Transcript 30.2 Respiration and Gas Exchange

30.2 Respiration and Gas Exchange
The respiratory system exchanges oxygen and carbon
dioxide.
• picks up oxygen from inhaled air
• expels carbon dioxide and water
30.2 Respiration and Gas Exchange
Path of air
• Nose & mouth – air
enters here. Nose is lined
with hair and mucus
membranes to help trap
particles.
• Epiglottis - flap of skin
that covers the trachea
when swallowing
• Larynx – “voice box”
where vocal cord are (2
ligaments)
nose
mouth
epiglottis
trachea
larynx
30.2 Respiration and Gas Exchange
Path of air
• Trachea – cartilaginous
“windpipe”
• Bronchi – tubes that lead to
each lung
• Bronchioles – branches off the
bronchi
• Alveoli – air sacs at the end of
the bronchi where gas
exchange with the blood occurs
bronchi
bronchi
trachea
bronchioles
lungs
lungs
30.2 Respiration and Gas Exchange
Breathing involves the diaphragm and muscles of the
rib cage.
• Air flows from areas of high pressure to low pressure.
Air inhaled.
Air exhaled.
Muscles and
rib cage relax.
Muscles contract and
rib cage expands.
Diaphragm flattens
and moves downward.
Diaphragm relaxes
and rises.
30.2 Respiration and Gas Exchange
The respiratory system moves gases into and out of the
blood.
• The lungs contain the bronchi, bronchioles, and alveoli.
• Millions of alveoli give the lungs a huge surface area.
• The alveoli absorb oxygen from the air you inhale.
30.2 Respiration and Gas Exchange
Gas exchange occurs in the alveoli of the lungs.
• Oxygen and carbon dioxide are carried by the blood to and
from the alveoli.
– oxygen diffuses from alveoli into capillary
– oxygen binds to hemoglobin in red blood cells
– carbon dioxide diffuses from capillary into alveoli
GAS EXCHANGES
ALVEOLI
capillary
alveolus
CO2 diffuses
into alveolus.
co2
o2
capillaries
O2 diffuses
into blood.
30.2 Respiration and Gas Exchange
Gas exchange occurs in the alveoli of the lungs.
• Breathing is regulated by the brain stem.
midbrain
pons
medulla
oblongata
spinal chord
30.2 Respiration and Gas Exchange
• Smoking is the leading cause of lung diseases.
30.2 Respiration and Gas Exchange
Smoking
•
•
•
•
Destroys alveoli.
Paralyzes the cilia that line your trachea and bronchi.
Causes genetic mutations leading to cancer.
Particles build up in your lungs and form tar.
30.2 Respiration and Gas Exchange
Lung diseases reduce airflow and oxygen absorption.
Emphysema destroys alveoli.
Person has trouble exhaling enough air and looks “barrelchested”
30.2 Respiration and Gas Exchange
– Asthma causes
bronchioles to
constrict due to
muscle spasms
– Attacks can be
triggered by
allergies, stress,
exposure to
smoke &
chemicals, or
exercise
30.2 Respiration and Gas Exchange
Respiratory diseases interfere with gas exchange.
– Cystic fibrosis
genetic disease
that produces
sticky mucus
- Clogs airways
- Allows
microorganisms
to thrive in lungs