-The Anatomy and Physiology of the Respiratory System

Question 1

-A person can live a

Answer 1

few weeks without food, a few days without water and only a few miniatures without oxygen

-Consistent removal of carbon dioxide from the body is just as important for survival as constant supply of oxygen.

Question 2

-The Airways

Answer 2

-The passageways between the ambient environments and the gas exchange units of the lungs (the Alveoli) are called conducting airways

-No gas exchange occurs in the conducting airways but the are important to the overall process of ventilation

-The conducting airways are divided into the upper and lower airways.

Question 3

-The Upper Airways -Consist of the

Answer 3

the nose, oral cavity, pharynx, and larynx

Question 4

-The primary functions of the upper airways are

Answer 4

-To act as a conductor of air

	-To humidify and warm the inspired air

	-To prevent foreign materials from entering the tracheobronchial tree

	-To serve as an important area involving speech and smell

Question 5

-The primary function of the nose are to

Answer 5

-Filter

	-Humidify

	-Warm the inspired air

Question 6

Anatomy of the nose

Answer 6

-Air enters the nasal cavity through the two opening formed by the septal cartilage called the nares

-The air passes through a slightly, dilated area called the vestibules, which contains hair follicles called vibrissae

-There are three bony protrusions on the lateral walls of the nasal cavity called the superior, middle, and inferior nasal turbinates, or conchae

-The turbinates separates inspired gas into several different airstreams

-This action increases the contract area between the inspired gas into several different airstreams

-This action increases the contact between the inspired air and the warm , moist surface of the nasal mucosa

Question 7

-Thick and immobile secretions lead to

Answer 7

-Excessive accumulation

	-Partial airway obstruction and airway collapse

Question 8

inserting an endotracheal tube

Answer 8

-It should be emphasized that the respiratory care practitioner must learn and differentiate the major anatomic landmarks when inserting an endotracheal tube

-For example, an endotracheal tube can easily be inserted into the patients esophagus rather than into the trachea, especially during an emergency situation, when this occurs, the patient stomach is ventilated as opposed to the lungs

-A misplaced endotracheal tube in the esophagus can be fatal

Question 9

-Larynx

Answer 9

-The larynx, or voice box, is located between the base of the tongue and the upper end of the tracheal

Question 10

-Larynx serves 3 functions

Answer 10

-It acts as a passageway of the air between the pharynx and threacha

	-It serves as a protective mechanism against the aspiration of solids and liquids

	-It generates sounds for speech

Question 11

-Cartilages of the larynx

Answer 11

-Consist of a framework of 9 cartilages

-3 Are single cartilages (Thyroid, Cricoid, and epiglottis

-3 are paired cartilages (Arytenoid, corniculated, and cuneiform)

-The thyroid cartilage ( commonly known as the adams apple) is the largest cartilage of the larynx

Question 12

The epiglottis

Answer 12

-The epiglottis is a broad spoon shaped structure. It prevents the aspiration of food and liquids by covering the opening of the larynx during swallowing

-The epiglottis and the base of the tongue are connected by folds of mucous membranes, which form a small space (the vallecula) between the epiglottis and base of the tongue.

Question 13

-The vallecula

Answer 13

-The vallecula serves as the important anatomic landmark when inserting an endotracheal tube.

Question 14

-The cricoid cartilage

Answer 14

-The cricoid cartilage is attached to the first C shaped cartilage of the trachea

-The interior of the larynx is lined by mucous membranes that forms two pairs of folds that protrude inward

-The upper pair are called the false vocal folds because the play no role in vocalization

-The lower pair functions as the true vocal folds (Vocal cords)

-The space between the true vocal cords is termed the glottis

Question 15

the narrowest point in the larynx

Answer 15

-In the adult, the glottis is the narrowest point in the larynx

-In the infant the cricoid cartilage is the narrowest point

Question 16

Glottic and subglottic swelling

Answer 16

-Glottic and subglottic swelling (Edema secondary to viral or bacterial infection are commonly seen in infants and young children.

-This is known as the croup syndrome (laryngotracheobronchitis and acute epiglottis)

-Below the vocal cords, the laryngeal mucosa is called by pseudostratified ciliated columnar epithelium

Question 17

Valsalva maneuver

Answer 17

-A 2nd vital function of the larynx is effort closure during exhalation, also known as Valsalva maneuver

-During the maneuver there is a massive undifferentiated adduction of the laryngeal walls including both the true and false vocal folds

-As a result the lumen of the larynx is tightly sealed, preventing air from escaping during physical work such as lifting, pushing, coughing, and clearing airways, vomiting, urination, defecation, and parturition

Question 18

-The lower airways

Answer 18

-After passing through the larynx, inspired air enters the tracheobronchial tree, which consist of a series of bronching airways commonly referred as Generations

-These airways become progressively narrower, shorter, and more numerous as they branch throughout the lungs

-In general the airways exist in two major forms

Cartilaginous airways

Non Cartilaginous airways

-The cartilaginous airways serve only to conduct air between the external environment and the site of gas exchange

-The non cartilaginous airways serve both as conducting of air and sites of gas exchange

Question 19

-The tracheobronchial tree is composed of 3 layer

Answer 19

An epithelial lining

The Lamina propria

And a cartilaginous layer

Question 20

The epithelial lining

Answer 20

-The epithelial lining is predominantly composed of pseudostratified ciliated columnar epithelium

-As the bronchioles become progressively smaller the columnar structure of the epithelium decreases the height and appears more cuboidal than columnar

-The cilia progressively disappears in the terminal bronchioles and are absent in the respiratory bronchioles

-A mucus layer commonly referred to as the mucus blankets cover the epithelial lining of the TB tree

Question 21

mucus blankets of the epithelial lining

Answer 21

-A mucus layer commonly referred to as the mucus blankets cover the epithelial lining of the TB tree

	-The blanket is composed of 95% water with the remaining 5% consisting of glycoproteins, carbohydrates, lipids, DNA, some cellular debris and foreign particles

-The mucus is produced by

	1.)Goblet cells

	2.) And the submucosal or bronchial glands

Question 22

-The mucus blanket has two distinct layers

Answer 22

The sol layer which is adjacent to epithelial lining

And the Gel layer which is the more viscous layer adjacent to the inner luminal surface

Question 23

mucociliary transport mechanism or the mucociliary escalator

Answer 23

-The cilia move in a wavelike fashion through the less viscous SOL layer and continually strike the innermost portion of the gel layer (about 1550 times per minute)

-The action propels the mucus layer, along with any foreign particles stuck to the gel layer, toward the larynx and into the oropharynx

Question 24

Number of factors that slow down the rate of the mucociliary transport

Answer 24

-Some common factors are

		-Cigarette smoke

-Dehydration

-Positive pressure ventilation

-Endotracheal suctioning

-High inspired oxygen concentration

-Hypoxia

-Atmospheric pollutants

-General anesthetics

-Parasympatholytic (atropine)

Question 25

lamina propria

Answer 25

-Is the submucosal layer of the TB tree

-Contains tiny blood vessels, lymphatic vessels, amd branches of the vagus nerve

-Also found in the lamina propria are two sets of smooth muscle fibers

	-these smooth muscle fibers wrap around the TB tree in fairly close spirals, one clockwise and the other counterclockwise

	-Also found in the lamina propria are Mast cells

Question 26

Mast cells of the lamina propria

Answer 26

-When mast cells are activated, numerous substances are released from the cells which can significantly alter the diameter of bronchial airways

-When antigen reacts with a mast cell it causes the cell to degranulate (break down) and cause the cell to release potent chemical mediators

Question 27

chemical mediators of mast cells

Answer 27

-histamine

				-Heparin

				-Slow reacting substance of anaphylaxis

				-Platelet activating factor (PAF)

				-Eosinophilic chemotactic factors of anaphylaxis (ECF-A)

-The release of these chemicals causes increased vascular permeability, smooth muscle contraction increased mucus secretion and vasodilation with edema

	-Such reaction in the lungs can be extremely dangerous and is seen in individuals during an allergic reaction and or asthmatic episode

	-During an asthmatic attack patients demonstrate bronchial edema, bronchospasm and wheezing increased mucus production, mucus plugging, air trapping, and lung hyperinflation.

Question 28

-The Cartilaginous Layer

Answer 28

-The cartilaginous layer is the outermost layer of the TB tree and progressively diminishes in size as the airway extend into the lung

-The cartilage is completely absent in bronchioles less than 1mm in diameter

Question 29

-The Cartilaginous Airway

Answer 29

-Consist of trachea, main stem bronchi, lobar bronchi, segmental bronchi, subsegmental bronchi.

-Collectively, the cartilaginous airway are referred to as the conducting zone

Question 30

-Trachea

Answer 30

-The adult trachea is about 11 to 13 cm long and is 1.5 to 2.5 am in diameter

-The trachea divides into the right and left main stem bronchi

-The bifurcation of the trachea is known as the carina

-Clinically the tip of the endotracheal tube should be about 2 c, above the carina the correct position of endotracheal tube is verified with the chest X ray (CXR)

-When an endotracheal tube is inserted to deeply (beyond the carina), it most commonly enters the right main bronchus

-When this condition is identified, the endotracheal tube should be pulled back immediately

Question 31

-Main Stem Bronchi

Answer 31

-The right main stem bronchus branches off the trachea at about 25 degree angle, the left lung main stem bronchus forms an angle of 40 to 60 degrees with the trachea

-The right mainstem bronchus is wider, more vertical, and about 5cm shorter than the left main bronchus


-The main stem bronchi are the TB trees first generation

Question 32

-Lobar Bronchi

Answer 32

-The right main stem bronchus divides into the upper, middle, lower lobar bronchi

-The left main bronchus branches into the upper and lower lobar bronchi are the TB trees second generation

Question 33

-Segmental Bronchi

Answer 33

-A third generation of bronchi branch off the lobar bronchi to form the segmental bronchi, there are 10 segmental bronchi in the right lung and 8 in the left lung

Question 34

How many lobes in the lungs

Answer 34

-Right lung has 3 lobes upper, medial, and lower

-Left lung has 2 lobes upper and lower

Question 35

-Subsegmental Bronchi

Answer 35

-The TB tree continues to subdivide between the fourth and approximately the ninth generation into progressively smaller airways called subsegmental branches. These bronchi range in diameter from 1 to 4m. Peribronchial connective tissue contains nerves, lymphatics, and bronchial arteries surrounding the subsegmental bronchi to about the 1-mm diameter level. Beyond this point, connective tissue sheaths disappear.

Question 36

-NonCartilaginous Airways

Answer 36

-The non cartilaginous airways are composed of the bronchioles and terminal bronchioles

Question 37

Bronchioles

Answer 37

• When the bronchi decreases to less than 1mm in diameter and are no longer surrounded by connective tissue sheaths, they are called bronchioles the bronchioles are surrounded by spiral muscle fibers and the epithelial cells are more cuboidal in shape

At this level, cartilage is absent and the lamina propria is directly connected with the lung parenchyma. The rigidness of bronchioles are very compared with cartilaginous airway

Question 38

Terminal Bronchiole

Answer 38

-The conduction tubes of the tracheobronchial tree ends with the terminal bronchioles between the 16th and 19th generations. The average diameter of the terminal bronchioles is about .5mm

-At this point, the cilia and mucous glands progressively disappear and the epithelium flattens and becomes cuboidal in shape. Also found in the terminal bronchioles is the presence of clara cells.

-As the walls of terminal bronchioles progressively become thinner, small channels called the canals of lambert begin to appear between the inner luminal surface of terminal bronchioles and adjacent alveoli that surround them; however their function is unknown.

Question 39

-The sites of gas exchange

Answer 39

-The structures distal to the terminal bronchioles are the functional units of gas exchange. They are composed of about three generations of respiratory bronchioles, followed by about three generations of alveolar ducts and finally ending in 15 to 20 grape like clusters, the alveolar sacs. The respiratory bronchioles characterized by alveolar ducts that arise from the respiratory bronchioles are completely composed of alveoli separated by septal walls that contain smooth muscle fibers

-Most gas exchange takes place at the alveolar capillary membrane. In the lungs of the adult male, there are approximately 300 million alveoli and small pulmonary capillaries cover about 85 to 95 percent of the alveoli. This arrangement provided an average surfice of 70 m2 (about the size of a tennis court) available for gas exchange.

Question 40

-Alveolar Epithelium

Answer 40

-The alveolar epithelium is composed of two principal cell types, the type one cells, of squamous pneumocytes.

-The type 1 cells are primarily composed of cytoplasmic ground substance. They are broad, thin cells that form about 95% of the alveolar surface. They are .1 to .5ums thick and are the major sites of alveolar gas exchange. Type 1 cells die they are replaced by type 2 cells that convert type 1 cells to type 2 cells that convert type 1 cells. Type 1 cells are unable to reproduce, while type 2 cells can. TYpe 2 cells form the remaining 5 percent of the total alveolar surface.

Question 41

-Type 2 Alveolar Cells

Answer 41

-Have microvilli and are cuboidal in shape. They are believed to be the primary source of pulmonary surfactant. Surfactant molecules are situated at the air liquid interface of the alveoli and play a major role in decreasing the surface tension of the fluid that lines the alveoli.

Question 42

-Pores of Kohn

Answer 42

-The pores of kohn are small holes in the walls of interalveolar septa. They are 3 to 13 microns in diameter and permit gas to move between adjacent alveoli. The formation of pores may include one or more of the following processes

1.)The desquamation (shredding and peeling) of epithelial cells due to disease.

2.)The normal degeneration of tissue cells as a result of macrophage, which may leave holes in the alveolar walls, disease involving the lung parenchyma accelerating the formation of alveolar pores of kohn, and the number and size of pores increase progressively with age.

Question 43

-Alveolar Macrophages

Answer 43

-Alveolar macrophages, or type 3 alveolar cells, play a major role in removing bacteria and other foreign particles that are deposited with the Acini. Macrophages are believed to originate from stem cell precursors in the bone marrow. Then as monocytes they presumably migrate through the bloodstream to the lungs, where they move about or are embedded in the extracellular lining of the alveolar macrophages that reproduce within the lungs.

Question 44

-Interstitum

Answer 44

-The alveolar capillary clusters are surrounded, supported and shaped by the interstitium. The interstitium is a gel-like substance composed of hyaluronic acid molecules that are held together by a weblike network of collagen fiber. The interstitium has two major compartments, the tight space and the loose space. The tight space is the area between the alveolar epithelium and the endothelium of the pulmonary capillaries. The area where most of the gas exchange occurs.

-The loose space is primarily the area that surrounds the bronchioles, respiratory bronchioles, alveolar ducts and the alveolar sacs. Lymphatic vessels and neural fibers are found in this area. Water contents in this area can increase by more than 30% before significant pressure changes develop

Question 45

-Shape and dimensions of the lung

Answer 45

-The apex of the lung is somewhat pointed and the base is broad and conserved to accommodate for the convex diaphragm. The Apex of the lung rises to about the level of the 1st rib. In a normal adult at the end of exhalation, the base extends anteriorly to about the level of the 6th rib. (Xiphoid process) and posteriorly to about the level of the 11th rib(two ribs below the inferior angle of the scapula)

-The mediastinal border of each lung is concave to fit the heart and other mediastinal border is hilum, where the main stem bronchi, blood vessels, lymph vessels, and various nerves enter and exit the lungs.

Question 46

-Right Lung

Answer 46

-The right lung is larger and heavier than the left lung. It is divided into the upper, middle, and lower lobes by the oblique and horizontal fissures. The oblique fissure extends from the costal to the mediastinal border of the lung and separates the upper and middle lobes from the lower lobe. The horizontal fissure extends horizontally from the oblique fissure to about the level of fourth costal cartilage and separates the middle from the upper lobe

Question 47

-Left Lung

Answer 47

-The left lung is divided into only two lobes: the upper and the lower. These two lobes are separated by the oblique fissures, which extends from the costal to the mediastinal borders of the lung.

	-All lobes are further subdivided into bronchopulmonary segments. The segments are numbered to demonstrate their relationship.

Question 48

-The Pleural Membranes

Answer 48

-Two moist, slick surfaced membranes called visceral, and parietal pleura are closely attached to the outer surface of each lung and extend into each of the interlobar fissures. The parietal pleura lines the inside of the thoracic walls, the thoracic surface of the diaphragm, and the lateral portion of the mediastinum. The potential space between the visceral and parietal pleura is called the pleural cavity.

-The visceral and parietal pleura are held together by a thin film of serous fluid, somewhat like two flat, moistened pieces of glass. This fluid layer allows the two pleural membranes to glide over each other during inspiration and expiration. Thus, during inspiration, the pleural membrane holds the lung tissue to the inner surface or the thorax and diaphragm, causing the lungs to expand. Because the lungs have a natural tendency to expand and negative or subatmospheric pressure ( negative intrapleural pressure) normally exists between the parietal and visceral pleura.

Question 49

-The Thorax

Answer 49

-The thorax houses and protects the organ of the cardiopulmonary system. 12 thoracic vertebrae from the posterior midline border of the thoracic cage. The sternum forms the anterior border of the chest. The sternum is composed of the manubrium sterni, the body of the sternum, and the xiphoid is called the manubriosternal joint, and is referred to as the Sternal angle or angle of louis.

Question 50

Sternal angle or angle of louis.

Answer 50

-Clinically , the angle of louis provides an important palpable landmark. It identifies

		-1) The approximate level of the second pair of costal cartilage

		-2) The level of intervertebral disc between T4 and T5

		-3)The approximate beginning and end of the aortic arch

		-4) The bifurcation of the trachea into the left and right mainstem bronchi

Question 51

-The 12 pairs of ribs form the lateral boundaries of the thorax.

Answer 51

The ribs attach directly to the vertebral column posteriorly and indirectly to the sternum by way of their costal cartilage. Because the cartilage of the 8th, 9th, and 10th ribs attaches to the cartilage of the ribs above, they are referred to as false ribs.