A.
General Organization (Fig 24.1)
1.
Atmosphere ‑‑> nose ‑‑>
pharynx ‑‑> larynx ‑‑> trachea ‑‑>
bronchi ‑‑> lungs
2.
Also the reverse for gases to be eliminated (CO2)
3.
Definitions:
a)
Pulmonary ventilation: tidal movement of air into and
out of the lungs
b)
External respiration: gas exchange between alveolar air
and blood
c)
Gas transport: oxygen and carbon dioxide transport via
cardiovascular system
d)
Internal respiration: gas exchange between systemic
capillaries and tissues
B.
Overview
1.
Conducting and respiratory (resp. bronchioles &
alveoli) zones
a)
Conducting
(1)
Upper respiratory system
(a)
Warms and humidifies air, removes particulates
(2)
Lower respiratory system
2.
Functions
a)
Gas exchange between air & circulation
b)
Move air to respiratory zone (tidal form of respiration)
c)
Protection from:
(1)
Dehydration
(2)
Microorganisms & particulates
(3)
Alterations in blood volume, BP, pH
d)
Producing sounds
3.
(Lower) Respiratory Epithelium (Fig 24.2)
a)
Pseudostratified ciliated columnar epithelium
(1)
Secretion of mucus and continuous upward movement
(traps particulates)
C.
Upper Respiratory System
a)
External nose (ext. nares)
(1)
Septal cartilage, lateral nasal, alar cartilages
(2)
Dorsum nasi
b)
Nasal cavity (internal nares)
(1)
Hard & soft palate
(2)
Nasal conchae
c)
Paranasal sinuses
d)
Nose functions
2.
Pharynx (throat; Fig.
24.3c,
24.3d)
a)
Composed of skeletal muscles, lined w/ mucous membrane.
b)
Both respiratory and digestive in function (air, food,
drink).
c)
Subdivisions
(1)
Nasopharynx
(a)
Borders: nasal conchae, soft palate
(b)
Contains pharyngeal tonsil
(2)
Oropharynx
(a)
Borders: soft palate, base of tongue (top of
epiglottis)
(3)
Laryngopharynx
(a)
Borders: hyoid & esophagus
D.
Lower Respiratory System
1.
Larynx (voicebox; Fig
24.4ab,
24.4cd)
a)
Short passageway
(C4‑C6) connecting pharynx w/ trachea
b)
Muscle and CT
walls are held together by nine pieces of cartilage.
c)
Three single cartilages – epiglottis, thyroid, cricoid
d)
Three paired
cartilages – cuneiform, corniculate, arytenoid
e)
Vocal Cords (Fig
24.5)
(1)
Two sets of paired mucous membrane folds
(a)
Ventricular
folds (false vocal cords) ‑ upper.
(b)
Vocal folds
(true vocal cords) ‑lower.
2.
Trachea (windpipe;
Fig 24.7)
a)
Extends about 12 cm, C6‑T5, where it divides
(rt/lft prim. bronchi); 2.5 cm in
b)
Lies anterior to esophagus
c)
Structure
(1)
Bronchi (branches of trachea; Fig
24.7,
24.9)
(a)
Right primary bronchus ‑ more vert., wider than
left; feeds rt. lung.
(b)
Left primary bronchus ‑ to left lung
(c)
Secondary or lobar bronchi ‑ right has 3 lobes,
left has 2 lobes.
(d)
Tertiary or segmental bronchi
(i)
As bronchi branch out & become smaller, cartilage
rings are replaced with plates
(e)
Bronchioles ‑ branch from segmental bronchi;
smooth muscle replaces cartilaginous plates
(f)
Terminal bronchioles ‑ last branch of bronchial
tree before gas exchange areas.
(g)
Respiratory bronchioles ‑ microscopic branches of
terminal bronchioles – have pouches that support gas exchange. (Fig 24.11)
(2)
Alveolar ducts ‑ further subdivisions which give
rise to alveoli. (Fig 24.11aL,
24.11aR)
(3)
Alveoli ‑ thin, cup‑shaped out‑pouching
of epithelial cells (Fig 24.11aR,
24.12a,
24.12cd)
(1)
Parietal pleura
(2)
Visceral pleura
(3)
Pleural cavity (pneumothorax)
b)
Bilateral structures located in thorax
c)
Each lung occupies own pleural cavity (potential space
between visceral pleura
d)
Separated from heart, other structs by mediatinum
e)
Each lung has base, apex.
f)
Landmarks
g)
Lobes – Left: sup/inf, Right: sup/middle/inf
(1)
Separated by Fissures – Left: oblique, Right:
horiz/oblique
h)
Bronchopulmonary segments – 2-4 per lobe (Fig 24.10)
(1)
Ex: left superior lobe has apical/anterior/sup
lingular/inf lingular segments, each supplied by a tertiary (segmental)
bronchus
i)
Lobules – small subdivisions of lobes
4.
Respiratory muscles & Pulmonary Ventilation (Fig
24.14)
a)
Inspiration – contraction of diaphragm (external
intercostals)
b)
Expiration – relaxation of diaphragm (internal
intercostals)
5.
Neural Control of Ventilation (Fig 24.15)
a)
Pons – pneumotaxic, apneustic centers
b)
Medulla – rhythmicity areas: dorsal & ventral
respiratory groups
6.
Pathology
a)
COPD (chronic obstructive pulmonary disease)
b)
Obstructive emphysema – deterioration of alveolar &
resp bronchiolar walls
c)
Chronic bronchitis – excessive mucus secretion,
inflammation/fibrosis of mucosa
d)
Cystic Fibrosis
