The Respiratory System
• The respiratory system is the group of organs that
takes in oxygen and gets rid of carbon dioxide
• Respiration is another name for breathing
• Respiration is the transport of oxygen from outside
the body to cells and the transport of carbon
dioxide and wastes away from the cells
• When we inhale, oxygen in the air moves into the
blood from the lungs
• Oxygen is used for cellular respiration
The O₂/C O₂ Exchange
• When we exhale, carbon dioxide is released from
the body
• When we inhale, O₂ in the air moves into the blood
from the lungs
• O₂ leaves the blood and enters the body cell
through the capillaries
• O₂ is used for cellular respiration
• When we exhale, CO₂ is released from the body
• CO₂ moves from the body cells to the capillaries
• Blood carries CO₂ through the heart and to the
lungs
• CO₂ moves out of the lung capillaries and into the
lungs to be exhaled
Parts of the Respiratory System
• Air enters your respiratory system through your
nose and your mouth
• Air flows into the pharynx, or throat
• The pharynx branches into two tubes
• One tube leads to the stomach
• The other tube leads to the lungs
• The larynx is the part of the throat that holds the
vocal chords
• When air passes across the vocal chords, they
vibrate, making a voice
Parts of the Respiratory System
• The larynx is connected to the trachea, or windpipe
• Air flows from the larynx through the trachea to
the lungs
• The trachea splits into two branches called bronchi
(bronchus, singular)
• The bronchi connect to each lung
• The bronchi branch off into smaller tubes called
bronchioles
• Bronchioles lead to tiny sacs called alveoli
• Alveoli are surrounded by blood vessels
• Gases move between the blood vessels and alveoli
Parts of the Respiratory System
• As you breathe, air is sucked into and forced out of
the alveoli
• Breathing is carried out by the diaphragm and the
rib muscles
• The diaphragm is a dome-shaped muscle below the
lungs
• When you inhale the diaphragm contracts, or
moves down
• The volume of the chest increases
• This creates a vacuum and air is sucked in
• Exhaling is the reverse process
Disorders of the Respiratory System
• Asthma – condition in which airways are narrowed
because of inflammation of the bronchi
• Pneumonia – inflammation of the lungs that is
usually caused by bacteria or viruses – alveoli fill
with fluid
• Emphysema – alveoli have been damaged so
oxygen cannot pass across into the blood as well as
it should – often linked to long term use of tobacco