A&P Unit 5

Airway consists of the following structures:

nose/mouth, pharynx, larynx, trachea, bronchi

Nasal passages

lined with ciliated cells to filter air, mucus membranes to moisten air, blood capillaries to warm air

What type breathing is preferred?

nasal breathing

Pharynx

region behind nose and mouth, common passage for food and air

What are the 3 sections of the pharynx?

Nasopharynx, Oropharynx, Laryngopharynx

Larynx

voice box below pharynx

What is the largest section in the larynx of the 9 cartilages?

thyroid cartilage (adams apple; suspended from hyoid bone)

What folds down and covers the larynx during swallowing?

epiglottis

Trachea

tube-like passageway for air from larynx to primary bronchi (consists of C-shaped rings of cartilage; located very interior in the neck but central in chest)

Primary (main stem) bronchi/bronchus

splitting of the trachea to allow air to reach both lungs (right & left)

Carina

splitting point of trachea

Secondary bronchi

division of the primary bronchi to allow air to reach the lobes of each lung

How many secondary bronchi are on the right side?

three

How many secondary bronchi are on the left side?

two

Bronchiole

small branches off secondary bronchi for distribution of air throughout each lung

Trachea and bronchi are covered with _____ to create and expel mucus

ciliated columnar epithelial cells

Alveoli

microscopic air sacs

Alveoli purpose:

o2 and CO2 are exchanged with the bloodstream (not radiographically visible)

Foreign bodies are more likely to enter the

right lung

Foreign objects enter the right lung because

right primary bronchus is more vertical and larger in diameter

Apex (apices)

most superior portion of the lungs

Hilum (hila)

slit in the medial aspect of the lungs where bronchi and blood vessels enter and leave the lungs

Base

most inferior portion of lungs that rests against the diaphragm muscle

Costophrenic angle

inferior corners of lung that lie lateral and posterior

Lobes (right)

superior, middle, inferior

Lobes (left)

superior and inferior

Fissures

separations between the lobes of a lung (not normally seen on chest radiographs, overlap front to back)

Upper lobe extends

inferior in front

Lower lobe extends

superior in back

Diaphragm

“dome-shaped” muscle under the lung bases that control breathing

The diaphragm separates what two cavities

thoracic and abdominal

Breathing in the diaphragm occurs from the

“top down”

The diaphragm attaches to ____ at the central tendon

lung bases

The three openings of the diaphragm are

esophagus, aorta, and inferior vena cava

Hemidiaphragm

one half of the diaphragm

The RIGHT hemidiaphragm is more superior than LEFT because of

the liver under the RIGHT hemidiaphragm

Mediastinum

space between lungs

Several important structures reside in the mediastinum such as:

trachea, esophagus, heart, aorta, inferior vena cava, thymus gland

Mediastinum shift

mediastinal structures being pushed or pulled to one side due to pathology

Pleura

double-walled epithelial membrane lining surrounding each lung

What is the purpose of the pleura?

to reduce friction during breathing

Parietal pleura

the outer lining of the lungs

Visceral pleura

the inner lining of the lungs

Bony thorax includes:

ribs (12 pairs), sternum, clavicle, scapula, thoracic vertebra (T1-T12), lower cervical vertebra (C4-C7)

Bony landmarks include:

larynx (C4-C6), thyroid cartilage (C5), apices (T1), trachea (C6-T4/T5)

Respiration

the process of taking air into the lungs (inspiration/inhalation) and exhaling air out of the lungs (expiration/exhalation)

During inspiration the diaphragm moves

down (creates a negative pressure with the outside atmosphere)

During expiration the diaphragm moves

up (creates excessive pressure in the thorax)

Vital capacity

total lung capacity

Tidal volume

average intake of air in normal respiration

Expiratory reserve

the amount of air that can be forced after tidal volume

Residual volume

the amount of air left in the lungs after forceful respiration

Normal breathing =

15 mph

Forced expiration =

100 mph

Sneeze=

600 mph

Alveolar exchange

the process of exchanging o2 and CO2 with bloodstream (based on the diffusion of molecules across the permeable alveolar wall)

Arterial blood

bright red (due to high o2 content)

Venous blood

very dark blood (high CO2 content)

Pulse oximeter

the non-invasive device that measures the % of oxygen saturation in skin

Oxygen saturation should be

95%

Oxygen should NOT fall below

95%

What percent of CO2 actually diffuses out of the blood into the lungs?

12%

Blood pH always needs to be at

\~7.4

Hyperventilating will cause excessive CO2 to be

exhaled

Raising the blood pH can lead to

hypocapnia

Hypocapnia

breathing out too much CO2

Hyperventilation can be triggered by

pain

Pneumonia

inflammation of the lungs caused by viral or bacterial infection

Emphysema

long term destruction to the alveolar walls, preventing adequate gas exchange, and leaving air trapped in the lungs

Lung cancer

“mutated” cells that grow rapidly and engulf healthy cells

Asthma

allergic disorder characterized by thickening of the bronchial tree and excessive mucus production

Pneumothorax

“collapsed lung”

Atelectasis

incomplete expansion of the lung due to obstruction or other forces (sponge sticking together)