions.
H2O + CO2
H2CO3
H+ + HCO3-
Much of the hydrogen carbonates ions produced
are carried in the blood plasma and some in red
blood cells.
TISSUE CELLS
1
2
3
5
HCO3
4
HCO3
5
1
IN THE LUNGS
CO2 5
CO2
5
4
1
3
1
HCO3
CO2
2
HCO3
HCO3
1
5
5
CO2
HCO3
CO2
Inspired air and expired air
Inspired air
Expired air
Oxygen
21%
16.4%
Carbon
dioxide
Nitrogen
0.03%
4.0%
78%
78%
Water vapour variable
saturated
Temperature
Body
temperature
little
variable
Dust particles variable
What is Wrong with Smoking?