Download Respiratory Anatomy (441-447) Oversees gas exchanges that occur

Respiratory Anatomy (441-447)
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Oversees gas exchanges that occur between the blood and external environment
Anatomy of the Respiratory System
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Alveoli are only part that conduct gas exchange
Passageways purify, humidify, & warm air
I.
Nose
a. Air enters through nostrils or nares
b. Opening in nose = nasal cavity which is divided by the nasal septum
c. Nasal cavity is lined with respiratory mucosa to produce mucus (helps
purify air, moistens air); resp. mucosa is superficial to a network of veins
that help warm blood  why it’s easy to get a nosebleed
d. Lysozyme enzymes chemically destroy bacteria trapped in mucus
e. Olfactory receptors, located in the mucosa in the super nasal cavity, allow
people to smell
f. Ciliated cells move nasal mucosa to the throat where it is swallowed and
digested by the stomach
g. Lateral walls of nasal cavity are uneven and form three mucosa-covered
projections/lobes called the conchae inc surface area of mucosa to
maximize warming and to deflect inhaled debris onto mucus-coated surfaces
in the nasal cavity
h. Nasal cavity is separated from the oral cavity by the palate (anteriorly the
palate is composed of bone hard palate; the posterior portion of the
palate lacks bone  soft palate)
*Cleft palate is a genetic condition that results when the bones of the hard palate fail to
fuse leaving a hole between the oral and nasal cavities; causes difficulty eating and
speaking
i. Nasal cavity is surrounded by the nasal sinuses in the cheek (maxillary),
forehead (frontal), between nose and brain (sphenoid), around eye
(ethmoid); purpose is to lighten skull, resonate speech, produce mucus that
drains into nasal cavity
*rhinitis- inflammation of the nasal mucosa caused by cold viruses or allergens that
results in excess mucus production often cause infections in the sinuses or tear ducts
because the nasal mucosa is found continuously through all of those structures
*sinusitis- inflammation of the sinus (causes changes in voice, sinus headaches over
the inflamed area)
II.
Pharynx AKA throat
a. Is a muscular passageway (5 in. long) from nasal cavity down posterior of
mouth via the posterior nasal aperture through which air and food pass; 3
parts
i. Nasopharynx – pharynx in nasal cavity
ii. Oropharynx- pharynx in mouth
iii. Laryngopharynx- inferior portion near the voice box
*When you eat, food travels through the oropharynx and laryngopharnxy then goes
down the esophagus whereas inhaled air would follow the same path except pass
through the larynx to the lungs
b. Pharynx is connected to the ears via the pharyngotympanic tubes (drain
middle ear into the nasopharynx, have continuous mucosa)
c. Tonsils (pharyngeal, palatine, & lingual) are found in pharynx; purpose is to
help fight diseases
*Tonsillitis is inflammation of the tonsils. If the pharyngeal tonsil is inflamed it can
obstruct air’s path from the nasal cavity to the lungs. In the past tonsils were often
removed but now most cases of tonsillitis can be treated with antibiotics
III.
Larynx AKA voice box
a. Directs food and air into the proper channels
b. Formed by hyaline cartilages and a spoon-shaped flap of elastic cartilage the
epiglottis
c. Epiglottis protects superior opening of the larynx to prevent food (not air)
from entering the lungs
i. Epiglottis is always open until we swallow
ii. Upon swallowing the larynx is pulled upwards and the epiglottis tips
forming a lid over the larynx
d. Largest cartilage, thyroid cartilage, is shield-shaped and protrudes
anteriorly making the Adam’s apple
e. Coughing is a reflex designed to expel substances from the larynx and
prevent them from entering the lungs
i. Only works when conscious… NEVER give water to someone who is
unconscious!
f. Some mucus membranes in the larynx form a pair of folds, vocal cords,
which vibrate when air is expelled from the lungs allow us to speak; the
small space between the vocal cords is the glottis
IV.
Trachea AKA windpipe
a. Air enters trachea from larynx and travels ~4 in. /mid-chest level
b. Walls are reinforces with c-shaped rings of hyaline cartilage and have cilia
to propel mucus out of the respiratory tract and to the throat
i. open parts of the rings face posteriorly where the esophagus sits so
the esophagus can expand while food is swallowed
ii. c rings keep trachea open despite pressure from esophagus
*Heimlich Maneuver- procedure where the air in a person’s lungs is used to dispel an
object that is obstructing the trachea or glottis
* Smoking damages the cilia that line the respiratory tract inhibiting the body’s ability to
expel mucus… coughing is the only way to remove mucus hence smoker’s cough
V.
Main Bronchi AKA Primary Bronchi
a. Formed when the trachea bifurcates
b. Right bronchus is wider, shorter, & straighter and is often where objects
become lodged
c. Connect the trachea to the lungs
d. Once inside the lungs, bronchi divide into smaller branches (secondary,
terciary,… bronchi) and end in the smallest conducting pathways called
bronchioles (last tube for air to travel through until it reaches the alveoli)
e. Alveoli (individual grapes in a bunch) are the only sight of gas exchange
VI.
Lungs
a. Large, spongy organs that occupy the entire thoracic cavity except for the
mediastinum (the central area where the heart, major blood vessels,
primary bronchi, esophagus are found)
b. Weighs ~2 lbs each
c. Right lung is larger than the left (has a cardiac notch where the heart sits)
d. Right  3 lobes; left  2 lobes
e. Narrow, superior portion of each lung = apex
f. Wide, inferior portion on the diaphragm is the base
g. Surface of each lung is covered with the visceral pleura
h. The lining of the thoracic cavity if covered with parietal pleura
i. Pleura- layer of simple squamous epithelium that secretes pleural fluid into
the space between the pleura (pleural space) to reduce friction between
the lungs and wall of the chest cavity as the lungs expand and contract
j. Pleura hold lungs tightly to the wall of the thoracic cavity… this is necessary
for normal lung function
*Pleurisy is inflammation of the pleura. Could be caused because too little pleural fluid
is being produced causing the pleura to rub and become irritated resulting in painful
inspirations. Could also be caused by an accumulation of pleural fluid which hinders
breathing
VII.
Respiratory Membrane
a. Alveolar walls lined with squamous epithelial cells
b. Alveoli are surrounded by a “cobweb” of pulmonary capillaries where gas
exchange occurs
c. Alveolar pores connect air sacs so if a bronchiole becomes blocked, the
alveoli at the end of the tube can still carry out gas exchange