Transcript Gas exchange - Mr Hartan`s Science Class

THE RESPIRATORY
SYSTEM
GAS EXCHANGE
ASSESSMENT STATEMENTS
1. Distinguish between ventilation, gas exchange and cell
respiration.
2. Explain the need for a ventilation system.
3. Describe and label a diagram of the ventilation system,
including trachea, lungs, bronchi, bronchioles, and
alveoli.
4. Draw and label a diagram of the ventilation system,
including trachea, lungs, bronchi, bronchioles and
alveoli
5. Explain the mechanism of ventilation of the lungs in
terms of volume and pressure changes caused by
intercostal muscles, the diaphragm and abdominal
muscles.
FAST FACTS ABOUT THE RESPIRATORY
SYSTEM
• The surface area of the lungs is roughly the
same size as a tennis court.
• A sneeze travels faster than a cough (60 vs. 100
mph).
• A person at rest breathes about 12x-15x/min.
17,000x/day and over 6 million times/year.
• The right lung (3 lobes) is slightly larger than the
left (2 lobes).
• Mean alveolar number is 480 million (Range:
274-790 million). An adult alveolus ranges in size
from 0.2 - 0.3 mm.
FUNCTIONS OF THE RESPIRATORY
SYSTEM
1. The organs of the respiratory system are designed
to serve as gas exchangers for the body.
2. The respiratory system filters, warms, and humidifies
the air we breathe.
3. The primary function of the respiratory system is to
deliver air to the circulatory system and remove
carbon dioxide (waste) from the circulatory system,
sustaining cell respiration.
4. Along with the circulatory system, the respiratory
system aids in the distribution of heat.
BASIC TERMINOLOGY
Breathing/Ventilation: The mechanical process
by which we breathe in and out. NOT the same
as Cellular Respiration.
External Respiration: The exchange of gases
between the atmosphere and the blood.
Internal Respiration: The exchange of gases
between the blood and the body’s cells.
THE RESPIRATORY SYSTEM
THE PATH OF AIR
1. Air enters your mouth and nose. Hairlike structures
called cilia trap foreign particles and sweep them
toward the throat. Filtered air then passes through the
upper throat (pharynx).
2. The epiglottis allows air to pass from the larynx to a the
trachea (windpipe). The trachea branches into two
large tubes called the bronchi—leading to the lungs.
3. Each bronchus branches into smaller tubes called
bronchioles. Each of these small tubes branches into
even smaller passageways, ending in individual air
sacs (grape-like clusters) called alveoli.
GAS EXCHANGE & DIFFUSION
(THE PROCESS OF SWAPPING ONE GAS FOR ANOTHER)
Occurs in the alveoli of the lungs. The alveoli are uniquely
structured to facilitate gas exchange.
• Oxygen diffuses from air in the alveolar sacs to the
blood in the capillaries.
• Carbon dioxide diffuses in the opposite direction (from
an area of high to low concentration).
• Both oxygen and carbon dioxide only need to diffuse
through 3 cells (including the red blood cell).
Remember: Diffusion is the random molecular motion of
molecules -- molecules passively move from areas of
higher concentration to area of lower concentration
SIMPLE DIFFUSION
VISUALIZING THE RESPIRATORY
SYSTEM
THE MECHANICS OF VENTILATION
(INHALATION & EXHALATION)
THE MECHANICS OF BREATHING
• Inhalation is the act of taking air into the lungs. The
diaphragm contracts, causing the chest cavity to
expand as the diaphragm moves down.
• During exhalation, the diaphragm relaxes and returns to
its normal resting position. This reduces the size of the
chest cavity as the diaphragm moves up.
VENTILATION OF THE LUNGS
(INHALATION)
The external intercostal muscles contract, moving the
ribcage up and out.
The diaphragm contracts (flattens and moves down).
These muscle movements increase the volume of the
thorax.
The pressure inside the thorax drops below atmospheric
pressure.
Air rushes/flows into the lungs from outside the body
until the pressure inside the lungs equals atmospheric
pressure.
VENTILATION OF THE LUNGS
(EXHALATION)
The internal intercostal muscles contract, moving the
ribcage down and in. The externals relax.
The abdominal muscles contract, pushing the
diaphragm up into a dome shape. The diaphragm
relaxes.
These muscle movements decrease the volume of the
thorax.
The pressure inside the thorax rises above atmospheric
pressure.
Air flows/rushes from the lungs to outside the body until
the pressure inside the lungs falls and equals
atmospheric pressure.
THE MECHANICS OF VENTILATION
(ANIMATIONS)
AUTONOMIC NERVOUS SYSTEM
CONTROL
http://science.howstuffworks.com/life/humanbiology/lung3.htm
• Respiration rate is controlled by the part of the
brain called the medulla oblongata (brain stem).
• Respiration rate can be influenced by:
1. Oxygen/CO2 concentration, blood pH, Chemical
Irritants (cigarette smoke) and Signals from other brain
regions (hypothalamus, cortex).
1. Drugs can influence respiratory system functioning.
RESPIRATORY SYSTEM DISORDERS
RESPIRATORY SYSTEM DISORDERS