The Respiratory System:Breath deeply the air of knowledge

Chpt 23

Respiratory System

• Function: supply body with oxygen and dispose of carbon dioxide

Requirements

1. pulmonary ventilation (movement of air into and out of lungs)

2. external respiration (gas exchange between blood and lungs)

3. transport of respiratory gases (via blood)4. internal respiration (gas exchange

between blood and cells)

5 Functions of the Respiratory System

1. Provides extensive gas exchange surface area between air and circulating blood

2. Moves air to and from exchange surfaces of lungs

3. Protects respiratory surfaces from outside environment

4. Produces sounds-speaking, singing5. Helps maintain pH

Anatomy of the Respiratory System

Figure 23–1

Anatomy: Nose

Functions• provides airway for

respiration• moistens and warms

entering air• filters air • serves as a resonating

chamber for speech• houses olfactory

receptors

Mucus

Nasal Structuresa. External nose: bridge, root, dorsum

nasi, apex, external nares, alaeb. Nasal cavity: nasal septum, internal

nares (aka posterior nares or choanae), hard palate, soft palate, vestibule (with sebaceous and sweat glands and vibrissae)

c. Mucous membranes of the nasal cavity

a. olfactory mucosa (with smell receptors)b. respiratory mucosa- secrete sticky mucus

with antibacterial substancesd. Conchae- superior, middle, and

inferior; help to trap particles

Sinuses

• Paranasal sinuses– Frontal– Sphenoid– Ethmoid– Maxillary

• Function to lighten skull & warm and moisten the air

The Nasopharynx a. only an air

passagewayb. during swallowing,

closed off by the soft palate and uvula to prevent food from entering the nasal cavity

c. pseudostratified ciliated columnar

d. Pharyngeal tonsil (adenoids)

The Oropharynx

1. swallowed food and inhaled air

2. palatine & lingual tonsils

3. stratified squamous

The Laryngopharynx

1. Inferior portion of the pharynx

2. stratified squamous

3. where resp. and dig. pathways diverge

Larynx aka voice box

• Functions– open airway– switching

mechanism to route air and food into proper channels

– voice production via vocal cords

Larynx aka voice boxAnatomy

– 9 cartilages connected by membranes and ligaments (8 are hyaline)– 9th cartilage is the epiglottis- elastic; closes over trachea during

swallowing– Vocal folds aka true vocal cords- avascular; vibrate as air passes

through them to produce sound– Medial opening between vocal folds is the glottis

Anatomy of the Trachea

Figure 23–6

Trachea aka windpipe10-12 cm long; 2.5 cm diam

• Layers of tracheal wall (internal to external)1. Mucosa- pseudostr.

ciliated columnar2. submucosa3. adventitia- with 16-20

rings of C-shaped hyaline cartilage, allowing flexibility

Trachea aka windpipe • 15–20 tracheal cartilages:

– strengthen and protect airway– discontinuous where trachea contacts esophagus

• Ends of each tracheal cartilage are connected by:– an elastic ligament and trachealis muscle

• The carina (“keel”) marks the point where the trachea splits into the 2 primary bronchi (approx T7).

The Bronchial Tree• R and L primary

bronchus• Secondary (lobar)

bronchi- 3 R, 2 L• About 20 smaller

branches• Bronchioles- less than

1 mm in diameter

• The Respiratory Zone: thin-walled alveoli (clustered into the alveolar sacs) where gas exchange occurs

Lungs

1. apex- narrow, superior tip2. base- concave, inferior

surface on diaphragm3. L lung 2 lobes- upper and

lower separated by oblique fissure

4. R lung 3 lobes- upper, middle, and lower separated by the horizontal and oblique fissures

5. Each lung lobe is divided into 10 bronchopulmonary segments

Lung lobes

Relationship between Lungs and Heart

Figure 23–8

Figure 23–8

Pleural Cavities and Pleural Membranes

Pleural Cavities and Pleural Membranes

• 2 pleural cavities:– are separated by the mediastinum

• Each pleural cavity:– holds a lung – is lined with a serous membrane (the pleura)

The Pleura

• Consists of 2 layers: – parietal pleura – visceral pleura

• Pleural fluid:– lubricates space between 2 layers

Pleurae (membrane around the lungs)Parts of the parietal pleura. (parietal pleura in blue; visceral pleura in purple)

Grab a copy of the article: Struggling to Inhale

• ANSWER THE FOLLOWING QUESTIONS• There are 2 different words for croup. List

them and write what they each mean.• Explain how the virus that causes croup

causes infection.• What is the treatment for croup?• What is a cricothyrotomy? Explain how

doctors perform these.• What type of infection did the older patient

have?