espiratory System

Chapter 7

Related Combining Forms

espiratory System

Chapter 7

Related Combining Forms

StructureRelated Combining Forms
Bronchibronch/o, bronchi/o
Lungspneum/o, pneumon/o, pulmon/o

Functions of Respiratory System

Delivers air to the lungs

Conveys oxygen from inhaled air to blood

Expels waste products through exhalation

Produces airflow through larynx making speech possible

Structures of Respiratory System

Structures of Respiratory System

Upper respiratory tract

Nose, mouth, pharynx, epiglottis, larynx, and trachea

Lower respiratory tract

Bronchial tree and lungs

Located within and protected by thoracic cavity

Structures of Respiratory System


Air enters through nose, and passes through nasal cavity


External openings of nose

Nasal septum

Wall of cartilage dividing the nose into two equal sections



Thin hair located inside nostrils

Filter incoming air to remove debris

Mucous membranes

Specialized tissues lining parts of the respiratory, digestive, reproductive, and urinary systems



Secretion produced by mucous membranes

Helps moisten, warm, and filter air entering the nose

Olfactory receptors

Nerve endings acting as receptors for sense of smell

Also important also for sense of taste


Help protect body from infection entering through nose or mouth

Palatine tonsils

Located at back of the mouth

Nasopharyngeal tonsils

Located behind the nose and roof of the mouth


Paranasal Sinuses

(para-: near; nas: nose; -al: pertaining to)

Air-filled cavities lined with mucous membrane

Located in bones of the skull

Three functions

Make bones of skull lighter

Give resonance to the voice

Secrete mucus to lubricate nasal cavity

Paranasal Sinuses

Four pairs

Frontal sinuses

Located in frontal bone just above eyebrows

Infection causes pain in this area

Sphenoid sinuses

Located in sphenoid bone behind eye and under the pituitary gland

Near the optic nerves

Infection may damage vision

Paranasal Sinuses

Maxillary sinuses

Located in maxillary bones under the eyes

Infection causes pain in posterior maxillary teeth

Ethmoid sinuses

Located in ethmoid bone between nose and eyes

Separated from orbital cavity by thin layer of bone


Commonly known as throat

Receives air and food

Three divisions


(nas/o: nose; -pharynx: throat)

Posterior to nasal cavity; continues downward toward the mouth

Transports air only

Opens into the oropharynx



(or/o: mouth; -pharynx: throat)

Visible when looking into the mouth

Shared by respiratory and digestive systems

Transports air, food, and fluids to the laryngopharynx



(laryng/o: larynx; -pharynx: throat)

Shared by respiratory and digestive systems

Air, food, and fluids continue to the opening of esophagus and trachea; air enters trachea; food and fluids enter esophagus


Also known as voice box

Located between pharynx and trachea

Supported by nine cartilages; largest is thyroid cartilage (Adam’s apple)

Contains vocal cords that

Separate to allow passage of air

Close to assist with sound production

Protective Swallowing Mechanisms

Two mechanisms prevent entrance of food or water into trachea

Soft palate moves up and backward to close off the nasopharynx

Prevents food from entering the nose

Epiglottis swings downward and closes off the laryngopharynx

Prevents food from entering the trachea and lungs


Commonly known as windpipe

Transports air to and from lungs

Located in front of the esophagus

Held open by flexible C-shaped cartilage rings

Allow food to pass down the esophagus



Primary bronchi branch from trachea to convey air into the two lungs

Each bronchus divides and subdivides into increasingly smaller bronchioles


Also known as air sacs

Located at the end of each bronchiole

Site of gas exchange

Produce surfactant that reduces surface tension of the fluid in the lungs preventing collapse during exhalation


Right lung has three lobes

Upper (superior), middle, lower (inferior)

Left lung has two lobes

Upper (superior), lower (inferior)

Space is restricted due to location of the heart



Middle section of chest cavity

Located between the lungs

Contains connective tissue

Contains organs

Heart and its veins/arteries, esophagus, trachea, bronchi, thymus gland, lymph nodes


Moist membrane covering outer surface of lungs and lining inner surface of thoracic cavity

Parietal pleura

Outer layer

Attached to chest wall

Lines thoracic cavity, covers diaphragm, and forms sac containing each lung


Visceral pleura

Inner layer

Attached directly to each lung

Pleural cavity (space)

Fluid-filled space between parietal and visceral pleural membranes

Fluid acts as a lubricant


Muscle separating thoracic cavity from the abdomen

Breathing occurs as diaphragm contracts and relaxes

Contraction stimulated by phrenic nerves



Exchange of oxygen for carbon dioxide

1 inhalation + 1 exhalation = 1 respiration

Inhalation and Exhalation


Breathing in

Diaphragm contracts, and pulls downward; thoracic cavity expands causing vacuum drawing air into lungs


Breathing out

Diaphragm relaxes, and moves upward; thoracic cavity narrows forcing air out of lungs

Inhalation and Exhalation

External Respiration

With inhalation of air into alveoli, oxygen is passed into capillaries and carried by erythrocytes to body cells

Carbon dioxide, as a waste product, is passed into bloodstream and transported into air spaces for exhalation

Internal Respiration

Exchange of gases within cells of blood and tissues

Oxygen passes into cells; carbon dioxide passes into bloodstream where it is transported to the lungs, and expelled during exhalation

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