The Respiratory system
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Transcript The Respiratory system
The Respiratory
System
Day 2 Notes – Process of Breathing
Inhalation vs.
Exhalation
Muscles of the
Respiratory System
Diaphragm: dome-shaped muscle separating thoracic
and abdominal cavities
External intercostals: pulls ribs to elevate rib cage;
inspiratory muscles
Internal intercostals:
depresses rib cage
Inspiratio
n
Diaphragm contracts &
flattens
External intercostals lifts
rib cage
Lungs stretched to larger
size
Volume in thoracic cavity
increases
Air pressure inside lungs
decrease
Air sucked into lungs
Expiratio
n
Inspiratory muscles
relax
Internal intercostals
depress ribcage
Rib cage descends, lungs
recoil
Volume in thoracic
cavity decreases.
Pressure in thoracic
cavity increases
Gases forced out
Air Content
Inspiration
Content
Exhalation
21%
Oxygen
17%
0.04%
Carbon Dioxide
4.04%
78%
Nitrogen
78%
0.96%
Inert Gases
0.96%
Vital Capacity (VC): total exchangeable air
VC = TV + IRV + ERV
Tidal Volume (TV): amount of air in/out during
normal, relaxed breathing (~500ml)
Inspiratory Reserve Volume (IRV): additional air
that can be forcibly inhaled breathing in a normal
tidal volume (~3100)
Expiratory Reserve Volume (ERV): additional air
that can be forcibly exhaled after the expiration of a
normal tidal volume(~1200)
Residual Volume (RV): air still left in lungs (~1200)
allows gas exchange to continue between breaths
Respiratory capacity
Factors that affect capacity: size, age, sex,
physical condition
spirometer
Used to measure respiratory capacities
Gas transport in blood
Oxygen: attaches to hemoglobin molecules
inside RBC’s
Hemoglobin: respiratory pigment, contains 4
heme groups with iron (Fe)
Gas transport
in blood
Carbon dioxide:
Transported as
bicarbonate ions
(70%)
Bound to
hemoglobin (23%)
Dissolved in plasma
(7%)
Controlling Respiration
Control center =
medulla oblongata
Responds to pH changes in
blood
High CO2 carbonic acid
forms lowers pH
O2 sensors in the aorta
and carotid arteries
External Respiration
Ventilation
– exchange of air between lungs and atmosphere
Physical process during which oxygen is taken up
by capillaries of lung alveoli and carbon dioxide is
released from blood.
Gas Exchange in
pulmonary capillaries
Breathing is largely an
involuntary activity
Internal Respiration
• Tissue respiration/cellular respiration
• Refers to a metabolic process in which oxygen is
released to tissues or living cells and carbon dioxide is
absorbed by the blood.
• Once inside the cell the
oxygen is used for producing
energy in the form of ATP
• All cells require oxygen for
metabolism
• All cells require means to
remove carbon dioxide
• Gas exchange at cellular level