Download Respiratory System

 Supply oxygen and dispose of carbon dioxide
 Enable speech production
To accomplish this, 4 independent processes, collectively called
respiration must occur:
1. Pulmonary ventilation
2. External respiration
3. Transport of respiratory gases
4. Internal respiration (gas exchange between blood & tissue cells)
Only the first two processes are the direct responsibility of the
respiratory system. However, the other two must occur in order for
oxygen to be obtained and for carbon dioxide to be removed.
 Movement of air into an
out of the lungs so that
gases in the air sacs (alveoli)
of the lungs are
continuously changed and
refreshed.
 This air movement is
known as ventilation or,
more commonly, breathing.
 Ventilation
 exchange of air between
lungs and atmosphere
 Gas Exchange in pulmonary
capillaries
 Oxygen and Carbon
Dioxide
 Diffusion, based on
concentration gradient
 Breathing largely involuntary
activity
 Transport of O2 and CO2
between lungs and tissue cells
of the body
 Accomplished by
cardiovascular system
 Blood is the transporting fluid
 All cells require oxygen
for metabolism
 All cells require means
to remove carbon
dioxide
 Gas exchange occurs at
cellular level
 Also simple diffusion,
based on concentration
gradient
 Upper respiratory tract
 Nose/Mouth
 Pharynx
 Epiglottis
 Lower respiratory tract
 Larynx
 Trachea
 Bronchi
 Lungs
 Bronchioles
 Alveoli
 Nose is the only externally visible
part of the respiratory system
 Numerous functions:
 Airway for respiration
 Moistens and warms entering air
 Filters inspired air and cleanses it
of foreign matter
 Resonating chamber for speech
 Houses olfactory receptors
 Mouth can be used in lieu of the nose
as an airway for respiration.
 Air will be less “treated”
 Nasopharynx
 adenoids or
pharyngeal tonsils
 oropharynx
 palatine tonsils
 laryngopharynx
 larynx
 Oropharynx and laryngopharynx serve as a common passageway
for both food and air
 Epiglottis acts as a lid or flap that covers the larynx and trachea
(airway) so food does not enter the lungs.
 “voice box”
 Three main functions:
 Patent (open) airway
 Switching mechanism to
route food and air into
proper channels
 Voice production (houses
vocal cords)
 Windpipe or airway
 Mucous membrane lining with
cilia
 Smooth muscle with c-shaped
cartilage rings
 divides into two branches:
bronchi
 no gaseous exchange
 Bronchus = singular
 c-shaped cartilage rings with
smooth muscle
 Each bronchi divides into
bronchioles
 Terminate in air sacs called
alveoli
 Two circulations
 Pulmonary circulation
 Bronchial circulation
 Innervated by parasympathetic and
(rare) sympathetic motor fibers
 Each lung enclosed in pleura
 parietal pleura (outer)
 visceral pleura (inner)
 Lubricating pleura fluid
 “air sacs”
 Alveolar wall membranes one
cell thick and surrounded by
capillaries
 Location of gaseous exchange