Explain the gross anatomy and functions of
the respiratory system.
Discuss the structure and functions of the
upper and lower respiratory tracts in detail,
including a description of the histology in
each region.
Identify the pleural cavities, its membranes
and the muscles of ventilation.
Respiratory System
Function
Major Functions
Upper respiratory system:
1. Air conditioning
2. Defense against
pathogens
Lower respiratory system:
1. Speech & other
respiratory sounds
2. Gas exchange
3. Maintenance of
homeostasis, e.g. pH
Fig 24-1
Respiratory Epithelium
Structure?
Mucus
produced by
________
Defense by means of
•filtering hairs
•ciliary escalator
•sticky mucous
Mucus escalator
Nasal Conchae
Superior, middle and
inferior
Other name: “Turbinate
bones” because they
create ______
Advantage ?
! Respirator breathing !
Fig 24.3
Upper Respiratory System
1) Nose
 external and internal nares
 turbinates or conchae (superior, middle, and inferior)
 nasal septum
 hard palate
2) Pharynx - shared passageway for respiratory and digestive
systems
 nasopharynx - part above uvula and posterior to internal nares
 oropharynx – portion visible in mirror when mouth is wide open
uvula - posterior edge of soft palate
 laryngopharynx – between the hyoid bone & the esophagus
Fig 24.3c
Lower Respiratory
System
C3
Anything below Pharynx
C4
C5
C6
C7
Larynx: Cartilaginous
cylinder (from C4- C7)
Made up of 9 cartilages
– 3 large unpaired (know these!)
– 3 small paired (involved in construction of voice box
Stabilized by ??
Fig 24.4
Trachea
Passageway to lungs (attached
via ligament to ?)
Lining ?
Incomplete cartilage rings (Cshaped) - completed by
trachealis muscle.
Significance?
Annular ligament
Fig 24-7
Tracheal Blockage
Heimlich Maneuver or
abdominal thrust
or
Tracheostomy
From Bronchi to Lungs
Fig 24.9
 1 bronchi (enter lungs at hilus, complete
cartilage rings)
 2 bronchi (from now on cartilage plates)
 3 bronchi
Fig 24.11
 Bronchioles
 Terminal bronchioles
 Respiratory bronchioles
 Alveolar ducts
 Alveolar sacs
Conducting
portion
Respiratory
portion
Paired Lungs
Situated in _________
Subdivided into lobes (each
supplied by 2 bronchus)
Right lung: 3 lobes
(rel. broad and short)
Fig 24-8
Why?
Left lung: 2 lobes (long and narrow)
Right and left lung separated by __________
Lung hilus
Fig 24-8
Alveolar Organization
Alveoli are site of gas exchange
Close association with capillaries
Lots of elastic fibers in alveolar wall
Fig 24-11
Alveolar cells
Fig 24-12
Type I cells – respiratory epitheliocytes
Type II cells – septal cells – produce surfactant
Alveolar Macrophages – dust cells – phagocytic
Respiratory Membrane
Different from respiratory
epithelium
Super thin. Made up of 4
layers:
1. epithelium of alveolus
2. its basement membrane
back to back and fused to
the
3. basement membrane of
capillary endothelium
4. endothelium of capillary
Emphysema
Chronic progressive
enlargement of alveoli
accompanied by
destruction of their
wall
Due to prolonged
exposure to respiratory
irritants (??)
Pleural Cavities and Membranes
Two cavities separated by
mediastinum
Fig 24-13
Lining of cavities?
pleurisy
Pneumothorax
Conducting blood supply to the
lungs via bronchial arteries.
Venous return to pulmonary
veins (consequence ?)
Pulmonary Embolism
See p. 805
Causes for development of
emboli in veins of legs:
Immobilization
Trauma
Long surgeries
Oral contraceptives
Obesity
Cigarette smoking
Hypertension
Respiratory Muscles
Diaphragm: depresses  inhalation
External intercostals: elevate ribs  inhalation
Internal intercostals: depress ribs  active
exhalation
Accessory muscles - serratus anterior, scalenes,
pectoralis minor, sternocleidomastoid, internal and
external obliques, transverse abdominus, rectus
abdominus
Fig 24-14