RESPIRATORY SYSTEM

I.   INTRODUCTION

–  respiration: process of gas exchange in the body
–  respiratory system may be divided into a conducting portion and a respiratory portion
*  conducting portion: “conducts”  & transfers air, no gas exchange here

 

*  nose and paranasal sinuses, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles to the terminal bronchioles

*  respiratory portion: gas exchange occurs here
*respiratory bronchioles, alveolar ducts, alveoli

–   Inhalation: “breathing in, inspiration”
–  Exhalation:  “breathing out, expiration”

 

II.  FUNCTIONS OF RESPIRATORY SYSTEM      

A.  Respiration/Gas Exchange:

B.  Warms and humidifies inspired air:

 

 

C.  Filters inspired air:

 

 

 

D.  Phonation (producing sounds):

 

E.  Olfaction (Smell):
–  upper portion of the nasal cavity has olfactory epithelium (pseudostratified ciliated columnar epithelium plus bipolar neurons)

 

 

III. NOSE, NASAL CAVITY AND PARANASAL SINUSES
–  nose
*  nostrils (external nares)

– nasal cavity is the internal nose
*  subdivided by a nasal septum
*  floor: hard and soft palate

*  on lateral sides are 3 pairs of bones:

1)  superior nasal conchae
2)  middle nasal conchae
3)  inferior nasal conchae

*  function of these bones:

*  pseudostratified ciliated columnar epithelium
*  top of nasal cavity: olfactory epithelium                      
*  functions of the nasal cavity include: 

–  Paranasal Sinuses:  paired cavities/spaces within some of the skull bones that connect to the nasal cavity
*  maxillary, ethmoid, sphenoid, frontal

*  functions:
1)

2)

IV.  PHARYNX
–  “throat”
–  connects the nasal cavity and mouth, to the larynx and esophagus
– contains several groups of tonsils
* function of tonsils:

A.  Nasopharynx:
–  directly behind the nasal cavity
– inferior/lower border is soft palate

 

–  pseudostratified ciliated columnar epithelium                          
–  auditory (eustachian) tubes:

 

 

 

B.  Oropharynx:
–  from the soft palate to the hyoid bone
– directly behind oral cavity
–  both air and food travel in here
–  nonkeratinized stratified squamous epithelium

 

C.  Laryngopharynx:
–  from hyoid bone to superior border of esophagus

–  transports both food and air
–  nonkeratinized stratified squamous epithelium

V.   LARYNX
–  in front of esophagus

–  functions:
1) 

2) 

 

 

–  contains many different cartilages, connected together by ligaments

1)  thyroid cartilage: forms anterior and lateral walls of larynx

2)  Cricoid cartilage:  a ring of cartilage underneath thyroid cartilage, and directly above trachea
3)  Epiglottis:  spoon-shaped cartilage at top of larynx

* function:

 

4)  2 Arytenoid Cartilages:

–  left and right vocal folds (“true vocal cords”) attach from arytenoid to thyroid cartilage

*  sound is produced when the cords vibrate against the pressure of air

**  more air being forced through the larynx - louder sound!

REVIEW THE PROCESS OF PHONATION BY ANSWERING THE
QUESTIONS IN THE  PHONATION LEARNING EXERCISE

VI.  TRACHEA
–  connects to larynx superiorly

–  travels from neck into the mediastinum, where it splits into left and right primary bronchi
–  composition:

a)  pseudostratified ciliated columnar epithelium

 

 

b)  c-shaped rings of hyaline cartilage

 

 

What do you think? In chronic smokers, the epithelial lining of the trachea and bronchi will transform to a stratified squamous epithelium.  Why does this change occur and what are some of the consequences of having this epithelium in the trachea?

VII. LUNGS

A.  Pleura:
-- pleura: thin serous membrane

 

*  secretes serous fluid

-- Parietal Pleura

 

 

–   visceral pleura

 

 

-- pleural cavity

 

 

B.  Blood Supply to the Lungs:

–  pulmonary arteries carry blood  ________ in oxygen from heart to the lungs

–  pulmonary veins carry blood ________ in oxygen back to the heart

 

C.  Surface Anatomy of Lungs:
–  Right Lung:
* superior, middle, and inferior lobe

--  Left Lung:
* superior and inferior lobe

 

 

 

 

 

 

VIII. BRONCHIAL TREE

–  As inspired air travels in these tubes, the tubes get progressively smaller

*  largest bronchi have pseudostratified ciliated columnar epithelium - this epithelium changes to cuboidal and then to simple squamous as you travel down

*  cartilage disappears in the smaller tubes, and is replaced by smooth muscle in the bronchioles

A.  Conducting Portion of the bronchial tree:

1.  Left and Right Primary Bronchi: one goes to each lung
*  these structures are OUTSIDE the lung
*  irregular plates of cartilage
* once they enter the lung they divide into:

2.  Secondary (Lobar) Bronchi: go to one lobe of each lung
*  cartilage plates

3.  Tertiary (Segmental) Bronchi: these supply one specific segment of the lung (bronchopulmonary segments)

*  still have some cartilage
* segmental bronchi divide into smaller bronchi, and these smaller bronchi divide into bronchioles

4.  Bronchioles:
*  no cartilage here!
*  cartilage replaced by smooth muscle
* last generation of bronchioles in conducting portion: terminal bronchioles

 

B.  Respiratory Portion: gas exchange occurs

1.  Respiratory Bronchioles:

 

 

2.  Alveolar Ducts:

 

 

3.  Alveoli: smallest units of respiratory portion

 

 

*  simple squamous epithelium

 

 

*  respiratory membrane is the simple squamous epithelium of the alveolus + the simple squamous epithelium of a pulmonary capillary

WHAT ARE THE MAIN DIFFERENCES BETWEEN BRONCHI AND BRONCHIOLES?
COMPARE AND CONTRAST THESE STRUCTURES BY COMPLETING
THE  BRONCHI VS. BRONCHIOLES MEMORY MATRIX .

•COMPARE THE TYPES OF EPITHELIUM LINING CERTAIN RESPIRATORY
STRUCTURES BY COMPLETING THE
RESPIRATORY SYSTEM: EPITHELIUM MEMORY MATRIX .

THEN, LEARN THE PATHWAY THAT INSPIRED AIR TAKES THROUGH
THE BODY WITH THE  AIR FLOW LEARNING EXERCISE

FINALLY, REVIEW THE ANATOMICAL CHARACTERISTICS OF SOME
RESPIRATORY STRUCTURES WITH THE
RESPIRATORY COMPONENTS MEMORY MATRIX

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