Bronchial tree alveoli lungs review

1. The Bronchial Tree

2. Bronchial tree
The trachea branches
into the bronchial tree.
The first split produces
two bronchial tubes
called the primary
bronchi (sing. bronchus)
The left primary
bronchus leads to the left
lung while the right
primary bronchus leads
to the right lung.
Right primary bronchus
Left primary bronchus
Trachea

3. Bronchial tree
The primary bronchi then
branch into secondary
bronchi, which lead to
each of the lobes of the
lungs.
The right primary
bronchus will branch three
times (3 lobes), while the
left primary bronchus will
branch only twice (2
lobes).

4. Bronchial tree
The secondary bronchi
continue to divide into
smaller and smaller
tubes called tertiary
and quaternary
bronchi until they
finally reach the
smallest tubes called
the bronchioles.
T
T
T
T
T

5. Bronchial tree
The primary, secondary,
tertiary, and quaternary
bronchi are much like the
trachea in composition
but as they get smaller
they lose the cartilage and
fibrous tissue until the
bronchiole walls are
composed of only a thin
layer of muscular and
elastic tissue.

6. The Alveoli

7. Alveoli
The bronchioles end in a
cluster of minute air
sacs called the alveoli
(sing. alveolus). The
alveoli have a wall
composition similar to
that of capillaries with a
thickness of about .
00004 in.

8. Alveoli
An extensive network
of capillaries surrounds
each alveolus.
Pulmonary arteries bring
deoxygenated (blue) blood
from the heart to the
capillary network
surrounding each alveolus.

9. Alveolar Capillary Network
O
2
and CO
2
diffuse back and forth between the alveoli
and the blood (RBC) in the capillaries thus allowing
the RBC to drop off CO
2
for exhalation and pick up O
2

for aerobic metabolism in the cells of the body.

10. Alveoli
Pulmonary veins then
carry the freshly
oxygenated (red) blood
away from the capillary
network and back to the
heart.
The process just described – the movement of
oxygen from outside the body to inside – is not
the act of breathing, instead it is the process of
respiration.

11. Respiration is not actually
the physical act of breathing,
but rather the movement of
oxygen from the atmosphere
to the cells of the body.
Respiration includes:
External respiration – is the
passage of O
2
and CO
2
to and
from the alveoli and RBC.
Internal respiration – is the
passage of O
2
and CO
2
to and
from RBC and body cells .
Cellular respiration – is the release of energy
from the oxidation of food materials (which
means using the oxygen to “burn” food).

12. The Lungs

13. Lungs
A pair of lungs contains
about 300 million alveoli.
This subdivides the volume
of the lungs and creates a
total alveolar surface area
of about 1000 ft.
2
(like a
room 33 ft. x 30 ft.).
The advantage to having
this is that it allows for a
very large surface area
for gas exchange.

14. Lungs
The lungs are “pink” in
color, cone shaped and they
extend from the diaphragm
to the root of the neck. Each
primary bronchus enters its
respective lung at the hilus
of the lung (a depression on
the surface of a bodily
organ around the point of
entrance or exit of vessels,
nerves, or ducts).
hilus

15. Lungs
At the hilus, the pulmonary
arteries & veins, bronchial
arteries & veins, nerves and
lymphatic vessels enter and
leave the lungs. Lymph
nodes and aereolar tissue
also come together at this
point to form the root of the
lung. Except for at the root,
the lungs are freely movable
within the chest cavity.
Root

16. Lungs
Because the heart appears
“tilted”, meaning the heart
is larger on the left side,
there is more room on the
right side of the thoracic
cavity so this extra space is
taken up by lung tissue.
This means the left lung is
less massive, and therefore
smaller than the right.
Note the color of healthy lungs

17. Lungs
Thus, the right lung is larger and broader than the
left, but it is also shorter than the left lung because the
diaphragm rises higher on the right to allow room for
the liver.
Liver

18. Lungs
The right lung is
divided into three (3)
lobes – the superior
or upper, middle, and
inferior or lower. The
left lung is divided
into two (2) lobes –
the superior or upper
and the inferior or
lower.

19. Lungs
The lungs are “light”, porous, and spongy (they would
float in water). Each lobe is supplied by a secondary
bronchus and a major branch of the pulmonary artery.
Each lobe is broken down into subgroups called sub
lobes. Each sub lobe receives a tertiary bronchus.
Note the 3
lobes of the
right lung and
the 2 lobes of
the left lung

20. Nostril
Nasal cavity
Nose hairs
Mucous membranes
Sinus openings***
Olfactory bulbs
Nasal septum
Review & addendum
*** Addendum to follow – additional notes on the sinuses
Blue – respiratory tract structures “passed through”
Green – accessory structures “passed by”

21. The Paranasal Sinuses
- Maxillary
- Sphenoidal
- Ethmoidal
- Frontal
The sinuses are “air spaces” in the bones of the skull
which are open to the nasal cavity. Their primary
function is to lighten the bones of the skull, but they
also contribute mucus to the nasal cavity and act as a
resonating chamber for sound production.

22. Acute sinusitis is very common with more than 24
million cases occurring in the United States annually.
Roughly ninety percent of adults have had sinusitis at
some point in their life.
Sinusitis
Sinusitis is simply the
inflammation of the
paranasal sinuses, usually
due to infection or allergy.
Most cases are due to a
viral infection (the
“common” cold) and lastonly about 10 days.

23. Sinusitis can be classified
into three categories:
Acute – lasting less than
four weeks
Subacute – lasting 4 to 8
weeks
Chronic – lasting for 8
weeks or more
All three “types” of sinusitis have similar symptoms,
and are thus often difficult to distinguish on any basis
other than duration.

24. During a cold or an allergy, the sinuses may become
blocked by swelling of the mucous membranes.
Drainage into the nasal cavity is stopped, but the
formation of the mucus continues, and pressure builds
up in the sinuses causing headaches – sometimes
severe. The condition can become chronic making it
necessary to open the wall of the sinus surgically.
This is called “draining the sinuses.”

25. Sinus Headaches
•Maxillary - can cause
pain in the cheek area
•Frontal - can cause
pain above eyes
•Ethmoid - can cause
pain mostly between the
eyes
•Sphenoid - can cause
pain or pressure behind
the eyes or the top of the
head

26. Review

27. Secondary Bronchi
Primary Bronchi
Tertiary Bronchi
Quaternary Bronchi
Bronchioles
Alveoli
Nostril
Nasal cavity
Nasopharynx
Oropharynx
Larynx
Nose hairs
Mucous membranes
Sinus openings
Olfactory bulbs
Nasal septum
Pharyngeal tonsils (adenoids)
Eustachian (auditory) tubes
Palatine tonsils
Tongue
Oral cavity
Uvula
Lingual tonsils
Epiglottis
Vocal cords
Trachea
Laryngopharynx
Cilia
Blue – respiratory tract structures “passed through”
Green – accessory structures “passed by”