Anatomy of the Respiratory System
Anatomy of the Respiratory System
Objectives
· List the structures that make up the respiratory system
· Distinguish between the upper respiratory tract and the lower respiratory tract
· Explain the difference between the conducting zone and the respiratory zone, listing the anatomical structures that are a part of each
Basic Anatomy of the Respiratory System
[Section 22.1: Organs and Structures of the Respiratory System]
[Section 22.1.1: Conducting Zone]
[Figure 22.2: Major Respiratory Structures]
The organs of the respiratory system are divided anatomically into:
The upper respiratory tract:
Nose
Nasal cavity (made of a hard and soft palate)
Sinuses
Pharynx
The lower respiratory tract:
Larynx
Trachea
Bronchi
Lungs
But, the respiratory system may also be divided functionally into:
The conducting zone
organs and structures not involved in gas exchange
The respiratory zone
the locations where the exchange of O2 and CO2 occur
Structures of the Conducting Zone
Nose
[Section 22.1.1.1: The Nose and its Adjacent Structures]
External nares (the nostrils)
· hair in the vestibule removes airborne particles
· primary route for entering air
Nasal Septum
· divides nasal cavity
· bony portion = perpendicular plate of the ethmoid bone and vomer bone union
· works with cartilage to form full septum
Nasal conchae (aka, turbinates)
· cause the air to swirl in the nasal cavity and come in contact with mucous membrane covering (which catches debris/dust)
· heat and humidify the air for respiration – allows diffusion of gases in lung
Pharynx
[Figure 22.6: Divisions of the Pharynx]
Uvula
flips up during swallowing to prevent fluids from entering the nasopharynx (soft palate also raises to prevent food from entering)
The Pharynx is divided into 3 anatomical regions:
1. Nasopharynx
· Passageway for airflow from nasal cavity
· Has pseudostratified ciliated columnar epithelieum, pharyngeal tonsils, and eustachian tubes
2. Oropharynx
· common passageway for food, water, and air
· stratified squamous epithelium (in common with oral cavity)
· Contains palatine and lingual tonsils
3. Laryngopharynx
· Passageway for food
· stratified squamous epithelium
Larynx
During swallowing, the hyoid bone lifts causing the epiglottis to lower and protect the glottis, which consists of the opening in the larynx and the vocal cords.
Glottis
· false vocal cords (Vestibular ligaments and folds)
o During coughing or sneezing, close over the glottis
o Superior to the true vocal cords
· true vocal cords (Vocal ligaments and folds)
o Responsible for sound production
o Only produces sound when air is exhaled over them
o Sounds change when cords are stretched or relaxed
Larynx (Voice Box)
Made up of 9 cartilages:
1 thyroid cartilage (Adam’s apple)
1 cricoid cartilage (connects larynx to trachea)
1 epiglottis
2 arytenoid cartilages
2 corniculate cartilages
2 cuneiform cartilages
Trachea
Lungs
[Section 22.1.1.5: Bronchial Tree]
[Section 22.1.2: Respiratory Zone]
[Figure 22.10: Respiratory Zone]
[Figure 22.11: Structures of the Respiratory Zone]
The right lung of a human has 3 lobes, while the left lung only has 2
Bronchial Tree
· 1° bronchus (R & L)
· 2° bronchus (R & L)
o R = 3
o L = 2
o (corresponds to # of lobes)
· 3° bronchus (R & L)
o R = 3, 2, 5
o L = 5, 5 (during development)
o Fusion events lead to 8 or 9 total after development
Bronchioles
· lack cartilage
· have layer of smooth muscle
· terminal bronchioles
· have cilia, give off 2 or more respiratory bronchioles
· respiratory bronchioles
· divide into 2-10 alveolar ducts
respiratory bronchioles divide into thin walled passages called alveolar ducts
alvoelar ducts end in grapelike clusters of alveoli called alveolar sacs
the alveoli provide large surface area (~70sq.m) for gas exchange
Alveoli
[Section 22.1.2: Respiratory Zone]
[Figure 22.10: Respiratory Zone]
[Figure 22.11: Structures of the Respiratory Zone]
Gross Anatomy of the Lungs
[Section 22.2.1: Gross Anatomy of the Lungs]
[Section 22.2.3: Pleura of the Lungs]