Respiratory System Flashcards
Respiration
Exchange of gases between the atmosphere and cells of the body
A. Occurs via activities of both the respiratory and cardiovascular systems
B. Respiratory System = Organs involved in the exchange of gases between the atmosphere and the blood. The cardiovascular system is then responsible for the portion respiration that involves exchange between the blood and the body’s cells.
External Nose
- Of clinical importance because much of a person’s identity and appearance is represented by the external nose. Deformity or injury can have devastating effects on one’s personality or social interactions
- Physiological Functions
a. increase surface area of nasal cavity for warming, humidifying, and filtering inhaled air
b. modifies the sounds produced by the larynx - Anatomical Structure = a framework of mostly cartilage and some bone covered externally with skin and internally with a mucous membrane
a. bridge of the nose is formed by 2 nasal bones (only bone of external nose – majority of framework is cartilage)
b. room of the nose is the portion between eyes
c. apex of nose is the tip
d. alae (ala) describes the convex flared portion over the nostrils formed by alar cartilages beneath the skin
e. external nares are the nostrils, or the open of the nasal cavity to the outside
Nasal Cavity
a continuous chamber within the external and internal nose which extends from the nostrils to the nasopharynx.
1. Function – already described above (external nose)
2. Nasal Cavity is continuous posteriorly with the nasopharynx via openings called the internal nares
3. Nasal Septum – divides the nasal cavity into a right and left portion
a. anterior portion is composed mostly of cartilage
b. two bones unite to form the posterior portion of the septum
- vomer
- perpendicular plate of the ethmoid bone
4. Floor of the nasal cavity
a. anteriorly = palatine processes of the maxillary bones
b. posteriorly = horizontal plates of the palatine bones
c. posterior to the palatine bones if the soft palate
5. Roof of the nasal cavity = cribiform plate of the ethmoid bone
6. Lateral Walls of the nasal cavity = primarily composed of the ethmoid bone.
a. Three scroll-like formations called nasal conchae extend from
the wall into the nasal cavity.
- Superior and Middle Nasal Conchae = part of the
ethmoid bone
- Inferior Nasal Conchae = separate bone
b. Beneath conchae is a space called a meatus (superior, middle
and inferior) lined with very vascularized mucous membrane
which easily becomes swollen when inflamed and causes
obstruction of air flow.
c. Function of meati and conchae is to cause turbulence of the air, which will aid in warming and humidifying.
7. vestibule = area just inside of openings to the nostrils. Lined with stratified
squamous epithelium. Also contains coarse hairs.
8. pseudostratified ciliated columnar epithelium = epithelium of nasal cavity
beyond vestibule to pharynx
9. paranasal sinuses = cavities within the bone of the skull which all open into the
nasal cavity. Function is basically unknown.
a. Frontal Sinus
b. Ethmoidal Sinuses
c. Sphenoidal Sinuses
d. Maxillary Sinuses
10. Epistaxis = nosebleed
Pharynx
= throat
A. Location – posterior to the nasal cavity, oral cavity, and the larynx. Extends from the internal nares posterior to the nasal cavity to the esophagus posterior to the larynx.
B. Composed of skeletal muscle arranged in a tubular structure surrounding a lumen lined with a mucous membrane.
C. Dual function. Functions as a passageway for air as well as for food and water.
D. Divided into three portions anatomically:
- Nasopharynx = uppermost portion
a. posterior to the nasal cavity – it extends inferiorly as far as the soft palate
b. receives openings of the two eustachian tubes (auditory tubes) which connect to the middle ear cavity
c. contains pharyngeal tonsils (adenoids)
d. lined with pseudostratified ciliated columnar epithelium, same as the nasal cavity - Oropharynx = middle portion
a. posterior to the oral cavity – it extends inferiorly a far as the level of the hyoid bone
b. oral cavity opens into oropharynx via opening known as the fauces, a common passageway for both air and food
c. epithelium = stratified squamous epithelium
d. contains both the palatine tonsils and the lingual tonsils - Laryngopharynx = inferior portion
a. posterior to the larynx – extends inferiorly as far as the level of the cricoid cartilage
b. continuous inferiorly with the esophagus
c. opens anteriorly into the larynx
d. dual function for transport of both air and food
e. lined with stratified squarmous epithelium
Larynx
A. A short passageway between the pharynx and the trachea
B. Contains the structures necessary for phonation
C. Framework is composed of nine pieces of cartilage
1. Thyroid Cartilage = majority of anterior wall of larynx
a. forms thyroid prominence or “Adam’s apple”
b. larger in males than females
c. vocal cords connected anteriorly inside
2. Cricoid Cartilage = inferior and majority of posterior walls of the larynx
3. Arytenoid Cartilages (2) = paired cartilages located on the posterior superior border of the cricoid cartilage
a. attach to vocal cords and to the intrinsic muscles of the larynx
b. rotation of these cartilages in a vertical plane creates variable tension on the vocal cords and regulates pitch of vibration
4. Epiglottis = cartilage which closes over superior portion of glottis (opening to the inferior larynx and trachea) when swallowing
a. leaf shaped and attached anteriorly to thyroid cartilage
b. helps to prevent swallowed material from being aspirated into
the airways and lungs
5. Corniculate Cartilages (2) = less important cartilages which are small cone-
shaped structures on the superior apex of arytenoid cartilages
6. Cuneiform Cartilages (2) = less important cartilages which are found within the membrane in the superior lateral portion of the larynx connecting the epiglottis with the arytenoid cartilage
D. Epithelium of the Larynx
1. Above vocal cords = stratified squamous like lower pharynx
2. Below vocal cords = pseudostratified ciliated columnar epithelium like airways
E. Cough reflex – epithelium of larynx contains nerve endings, which are stimulated by
contact with any material other than a gas producing a cough intended to expel the foreign material.
F. Ventricular Folds = folds which assist in closing the glottis when swallowing
1. located parallel but superior to vocal cords
2. often called “false vocal folds”
G. Vestibule = area of the inner larynx above ventricular folds
H. Vocal Cords = elastic ligaments spanned between the thyroid and arytenoid cartilages
which when stretched vibrate as air is forced over them creating sound. These sound are formed into words in oral cavity.
1. thicker and longer in males than females (deeper voice)
2. covered with stratified squamous epithelium
Trachea
= tubular passageway for air
A. Composed of “c-shaped” cartilages giving support to an otherwise membranous tube
(appearance like a vacuum cleaner hose)
B. Extends from the cricoid cartilage of the larynx to its division into a right and left primary bronchus within the mediastinum of the thorax.
C. Epithelium = pseudostratified ciliated columnar epithelium
1. Cilia beat in coordinated rhythmic waves to remove dust and foreign particles that are inhaled.
2. Inhaled material is continuously moved out of the airways toward the esophagus
Bronchi
A. Right and Left Primary Bronchi
1. Initial branches of the trachea to go to the right and left lung respectively
2. Right bronchus takes a more direct route and is shorter than the left bronchus. As a result, aspirated objects are much more likely to lodge in the right lung than the left.
3. Structure of the primary bronchi is identical to the trachea except for a slightly smaller diameter.
B. Secondary Bronchi = Lobar Bronchi – once within tissue of the lung itself, the primary bronchi branch into a separate smaller bronchus to supply each lobe of the lung.
1. three lobar or secondary bronchi in the right lung
2. two lobar or secondary bronchi in the left lung
C. Tertiary Bronchi = Segmental Bronchi – secondary bronchi further divide into smaller bronchi which supply each of the anatomical segments of the lungs
D. Bronchioles – Tertiary or segmental bronchi branch into smaller airways called bronchioles. Bronchioles branch out throughout the lung tissue dividing into smaller and smaller diameter branches. Smallest bronchioles are called Terminal Bronchioles. As bronchioles become smaller and smaller one sees the following trends:
1. decrease in amount of cartilage, and it eventually disappears
2. decrease in the amount of smooth muscle
3. decrease in the height of the epithelium and one sees a transition from pseudostratified ciliated columnar to cuboidal epithelium
E. Asthma = an allergic condition where exposure to an antigen (in air or food) will cause
contraction of smooth muscle in the bronchioles causing them to contract and actually close airways and preventing adequate air exchange
Lungs
A. Large funnel- or cone-shaped organs within the thoracic cavity
B. Thoracic cavity divided into two separate pleural cavities by the centrally located compartment called the mediastinum
C. Pleural Membrane
1. Visceral Pleura – adherent to lung surface
2. Parietal Pleura – adherent to the inner thoracic wall
3. Pleural Cavity – potential between visceral and parietal pleura. This cavity surrounds but technically lungs are not contained within it. Cavity contains only a small amount of air and lubricating fluid.
4. Pathology of the Pleural Cavity
a. Pleurisy – inflammation of the pleural membrane
b. Hemothorax – blood in the pleural cavity
c. Pneumothorax – excess air in the pleural cavity
D. Gross Anatomy of the Lung
1. Base – concave inferior aspect covering dome shaped diaphragm.
Anteriorly this is about at the level of the 7th intercostal space
2. Apex – superior tip at about the level of the clavicle
3. Costal Surface – against the inside of the rib cage
4. Mediastinal Surface – against the mediastinum medially
5. Diaphragmatic Surface – against the diaphragm inferiorly
6. Hilus = Root of the Lung – portion of the lung where bronchi, nerves, arteries, lymphatics, and veins enter and exit the lung.
7. Bronchial Segments, Lobes, and Fissures – portions of the lungs called lobes are separated by deep visible separations called fissures. Each of the lobes is functionally separated into smaller portions called bronchial segments, but these divisions are not readily visible
a. right lung
- 3 lobes = superior, middle, and inferior
- 2 fissures = horizontal and oblique
-10 bronchial segments (don’t have to learn names)
b. left lung
-2 lobes = superior and inferior
-1 fissure = oblique
-8 bronchial segments (don’t have to learn names)
-cardiac notch – accommodates the heart which projects toward the
left side of the thorax
E. Respiratory Portion of the Lung
1. Alveolus = functional unit of respiratory system = site where gas exchange
actually takes place = small microscopic sac surrounded by capillaries
2. Epithelium = two cell types
a. Type I Cell = squamous pulmonary epithelial cells = small alveolar cells
= flat squamous cells across which gas exchange occurs
b. Type II Cell = septal cells or great alveolar cells = Taller cuboidal cells
which produce the important surface tension reducing agent called surfactant
c. Other cell types associated with alveoli:
- free roaming macrophages, sometimes called “dust cells”
- endothelial cells of the surrounding capillaries
- blood cells within the capillaries
3. The Respiratory Membrane = alveolar-capillary membrane
a. This membrane is composed of several layers through which gases must
pass for exchange between alveoli and the blood.
b. Composed of the following layers:
-Epithelial cells of the alveolar wall = type I and type II cells
-Basement membrane
-Endothelial cells of the capillary
c. Alveolar wall is only about 4 micrometers thick d. There are about 300 million alveoli in the lungs e. Estimated average surface area for exchange of gas collectively in the alveoli about 70 square meters 4. Pathology = Emphysema – where chronic stress on the tissue of the alveoli causes cell death resulting in huge pockets of air that are not exchanged with each breath.
