The document discusses the process of breathing and the human respiratory system. It defines breathing as the process of gas exchange that occurs during inhalation and exhalation, resulting in oxygen intake and carbon dioxide loss. The respiratory system allows this gas exchange through specialized structures like lungs. The human respiratory system includes the nose, pharynx, larynx, trachea, bronchi, bronchioles and alveoli. In the alveoli, gas exchange occurs through diffusion as oxygen moves from the alveoli into the blood and carbon dioxide moves out. Smoking damages the lungs by paralyzing cilia and increasing risk of cancer and emphysema. Cystic fibrosis affects lung health by causing thick, sticky muc

1. BREATHING
• Gas exchange
• Dr. SaBa Qureshi

2. CONTENTS
• Definition
• Reason we breath
• Functions of respiratory system

3. DEFINITION
• The process of inhalation and exhalation in
which gas exchange of the body and outer
envoirment takes place resulting in oxygen
intake and carbondioxide loss

4. • Why do we breathe? Think of all the reasons
1.We need oxygen for respiration
2.We need oxygen for metabolic processes in our
body
3.Carbondioxide can cause acidity in our body
leading to death of living cells
REASON WE BREATH

5. Respiratory system function
• Respiratory systems allow animals to move
oxygen (needed for cellular respiration) into
body tissues and remove carbon dioxide
(waste product of cellular respiration) from
cells.

6. TYPES OF RESPIRATORY SYSTEM
1. Respiration by diffusion
2. Respiration by gills
3. Respiration by lungs

7. Gas exchange by Diffusion
• Some animals simply
allow gases to diffuse
through their skins.
• These animals have a low
metabolic rate. Why?
• All of these are aquatic
animals. Why?

8. Specialized structures
• Structures specialized
for gas exchange
include:
• gills (aquatic animals)
• spiracles (terrestrial
insects)
• lungs (most terrestrial
vertebrates)

9. Countercurrent Exchange
• In a countercurrent
system, equilibrium is
not reached, so gas
exchange continues,
increasing efficiency.

10. Fish Gills
• Fish increase gas exchange
efficiency using
countercurrent exchange.
• Running blood through the
system in the opposite
direction to water keeps a
diffusion gradient
throughout the entire
exchange.

11. Human respiratory system
• Parts of the respiratory
system include:
• Nose
• Pharynx
• Larynx
• Trachea
• Bronchi
• Bronchioles
• Alveoli

12. NOSE
• An externally visible organ of respiratory system
• Has two nasion
• Has following protective mechanisms
1. Angulation prevents direct entrance
2. Nasal hairs
3. Cillia
4. Mucus secreting cells
5. Mechanism of sneezing

14. PHARYNX
• 2nd
part f respiratory system
• Interconnects the mouth and nose
• That’s why breathing is possible through mouth
• In some circumstances food can be given
through nose
• Soft palate separates the nose from mouth
entrance

16. LARYNX
• Is the part of windpipe of respiratory system
• Has following protective mechanisms
1. Cillia
2. Globlet cells

18. TRACHEA
• Is the pipe through which oxygen come and co2
leaves during breathing
• Has many protective response
1.Cillia
2.Globlet cells

20. BRONCHI
• When trachea spilt in to two pipes to reach two
lungs these two pipe type structures are called
bronchi
• Inside them is moist lining covered from outside
by cartilage and muscle that give it strength

22. BRONCHIOLES
• When bronchi further split in the lungs to give
oxygen to the greater part of lungs thse
structures are called bronchioles
• The end pipe is called terminal bronchiole

24. Alveoli
• The alveoli are moist,
• thin-walled pockets
• which are the site of gas exchange.
• A slightly oily surfactant
• prevents the alveolar walls
• from collapsing and sticking together.

25. In the alveolus
• The respiratory surface
is made up of the
alveoli and capillary
walls.
• The walls of the
capillaries and the
alveoli may share the
same membrane.

26. Moving air in and out
• During inspiration
(inhalation), the
diaphragm and
intercostal muscles
contract.
• During exhalation,
these muscles relax.
The diaphragm domes
upwards.

27. MOVEMENTS DURING BREATHING
1. The rib muscles relax.
2. The diaphragm contracts.
3. Air leaves the alveoli.
4. Air moves between the chest wall and
the lung.

28. Circulation and Gas
Exchange
• Both these systems are
interconnected
• There are small
capillaries in the walls
of alveoli
• And this is the place
where simple diffusion
occurs
• Oxygen goes inside
• CO2 goes outside

29. Gas exchange
• Air entering the lungs
contains more oxygen
and less carbon dioxide
than the blood that
flows in the pulmonary
capillaries.

30. Oxygen transport
• Hemoglobin binds to
oxygen that diffuses
into the blood
stream.
• One hemoglobin
molecule can bind 4
o2 at one time

31. Carbon dioxide transport
• Carbon dioxide can
dissolve in plasma,
and about 70% forms
bicarbonate ions.
• Some carbon dioxide
can bind to
hemoglobin for
transport.

32. At the cells
• Cells use up oxygen quickly for cellular
respiration.
• By diffusion gradient.
• Cells create carbon dioxide during cellular
respiration,
• so CO2 levels in the cell are higher than in
the blood coming to them.
• And thus theCO2 leaves

33. Diffusion of O2 from lungs to blood
is rapid because:
1. Active transport moves oxygen.
2. Hemoglobin takes up oxygen, keeping plasma
concentration low.
3. Blood plasma is oxygen-rich.

34. Most of the oxygen in blood is:
1. In the white cells.
2. Bound to hemoglobin.
3. Combined with carbon to make carbon dioxide.
4. Dissolved in the plasma.

35. SMOKING AND LUNGS

36. Effects of smoking
• Inhaled smoke contains:
• CO2, which affects the
CO2 diffusion gradient.
• carcinogenic chemicals
that can trigger tumors.
• toxic nicotine, which
paralyzes cilia that
normally clean the
lungs.

37. Emphysema
• Besides cancer, smoking
can also lead to
emphysema. Alveoli
become dry and brittle,
and eventually rupture.
• Both active and passive
smoking (“second-hand”
smoke) can lead to can
lead to lung problems.
All types of smoke, not just tobacco, can
cause cancers and emphysema.

38. Cystic Fibrosis
• Cystic fibrosis is one of
the most common
inherited disorders in the
Caucasian population in
the U.S.
• CF is caused by mutation
of a single gene, the
CFTR gene, which
controls salt balance in
the lungs.

39. Cystic Fibrosis
• A normal CFTR protein
regulates the amount of
chloride ions across the
cell membrane of lung
cells.
• If the interior of the cell
is too salty, water is
drawn from lung mucus
by osmosis, causing the
mucus to become thick
and sticky.

40. Cystic Fibrosis
• At this point there is no
cure for CF, though there
are therapies that have
extended the lives of CF
patients, including lung
transplants.
• Gene therapy may one
day insert “good” CFTR
genes into lung cells to
make them operate
normally.

41. • When people quit smoking, if the lungs are not
damaged they can often clean themselves
because the cilia are no longer paralyzed.
People with cystic fibrosis have trouble with
lung infections because their lung mucus is thick
and sticky. What roles do cilia and mucus play in
lung health?
W
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42. THANK-YOU