Week 4 Flashcards
embryonic heart tube formation
forms from mesoderm in the 3rd week (days 18-22)
angioblasts
endocardial cells that differentiate from mesorderm in the formation of the heart tube surrounded by myoblasts
Truncus Arteriosis forms which adult structure(s)?
proximal aorta and pulmonary trunk
Bulbus Cordis forms which adult structure(s)?
Conus Arteriosis (RV), Aortic Vestibule (LV), and Trabeculated RV
Primitive Ventricle forms which adult structure(s)?
trabeculated LV
Primitive Atrium forms which adult structure(s)?
trabeculated RA and trabeculated LA
Sinus Venosus forms which adult structure(s)?
smooth RA and Coronary sinus
What’s the order of the regions of the embryonic heart?
top to bottom:
T B V A S
Truncus Arteriosus, Bulbus Cordis, Primitive Ventricle, Primitive Atrium, Sinus Venosus.
Arterial end at the top, Venous end at the bottom, BVA in the middle
What direction does the ventricular region of the heart move in “looping”?
ventrally, caudally, and to the right
What direction does the atrial region of the heart move in “looping”?
dorsally, cranially, and to the lefrt
What structures are required for “looping”?
cilia and dynein
What veins carry blood from the yolk sac to the heart?
vitelline veins
What veins carry blood from the placenta to the heart?
umbilical veins
What veins carry blood from the embryo to the heart?
cardinal veins
When does septation occur in the embyonic heart?
between 27-37 days
What occurs in septation of embryonic heart?
the single primitive atrium, ventricle, and outflow tract (truncus arteriosus) are separated by formation of septa (walls)
What is septum primum?
it grows from the roof of the common atrium down toward the atrioventricular canal
When does Septum Primum begin to form?
at the end of the 4th week
What is the foramen primum?
The septum primum does not form completely at first, leaving this foramen
What is foramen secundum?
Before foramen primum closes, cell death occurs in the septum primum forming this foramen secundum
What is septum secundum?
It form to the right of the septum primum, but also does not form completely
What is foramen ovale?
an opening in the septum secundum that allows blood flowing in from the IVC to push agains the septum primum and pass directly from the right atrium to the left atrium through the foramen secundum
What can cause atrial septal defects to occur?
If the septum secundum doesn’t grow enough or if the foramen secundum is too large
What are endocardial cushions?
They are proliferating endocardial cells on the dorsal and ventral walls of the heart. They grow toward each other and fuse, separating the single opening into 2.
They also form the atriventricular valves
How does septation of the ventricles occur?
Formation of a muscular and membranous septum.
Formation of the muscular septum
it develops from myoblasts in the midline on the floor of the primitive ventricle. It grows towards the fused endocardial cushions
Formation of the membranous septum
it forms from the fused endocardial cushions and the inferior ends of the conotruncal ridges of the truncus arteriosus
most common congenital cardiac defect
membranous ventricular septal defect
what is septation of the outflow tract and when does it occur?
splits the outflow tract into the aorta and pulmonary trunk beginning at week 5
How does septation of outflow tract happen
Occurs when neural crest cells migrate into the endocardium of the truncus arteriosus causing endocardial cells to proliferate and migrate to form the conotruncal ridges
What are the conotruncal (truncoconal) ridges?
a pair of opposing ridges that spiral around the truncus arteriosus and fuse in the middle, causing the spiral course of the aorta and pulmonary trunk
What are some defects in formation of the aorticopulmonary septum?
Persistent truncus arteriosus (no septum forms), transposition of the great vessels (the septum doesn’t spiral) and tetralogy of fallot ( the septum forms asymmetrically)
Persistent truncus arteriosus
no septum forms
transposition of the great vessels
the septum doesn’t spiral in septation of truncus arteriosus
tetralogy of fallot
the septum in truncus arteriosus forms asymmetrically
What are the 3 shunts in fetal circulation
ductus venosus, foramen ovale, and ductus arteriosus
What does ductus venosus do
shunts blood from the umbilical vein to the IVC, bypassing the fetal liver
what does foramen ovale do
shunts blood that enters right atrium from IVC to the left atrium
what does ductus arteriosus do
blood from the SVC still manages to get into the right ventricle, which goes to the pulmonary trunk
ductus arteriosus shunts blood from the pulmonary trunk to the descending aorta, bypassing the lungs
Why does blood bypass the lungs in fetal circulation
pressure/pulmonary vascular resistance is high due to amniotic fluid in the lungs
Pressure changes in circulation after birth
Pressure in left atrium increases, pressure in right atrium decreases, and pressure in lunch decrease
what causes pressure change in left atrium after birth?
lungs fill with air, blood flows into lungs, and returns to the left atrium increasing its pressure
what causes pressure change in right atrium after birth?
the umbilical veins constrict, decreasing pressure in RA
what cause the foramen ovale to close after birth?
increased pressure in the LA pushes the septum primum and secundum together, by about 3 months they fuse
what is probe patency?
incomplete fusion of foramen ovale after birth. it occurs in about 20-25% of people. Also called patent foramen ovale
what causes the ductus arteriosus to constrict?
peptide hormone Bradykinin constricts the ductus arteriosus, and it is fully closed within 24 hours of birth
what keeps ductus arteriosus open before birth?
Prostaglandin E2 from the placenta
What is the adult remnant of the ductus venosus?
ligamentum venosum
What is the adult remnant of foramen ovale?
fossa ovale
What is the adult remnant of ductus arteriosus?
ligamentum arteriosum
What are the stages of embryonic lung development?
Embryonic, pseudoglandular, canalicular, saccular, and alveolar
(Every Pulmonologist Can See Alveoli)
What happens in embryonic stage of lung development?
Weeks 3-6
lung bud from the foregut branches to form tertiary (segmental) bronchi
What happens in pseudoglandular stage of lung development?
Weeks 6-16
bronchi branch to form terminal bronchioles
What happens in canalicular stage of lung development?
Weeks 16-26
Terminal bronchioles divide into respiratory bronchioloes and alveolar ducts; surrounded by capillaries. Also airways increase in diameter
What happens in saccular stage of lung development?
Weeks 26-36
Alveolar ducts divide into terminal sacs (primitive alveoli) with type I and II pneumocytes
What happens in alveolar stage of lung development?
Weeks 36 to 8 years old
Alveoli increase, mature, and have well-developed epithelial-endothelial contacts
What can errors in embryonic stage of lung development cause?
tracheoesophageal fistula
Respiration is impossible during which before which stage of lung development?
canalicular (weeks 16-26); the formation of alveoli and their associated capillaries are required for respiration
When does respiration become possible?
25 weeks
When do pneumocytes begin to develop?
at 20 weeks, during the canalicular stage of lung development
What do type II pneumocytes do
make surfactant, which decreases surface tension of alveoli to keep them from collapsing
how many alveoli are present at birth versus at 8 years old
20-70 million versus 300-400 million
Origin of epithelium of larynx, trachea, bronchi and lungs
endodermal
What separates the developing lung bud from the esophagus
a mesodermal septum
What is tracheoesophageal fistula?
Error in embryonic stage of lung dev; Occurs when the mesodermal tracheoesophageal septum does not form correctly. Trachea can communicate with the esophagus.
Depending on variant, food/drink can enter lungs from esophagus or the esophagus can end as a blind-ended tube (esophageal atresia)
fistula definition
abnormal connection
What is respiratory distress syndrome (RDS)?
a common problem in premature infants; most often occurs in babies born before 28 weeks, but can occur in babies born before 37 weeks.
Occurs when there is not enough surfactant in lungs, and can cause infants to require extra oxygen and help with breathing.
Surfactant
made by type II pneumocytes starting around week 26; keeps alveoli from from collapsing by decreasing their surface tension
Hypertrophy of heart
thickening of cardiac muscle due to overworking
atrophy of heart
thinning of the cardiac muscle
necrosis of heart
damage induced cell death in heart muscle
what is heart tissue
the bulk of it is striated, involuntary cardiac muscle, which can undergo hypertrophy, atrophy, necrosis, and apoptosis
what are the 3 layers of the heart
epicardium, myocardium, and endocardium
epicardium
AKA visceral pericardium
thin layer of simple squamous mesothelial cells covering fibrous and adipose CT. Contains nerves and blood vessels that supply the heart
myocardium
thickest layer of heart; bundles of cardiac muscle cells organized into spiraling fascicles.
What distinguishes cardiac muscle cells?
striations, intercalated discs, branched fibers, and centrally located nuclei. NO neuromuscular junctions!
endocardium
simple squamous epithelium over a layer of variable thickness CT called subendocardium.
Where are purkinje fibers found?
in the subendocardium
density of mitochondria in cardiac muscle cells
higher than skeletal muscle; 40% compared to 2%
what are intercalated discs
specialized junctional complexes that join cardiac muscle cells to each other. They contain desmosomes, adherens junctions, and gap junctions.
SA node
AKA pacemaker
in normal conditions, SA node spontaneously generated electrical activity. The impulse is propagated through the right atrium and to the left atrium and AV node
AV node
area of specialized tissue between atria and ventricles specifically near the opening of the coronary sinus (koch’s triangle). It conducts the normal electrical impulse from the atria to the ventricles
bundle of his (atrioventricular bundle)
transmits the electrical impulse from the AV node through the cardiac skeleton and membranous interventricular septum to the apex of the muscular interventricular septum where it splits into the bundle branches
left and right bundle branches
a group of purkinje fibers that run in the subendocardial space along the interventricular septum and give rise to purkinje fibers that are distributed to the the cells of the ventricular muscle
purkinje fibrers and cells
they conduct cardiac action potentials more quickly/efficiently than any other cells in the heart.
large light-staining cells in H&E staining. Few myofilaments and increased glycogen and gap junctions
vascular flow direction
arteries of decreasing diameter > arterioles > capillary beds > venules > veins of increasing diameter
layers of the blood vessels (except for capillaries)
Innermost is tunica intima, then tunica media, then tunica adventitia
tunica intima
single layer of squamous endothelial cells at the lumen of the vessel
tunica media
concentric layers of smooth muscle cells with elastic fibers, type III collagen, and proteoglycans.
What is primarily responsible for the regulation of vascular tone, vessel diameter, and blood pressure?
the smooth muscle of tunica media
what controls contraction of smooth muscle in blood vessels?
autonomic nerves, hormones, and local physiologic conditions
tunica adventitia
connective tissue layer containing fibroblasts, type I collagen, and elastic fibers. Can contain vaso vasorum and autonomic nerve fibers that control contraction of smooth muscle in tunica media
What differentiates veins and arteries of similar size?
Veins will have less well developed tunica media and often contain valves to prevent backflow of blood in a low pressure system. In sections, the artery will hold its circular shape, while veins will usually be collapsed
arterioles
have only 1-3 layers of smooth muscle cells. Important for regulation of blood flow into capillary beds
function of capillaries
site of fluid, gas, and small molecule exchange between blood and tissues.
capillary composition
single layer of endothelial cells and a basement membrane.
Pericyte
a smooth muscle-like cell; in some tissues a pericyte will associate with the outer wall of the capillary acting as a sphincter to control capillary blood flow
continuous capillary
found in muscle, nerve, and connective tissue
have tight intercellular junctions to restrict leakage and utilize pinocytotic vesicles
fenestrated capillary
found in GI and endocrine systems
contain permanent channels or fenestrations (pores) across the endothelial cells
sinusoidal capillary
found in bone marrow, liver, spleen, and lymph nodes
contain large discontinuities between the endothelial cells
what is angiogenesis
formation of new capillaries from existing capillaries. The process follows a consistent series of steps in all tissues.
Can be normal or pathalogic (excessive and abnormal angiogenesis in diabetic retinopathy)
steps of angiogenesis
- stimulation of endothelial cells by angiogenic factors, such as vascular endothelial growth factor (VEGF)
- degradation of the vessel basement membrane by activated endothelial cells and the formation of endothelial sprouts
- proliferation of endothelial cells and formation of new capillary roots
- new vessel stabilization/ maturation (new basement membrane formation and association of pericytes)
conducting portion of respiratory system
provides tubular conduit through which air can travel to and from lungs and plays role in conditioning the inspired air.
consists of trachea, bronchi, and bronchioles
layers of the organs in conducting portion of the respiratory system
mucosa, lamina propria, submucosa, and adventitia
mucosa of conducting portion
layer of ciliated pseudostratified columnar epithelium with goblet cells (called “respiratory epithelium). It cleans, moistens, and warms the inspired air before it enters the lungs.
function of goblet cells
produce a rich mucous secretion. These are abundant in the upper portions of the conducting portion of respiratory system
What changes occur as we move further down the conducting portion and approach the respiratory portion?
number of goblet cells decrease and ciliated pseudostratified columnar epithelium transitions to a simple columnar and cuboidal epithelium
lamina propria of conducting portion
thick, loosely organized vascularized CT that supports the mucosa
submucosa of conducting portion
forms the bulk of the thickness of the wall and contains 3 main components in varying amounts depending upon the level of the bronchial tree: smooth muscle cells, hyaline cartilage, and seromucous glands
function smooth muscle cells in submucosa
smooth muscle contracts and restricts/regulates the amount of airflow through the conducting tubes
function hyaline cartilage in submucosa
important in preventing collapse of tubular walls. can form c-shaped rings, irregular rings, and small plates
trend of components of submucosa as we move down the bronchial tree
as the diameter of the tubes decreases, the quantity of bundles of smooth muscle tends to increase and the cartilage tends to decrease.
structure of trachea
thin walled tube about 10 cm long extending from the larynx to the point at which it divides into the 2 main bronchi. it has 16-20 c-shaped rings of hyaline cartilage in the submucosa. they have fibroelastic cartilage and smooth muscle on the posterior aspect
primary bronchi
trachea divides into 2 primary bronchi, one for each lung
secondary or lobar brinchi
divisions of the primary bronchi, they are smaller in diameter each supply a lobe of the lung
tertiary or segmental bronchi
divisions of the secondary bronchi. they supply the segments of the lung and give rise to bronchioles
trend of bronchi histologically as you proceed toward the bronchioes
epithelium becomes more simplified, seromucous gland decrease in quantity, amount of cartilage decreases, and bundles of smooth muscles and elastic connective tissue increase
structure of bronchioles
last and simplest part of the conducting portion. consist of airways with diameters of 5mm or less. Mucosa contains NO glands or cartilage. epithelium is now cuboidal. submucosa contains mainly smooth muscle and elastic fibers
respiratory portion of respiratory system
is the site of gas exchange in the lung; consists of respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli
structure of respiratory bronchioles
each terminal bronchiole divides into 2 or more respiratory bronchioles. Mucosa resembles that of terminal bronchioles except the walls are interrupted by numerous saccular alveoli
structure of alveoli
sac-like structures about 200 micrometers in diameter that are organized into larger structures called acini. Oxygen and carbon dioxide are exchanged between air and blood here. alveoli covered by rich capillary network, fibroblasts, and elastic and reticular fibers
how many alveoli in mature adult lungs?
about 300 million alveoli with SA of 140 meters squared form the parenchymal structure of lungs
type I alveolar cells/pneumocytes
squamous cells that make up about 97% of the alveolar surface. They all have desmosomes and tight occluding junctions and a form a gas permeable barrier of minimal thickness
type II alveolar cells/ pneumocytes
interspersed among the type I cells. Cuboidal in shape. Resemble secretory cells; produce pulmonary surfactant
content of lamellar bodies in type II pneumocytes
lipid, glycosaminoglycans, and protein
alveolar macrophage
AKA dust cell
derived from monocytes and can be found on interior of alveolus or on its outer surface. Often contain large amounts of carbon and dust, which they phagocytose from the alveolar lumen
components of blood-air barrier
1) surface and cytoplasm of type I pneumocytes 2) fused basal laminae of alveolar cells and the capillary endothelial cells 3) the cytoplasm of the endothelial cells
function of blood-air barrier
separates air in the alveoli from blood in the capillary; oxygen from alveolar air diffuses through layers of the alveolar wall toward the capillary while carbon dioxide diffuses in the opposite direction
thoracic inlet
superior thoracic aperture; bounded by T1 vertebra, first pair of ribs, and superior border of manubrium
thoracic outlet
inferior thoracic aperture; bounded by T12, xyphoid process, and 7th-10th costal cartilages. Opening is closed by the diaphragm
intercostal muscles
raise and lower the ribs for respiration
intercostal nerves
the ventral rami of the thoracic spinal nerves
innervation of diaphragm
phrenic nerve (ventral rami of C3, C4, and C5)
3 main openings of diaphragm
aortic haitus, esophageal hiatus, caval opening
aortic hiatus
opening in diaphragm at the level of T12
is through the right and left crura and marks the termination of thoracic aorta/beginning of abdominal aorta, thoracic duct, and often azygos vein
esophageal hiatus
opening of diaphragm at the level of T10
within the muscular part of diaphragm and transmits the esophagus and vagus nerves
caval opening
opening of diaphragm at level of T8
located within the central tendon and contains IVC and sometimes right phrenic nerve
What divides superior and inferior mediastinum?
a line drawn horizontally from the sternal angle (jxn of manubrium to body) to the lower border of T4
anterior mediastinum
contains CT, fat, and remnants of the thymus gland
middle mediastinum
contains the heart and roots of the great vessels (SVC, aorta, pulmonary trunk and pulmonary veins) enclosed in the pericardial sac as well as the phrenic nerves
posterior mediastinum
contains descending aorta, azygos vein, thoracic duct, esophagus, trachea, and vagus nerves
what is the only point of attachment for lungs in the thoracic cavity?
the root or hilum of the lung, where the pulmonary arteries, veins, and primary bronchi enter the lungs
visceral pleura
the part the the serous membrane that covers the lung
parietal pleura
the portion of the serous membrane that line the thoracic cavity
pleural cavity
the space between the visceral and parietal pleura; it contains about 15 mL of pleural fluid that lubricates the surfaces of pleural membranes and facilitates association of lungs with the thoracic wall
pneumothorax
accumulation of air in the pleural cavity causing the lung to collapse
costodiaphragmatic recess
recess within the pleural cavity formed by the reflection of the costal and diaphragmatic pleura; can collect fluids that can be aspirated
costomediastinal recess
recess within the pleural cavity where the costal and mediastinal pleura meet; can collect fluid that can be aspirated
pleural effusion
abnormal accumulation of fluid in pleura space; can be treated by thoracentesis, which need to be done 1-2 intercostal spaces below the effusion, but no lower than the 8th intercostal space to avoid damage to liver, spleen, and diaphragm
innervation of costal parietal pleura
intercostal nerves
innervation of mediastinal parietal pleura and diaphragmatic parietal pleura
phrenic nerves
innervation of visceral pleura
autonomic nerves
pericardium
fibro-serous sac that encloses heart and roots of the great vessels (SVC, IVC, ascending aorta, pulmonary trunk, and pulmonary veins)
Fibrous pericardium
the outer surface of the pericardium; strong, dense, and fibrou; blends with the adventitia of the roots of the great vessels and the central tendon of the diaphragm
serous pericardium
consists of parietal layer and visceral layer
parietal pericardium
lines the inner surface of the fibrous pericardium
visceral pericardium
forms the outer layer of the heart (epicardium) and the roots of the great vessels. visceral pericardium reflects back to become the parietal pericardium at the roots of the great vessels, forming the pericardial sinuses
pericardial cavity
a potential space between visceral pericardium and parietal pericardium
transverse pericardial sinus
lies posterior to the ascending aorta and pulmonary trunk and anterior to the SVC. It is surgically important because you can make a ligature through the sinus between arteries and veins to stop blood circulation
oblique sinus
located behind the heart, surrounded by a reflection of serous pericardium around the right and left pulmonary veins
direction of flow in the heart
IVC and SVC > right atrium > tricuspid > right ventricle > pulmonary valve > pulmonary trunk > lungs > pulmonary veins > left atrium > mitral (bicuspid) valve > left ventricle > aortic valve > aorta > body
semilunar valves
the aortic and pulmonic valves; they are tricuspid (having 3 cusps)
where can you find the openings for coronary arteries in the aorta?
adjacent to the left and right cusps fo the aortic valve
coronary flow
coronary valves fill when the aortic valve closes; thus coronary flow occurs during diastole
what causes AV valves to open and close?
pressure gradients across the valve
cardiac skeleton
collection of dense fibrous CT in the form of 4 interconnected rings in a plane between the atria and ventricles; it helps maintain integrity of the valve openings and provides points of attachment for the cusps. Also electrically separates the atrial from ventricular musculature as the collagen fibers are impermeable to electrical propagation
anterior surface of the heart
covered by the sternum and 3rd-6th costal cartillages
posterior surface of heart
in front of the posterior mediastinum. also called the base
inferior (diaphragmatic) surface of heart
the heart rests on this surface
what can be some consequences of left atrial enlargement?
compression of esophagus (causing dysphagia) or hoarseness (due to compression of left recurrent laryngeal nerve)
the left atrium is most posterior
anterior and posterior sulci
mark the separation between right and left ventricles and contain the coronary arteries and veins that supply the heart
coronary sulcus
marks the division between the atria and ventricles
vertebral level that passes through the sternal angle
T4-T5
what does the sternal angle represent
separation of superior and posterior mediastinum; ascending aorta becomes aortic arch then aortic arch becomes thoracic aorta and trachea bifurcates
what are the landmarks for the margins of the heart?
upper limit of heart reaches as high as the 3rd costal cartilage and 2nd intercostal space on left side of sternum
right margin of the heart extends from 3rd costal cartilage to near the right 6th costal cartilage
left margin of the heart descends laterally from the 2nd intercostal space to the apex located near the midclavicular line in the 5th intercostal space
lower margin of the heart extends from the sternal end of the right 6th costal cartilage to the apex in the 5th intercostal space near the midclavicular line
which ventricular wall is thicker?
left
trabeculae carneae
muscular ridges of myocardium found in ventricles
septomarginal trabecula (moderator band)
distinct band of trabeculae carneae that forms a bridge between the interventricular septum and the base of anterior papillary muscle of the right ventricle.
Provides pathway for part of the cardiac electrical conduction system
papillary muscles
cone-shaped muscles that extend from the ventricular walls and septum, their apices are attached to cordae tendineae that extend and attach to the cusps of the AV valves. Their contraction prevents cusps of AV valves from everting into atrium during ventricular contraction (preventing ventricular regurgitation)
atria anatomy
mainly smooth walls
pectinate muscles
muscular ridges found in the right atrium. also found in the auricles of both atria
sinus venarum
the smooth portion of the muscular walls of the right atrium
crista terminalis
boundary between the pectinate muscles and the sinus venarum
blood supply to the heart
coronary arteries (the first branches off the ascending aorta) supply the heart, coronary venous blood is returned through the coronary sinus which drains into the right atrium through the opening of the coronary sinus
branches off the right coronary artery
posterior descending artery, right marginal artery, SA nodal artery, AV nodal artery
posterior descending artery supplies
right atrium, right/left ventricle, 1/3 of septum
right marginal artery supplies
right ventricle
SA nodal artery supplies
SA node and surrounding myocardium
AV nodal artery supplies
AV node and surrounding myocardium
Branches of left coronary artery
left anterior descending artery, left marginal artery, circumflex artery
left anterior descending artery supplies
right ventricle, left ventricle, 2/3 of septum
left marginal artery supplies
left ventricle
circumflex artery supplies
posterior surface of left ventricle
dominance of coronary blood supply
refers to the artery that gives rise to the posterior interventricular artery. Right dominant is about 85% of population
parasympathetic innervation of heart
through the vagus nerve
preganglionic fibers from the vagus nerve originate from neurons in the brainstem
sympathetic innervation of heart
T1-T4 levels of sympathetic trunk
axons of preganglionic neurons originate in the IML of T1-T4 and exit via ventral root. Some synapse at the same level, while others ascend in the sympathetic trunk
Afferent nerves of the heart
travel back to the spinal cord following the T1-T4 sympathetic nerves
referred somatic pain
pain arising from musculoskeletal or connective tissue
ie fibrous pericardium, mediastinal pleura, and diaphragm are innervated by phrenic nerves, thus pain from these areas is referred to the shoulder or neck and is usually localized and sharp
referrred visceral pain
for example: visceral afferents from the heart enter at the T1-T4 spinal cord segments traveling with sympathetics. The pain is felt as coming from the chest and medial arm and is usually dull and diffuse
where to auscultate for aortic valve?
left of sternum (patient’s right) inferior to sternal angle
where to auscultate for pulmonary valve
right (patient’s left) of sternum inferior to sternal angle
where to auscultate for tricuspid valve
right (patient’s left) of the sternum at the level of the 5th rib
where to auscultate for mitral valve
right (patient’s left) of sternum near the nipple
What produces heart sounds
closure of AV valve (lub, S1) and closure of semilunar valves (dub, S2)
carina
the level where the trachea bifurcates into right and left primary bronchi at the level of the sternal angle
right main bronchus
shorter, wider, and more vertical than the left; more foreign bodies that enter through trachea will be lodged here
blood supply to tracheobronchial tree
brachial arteries that arise from the descending aorta
organization of right lung
superior lobe > horizontal fissue > middle lobe > oblique fissure > inferior lobe
left lung
superior lobe > oblique fissure > inferior lobe
innervation of the lung
vagus nerves and T1-T4 levels of sympathetic trunk
