Transcript Chapter 37.3: The Respiratory System

• Do not perform this activity if you have any breathing problems. Working
with a partner, count the number of breaths you take in 15 seconds.
Multiply that number by 4 for the number of breaths per minute. Your
partner will act as the timer/recorder. Repeat the procedure three times
and take an average. Now, take a deep breath and hold it for as long as
you can. Have your partner record your time. Repeat the procedure
three times and take an average. Switch roles with your partner and
repeat the procedure. Exchange data with other groups and answer the
following questions.
1.
What was the range of breathing rates?
2. Why are there differences in breathing rates among members of the class?
3. What was the average length of time classmates could hold their breath?
4. What factors might affect how long you could hold your breath?
5. A child having a tantrum declares she is going to hold her breath “until I turn blue!” Do you
think this is possible? Explain your answer.
The
Respiratory
System
Respiration
Respiration is the exchange of gases
between an organism and the environment
• In humans, as with most organisms, it is
the release of carbon dioxide and the
uptake of oxygen
The Respiratory System
• The basic function performed by the
respiratory system in humans is to bring
about the exchange of oxygen and carbon
dioxide between the blood, the air, and
tissues
Parts of the Respiratory System
• The respiratory system consists of the
nose/mouth, pharynx, larynx, trachea,
bronchi, bronchioles, and alveoli
• Several blood vessels are included in the
respiratory system, especially the
pulmonary artery, pulmonary vein, and
capillaries.
Movement of Oxygen and Carbon
Dioxide In and Out of the
Respiratory System
Oxygen-rich
air from
environment
Bronchi
Nasal
cavities
Bronchioles
Trachea
Pharynx
Oxygen and
carbon dioxide
exchange at
alveoli
Pharynx
Trachea
Alveoli
Nasal
cavities
Bronchi
Bronchioles
Carbon
dioxide-rich
air to the
environment
Structures (cont’d)
• Nose/Mouth –
– Air enters the respiratory system through
these two structures
Air is filtered, warmed, and moistened
The Human Respiratory System
• A thin layer of mucus is produced on the
lining of the tubes of the respiratory
system
This thin layer traps particles of dust or
smoke
Cilia clean the passageways by sweeping the
dirt away from the lungs
Structures (cont’d)
• Pharynx –
– Back of mouth
• Found behind the uvula
– Serves as a passageway for
both air and food
Structures (cont’d)
• Larynx –
– Voice box, Adam’s apple
– Contains vocal cords
• 2 loose flaps of tissue
– Top of the trachea
Structures (cont’d)
• Trachea –
– Windpipe
• Tube made of cartilage that carries air to the lungs
– Contains cells that produce mucus
• Mucus traps dirt found in air
– Contains cilia
• Tiny hairs that move dirt out of the tubes
Structures (cont’d)
• Bronchi –
– 2 branches that come off of trachea
– Each tube leads to lungs
• Bronchioles –
– Branches of the bronchi
– Found inside lungs
• Each tube is surrounded by smooth muscle
which helps control size of passageways
• Bronchitis  inflammation and irritation of
bronchi and bronchioles
Review
• What is the function of the Respiratory
system?
• After the pharynx air passes through the
blank , blank and blank to reach the alveoli.
Fill in the blanks.
• What is the function of the mucus and cilia?
• Where are the vocal cords found?
• What keeps food from entering the trachea?
• Where is the site gas exchange going to
occur?
Structures (cont’d)
• Alveoli –
– Small structures at the end of each bronchiole
– Occur in clusters
Place where gas exchange occurs
• Oxygen into blood, carbon dioxide into lungs
• Each is surrounded by capillaries
Gas Exchange and Hemoglobin
• 300 million alveoli are in a healthy lung
– Provides a large surface area for gas exchange
Oxygen dissolves in the moisture in the alveoli
– It can then diffuse into the capillaries
– Carbon dioxide diffuses in the opposite direction
• Hemoglobin binds with so much oxygen that it
increases the oxygen carrying capacity of the blood
more than 60 times
Gas Exchange and Hemoglobin
• Hemoglobin binds with so much oxygen
that it increases the oxygen carryingcapacity of the blood more than 60 times
Breathing
• Breathing is the movement of air into and
out of the lungs
Force that drives breathing is air pressure
– No muscles are directly connected to the lungs
Breathing
• Lungs sit in two sacs = pleural membranes
• At the bottom of the chest cavity is the
diaphragm
Inhaling
• When you inhale, the diaphragm
contracts and expands the volume of the
chest cavity
• Because the chest cavity is tightly sealed,
this creates a partial vacuum inside the
cavity
– Air rushes into the lungs as a result
Exhaling
• Exhaling is a passive event
• Diaphragm relaxes and lungs return to
normal size, placing pressure on the lungs
– Air rushes out of the lungs
Figure 37-15 The Mechanics of Breathing
Inhalation
Air
inhaled
Rib cage
rises
Diaphragm
Exhalation
Air
exhaled
Rib cage
lowers
Diaphragm
Breathing Control
• Breathing is voluntary to a point, then it
becomes involuntary
– Nervous system will take over
– Medulla oblongata in the brain reads the
amount of carbon dioxide in the blood
If the level of carbon dioxide gets too high, the
diaphragm will increase contractions