Respiration
Learning Objectives
• (a) identify on diagrams and name the larynx, trachea,
bronchi, bronchioles, alveoli and associated capillaries
• (b) state the characteristics of, and describe the role of,
the exchange surface of the alveoli in gaseous exchange
• (c) describe the removal of carbon dioxide from the lungs,
including the role of the carbonic anhydrase enzyme
• (d) describe the role of cilia, diaphragm, ribs and
intercostal muscles in breathing
• (e) describe the effect of tobacco smoke and its major
toxic components - nicotine, tar and carbon monoxide, on
health
• (f) define and state the equation, in words and symbols,
for aerobic respiration in human
• (g) define and state the equation, in words only, for
anaerobic respiration in human
Why do living organisms
respire?
• Need energy to move, excrete, grow,
reproduce and maintain themselves.
• Food contains chemical energy.
• Respiration is the release of this
energy when food (glucose) is broken
down in living cells.
Respiration
• The oxidation of
food substances
with the release of
energy in living
cells.
Aerobic Respiration
Aerobic Respiration
• Breakdown of glucose in the presence of oxygen with the
release of relatively large amount of energy.
• Carbon dioxide and water are released as waste products.
• Enzymes catalysed the reactions in the mitochondria.
+ 2898 kJ
What is the energy used
for?
1.
2.
3.
4.
Cell division and growth
Synthesis of proteins, fats and vitamins
Transmission of nerve impulses
Maintenance of a constant body
temperature
5. Active transport in the absorpton of
food substances by the small intestine
6. Muscular contractions e.g. heartbeat &
respiratory movements.
Anaerobic Respiration
Anaerobic Respiration
• Breakdown of glucose in the absence
of oxygen to release energy.
• Can take place in yeast as well as the
muscles.
Yeast
• Respires anaerobically when oxygen is
absent.
• Little energy is released.
• Yeast cannot be very active under such
situations.
• Alcoholic fermentation
+ 210 kJ
Anaerobic Respiration
(Muscles)
• Muscle cells
normally respire
aerobically.
• Carry out
anaerobic
respiration when
there is a shortage
of oxygen.
Differences
•
•
•
•
Aerobic
Respiration
Uses oxygen
No alcohol or
lactic acid made
Large amount of
energy released
CO2 always
released
•
•
•
•
Anaerobic
Respiration
Do not use oxygen
Alcohol or lactic
acid made
Small amount of
energy released
CO2 sometimes
released
What happens during
exercise?
• Vigorous muscular
contraction -->
muscles first use
oxygen to respire.
(aerobic)
• Panting --> to
remove carbon
dioxide and take in
more oxygen.
• Heart beats faster
so that more
oxygen can be
brought to the
muscles.
• LIMIT to the rate
of breathing and
heartbeat. They
CANNOT keep on
increasing.
• To continue vigorous exercise, more
energy needs to be released.
• Muscle cells carry out ANAEROBIC
respiration.
• Lactic acid is produced.
GLUCOSE ------> Lactic acid +small
amount of energy
C6H12O6 ---- 2CH3CH(OH)COOH + 150 kJ
• Lactic acid slowly builds up in the
muscles.
• Muscle has an “OXYGEN DEBT”.
• Lactic acid cause fatigue
• Body needs to rest & recover
• Muscular pain is due to the lactic
acid.
What happens during
RESTING?
• Lactic acid is removed from the muscles and
transported to the liver.
• Some of the lactic acid is oxidized to energy.
• Converts remaining lactic acid into glucose
Oxidized
Lactic acid ---------------------> Energy
(muscles)
remaining -------------------> glucose
lactic acid
muscle
How do we know organisms
respire?
1. To find out whether carbon dioxide
is given off during respiration
2. To find out if carbon dioxide is
given off during fermentation
3. To find out if heat is released
during respiration
Gaseous exchange
Gaseous exchange
• Process of the
transfer of oxygen
from the air to the
cells and the
transfer of carbon
dioxide and water
from the cells back
to the
surroundings.
Tissue Respiration
Tissue Respiration
• Oxidation of food with the release of
energy.
• Occurs within the cell or tissues
(internal respiration)
Gaseous Exchange in Man
The Structure of the
Respiratory System
• The organs involved are:
2 lungs in the thorax;
The air passages leading to them.
• Each lung is filled with many tiny air
sacs called alveoli, where oxygen
diffuses into the blood.
The Air Passage Way
• Consist of:
the nasal passages/cavity, pharynx,
larynx, trachea, bronchi &
bronchioles.
• Air enters by 2 external nostrils --2 nasal passages --- 2 internal
nostrils --- pharynx --- larynx --trachea (via glottis) --- bronchi --bronchioles --- alveoli.
Path of Air Through the Respiratory System
atmosphere
atmosphere
external nostril
external nostril
atmosphere
external nostril
nasal passages
nasal passages
external nostril
atmosphere
external nostril
nasal passages
pharynx
nasal passages
pharynx
external nostril
atmosphere
external nostril
nasal passages
pharynx
nasal passages
pharynx
larynx
external nostril
larynx
atmosphere
external nostril
nasal passages
pharynx
nasal passages
pharynx
larynx
trachea
external nostril
larynx
trachea
atmosphere
external nostril
nasal passages
pharynx
nasal passages
external nostril
larynx
trachea
pharynx
larynx
bronchi
trachea
bronchi
atmosphere
external nostril
nasal passages
pharynx
nasal passages
external nostril
larynx
trachea
pharynx
larynx
bronchi
trachea
bronchi
bronchioles
bronchioles
atmosphere
external nostril
nasal passages
nasal passages
pharynx
external nostril
pharynx
larynx
trachea
larynx
trachea
bronchi
bronchi
bronchioles
alveoli
cluster of alveoli
(air sacs)
bronchioles
The Air Passage Way
The Nose
• Air enters through two external
nostrils (nares)
• Nasal passages lined with hairs and
moist mucous membrane
• Trap dust & foreign particles,
including bacteria.
• Air is warmed and moistened;
• Detect harmful chemicals (by
sensory cells).
The Trachea
• lies in front of esophagus
• supported by C-shaped rings of
cartilage (which ensure it is always
kept opened)
• Epithelium has gland cells to secrete
mucus which traps dust particles
• bears cilia to sweep dust particles
upwards into pharynx
Lining of Trachea
Gland cell
nucleus
The Lungs
• Each lung lies in the pleural cavity.
• The pleural cavity is lined by 2
transparent pleural membranes
• Inner pleuron covers the lungs
• Outer pleuron in contact with
thoracic wall and diaphragm
• The pleural fluid helps to reduce
friction on the lungs when they rub
against the rib cage during
inspiration.
• The lower end of the trachea divides
into 2 bronchi (singular: bronchus),
one to each lung.
• Within the lungs, the bronchial tubes
divide into smaller tubes – the
bronchioles (*NO cartilage).
• Each bronchiole ends with many air
sacs called alveoli.
A cluster of alveoli
Adaptations of lungs for
efficient gaseous exchange
• Alveoli provide a large surface area
(100 m2)
• The wall of alveolus is very thin. Only
one cell thick. Allows easy diffusion
of O2 & CO2
• A thin film of moisture covers the
surface of the alveolus. O2 dissolves
in this liquid before diffusing across
the wall of the alveolus.
• The walls of the alveoli are richly
supplied with blood capillaries. The
flow of blood maintains the
concentration gradient of gases.
The Chest cavity
• Chest wall is supported by ribs
• Two sets of intercostal muscles (internal
and external) control the movement of the
ribs
• The diaphragm separates the thorax from
the abdomen
• The intercostal muscles and the diaphragm
contract and relax, causing the volume of
thoracic cavity to change
Mechanism of Breathing
When you breathe in or inspire, the following events take place:
Movement of rib cage during inspiration
Front view
Side view
vertebral
column
sternum
rib
rib cage
• Your diaphragm contracts and flattens.
Movement of rib cage during inspiration
Front view
Side view
vertebral
column
sternum
rib
rib cage
diaphragm
contracts and
flattens
• Your external intercostal muscles contract while your internal intercostal
muscles relax.
Movement of rib cage during inspiration
Front view
Side view
vertebral
column
sternum
rib
rib cage
diaphragm
contracts and
flattens
• Your ribs move upwards and outwards. Your sternum also moves up and
forward.
Movement of rib cage during inspiration
Front view
Side view
vertebral
column
sternum
ribs and
sternum
raised
rib
ribs and
sternum
raised
Ribs swing up
rib cage
diaphragm
contracts and
flattens
• The volume of your thoracic cavity increases.
Movement of rib cage during inspiration
Front view
Side view
vertebral
column
sternum
ribs and
sternum
raised
rib
ribs and
sternum
raised
Ribs swing up and
increase volume of thorax
rib cage
diaphragm
contracts and
flattens
volume of
thorax
increases
• Air pressure in your lungs causes them to expand to fill up the enlarged
space in your thorax.
Movement of rib cage during inspiration
Front view
Side view
vertebral
column
sternum
ribs and
sternum
raised
rib
ribs and
sternum
raised
Ribs swing up and
increase volume of thorax
rib cage
diaphragm
contracts and
flattens
volume of
thorax
increases
and lungs
expand
• Expansion of your lungs causes the air pressure inside them to decrease.
Movement of rib cage during inspiration
Front view
Side view
vertebral
column
sternum
ribs and
sternum
raised
rib
ribs and
sternum
raised
Ribs swing up and
increase volume of thorax
rib cage
diaphragm
contracts and
flattens
lungs
expand,
causing air
pressure
inside lungs
to decrease
• Atmospheric pressure is now higher than the pressure within your lungs.
This causes air to rush into your lungs.
Movement of rib cage during inspiration
Front view
Side view
air enters lungs
vertebral
column
sternum
ribs and
sternum
raised
rib
ribs and
sternum
raised
Ribs swing up and
increase volume of thorax
rib cage
diaphragm
contracts and
flattens
lungs
expand,
causing air
pressure
inside lungs
to decrease
When you breathe out or expire, the following events take place:
Movement of rib cage during expiration
Front view
Side view
vertebral
column
sternum
rib
rib cage
• Your diaphragm relaxes and arches upwards.
Movement of rib cage during expiration
Front view
Side view
vertebral
column
sternum
rib
rib cage
diaphragm
relaxes and
arches
upwards
• Your internal intercostal muscles contract while your external intercostal
muscles relax.
Movement of rib cage during expiration
Front view
Side view
vertebral
column
sternum
rib
rib cage
diaphragm
relaxes and
arches
upwards
• Your ribs move downwards and inwards. Your sternum also moves down
to its original position.
Movement of rib cage during expiration
Front view
Side view
vertebral
column
sternum
rib
ribs and
sternum
raised
Ribs swing down
ribs and
sternum
returned to
original
position
rib cage
diaphragm
relaxes and
arches
upwards
• The volume of your thoracic cavity decreases.
Movement of rib cage during expiration
Front view
Side view
vertebral
column
sternum
rib
volume of
thorax
decreases
ribs and
sternum
returned to
original
position
ribs and
sternum
raised
Ribs swing down and
decrease volume of thorax
rib cage
diaphragm
relaxes and
arches
upwards
• Your lungs are compressed and air pressure inside them increases as the
volume decreases.
Movement of rib cage during expiration
Front view
Side view
vertebral
column
sternum
rib
ribs and
sternum
raised
Ribs swing down and
decrease volume of thorax
lungs are
compressed,
causing air
pressure
inside lungs
to increase
ribs and
sternum
returned to
original
position
rib cage
diaphragm
relaxes and
arches
upwards
• Air pressure within the lungs is now higher than atmospheric pressure.
The air is forced out of your lungs to the exterior.
Movement of rib cage during expiration
Front view
Side view
air expelled
from lungs
vertebral
column
lungs are
compressed,
causing air
pressure
inside lungs
to increase
sternum
rib
ribs and
sternum
raised
rib cage
Ribs swing down and
decrease volume of thorax
diaphragm
relaxes and
arches
upwards
Inhalation
When you inhale, you…
Relax your
Internal intercostal muscles and
Contract your
External intercostal muscles
Exhalation
When you exhale, your…
External intercostal muscles
Relax and your
Internal intercostal muscles
Contract
Gaseous exchange in
alveoli
Oxygen
• Alveolar air contains higher concentration
of oxygen than the blood.
• Oxygen dissolves in the moisture lining and
diffuses into the blood capillaries.
• Oxygen combines with haemoglobin to
form oxyhaemoglobin.
Carbon dioxide
• Tissue cells produce carbon dioxide during
aerobic respiration.
• Carbon dioxide diffuses into the blood and enters
red blood cells.
• Carbon dioxide reacts with water to form
carbonic acid catalysed by carbonic anhydrase.
• Carbonic acid converted into hydrogencarbonate
ions which diffuse out of the red blood cells into
the plasma.
In the lungs
• Hydrogencarbonate ions diffuse back
into the red blood cells
• Converted into carbonic acid and
then into water and carbon dioxide
• Carbon dioxide diffuses out of blood
capillaries into the alveoli and out of
the lungs
How diffusion gradient is
maintained?
• Continuous supply of blood through
the capillary networks
• Continuous breathing of air in and out
of the alveoli
Differences between inspired air and
expired air
Component
Inspired air
Expired air
Oxygen
21%
16.4%
Carbon dioxide
0.03%
4.0%
Nitrogen
78%
78%
Water vapour
Variable
Saturated
Temperature
Variable
370C
Dust particles
Variable but
usually presnet
little
Lung Capacity
Residual air (1500 cm3)
• Air that is left behind
Tidal air (500cm3)
• Air that enters and leaves the lungs in each
breathing cycle
Complemental air (1500cm3)
• Additional air that can be taken in
Supplemental air (1500cm3)
• Additional air that can be forced out
Vital capacity (3500-4000cm3)
=tidal air + complemental air + supplemental air
Lung Capacity
Stimulus for breathing
• High concentration of carbon
dioxide in the blood or alveolar air
• Hyperventilation or overbreahting
can cause death as no breathing
occurs when there is no carbon
dioxide in the lungs
Tobacco smoke
•
•
•
•
Nicotine
Carbon monoxide
Tar
irritants
Effects of Tobacco
smoke on human health
Bronchitis
• Redness and swelling of the lining of air
passages
• Destruction of the cilia
• Dust and harmful chemicals are able to
move past the bronchi and invade the
alveoli
• Air passages become irritated and clogged
with mucus and dust
• Lots of phlegm and coughing
Asthma
• Irritants cause allergic reactions in
the respiratory tract
• Constriction of the respiratory tract
• Suffocation and death
Emphysema
• Violent coughing breaks partition
walls between air sacs
• Alveolar sacs may become less elastic
• Decrease surface area for gaseous
exchange
• Lungs become inflated with air
• Difficulty in breathing, wheezing
Lung cancer
• Carcinogenic compound, benzopyrene
causes cancer cells to be produced
• Tar and resin promote proliferation
of these cancer cells
• Shortness of breath
• Coughing up of mucus and blodd
Tar
• Contains cancer-causing
(carcinogenic) chemicals which induce
uncontrolled cell division of the
epithelium
• Paralyses cilia lining the air passages
Heart disease
• Nicotine stimulates release of
adrenaline
• Increases blood pressure and heart
rate
• Increases chance of blood clot and
plaque deposit on the walls of
coronary arteries
• Heart attacks and death
Smoking during
Pregnancy
• Restricts blood vessels reducing amount of
nutrients and oxygen to baby
• Low birth weight of baby
• Prone to illness
• Increase potential for birth defects and
abnormalities
• Increased chances of a miscarriage
• Increased chances of a premature birth
• Has a greater risk of baby being born dead
Respiration (Concept Map)
22 March 2016
RESPIRATION
• Oxidation of food substances
with the release of energy.
• Occurs in living cells.
• Enzymes are involved.
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84
RESPIRATION
• Oxidation of food substances
with the release of energy.
• Occurs in living cells.
• Enzymes are involved.
Aerobic Respiration
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85
RESPIRATION
• Oxidation of food substances
with the release of energy.
• Occurs in living cells.
• Enzymes are involved.
Aerobic Respiration
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Anaerobic Respiration
22 March 2016
86
RESPIRATION
• Oxidation of food substances
with the release of energy.
• Occurs in living cells.
• Enzymes are involved.
Aerobic Respiration
Anaerobic Respiration
• Oxygen is required.
• Large amount of energy is released.
• Carbon dioxide and water are produced.
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87
RESPIRATION
• Oxidation of food substances
with the release of energy.
• Occurs in living cells.
• Enzymes are involved.
Aerobic Respiration
• Oxygen is required.
• Large amount of energy is released.
• Carbon dioxide and water are produced.
Anaerobic Respiration
• Oxygen is not required.
• Small amount of energy is released.
• Lactic acid is produced in mammals. Ethanol
and carbon dioxide are produced in yeast.
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88
RESPIRATION
• Occurs in living cells.
• Enzymes are involved.
• Oxidation of food substances
with the release of energy.
Aerobic Respiration
• Oxygen is required.
• Large amount of energy is released.
• Carbon dioxide and water are produced.
Differences
Anaerobic Respiration
• Oxygen is not required.
• Small amount of energy is released.
• Lactic acid is produced in mammals. Ethanol
and carbon dioxide are produced in yeast.
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89
RESPIRATION
• Occurs in living cells.
• Enzymes are involved.
• Oxidation of food substances
with the release of energy.
Aerobic Respiration
• Oxygen is required.
• Large amount of energy is released.
• Carbon dioxide and water are produced.
Differences
Anaerobic Respiration
• Oxygen is not required.
• Small amount of energy is released.
• Lactic acid is produced in mammals. Ethanol
and carbon dioxide are produced in yeast.
Breathing mechanism
Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd.
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90
RESPIRATION
• Occurs in living cells.
• Enzymes are involved.
• Oxidation of food substances
with the release of energy.
Aerobic Respiration
• Oxygen is required.
• Large amount of energy is released.
• Carbon dioxide and water are produced.
Breathing mechanism
Differences
Anaerobic Respiration
• Oxygen is not required.
• Small amount of energy is released.
• Lactic acid is produced in mammals. Ethanol
and carbon dioxide are produced in yeast.
How the body takes in oxygen and removes carbon dioxide
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91
RESPIRATION
• Occurs in living cells.
• Enzymes are involved.
• Oxidation of food substances
with the release of energy.
Aerobic Respiration
• Oxygen is required.
• Large amount of energy is released.
• Carbon dioxide and water are produced.
Breathing mechanism
Differences
Anaerobic Respiration
• Oxygen is not required.
• Small amount of energy is released.
• Lactic acid is produced in mammals. Ethanol
and carbon dioxide are produced in yeast.
How the body takes in oxygen and removes carbon dioxide
Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd.
22 March 2016
92
RESPIRATION
• Occurs in living cells.
• Enzymes are involved.
• Oxidation of food substances
with the release of energy.
Aerobic Respiration
• Oxygen is required.
• Large amount of energy is released.
• Carbon dioxide and water are produced.
Breathing mechanism
Differences
Anaerobic Respiration
• Oxygen is not required.
• Small amount of energy is released.
• Lactic acid is produced in mammals. Ethanol
and carbon dioxide are produced in yeast.
How the body takes in oxygen and removes carbon dioxide
Inspiration
• External intercostal muscles contract,
internal intercostal muscles relax.
• Ribs move upwards and outwards.
• Diaphragm contracts and flattens.
• Volume of thorax increases.
• Air pressure in thorax decreases.
• Air flows into the lungs.
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93
RESPIRATION
• Occurs in living cells.
• Enzymes are involved.
• Oxidation of food substances
with the release of energy.
Aerobic Respiration
• Oxygen is required.
• Large amount of energy is released.
• Carbon dioxide and water are produced.
Breathing mechanism
Inspiration
• External intercostal muscles contract,
internal intercostal muscles relax.
• Ribs move upwards and outwards.
• Diaphragm contracts and flattens.
• Volume of thorax increases.
• Air pressure in thorax decreases.
• Air flows into the lungs.
Anaerobic Respiration
Differences
• Oxygen is not required.
• Small amount of energy is released.
• Lactic acid is produced in mammals. Ethanol
and carbon dioxide are produced in yeast.
How the body takes in oxygen and removes carbon dioxide
Expiration
• External intercostal muscles relax,
internal intercostal muscles contract.
• Ribs move downwards and inwards.
• Diaphragm relaxes and arches upwards.
• Volume of thorax decreases.
• Air pressure in thorax increases.
• Air flows out of the lungs.
Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd.
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94
RESPIRATION
• Occurs in living cells.
• Enzymes are involved.
• Oxidation of food substances
with the release of energy.
Aerobic Respiration
• Oxygen is required.
• Large amount of energy is released.
• Carbon dioxide and water are produced.
Breathing mechanism
Inspiration
• External intercostal muscles contract,
internal intercostal muscles relax.
• Ribs move upwards and outwards.
• Diaphragm contracts and flattens.
• Volume of thorax increases.
• Air pressure in thorax decreases.
• Air flows into the lungs.
Anaerobic Respiration
Differences
• Oxygen is not required.
• Small amount of energy is released.
• Lactic acid is produced in mammals. Ethanol
and carbon dioxide are produced in yeast.
How the body takes in oxygen and removes carbon dioxide
Expiration
• External intercostal muscles relax,
internal intercostal muscles contract.
• Ribs move downwards and inwards.
• Diaphragm relaxes and arches upwards.
• Volume of thorax decreases.
• Air pressure in thorax increases.
• Air flows out of the lungs.
Gaseous exchange
• Oxygen dissolves in film of moisture covering alveolar wall.
• Dissolve oxygen diffuses into blood capillaries.
• Carbon dioxide diffuses from blood into alveolar cavity.
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