Lung Anatomy, Histology, and Development Flashcards Preview

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Flashcards in Lung Anatomy, Histology, and Development Deck (45):

vertebrosternal ribs

ribs 1-7


vertebrocostal ribs

ribs 8-10


vertebral (floating) ribs

ribs 11-12


costodiaphragmatic recess

a region of parietal plerua that extends two ribs below the lung margins and is a site where fluid/blood can accumulate and be sampled

extends to the 12th rib posteriorly and 9th rib anterolaterally


structure of the right lung

three lobes - superior (upper), middle, and inferior (lower)

horizontal fissure separtes superior and middle lobes

oblique fissure separates middle and lower lobes


structure of the left lung

two lobes, superior and inferior separated by an oblique fissure

upper lobe has a "tongue-shaped" lingula that lies against the heart


components of the mediastinum

primary bronchus

pulmonary artery

pulonary veins

bronchial arteries off the descending aorta

autonomic plexus

lymphatic vessels and nodules


bronchial vs. pulmonary artery circulation

bronchial arteries come off of the descending aorta and supplies blood to the bronchi - drains into the pulmonary veins and some into the azygous system

pulmonary artery circulation is for alveoli and gas exchange


components of the autonomic plexus on the bronchi and pulmonary arteries

parasympathetics from the vagus nerve

postsynaptic sympthetics from the upper thoracic (T1-5) cardiopulmonary splanchnic nerves

reflex afferents in vagus (pain fibers in splanchnics)


Which side of the lung is aspirated material likely to go into?

right - right primary bronchus is shorter and more in line with the trachea than the left



the internal crest at the bifurcation of the trachea


eparterial bronchus

secondary (lobar) bronchi - right upper lobar artery


tertiary (segmental) bronchi

supply bronchopulmonary segments that are defined by the tertiary bronchi and the arteries that run with them

smallest lung units that can be surgically resected


Kerley B lines

radiologic descriptions of dilated lymphatics in interlobular septa at the periphery of the lung lower lobes


muscles used for inspiration


external oblique

accessory - scalenes, pectoralis minor, pectoralis major

serratous anterior


muscles used for expiration

internal oblique

abdominal muscles (rectus abdominus)


How many generations of branching of the airway are there?

23 generations


conducting portion of the airway

moves air into and out of the respiratory part

first 16 generations of branches away from the trachea


respiratory part of the airway

7 distal generation os branching that contains alveoli for gas exchange


branching sequence of the airway

trachea -> bronchi -> bronchioles -> respiratory bronchioles -> alveolar ducts -> alveolar sacs -> alveoli


cells of the conducting part of the airway from trachea through bronchi

pseudostratified columnar (respiratory) epithelium with cilia and mucous-secreting globlet cells


silhouette sign

the similar densities of pneumonia and the heart obscure the heart borders


C-shaped rings

strcutres that make up the trachea

entirely made up of hyaline cartilage

surrounds the lamina propria of loose connective tissue and submucosa of denser CT with mucous glands

no continuous muscle layer

elastic membrane between mucosa and submucosa

ends of the rings are united by a fibroelastic membrane and trachealis muscle


structure of the bronchi

cartilage plates rather than rings

continuous layer of smooth muscle under the cartilage plates

epithelium is the same, and goblet cells are present


structure of the bronchioles

lack of cartilage plates and glands (some cartilage may be present at branch points)

smooth muscle layer that is relatively thick


What happens to the epithelium during the transition from the largest bronchioles to the terminal bronchioles?

epithelium goes from ciliated, pseudostratified columnar in the largest bronchioles to simple cuboidal in the terminal bronchiole



the functional unit of the lung that contains all of the components of the alveoli


Clara cells

simple cuboidal cells that replace goblet cells and secrete a surfce active lipoprotein that keeps the wall sfrom sticking to each other



an airway fluid marker of pulmonary disease (Clara cell injury)


respiratory bronchioles

the first part of the airway where gas exchange occurs

alveoli start to line the walls

also ciliated and Clara cells (mostly Clara cells)


Describe gas molecule movement through the lungs.

velocity goes down corresponding to drastic opening of airways

air velocity increases a little with the first few generations of branching

in the lungs, the secondary and tertiary bronchi cross-sectional area is smaller

helps facilitate a cough, moves air faster through the big airways


type I alveolar cells (pneumocytes)

make up 40% of alveolar cells but 95% of the alveolar surface area because of their thin shape

lined by surfactant that prevents their collapse by reducing surface tension


alveolar septum (pulmonary membrane or air-blood barrier)

gas exchange happens here

consists of thin type I cell with its coating of usrfactant, the blood capillary endothelium, and a basal lamina shared by the two walls

very thin, 0.15-0.50 microns between air and blood


type II alveolar cells

comprise 60% of alveolar cells, but only 5% of the surface area

comprise the thick wall of the alveolar septum along with collagen fibrils, elastic fibers, fibroblasts, and macrophages

secrete phospholipid DPPC for reducing surface tension

secrete surfactant proteins that regulate the synthesis, secretion, and spreading of surfactant and modulate immune and allergic responses


alveolar ducts

the progression of respiratory bronchioles that consists of only rows of alveoli


alveolar sacs

the end of alveolar ducts with a cluster of alveoli opening into a central space

alveolar sacs may occur along the walls of alveolar ducts as well


elastic fibers

important for pulmonary stroma, oriented in all directions and help the lungs dilate



the obstruction of a bronchus


Where does the larnx, trachea, and lungs develop from?

laryngotracheal (lung bud) diverticulum of splanchnopleure that grows ventrally off the foregut


What gives rise to the carilage, smooth muscle, connective tissue, and visceral pleura?

splanchnic mesoderm


embryonic period of lung development

branching of the bronchi

the epithelim is undifferentiated simple cuboidal epithelium


pseudoglandular period

6 to 16 weeks

the airway resembles and exocrine gland

branching vessels to the level of terminal bronchioles, but no air exchange segments

epithelium begins to differentiate

blood vessels elaborate but are not closely applied to the airway


canalicular stage

16 to 26 weeks

branching down to primordial alveolar ducts surrounded by a rich vascular network

epithelium is thinning at the location of alveoli

breathing is possible, but surfactant is not yet produced

type I cells differentiate


saccular (terminal sac) stage

26 weeks to birth

elaboration of primordial alveoli with the differentation of Type I and Type II alveolar cells

surfactant is being produced, and preterm viability is possible


alveolar stage

32 weeks to 8 years

alveoli and acini continue to develop, and more generations of airway branching continue after birth

only about half the number of adult alveoli are present at birth