The Respiratory System
Respiration begins in the nose
Psuedostratified Columnar
Ciliated epithelial tissue lines
the nose to warm and
mositen the inhaled air.
Mucous cells are found
within the lining to allow
moistening of the air.
3 Areas of the Oral Cavity
1.
OROPHARYNX
-soft palate to epiglottis
-two sets of TONSILS
a. Palatine
b. Lingual
-the tonsils remove pathogens that
enter the pharynx. They contain
lymphocytes
► 2.
NASOPHARYNX
-located superior and posterior to the
soft palate.
-contains the PHARYNGEAL TONSILS
and TUBAL TONSILS
The soft palate
is a muscular
structure that
separates the
nasal cavity from
the oral cavity.
The soft palate
moves superiorly
to seal the nasal
cavity during
swallowing.
An 11-monthold girl's mother
noted this
asymptomatic
cyst on her
daughters soft
palate.
► 3.
LARYNGOPHARYNX
-inferior to the epiglottis and posterior
to the larynx.
- this division opens into the esophagus
and larynx.
The Lower Respiratory Tract
► The
TRACHEA begins at the level of C6 superiorly.
► Directly superior to the beginning of the trachea is
the LARYNX (vocal cords).
► The trachea bifurcates into the BRONCHI at the
sternal angle (T4 or T5) when supine (laying on
the back) or T7 when standing.
► The
trachea is composed of 16-20
cartilagenous rings (hyaline cartilage).
► These rings are flexible but keep the
trachea open.
► Each ring is open in the back (allows
flexibility)
► The
rings are approximately 1.5 inches in
diameter and held together by connective
tissue.
► The connective tissue is dense CT.
► Air can pass through the tube without
resistance.
► The
trachea must be able to filter debris
(dust or dirt). Coughing occurs when such
debris enters the trachea.
Principles of Animal Physiology
Respiratory System
►Mammalian
Air Respirers
respiratory pathway
Nasal cavity and trachea.
► Psuedostratified
epithelium.
►Mucous
columnar ciliated
cells (goblet cells)
►Sub-mucosal tubuloacinar seromucous gland
►Intraepithelial gland in chicken.
Principles of Animal Physiology
Respiratory System
►Ciliated
Air Respirers
respiratory epithelium cells
Histology of the trachea
cartilage
Ciliated
epithelium
Principles of Animal Physiology
Respiratory System
►Diagram
Air Respirers
representing the human airways
Principles of Animal Physiology
Respiratory System
►Respiratory
Air Respirers
zone structures
Bronchi
► Psuedostratified
columnar to columnar to
cuboidal epithelium with mucous cells and
mixed bronchial glands in all species except
goat.
Bronchioles
► Simple
columnar to cuboidal epithelium
 Ciliated cells
 Bronchiolar exocrine glands.
 Both secretory and metabolizing xenobiotic compounds.
 Adundant in horses and sheep.
 Min in carnivores, cattle and pigs.
Principles of Animal Physiology
Respiratory System
►Alveolus
Air Respirers
and associated pulmonary capillaries
►Alveolar epithelial cells
 Type I: flattened processes which cover most of
the inner surface
 Type II: produce and store surfactant
 Macropharges: phagocytic cells
 pores of Kohn - permit airflow between adjacent
alveoli, a process known as collateral ventilation
The Larynx
► The
LARYNX (voice box) is a modified
portion of the trachea.
► It is superior to the trachea.
► There are cartilaginous rings that are
connected by dense connective tissue
forming a tube.
► The
TYROID CARTILAGE is shaped like a shield
when viewed from the anterior surface. This is
the ADAM’S APPLE. This is not a complete ring.
► On the posterior side of the thyroid cartilage, the
CRICOID CARTILAGE extends superiorly to where
the thyroid cartilage would be. This cartilage is
sometimes called the SIGNET RING CARTILAGE.
► It
has a narrow band across the anterior
side.
► It is superficial to the thyroid cartilage
posteriorly where it is connected by the
CRICOTHYROID LIGAMENT (dense
connective tissue).
► Inferiorly, the cricoid is attached to the first
ring to the trachea by dense CT.
► The
EPIGLOTTIS is a spade shade cartilage that is
important during swallowing.
► It tips inferiorly to seal off the glottis and prevents
food from entering the trachea.
► The ARYTENOID CARTILAGE is below the
epiglottis at the entrance to the GLOTTIS.
► The GLOTTIS is a passageway into the trachea.
The thyroid cartilage forms the walls of the glottis.
The arytenoid cartilage extends inferiorly into the
glottis.
►
►
►
►
►
►
The arytenoid cartilages anchor the vocal cords.
The true vocal cords are located inferiorly inside the glottis.
As air passes over the vocal cords they flutter, producing
sound from the vibration.
Pitch can be changed by tightening or loosening the cords.
In humans, the tongue is used to make sense of the
sounds (make words). You cannot talk if your tongue is
not functioning.
There are folds covering part of the epiglottis called FALSE
VOCAL CORDS.
Epiglottis
Hyoid Bone
Thyrohyoid Ligament
Thyroid
Cartilage
Aryetnoid
cartilage
Cricoid
cartilage
ANTERIOR
trachea
Tracheal rings
POSTERIOR
Tracheostomy – Step 1
Step 2
The skin incision is
made with a Colorado
Needle mounted on an
electric knife (Bovie). A
steel blade scalpel is as
good and is preferred
by many surgeons.
Step 3
After incising the
subcutaneous tissue
and platysma, the
strap muscles are
separated in the
midline.
The strap muscles is
a name given to the
four infrahyoid
muscles that lie in
front of the larynx.
They are the
sternohyoid,
sternothyroid,
thyrohyoid and the
omohyoid.
Step 4
The isthmus of the
thyroid gland is either
retracted or divided in
the midline. (In this
picture, the isthmus has
been divided and
retracted laterally, along
with the strap
muscles.) The anterior
tracheal wall is divided
between the third and
fourth tracheal rings. A
clamp is used to widen
the tracheal
opening. The
endotracheal tube is
seen inside the tracheal
lumen
Normal vocal
cords as they
appear
through a 90
degree
telescope. The
cords are
partially
opened and
the opening
into the
trachea can be
seen between
them.
One may compare this person at a
high and a low pitch,
demonstrating the elongation of
the vocal cords that takes place to
raise pitch by contracting the
Cricothyroid muscles
Acute Laryngitis
Chronic Laryngitis
68 year old nonsmoker with
history of
gastroesophageal
reflux. She
complained of
daily belching and
burning in her
throat due to the
stomach acids.
Wider,
shorter, and
more vertical
than the left
Right
Primary
Bronchus
trachea
Left
primary
bronchus
Both primary bronchi have the same anatomic structure
as the trachea.
► The
primary bronchi divide to form SECONDARY
BRONCHI (lobar bronchi).
► There is one secondary bronchus for each lobe of
the lungs.
► There are 2 lobes on the left lung.
► There are 3 lobes on the right lung.
► These also have the same anatomy as the
trachea.
► The
secondary bronchi branch to form TERTIARY
BRONCHI.
► They continue to branch.
► As they get smaller, they lose their cartilage.
► When they lose their cartilage, they are called
BRONCHIOLES which are microscopic.
Histology of the
Bronchus
► The
bronchioles terminate in the ALVEOLI
through an ALVEOLAR DUCT.
► The walls of the alveoli are one-cell thick
and is covered in capillaries.
► The alveoli are the functional unit of the
lungs.
Bronchiole and Alveolar Duct
► There
are air sacs, where gas exchange occurs.
► Walls of the alveoli are highly vascularized.
► The alveoli are the terminal branches of the
BRONCHIAL TREE. This arrangement allows for a
drastic increase in surface area.
The Lungs
► The
right lung starts 1” above rib 1 and
crosses the clavicle at about the medial 1/3
of it. It progresses inferiorly to costal
cartilage 6 (midsternally). At the midaxillary
region, it is at rib 8 and rib 10 at the
vertebral border.
► The
right lung has 3 lobes (4 in the cat).
► The left lung starts about 1” above rib 1 and
crosses deep to the manubrioclavicular joint.
There it goes to the left and continues inferiorly to
rib 6.
► The left lung has an indentation called the
CARDIAC NOTCH. This area provides room for the
HEART.
► Lung
size varies from individual to
individual.
► The left lung has 2 lobes (3 in the cat).
► The lobes are anatomically and functionally
separate. Thus, they are independent of
each other.
► There
is a deep fissure between the lobes. The
lobes overlap each other like shingles.
► The OBLIQUE FISSURE on each lobe begins
posteriorly across from the root of the spine of the
scapula at T3. They come around laterally and
inferiorly in an oblique path and eventually reach
rib 6 on both sides.
► On
the right side, there is also a TRANSVERSE
FISSURE which follows rib 4 anteriorly. It joins
the oblique fissure midaxillary.
► On the posterior surface, one can see only 2 lobes
on each lung. On the anterior surface, you can
see the third lobe on the right lung.
► The
lobes are further divided into LOBULES.
These cannot be separated as easily as the lobes
can.
► They are functionally separate.
► They are also anatomically partitioned to allow
removal of a lobule while keeping the functionality
of the rest of the lung.
The
Pleural
Cavity
Slide of
Alveoli
Gaseous exchange
relies on simple
diffusion. In order to
provide sufficient oxygen
and to get rid of sufficient
carbon dioxide there
must be
•a large surface
area for gaseous
exchange
•a very short
diffusion path
between alveolar air
and blood
•concentration
gradients for
oxygen and carbon
dioxide between
alveolar air and
blood.
Intercostal Muscles
►
►
►
External Intercostals
 O: Inferior border of rib above
I: Superior border of rib below
 Fibers run OBLIQUE (down and forward)
 Aid in Inspiration (lift ribcage, increase dimensions)
Internal Intercostals
 O: Superior border of rib above
I: Inferior border of rib below
 Fibers run at RIGHT ANGLES to external intercostals
 Aid in expiration (depress ribcage, decrease dimensions)
Innermost Intercostals
 Attachments similar to Internal Intercostals, Attach ribs
 Fibers run Anterior/Posterior
Neurovascular Bundle of
Intercostals
► VAN
(vein, artery,
nerve)
 Intercostal vein
 Intercostal artery
 Intercostal nerve
► Sit
in Subcostal Groove
► Between Internal
Intercostal and
Innermost intercostal
muscles
During inspiration the diaphragm moves
downward allowing air to enter the
respiratory tract. The external
intercostals contract along with the
pectoral muscles.
During Expiration, the diaphragm moves
upward forcing air out the lungs. The
internal intercostals contract.