RESPIRATORY
SYSTEM
Chapter 16
COMPONENTS
Tubes that filter incoming air
Air transported to alveoli (gas exchange)
RESPIRATION
Respiration: process of gas exchange between
atmosphere and body cells
Consists of
 Ventilation
 Gas exchange between blood and lungs
 Gas transport in the bloodstream
 Gas exchange between the blood and body cells
 Cellular respiration
ORGANS
Upper Respiratory Tract (nose, nasal cavity, sinuses,
and pharynx)
Lower Respiratory Tract (larynx, trachea, bronchial
tree, and lungs)
Front
alsinus
Nasal
cavity
Soft palate
Hard
palate
Pharynx
Nostril
Epiglottis
Oral
cavity
Esophagus
Larynx
Trachea
Bronchus
Right lung
Left lung
NOSE
Supported by bone and cartilage
Provides an entrance for air
Nostril hair filters air
NASAL CAVITY
 Posterior to nose
 Cavity has passageways
 Lined with mucous membranes and help increase the
surface area available to warm and filter incoming air
 Particles in air can get trapped in mucus….
 What will flush the mucus out?
 Where will mucus go?
SINUSES
Air filled spaces in skull
Open to nasal cavity
Lined with mucus
Function: lighten skull; resonates voice
PHARYNX
Food and air pass through
Helps produce speech sounds
Superior
Frontal sinus
Middle
Inferior
Nasal
conchae
Sphenoidal sinus
Nostril
Pharyngeal tonsil
Hard palate
Uvula
Tongue
Nasopharynx
Opening of
auditory tube
Palatine tonsil
Oropharynx
Lingual tonsil
Epiglottis
Hyoid bone
Laryngopharynx
Larynx
Trachea
Esophagus
LARYNX
Between pharynx and trachea
Functions:
Prevents particles from entering trachea
Holds vocal cords
Epiglottic cartilage
Hyoid bone
Thyroid cartilage
Cricoid cartilage
Trachea
Hyoid bone
Epiglottic cartilage
Thyroid cartilage
Cricoid cartilage
Trachea
VOCAL CORDS
Two pairs
Changing tension controls pitch
Changing force of air controls loudness
EPIGLOTTIS
Flap that covers trachea during swallowing
TRACHEA
 Anterior to esophagus…..why?
 Extends into thoracic cavity
 Separates into right and left bronchi
 Inner wall lined with cilia and mucus……why?
 20 cartilaginous rings
BRONCHIAL TREE
Branched tubes leading from trachea to alveoli
Starts with two main bronchi (right and left….each
leads to a lung)
Bronchi lead to bronchioles
ALVEOLI
Bronchioles lead to alveolar ducts, which lead to
alveolar sacs, then end in alveoli
Gas exchange between blood and air
Larynx
Trachea
Right superior (upper) lobe
Left superior
(upper) lobe
Right main (primary)
bronchus
Lobar (secondary)
bronchus
Segmental (tertiary)
bronchus
Terminal bronchiole
Right inferior (lower) lobe
Right middle lobe
Respiratory bronchiole
Alveolar duct
Alveolus
Left inferior
(lower) lobe
Blood flow
Pulmonary
venule
Intralobular bronchiole
Pulmonary
arteriole
Blood flow
Smooth muscle
Alveolus
Pulmonary
artery
Capillary network on
surface of alveolus
Pulmonary
vein
Terminal
bronchiole
Respiratory
bronchiole
Alveolar
duct
Alveolar
sac
Alveoli
LUNGS
Right and left
 Right has 3 lobes, left has 2 lobes
Separated by mediastinum
Enclosed by diaphragm and thoracic cage (ribs)
Bronchus and blood vessels enter each lung
Plane of
section
Heart
Visceral
pleura
Pericardial
cavity
Parietal
pleura
Pericardium
Pleura
Right pleural
cavity
Left pleural
cavity
BREATHING MECHANISM
Ventilation
Composed of two parts: inspiration and exhalation
INSPIRATION
Flow of air into lungs
Diaphragm and intercostal muscles contract
The size of the thoracic cavity increases
Increase in volume of cavity = decrease in pressure
so air flows from high to low pressure
EXHALATION
Air leaving lungs
Largely a passive process which depends on natural
lung elasticity
As muscles relax, air is pushed out of lungs
Intra-alveolar
pressure
(760 mm Hg)
Diaphragm
Intra-alveolar
pressure
(758 mm Hg)