UPPER

Functions of the Respiratory System

1. Gas exchanges between the blood and external environment – Occurs specifically in the alveoli of the lungs

2. Passageways to the lungs purify, humidify, and warm the incoming air

Organs of the Upper Respiratory System1. Nose

nasal cavityparasinuses

2. Pharynxnasopharynxoropharynxlaryngopharynx

3. Larynxthyroid cartilageepiglottisvocal foldsglottis

4. Trachea

1. The Nose

• Only externally visible part of the respiratory system

Basic Anatomy:• External nostrils (nares)• Interior of the nose

nasal cavity nasal septumparasinuses

Nasal Cavity• Top of nasal cavity is the Cribriform plate

of the ethmoid bone contains openings for olfactory nerves

• The nasal cavity is lined with respiratory mucosa that– Moisten air (humidify)– Trap incoming foreign particles (purify)

• Lateral walls have projections called conchae (remember the nasal conchae)– Increase surface area– Increase air movement within the

nasal cavity in order to increase collection of foreign particles

Paranasal Sinuses• Cavities within bones

that are surrounding the nasal cavity and share mucosa from the nasal cavity are called sinuses

• Sinuses are located in the following bones– Frontal bone– Sphenoid bone– Ethmoid bone– Maxillary bone

Paranasal SinusesFunction of the sinuses– Lighten the skull–Act as resonance chambers for speech–Warms and moistens air–Produce mucus that drains into the nasal

cavity

Sinuses are connected which is why a sinus infection can cause secretion from the eyes and ears

http://www.youtube.com/watch?v=ge5uUHmk2bE&NR=1

2. Pharynx (Throat)• Muscular passage from nasal

cavity to larynx• Three regions of the pharynx

1. Nasopharynx—superior region behind nasal cavity also connects to middle ear

2. Oropharynx—middle region behind mouth, carries air and food

3. Laryngopharynx—inferior region attached to larynx, carries air and food

http://www.youtube.com/watch?v=HJHYTz14CkY&NR=1

3. Larynx (voice box)A. Thyroid cartilage– Largest of the hyaline cartilages– Protrudes anteriorly (Adam’s apple)

B. Epiglottis– Routes food to the esophagus and air toward the

trachea– When swallowing, the epiglottis rises and forms a

lid over the opening of the larynx

http://www.youtube.com/watch?v=Ri8bBhw9msQ

Structures of the Larynx (voice box)

C. Vocal folds (true vocal cords)– Vibrate with expelled air to create sound

(speech)

D. Glottis —opening between vocal cords

Video of Vocal Cordshttp://www.youtube.com/watch?v=-XGds2GAvGQ

4. Trachea (Windpipe)• Four-inch-long tube that connects larynx

with bronchi• Walls are reinforced with C-shaped hyaline

cartilage (allows esophagus, which is behind the trachea, the ability to expand for swallowing)

• Lined with ciliated mucosa– Beat continuously in the opposite direction of

incoming air– Expel mucus loaded with dust and other debris

away from lungs and into the esophagus