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The Respiratory System
Chapter 10, Page 334 – 351
What Is A Respiratory
System?
 The
system of organs involved in the
uptake and exchange of oxygen and
carbon dioxide between and organism
and its environment.
 Different organisms have different
respiratory systems!
Functions of Respiratory System
1. To maintain Homeostasis
2. To provide O2, and remove CO2, from
cells = Gas Exchange
3. Contributes to our ability to talk
Requirements of Respiratory
System
1. Big surface area for gas exchange
to occur at the rate to meet
organism’s need
2. A moist environment for gases to
dissolve
FISH GILLS
INSIDE HUMAN LUNGS
Organization of The Respiratory
System
Passage of Air Through Our
Respiratory System
Upper Respiratory Tract: pg 335
1. Nose, mouth
2. Nasal cavity
Upper Respiratory Tract Cont’d
5. Epiglottis: “flap” that stops food from
entering trachea
6. Trachea: “windpipe”
 Lower

Respiratory Tract:
(inside thoracic cavity)
• Bronchi (bronchus-singular) :

Two small passageways that branch off
the trachea and enter lungs.
• Bronchioles:
Fine tubes that branch from the bronchi.
 Lined with cilia and mucous

• Alveoli: pg 336/337
Tiny sacs (in grape-like clusters) at
end of bronchioles.
 Site of gas exchange (via diffusion).

• Pleura (pleuron
)
singular
Flexible membrane around lung.
Don’t write:
Alveoli clusters at end of
bronchioles.
Average
human lung
has 70 to 90
m2 alveoli
surface area.
That’s about
the size of a
tennis court!
Mechanics of breathing (pg 338)
 Gases
move from areas of high to low
pressure.
 What controls this pressure??


Intercostal muscles:on ventral surface and
ribcage
Diaphragm: muscle between thoracic and
abdominal cavity
Inhalation
 Intercostals


and diaphragm contract.
Ribs expand
Diaphragm lowers
 Vol.increase
and air pressure lowers
 Lungs expand, air moves in.
Expiration/Exhalation
 Diaphragm


and intercostals relax.
Ribs lower
Diaphragm rises
 Vol.
decreases, pressure increases.
 Lungs shrink, air is forced out.
Gas Exchange (pg339)

Between air in alveoli and
blood in capillaries
Lung Capacity
 Tidal

Volume:
vol. of air inhaled and exhaled in normal
breathing
 Inspiratory

reserve volume:
additional vol. that can be inhaled after
normal breath.
 Expiratory

(pg 340)
reserve volume:
additional volume that can exhaled beyond
normal breath.
 Vital
Capacity: total vol. of air that can
move in/out of lungs
+
tidal vol.
inspiratory reserve vol.
expiratory reserve vol.
vital capacity
 Residual



Vol:
air that remains in lungs and
passageways after full exhalation.
can’t get rid of it
prevents lung collapse
 Respiratory

efficiency:
rate of oxygen transport to
bloodstream from lungs.
Diseases:
 Lung



cancer:
Uncontrolled growth of abnormal lung cells.
Carcinoma: a malignant, spreading tumour.
Once tumour cells enter lymphatic system the
cancer “spreads”
Non-Smoker vs. Smoker
Black=from air
pollution and second
hand smoke
Black=tar
White=cancer
Causes of lung cancer :
 Cigarette


smoke:
87% of lung cancers.
Carcinogens cause lung cells to become
anaplastic (less differentiated and quick to
multiply since carcinogens damage DNA)
 Radon:


a radioactive colorless, ordorless gas.
from soil and radiotherapy
 Air
pollution
Amount and type of tar build up in
lung per year of smoking 1 pack/day
Treatments for Lung cancer:
 Surgery
 Radiation:

high energy x-ray that kills cancer cells.
 Chemotherapy:


medication that kills cancer cells by
preventing mitosis and causing apoptosis (cell
suicide).
Also kills normal cells: hair loss, nausea.
Diseases:
 Pneumonia:



Inflamed alveoli fill with fluid.
lowers oxygen intake.
Types:
• Lobar pneumonia: entire lobe
• Bronchial pneumonia: patches of lung
Lung with Pneumonia

Causes:
 Bacterial:

streptococcus pneumoniae,causes lobar
pneumonia
 Viral:

Shorter durations
 Parasitic:

Mycoplasma,hardest to fight off
Treatments:
 vaccines and antibiotics
 Asthma:




Inflammation of airways due to irritants
bronchioles constrict due to muscle
spasms
mucous build ups
Lowers oxygen intake.
Treatments
 Avoid
triggers ( smoke, dust, pets……)
 Medications:
• Broncho-dilators/puffers: reduce
inflammation
• Anti-inflammatory drugs: prevent
attacks