The Respiratory System
Chapter 22
Objectives
1. SC.912.L.14.44 - Describe the physiology of
the respiratory system including the
mechanisms of ventilation, gas exchange, gas
transport, and the mechanisms that control
the rate of ventilation.
2. SC.912.L.14.44 - Describe the physiology of
the respiratory system including the
mechanisms of ventilation, gas exchange, gas
transport, and the mechanisms that control
the rate of ventilation.
3. SC.912.L.18.6 - Discuss the role of
anaerobic respiration in living things and in
human society.
Functions
1. Provides
extensive gas
exchange surface
area between air
and circulating
blood
2. Moves air to and
from exchange
surfaces of lungs
Functions
3. Protects
respiratory
surfaces from
outside
environment
4. Produces sounds
5. Participates in
olfactory sense
Organization
• Upper Respiratory
System
– above the larynx
• Lower Respiratory
System
– below the larynx
Organs (Upper)
• Nose
– filters air
• Sinuses
– warm and
moisten air
• Pharynx
Larynx
• Voice box
• Made of cartilage,
surrounds the glottis
– Adam’s apple
• Epiglottis
– folds back over the glottis during
swallowing
– prevents entry of food & liquids into the
respiratory tract
Sound Production
• Air passes
through the
glottis
– vibrates vocal
folds
– produces sound
waves
Organs (Lower)
• Trachea
– windpipe
– made of 15-20 rings
of cartilage
• Lungs:
– bronchi
– bronchioles
– alveoli
Lobes of the Lungs
• Lungs have lobes separated by deep
fissures
• Right Lung
– 3 lobes
• Left Lung
– 2 lobes
– cardiac notch
Respiration
• External respiration
– includes all processes involved in
exchanging O2 and CO2 with the
environment
• Internal respiration
– involves the uptake of O2 and production of
CO2 within individual cells
Respiration
• C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP
Accessory Structures
• Diaphragm
– contraction results
in inhalation
– relaxation results
in exhalation
• Vocal cords
Gas Exchange
• Occurs between alveolar
air and capillary blood
• Depends on:
– partial pressure of the
gases
– diffusion of molecules
between gas and liquid
Composition of Air
• Nitrogen (N2) about
78.6%
• Oxygen (O2) about
20.9%
• Water vapor (H2O)
about 0.5%
• Carbon dioxide (CO2)
about 0.04%
Hemoglobin
• O2 binds to iron ions
in hemoglobin
molecules
• Carbon Monoxide
(CO)
– binds strongly to
hemoglobin
– takes the place of O2
– can result in carbon
monoxide poisoning
Changes in R.S. at Birth
1. Before birth:
–
–
pulmonary vessels
are collapsed
lungs contain no air
2. During delivery:
–
placental connection
is lost
–
blood PO falls
–
PCO rises
2
2
Changes in R.S. at Birth
3. At birth:
– newborn overcomes force of surface
tension to inflate bronchial tree and
alveoli and take first breath
Changes in R.S. at Birth
4. Large drop in pressure at
first breath:
–
–
–
pulls blood into pulmonary
circulation
closing foramen ovale and
ductus arteriosus
redirecting fetal blood
circulation patterns
5. Subsequent breaths:
–
fully inflate alveoli
Effects of Aging
1.
2.
3.
Elastic tissues deteriorate:
–
–
reducing lung compliance
lowering vital capacity
–
–
restrict chest movements
limit respiratory minute
volume
Arthritic changes:
Emphysema:
–
–
affects individuals over age
50
depending on exposure to
respiratory irritants (e.g.,
cigarette smoke)
Coordination of Respiratory &
Cardiovascular Systems
•
•
•
Improves
efficiency of gas
exchange
Increases
respiratory drive
Raises cardiac
output and blood
flow