Our body cells, as well as all living cells, need energy to live. Our cells obtain that energy through the enzymatic catabolism (chemical breakdown) of organic molecules that we eat. This energy is captured and then transferred to the high-energy bonds in adenosine triphosphate (ATP). Our cells can easily access and use the energy stored in these high-energy bonds of ATP. The vast majority of ATP is produced within the mitochondria of cells. This is why you may have learned that the mitochondrion is the powerhouse of the cell. The mitochondrial activity responsible for ATP production is known as aerobic metabolism. Aerobic metabolism requires oxygen and generates carbon dioxide. There is an intimate relationship between the respiratory system and the cardiovascular system as they work together to supply cells with oxygen and remove carbon dioxide. You have already studied the cardiovascular system. In this lab, you will look at the structures of the respiratory system that are responsible for the movement of oxygen and carbon dioxide. You will also examine the structures that link the respiratory system to the cardiovascular system, produce sound, and provide olfactory sensations.
The respiratory system is a dead-ended system through the head, neck, and thorax. It can be divided anatomically into an upper respiratory tract and lower respiratory tract. The upper respiratory tract includes the nose, nasal cavity, paranasal sinuses, and larynx. The lower respiratory tract includes the trachea, bronchi, bronchioles, and lungs.
The respiratory tract functions to carry air to and from the exchange surfaces of the lungs. The tract can be divided physiologically into a conducting portion and a respiratory portion. The conducting portion is also known as “dead air space”. The air is moved, cleaned, warmed, and humidified. No gas exchange occurs. The organs involved in the conducting portion begin at the nasal cavity and end at airways known as terminal bronchioles. The respiratory portion, which is associated with sacs called alveoli, allows actual gas exchange to occur.
The following outline begins with an overview of the preceding paragraphs. The remainder of the outline describes each organ of the respiratory system. You will be expected to identify all structures from appropriate models, slides, and/or diagrams.
I. OVERVIEW
A. Anatomically, . . .
1. a dead-ended system through the head, neck, and thorax
2. anatomic “1/2’s”
a. upper respiratory tract — parts in the head and neck
b. lower respiratory tract — parts in the thorax
3. organs
a. NASAL CAVITY
b. PHARYNX
c. LARYNX
d. TRACHEA
e. PRIMARY BRONCHI
f. LUNGS ( external view) / BRONCHIAL TREE (internal view)
B. Physiologically, …
1. gas exchange to support aerobic metabolism
2. functional “1/2’s”
a. conducting portion
1) air is moved, cleaned, warmed, and humidified
2) also known as “dead air space”
b. respiratory portion
1) site of gas exchange
2) involve alveoli
II. NASAL CAVITY
A. Boundaries
1. anterior – EXTERNAL NARES
2. posterior -INTERNAL NARES
3. superior – CRIBRIFORM PLATE OF ETHMOID BONE
4. inferior – HARD PALATE and SOFT PALATE
B. Internal partitioning of nasal cavity space
1. NASAL SEPTUM – midline partition formed by vomer bone and perpendicular plate of the ethmoid bone
2. CONCHAE – three shelf-like structures protrude from each
lateral wall of the nasal cavity
a. Superior, Middle, Inferior
3. MEATUSES – six narrow grooves of space inferior to conchae; airflow
turbulence produced
a. Superior, Middle, Inferior
C. Lining tissues
1. Olfactory mucosa (olfactory epithelium)
a. Contains receptors for the sense of smell
b. Located at the roof of the nasal cavity under the cribriform plate,
the superior nasal septum, and superior nasal conchae.
2. Respiratory mucosa
a. lines rest of nasal cavity
b. pseudostratified ciliated columnar epithelium w/ goblet cells
c. cilia beat back toward the pharynx
D. Miscellaneous structures
1. Vestibule – space within flexible tissue of the nose
2. Vibrissae – hairs within vestibule
3. Paranasal sinuses
a. connect to the nasal cavity via small tubes
b. contained in frontal, sphenoid, ethmoid, palatine, and maxillary
bones
III. PHARYNX
A. Smaller regions within . . .
1. NASOPHARYNX – posterior to the nasal cavity
a. from internal nares to uvula
b. a passageway for only air
c. lined with pseudostratified ciliated columnar epithelium w/
goblet cells
d. PHARYNGEAL TONSILS (adenoids) at the posterior wall
e. AUDITORY TUBES
2. OROPHARYNX – posterior to the oral cavity
a. from the uvula to tip of the epiglottis
b. a passageway for air and food
c. lined with stratified squamous epithelium
d. anterior border is FAUCES
e. PALATINE TONSILS at the lateral wall of fauces
f. LINGUAL TONSILS at the posterior aspect of the tongue
3. LARYNGOPHARYNX – posterior to epiglottis
a. from tip of epiglottis to start to esophagus
b. a passageway for air and food
c. lined with stratified squamous epithelium
d. air pathway and food pathway diverge here
IV. LARYNX (“voicebox”)
A. a cylindrical group of nine cartilages (3 large single + 3 small pairs)
B. suspended from the hyoid bone
C. all cartilages are hyaline cartilage except the epiglottis which is elastic cartilage
D. Three Large, Single Cartilages
1. THYROID CARTILAGE
a. Shield-shape, largest, forms most of the anterior and lateral walls
b. LARYNGEAL PROMINENCE = “Adam’s apple”
2. CRICOID CARTILAGE
a. ring-shaped, inferior in the group
3. EPIGLOTTIS
a. shoehorned-shape
b. elastic cartilage
E. Three small pairs of cartilages
1. ARYTENOID CARTILAGES
a. articulate with a superior aspect of the enlarged posterior cricoid
cartilage
2. CORNICULATE CARTILAGES
a. articulate with the superior aspect of arytenoid cartilages
3. CUNEIFORM CARTILAGES
a. located within aryepiglottic folds (tissue that extends between
lateral sides of each arytenoid and the epiglottis)
F. Laryngeal ligaments
1. Intrinsic ligaments
a. bind all nine cartilages together
2. Extrinsic ligaments
a. attach thyroid cartilage to the hyoid bone
b. attach cricoid cartilage to the trachea
3. Ventricular ligaments and Vocal ligaments
a. extend between the thyroid cartilage and arytenoids
b. covered by folds of tissue (stratified squamous epithelium)
c. FALSE VOCAL CORDS
1) Ventricular folds (ventricular ligaments + tissue
covering)
2) superior, relatively inelastic – no sound production
d. TRUE VOCAL CORDS
1) Vocal folds (vocal ligaments + tissue covering)
2) inferior, contains elastic vocal ligaments – sound
production
V. TRACHEA
A. Extends from the larynx to the CARINA
B. Just over 4 inches long with a diameter of about 1 inch
C. Branches into the RIGHT AND LEFT PRIMARY BRONCHI
D. Supported by 15 – 20 U – shaped TRACHEAL CARTILAGES
E. ANNULAR LIGAMENTS bind tracheal cartilages
F. TRACHEALIS MUSCLE – smooth muscle located posteriorly
G. Histology
DO–> View slide of the trachea …
1. MUCOSA
a. Pseudostratified ciliated columnar epithelium w/ goblet cells
b. lamina propria – loose connective tissue rich in elastic fibers
c. cilia beat upward toward pharynx
2. SUBMUCOSA
a. rich in seromucous glands
3. ADVENTITIA
a. fibrous connective tissue
b. reinforced by C-shaped rings of hyaline cartilage
which constantly hold it open
c. trachealis muscle (a smooth muscle) closes the
posterior aspect
VI. THE BRONCHIAL TREE (THE INTERNAL ANATOMY OF THE LUNGS)
A. Structures that complete the Conducting Zone
1. PRIMARY BRONCHI (PRINCIPAL BRONCHI)
a. to each whole lung
2. SECONDARY BRONCHI (LOBAR BRONCHI)
a. to each lobe of the lungs
b. the right side has 3 branches, the left side has two branches
3. TERTIARY BRONCHI (SEGMENTAL BRONCHI)
a. to each bronchopulmonary segment (specific regions of each lobe)
b. right side has 10 bronchopulmonary segments, the left lung has 8-9
4. BRONCHIOLES
a. marked by the absence of hyaline cartilage, increased smooth muscle
5. TERMINAL BRONCHIOLES
a. smallest conducting branches
(B.) Structures that compose the Respiratory Zone
6. RESPIRATORY BRONCHIOLES
a. scattered alveoli allow for some gas exchange
7. ALVEOLAR DUCTS
8. ALVEOLAR SACS
9. ALVEOLI
a. simple squamous epithelium
b. site of gas exchange
C. Histology
D. Blood supply
VII. THE LUNGS (EXTERNAL ANATOMY)
A. HILUS – medial groove providing access for pulmonary vessels and nerves
B. COSTAL SURFACE – follows contours of the rib cage
C. APEX – superior tip
D. BASE – broad, concave inferior surface
E. LOBES AND FISSURES
1. LEFT LUNG – smaller due to the location of the heart
a. Two Lobes
1) UPPER LOBE
———–OBLIQUE FISSURE separates
2) LOWER LOBE
2. RIGHT LUNG
a. Three lobes
1). UPPER LOBE
————HORIZONTAL FISSURE separates
2) MIDDLE LOBE
————OBLIQUE FISSURE separates
3) LOWER LOBE
F. THE PLEURAL MEMBRANES
1. a doubled set of serous membranes
2. PARIETAL PLEURA
a. covers mediastinum, lines the thoracic wall, and covers the surface
of diaphragm
3. VISCERAL PLEURA
a. covers the surface of lungs and lines fissures
4. PLEURAL CAVITY
a. serous fluid-filled space between parietal and visceral
pleura
