Transcript Bio stuff part 6

Human Respiratory System –
• Diaphragm – sheet
of muscle
• Pharynx – where
digestive and
respiratory systems
meet
• Larynx – voice box
– We produce
sounds by
exhaling, air
moves over vocal
cords
• Trachea – windpipe
• Bronchi – lead to
each lung
• Bronchioles –
smaller branches
structure and function
• Alveoli – clusters of
air sacs
– Where gas is
exchanged with
blood vessels
– Increase surface
area to allow for
more gas
exchange
Scanning
electron
micrographs
of alveoli
Take A Breath
• Alternation of inhalation and exhalation…
• When the diaphragm contracts air is “pulled” into the
lungs due to increase in volume and decrease in
pressure (negative pressure breathing)
• When diaphragm relaxes air is “pushed” out of the
lungs due to decrease in volume and increase in
pressure
• Automatic control centers in
the brain regulate breathing
• Nerves tell the diaphragm
when to contract (between
contractions the diaphragm
relaxes)
• Respiratory rate ~ 10-14
inhalations per minute
• This rate will change
depending on the level of
CO2 in the blood
– The more CO2 in the
blood the faster the
respiration rate
• Hyperventilation – purges
the blood of so much CO2
that the brain stops sending
messages to the diaphragm
– So breathing into a paper
bag will increase the
amount of CO2 taken into
the body and restore
What controls our
breathing?
Importance of Hemoglobin
• Oxygen does not readily dissolve in blood
• O2 will be carried through the blood by hemoglobin
molecules in red blood cells
• Hemoglobin consists of 4 polypeptide chains, heme
(chemical group) and iron
• Every iron atom can only bind to 1 O2molecule; therefore,
each hemoglobin can carry up to 4 O2 molecules
• O2 rich blood is bright red / O2 poor blood is dark red
(blue)
Problems with hemoglobin…
• Iron deficiency
causes anemia
• Hemoglobin can
also bind to CO
(carbon monoxide)
• CO interferes with
the delivery of O2 to
the body cells and
cellular respiration;
therefore, causes
death
– CO is also found in
cigarette smoke
Effects of
smoking
• Air pollutants can cause
respiratory problems
– CO, SO2, O3
• Tobacco smoke is one of
the worst forms of air
pollution
• It can contain > 4000
chemicals (many of which
are deadly)
• Epithelial tissues are very
delicate.
• Chemicals damage the
mucus and cilia making it
difficult to remove foreign
particles