Anatomy – Exam 1 (Part 2) Thoracic Wall, Lungs and Pleura ○ Objectives Thoracic Wall Describe the boundaries and reference lines of the thoracic cavity and the skeletal components (thoracic cage) of the thoracic wall What are the functions and surface landmarks associated with the thoracic cage? Describe the anatomy and articulations of a typical rib Describe the process of respiration and the associated movements of the thoracic wall Describe the anatomy of the breast. What is the clinical significance of the lymphatic drainage in this region? Describe the muscles that make up the thoracic wall What nerves, arteries and veins supply the thoracic wall? Describe the arrangement of the intercostals nerve, artery and vein within the intercostals space Describe the major anatomical compartments within the thoracic cavity: pleural cavities and the mediastinum Lungs and Pleura What distinguishes parietal from visceral pleura? Describe the 4 regions of parietal pleura What is the pleural cavity. How does it relate to the thoracic cavity. What are the costodiaphragmatic and costomediastinal recesses of the pleural cavity? Describe pathologies associated with the pleural cavity including: pneumothorax, hemothorax, chylothorax, and pleuritis (pleurisy) Describe the surfaces, lobes, and fissures of the right and left lung Describe the anatomy associated with the root or hilum of the lung Describe the anatomy of the trachea and bronchi. Why are aspirated foreign objects found in the right lung? Be able to explain the concept of bronchopulmonary segments Describe the blood circulatory systems (pulmonary and bronchial) associated with the lungs Describe the autonomic innervation of the lungs Describe the lymphatic drainage of the lungs Be able to relate the borders, lobes, fissures and sounds of the lungs as well as the pleural recesses to the surface anatomy of the thorax ○ Functions of Thoracic Cage Ventilation part of respiration Protects viscera Provides anchoring points for skeletal muscles ○ Structures Thorax – superior portion of the trunk Jugular notch – in between the sternocleidomastoid muscles Sternal angle (of the manubriosternal joint) – landmark for 2 nd rib which is basically the first one you can palpate Costal margin – made of cartilage Midclavicular line – inside nipple Intercostal space – takes the number of the rib above it Note – diaphragm comes up into the thorax a good bit ○ Skeletal Components Sternum Manubrium – top part; body; xyphoid process Ribs – 12 pairs True Ribs – ribs 1-7, line up with thoracic vertebrae False Ribs – ribs 8-10, because they share a common costal cartilage to attach to sternum ○ Note – 7 th rib is a little funny Floating Ribs – ribs 11-12, don‘t attach to sternum Costal Cartilages – links ribs 1-10 with body of sternum Superior thoracic aperture (thoracic inlet) – bordered by T1 vert, medial 1 st rib and manubrium Not bordered by clavicle Inferior thoracic apterture (thoracic outlet) – bordered by T12, 11 th & 12 th ribs, costal margin, xyphosternal juncture
38
Embed
Anatomy – Exam 1 (Part 2) - Wikispaces - UTCOMutcom2012.wikispaces.com/file/view/Anatomy+-+Exam+1+(Part+2).pdf · Anatomy – Exam 1 (Part 2) ... What is the clinical significance
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Anatomy – Exam 1 (Part 2)
Thoracic Wall, Lungs and Pleura ○ Objectives
Thoracic Wall
Describe the boundaries and reference lines of the thoracic cavity and the skeletal components (thoracic cage) of the thoracic wall
What are the functions and surface landmarks associated with the thoracic cage?
Describe the anatomy and articulations of a typical rib
Describe the process of respiration and the associated movements of the thoracic wall
Describe the anatomy of the breast. What is the clinical significance of the lymphatic drainage in this region?
Describe the muscles that make up the thoracic wall
What nerves, arteries and veins supply the thoracic wall?
Describe the arrangement of the intercostals nerve, artery and vein within the intercostals space
Describe the major anatomical compartments within the thoracic cavity: pleural cavities and the mediastinum
Lungs and Pleura
What distinguishes parietal from visceral pleura?
Describe the 4 regions of parietal pleura
What is the pleural cavity. How does it relate to the thoracic cavity. What are the costodiaphragmatic and costomediastinal recesses
of the pleural cavity?
Describe pathologies associated with the pleural cavity including: pneumothorax, hemothorax, chylothorax, and pleuritis (pleurisy)
Describe the surfaces, lobes, and fissures of the right and left lung
Describe the anatomy associated with the root or hilum of the lung
Describe the anatomy of the trachea and bronchi. Why are aspirated foreign objects found in the right lung?
Be able to explain the concept of bronchopulmonary segments
Describe the blood circulatory systems (pulmonary and bronchial) associated with the lungs
Describe the autonomic innervation of the lungs
Describe the lymphatic drainage of the lungs
Be able to relate the borders, lobes, fissures and sounds of the lungs as well as the pleural recesses to the surface anatomy of the
thorax
○ Functions of Thoracic Cage
Ventilation part of respiration
Protects viscera
Provides anchoring points for skeletal muscles
○ Structures
Thorax – superior portion of the trunk
Jugular notch – in between the sternocleidomastoid muscles
Sternal angle (of the manubriosternal joint) – landmark for 2nd
rib which is basically the first one you can palpate
Costal margin – made of cartilage
Midclavicular line – inside nipple
Intercostal space – takes the number of the rib above it
Note – diaphragm comes up into the thorax a good bit
○ Skeletal Components
Sternum
Manubrium – top part; body; xyphoid process
Ribs – 12 pairs
True Ribs – ribs 1-7, line up with thoracic vertebrae
False Ribs – ribs 8-10, because they share a common costal cartilage to attach to sternum
○ Note – 7th rib is a little funny
Floating Ribs – ribs 11-12, don‘t attach to sternum
Costal Cartilages – links ribs 1-10 with body of sternum
Superior thoracic aperture (thoracic inlet) – bordered by T1 vert, medial 1st rib and manubrium
○ Afferents – visceral pain (dull, hard to localize)
Histology of the Respiratory System ○ Objectives
Identify the anatomical components of the respiratory system Differentiate between the ventilation system, conducting and respiratory portions of the respiratory system. Be able to describe their components,
morphology and functions
Define the tissue layers and cell types found in the nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and alveolar airways. Relate the structure to the function of each of the above organs
Know how the epithelium of the larynx is adapted for voice production or altered by cigarette smoke Describe how the histology of the respiratory system is designed to meet functional requirements associated with gas exchange between the body and
the atmosphere Explain the structure of the alveolar-
capillary membrane Be able to describe the location and
structure of ciliated cells, mucus producing cells, alveolar macrophages, type I and type II pneumocytes and how they relate to their individual functions in the respiratory system
Identify the respiratory system cell types involved in and their functional relationship with carcinoid disease, asthma,
respiratory distress syndrome, heart failure and emphysema
○ Primary Function – gas exchange
between atmosphere and blood
○ Secondary Function – air
conditioning, olfaction, phonation
○ Major Divisions of the Respiratory
System
Conducting Portion – all the secondary functions
From nasal cavity to bronchioles
Respiratory Portion – where gas exchange occurs
From respiratory bronchioles to alveolar sacs
○ Generalized Respiratory Tissue Layers (from inside to out)
Delineate the superior, anterior, middle, and posterior mediastinum. Describe the major structures associated with the four regions of the mediastinum. Identify the contents of the superior mediastinum and relationship to the heart and lungs. Identify the borders of the posterior mediastinum. List the major vessels that occupy the posterior mediastinum.
Define the origin, course, and termination of the thoracic duct. Describe the path of the esophagus and trachea through the thoracic cavity. Describe the azygos system of veins. Describe and contrast the distribution of the vagi and phrenic nerves throughout the thoracic cavity. Discuss the relationship of the heart, pericardium, lungs, and pleura to structures in the posterior mediastinum.
○ Mediastinum
The anatomic region located between the lungs separating two pleural cavities.
Contains all the principal tissues and organs of the chest except the lungs.
It contains the heart, thymus gland, portions of the esophagus and trachea, and other structures
Boundaries
Sternum → vertebral column
Laterally by the pericardium, the membrane enclosing the heart
AND mediastinal pleurae, (part of parietal pleura that lines the
thoracic cage).
Sternal Angle – 2nd
costal cartilage to T4/T5 intervertebral disc
Junction of manubrium and sternum
Compartments
Superior Mediastinal Compartment – above sternal angle
○ Borders
Posteriorly – first four thoracic vertebrae
Above - continuous with the neck;
Below - continuous with both anterior and posterior mediastinal compartments.
○ 2nd
costal cartilage to T4/T5 interveterbral disc
Laterally - limited by parietal (mediastinal) pleura.
○ Contents of the Superior Mediastinum: Thymus Aortic arch – including the Brachiocephalic trunk, left common carotid artery, left subclavian artery
○ Everything below the sternal angle (below superior mediastina) is not the aortic arch
Superior Vena Cava – including the left and right brachiocephalic veins
Trachea – ends at bifurcation of the trachea Esophagus
Right vagus nerve
Left vagus nerve – including the Left recurrent laryngeal nerve
Borders - sternum anteriorly and pericardial sac posteriorly.
Contents - sternopericardial ligament, fat and lymph nodes
○ Middle Mediastinal Compartment – contains heart and pericardium
Borders - the anterior mediastinal compartment ventrally and the posterior mediastinum dorsally
Contents - the pericardium, heart, phrenic nerves, pericardiacophrenic vessels, stems of great vessels.
○ Posterior Mediastinal Compartment
Borders - pericardial sac anteriorly and the anterior surface of the vertebral bodies posteriorly
Contents - descending aorta, esophagus, azygous system of veins, vagus nerve, thoracic duct, lymph
nodes, thoracic splanchnic nerves.
○ The Thymus
A primary lymphoid organ
Located in the lower part of the neck and the anterior part of the superior mediastinum
Posterior to the manubrium and extends into the anterior mediastinum
The thymus continues to grow (age of 5-6 years) but after puberty it is largely replaced by fat
Blood supply – inferior thyroid and internal thoracic
Internal Thoracic (mammary artery) – descends into thorax lateral to the edge of the sternum, ends at 6th rib
Innervation - branch from vagus and sympathetic trunk
Lymphatics - anterior mediastinal nodes
Function – development and maintenance of immune system
○ Portions of the Aorta
Ascending aorta - from left ventricle to aortic arch -
mostly within pericardial sac
Aortic arch - above plane of sternal angle; courses
posteriorly and laterally
Branches – all travel superiorly
○ Brachiocephalic – moves to right of the trachea
(others move to left)
Divides into right subclavian and right
common carotid
○ Left Common Carotid –
○ Left Subclavian – lies against left lung and pleura
Descending portion of thoracic aorta
continuation of arch on left side of vertebrae
reaches midline at T12 as it passes through diaphragm
○ "I Ate 10 Eggs At Noon" – Inferior vena cava pierces at T8,
Esophagus at T10, Aorta at T12
○ Pulmonary Trunk and Pulmonary Arteries
Pulmonary Trunk - Courses upward and to the left
Divides into left and right pulmonary aa. in concavity
of aortic arch
ligamentum arteriosum – connects pulmonary trunk
to aorta (remnant from development)
Right pulmonary artery - posterior to ascending aorta
Left pulmonary artery - anterior to descending aorta
○ Great Veins of the Thorax
Generally veins are in plane anterior to arteries
Inferior vena cava - pierces diaphragm at T8 - immediately enters pericardium and heart
Left brachiocephalic vein - internal jugular + subclavian → joins right brachiocephalic vein (behind intercostal
space 1) → superior vena cava
courses obliquely to right in front of great aa.
Right brachiocephalic vein - joins left brachiocephalic vein → s. vena cava
formed similar to left - course vertically behind manubrium -
Superior vena cava – azygous veins + two brachiocephalics → superior vena cava
formed behind intercostal space 1
Connects to right atrium
Pulmonary veins - directly from root of lung to left atrium
○ Lymphatics of the Thorax
Anterior Mediastinal Nodes – near great vessels of mediastinum
Middle Mediastinal Nodes – drains bottom of trachea and proximal bronchioles
Posterior Mediastinal Nodes – drains area around heart
Thoracic Duct
drains all of body below diaphragm and left side of thorax.
cisterna chyli - dilation of origin of thoracic duct (abdomen)
Pathway - ascends through aortic hiatus of diaphragm. ascends between azygous vein and aorta to T4-5 plane.
crosses to the left at T4-5 to ascend behind the esophagus into neck
Empties into - internal jugular and subclavian veins.
Right Lymphatic Duct - 3 branches drains what the thoracic duct doesn't (upper right portion of thorax)
right jugular: drains the right side of head and neck
subclavian: drains right upper limb
bronchomediastinal: drains the right side of the thorax
Structure of lymph node – has 4 vessels going in, 2 vessels going out so that lymph has time to stay in node and
get cleaned
○ The Trachea
D-shaped tubes supported by cartilage
Path
Bifurcation at T4-5 Anteriorly: great vessels and thymus, Posteriorly: esophagus, Azygous vein to right of bifurcation, Aortic arch to left of bifurcation
Carina divides the bronchi
Blood supply: bronchial aa. and inferior thyroid aa.
Innervation: pulmonary plexus and branches of vagus and sympathetic trunk
○ The Esophagus
Muscular tube - striated muscle in neck, smooth muscle in lower third, mixed in middle
Left atrium is indented into the esophagus
Constrictions – cancers can happen here because of mechanical stress
superior end in neck
where aorta and left bronchus compress it
near gastric end
Innervation (all by vagal nerve) Striated muscle – innervated by vagal (recurrent branch)
Smooth muscle – innervated by parasympathetic vagal
Esophageal plexus - surrounds lower thoracic esophagus, contains mostly vagal fibers but some sympathetic
Arteries - esophageal branches of thoracic aorta anastomose with inferior thyroid aa. and left gastric aa.
Veins
submucosal plexus and surface plexus, drain to azygos system, may drain superiorly to inferior thyroid vv., may drain inferiorly to
gastric vein (portal-caval)
Courses through superior and posterior mediastinum (don't worry about this)
continuous superiorly with pharynx in neck
pierces diaphragm at T10 to join stomach upper portion in thorax, slightly left of midline
at lower end passes through diaphragm to left of midline
Sensory - parietal pleura, pericardium, central diaphragm
Right phrenic - descends along right side great veins: right brachiocephalic vein, s. vena cava, right atrium, i. vena cava, anterior troot of lung
Left phrenic - courses along left side of subclavian artery crosses left side of aortic arch anterior troot of lung, along left side of pericardial sac
○ Vagus Nerve
Preganglionic parasympathetic fibers for thoracic and abdominal viscera
Right vagus – not as close to lungs? enters thorax posterolateral to brachiocephalic vein, anterior to rt. subclavian artery
right recurrent branch hooks under subclavian artery to ascend near trachea and esophagus
descends to lateral side of trachea posterior to root of lung
descends on posterior esophagus to form esophageal plexus
passes through diaphragm with esophagus as posterior vagal trunk
Left Vagus – closer to lungs? enters thorax between carotid and subclavian arteries
descends to cross left side of aortic arch
Left Laryngeal Recurrent branch curves around aortic arch and ligamentum arteriosum to ascend in neck
between trachea and esophagus
Posterior to root of lung
onto anterior esophagus - forms esophageal plexus
Goes through diaphragm with esophagus as anterior vagal trunk
Branches of vagus in thorax: left recurrent laryngeal, br. to pulmonary plexus, br. to esophagus, br. to cardiac
plexus
○ Azygos System of Veins
Generally drains intercostal veins, some lumbar segmental veins
Azygos vein
formed by union of right ascending lumbar vein and right subcostal vein ascends along right side of vertebral column to T4 superficial to intercostal aa. thoracic duct to the left
arches over bronchus to join superior vena cava
tributaries (not as important)- right posterior intercostal vv. - 5-11 right superior intercostal vein - drains ICS 2-4 hemiazygous vein accessory
Development of the Respiratory System ○ Objectives
Define: pharynx, larynx, foregut, pharyngeal arches and pouches. List the germ layers of origin for: epithelium, glands, cartilage, smooth muscle,
and blood vessels of the respiratory system Describe the laryngotracheal groove. Define/describe the development of the laryngeal cartilages and musculature. Describe the process by which the trachea is separated from the esophagus by the
tracheoesophageal septum (folds). Describe the probable process by which a congenital tracheoesophageal fistula is created. What are the consequences of this defect? Define/describe the lung buds.
Correlate the first, second, and third divisions of the distal end of the primitive trachea with the bronchi of the adult lung.
Define/describe the four major phases in lung development. Describe the processes by which the intraluminal fluid contents of the respiratory system
are removed at and immediately after birth. Define/describe: surfactant. Where and when is it produced? What is its function? What are the consequences of a lack of surfactant in the lung? Define/describe: respiratory distress syndrome (RDS)/ hyaline membrane disease
(HMD). How are these pathological processes treated currently? Explain the formation of: congenital lung cysts, lung agenesis, and lung hypoplasia. Describe the major features of the time line for respiratory system development. How do
these features relate tthe survivability of a premature infant.
○ Structures
Laryngopharynx – inferior 1/3 of pharynx, develops from the foregut
Larynx – airway supported by thyroid, cricoid, arytenoid and epiglottic cartilages
Upper Respiratory Tract – external nares to laryngopharynx
Lower Respiratory Tract – larynx, trachea, bronchi and lungs
○ Results in atelectasis – alveoli collapse during expiration
○ Most common of all neonatal diseases
○ Will occur in premature babies born before week 32
○ Symptoms
Rapid, labored breathing begins shortly after birth
○ Doesn‘t happen right away because it takes a while for all the alveoli to collapse
Nostril flaring, grunting, cyanosis
Rib retraction – due to intercostal muscles pulled inward
Concavity to rib cage because not enough air in lungs (‗bell type rib cage‘)
○ Treatments
You can determine amount of surfactant by measuring phospholipids in amniotic fluid
○ If there isn‘t enough, then give mother betamethason (steroids) & thyroid hormone to stimulate
type II pneumocytes
After birth, give exogenous surfactant
After birth, give continuous positive airway pressure to keep alveoli open
○ Histologically
Liquid leaks into alveoli from capillaries due to the stress or atelectasis
○ Fluid builds up in the lungs
Heart and Pericardium ○ Objectives
Describe the location of the heart within the thoracic cavity and its relationship with the pericardium and the pericardial cavity. Describe the structure and function of the layers of the pericardium
Define the atrioventricular groove, anterior and posterior interventricular sulci, apex and base of the heart, anterior, posterior and diaphragmatic surface of the heart.
Describe the layers of the heart, relating structure and function. Describe the internal structure of the right atrium including: right atrial appendage, superior and inferior venae cava, crista terminalis, musculi pectinati,
coronary sinus, and fossa ovalis. Describe the internal structure of the left atrium, including: musculi pectinati, and the left atrial appendage. Describe the components and locations of the Tricuspid, Mitral and semilunar valves (Aortic and Pulmonary). Describe the surface projections and auscultation points for each of the heart valves on the chest wall.
Describe the normal heart sounds. Describe heart murmurs and explain valve stenosis and regurgitation. Describe the internal structure of the right ventricle including: trabeculae carneae, papillary muscles, septomarginal trabecula, and supraventricular crest. Describe the internal structure of the left ventricle, including: trabecuale carnea, and papillary muscles. Describe infundibulum and conus arteriosus. Describe the fibrous skeleton of the heart. Describe systole and diastole and relate these events tthe normal heart beat and cardiac cycle Describe the flow of blood through the heart, comparing and contrasting the pulmonary and systemic circulations.
○ Note – heart is one of the first organs to start working
○ Pericardium
Double-walled fibroserous sac which surrounds and covers the heart and roots of great vessels
Serous pericardium - serous, lining layer
Parietal layer - lines inside of fibrous pericardium
Visceral layer - covers outside of heart = epicardium (which is 'part' of the heart)
Fibrous pericardium – connective tissue layer outside of the parietal serous layer – forms bulk of the gross
pericardial sac - fused to adjacent connective tissue planes
Pericardial space - potential space between parietal and visceral layers - contains only a moistening layer of fluid
Conduction System and Coronary Circulation ○ Objectives
Conduction System:
Describe the components and function of the cardiac conduction system including the: sinu-atrial node, atrioventricular node, atrioventricular bundle (bundle of His), right and left bundle branches and the septomarginal fasciculus.
Describe the location of the SA node and AV node.
Describe the interatrial or internodal conducting tracts:
Describe the autonomic innervation of the heart and its influence in the regulation of the conduction system and control of the cardiovascular system.
Correlate the sequence of excitation of the components of the heart conduction system with a basic electrocardiogram trace image.
Compare and contrast normal sinus rhythm with sinus bradycardia, tachycardia, heart block and fibrillation.
Coronary Arteries:
Describe the origin and course of the right and left coronary arteries and explain the nature of their anastomoses.
Describe the following branches of the right coronary artery: sinoatrial (SA) nodal artery, right marginal artery, Atrioventr icular (AV) nodal artery,
terminal branches, posterior interventricular artery and septal branches
Describe the following branches of the left coronary artery: left circumflex artery, anterior marginal artery, obtuse marginal artery, atrial branches
and posterior marginal arteries, anterior interventricular artery, anterior diagonal artery and septal branches.
Describe the concept of Dominance of coronary circulation.
Describe the specific tasks required of the coronary circulation and how the coronary circulation is structurally and functionally adapted.
Define ischemic heart disease and describe the consequences of inadequate blood supply tthe heart muscle. Cardiac Veins:
Describe the venous drainage of the heart.
Describe the coronary sinus and the Thebesian valve (valve of the coronary sinus).
Describe the relationship of the coronary sinus and the left atrial wall.
Describe the distribution pattern of the tributaries of the coronary sinus: great cardiac vein, middle cardiac vein, oblique vein of the left atrium, and
small cardiac vein.
○ The Conducting System
Sinoatrial node (SA node) = pacemaker
located along upper end of sulcus terminalis - near SVC
initiates heart beat
supplied by both sympathetic and parasympathetic nerves
most superficial node and can be affected by pericarditis
Interatrial or internodal conducting tracts:
○ Bachmann’s bundle - originates in the SA and is the only tract that conducts action potentials to the left
atrium.
○ All run from SA node through RA to the AV node - Anterior internodal tract, Middle internodal tract,
Posterior internodal tract Atrioventricular node - located in interatrial septum adjacent to the ostium (opening) of coronary sinus inside the
Triangle of Koch.
Electrical relay station between atria and ventricles
Serves as a gate that slows the electrical current so that the atria contract fully before the ventricles
Triagle of koch - a roughly triangular area on the septal wall of the right atrium, between the tricuspid valve,
coronary sinus orifice, and tendon of Todaro, that marks the site of the atrioventricular node.
Tendon of Todaro – formed by the junction of the inferior vena cava and near the pulmonary valve
Atrioventricular bundle (of His) - extends from AV node along the IV septum
Collection of heart muscle cells specialized for electrical conduction that transmits the electrical impulses from
the AV node to the point of the apex of the 2 bundle branches
Bundle Branches - AV bundle divides into right and 2 left bundle branches in the septum (near junction of
membranous and muscular part of septum)
Purkinje fibers – Purkinje fibers carry the contraction impulse from the left and right bundle branches to the
myocardium of the ventricles.
Ventricular conduction system – bundle branches + Purkinje fibers
Septomarginal trabeculae (Trabeculum septum marginal) – fibers from the interventricular septum that run
directly to anterior papillary muscle in RV to make sure that it is stimulated first
Ectopic Pacemakers - Potential Pacemakers that aren‘t the SA node
If one pacemaker (the SA node) fails then others can take over,
but they have different bpm
○ Places around SA Node – 60-80 bpm
○ AV Node (nodal rhythm) – 40-60 bpm
○ Ventricles – 20-40 bpm
○ The EKG
P Wave - the sequential depolarization of the right and left atria
(SA node)
QRS Complex – right and left ventricular depolarization (usually
this is simultaneous) (bundle branches and Purkinje)
ST-T Wave – ventricular repolarization
U Wave – unknown
PR Interval – time interval between atrial contraction and
ventricular contraction
When impulse is in AV node and bundle of His
QRS Duration – duration of ventricular muscle depolarization
○ Heart Rhythm Abnormalities
Premature Ventricular Contraction – can be caused by hypoxia, electrolyte imbalance, stimulants, stress
Arrhythmias
Heart Block – failure of conduction system to transmit signals
○ Total heart block – damage to AV node → P Wave still present but nothing else is
Ventricular Fibrillation – charges all over firing randomly
○ Nerve Supply to the Heart
Sympathetic System
Excitatory – can raise heart rate to 230 bpm
↑ BP, ↑HR, Vasodilate the coronary arteries, ↑the force and speed of contraction (contractility) From upper thoracic spinal cord, through sympathetic chain to cardiac nerves
○ From cervical sympathetic trunk
○ From direct branches of sympathetic nerves from the thoracic trunk
○ Preganglionic level T1-T5, most ascend to synapse
Transmits ischemic pain and sensations to CNS
○ Nerves go to sympathetic trunk and get a little intermixed with left arm nerves - referred pain
Parasympathetic System
Inhibitory – can slow heart rate to 70-80 bpm
↓HR, ↓BP, Constrict the coronary arteries
Gets to heart via vagal nerve, specifically the right vagal nerve to the SA Node and the left vagal nerve to
the AV node
○ Vagus comes from both cervical branches and direct branches in thorax??
Sends visceral reflex activity to CNS via vagal nerve
○ aortic bodies – in wall of ascending aorta, monitors PCO2 and changes respiration rate
Cardiac Plexus
Has both sympathetic and parasympathetic contributions
Superficial Plexus – near aortic arch, receives input from
○ Parasympathetic - left inferior cervical branch of Vagus nerve (CN X)
○ Sympathetic - superior cervical sympathetic branches
Deep Plexus – near tracheal bifurcation receives input from all the rest
○ Parasympathetic – vagus nerve
○ Sympathetic – superior, middle and inferior (right) and middle and inferior (left)
○ Cardiac Blood Supply
Coronary Arteries
heart is fed during dyastole
Right Coronary Artery ○ Arises from right aortic sinus (behind semilunar valve).
Courses in atrioventricular (coronary) sulcus from the
aorta toward region of the posterior IV sulcus
○ Branches
Right marginal branch – feeds acute angle
Posterior interventricular branch (80%)
Sinoatrial branch - (55%)
Atrioventricular nodal branch - (85%) ??
Left Coronary Artery ○ Arises from left aortic sinus (behind semilunar valve).
Courses in the anterior IV sulcus where it divides.
○ SA node gets blood from right and left coronary arteries?
○ AV node gets blood from AV node artery (mainly right coronary artery)
Supply to Papillary Muscles
○ Left
Anterior - from LAD and circumflex
Posterior - only from posterior IV branch
○ Right
Anterior – LAD and right coronary artery
Posterior – posterior IV branch, right coronary artery, septal (from LAD)
Septal – from 1st, 2
nd, 3
rd septal arteries (from LAD)
Coronary Veins
Usually superficial to arteries
Anterior Interventricular vein - along course of LAD, feeds into →
Great Cardiac Vein – runs along left side of atrioventricular sulcus into →
Coronary Sinus – in posterior atrioventricular sulcus, much thicker and feeds directly into RA
Middle Cardiac Vein – feeds directly into coronary sinus from posterior IV sulcus area
Small Cardiac Vein – feeds directly into coronary sinus from
atrioventricular sulcus around right side
Myocardial O2 Supply and Demand
Supply – influenced by diastolic perfusion pressure, coronary vascular
resistance, O2 carrying capacity
Demand – responded to by wall tension, heart rate, contractility
Myocardial Infarction
Obstruction of each major coronary artery results in infarction of a
specific area of myocardium
Right Coronary Obstruction – inferior infarction, can involve posterior septum (30% of all cases)
Circumflex Artery Occlusion – lateral infarction (20% of all cases)
LAD Occlusion – anterior infarction artery of ‗sudden death‘ (50% of all cases)
Coronary artery bypass uses a vein but then after 10 years the vein will adopt properties of an artery
Determining Coronary Dominance
Crus Cordis – point where atrioventricular, interatrial and interventricular sulcus meet on anterior surface
Can be right dominant, balanced or left dominant
Dr. Gold says it is determined mainly by where SA node gets its blood supply from
Collateral Circulation
Network of tiny blood vessels, which under normal conditions are not open
Some collateral vessels may enlarge and become active when other coronary arteries narrow to the point that
blood flow to the heart is impeded.
Takes a while to become active
Cardiac Imaging ○ Objectives
None
○ Random Notes
Heart rotates to the left during development
Branches of LAD – diagonals
Branches of circumflex – marginals
Where artery of AV node comes from is what really determines dominance
RV papillary muscles have multiple connections to the interventricular septum
LV papillary muscles do not have multiple connections to the interventricular septum
LV is a little more smooth and does not have trabecular connections to the septa
If it did, then the fetus would die
Papillary muscles must contract before the ventricles
There is direct fibrous continuity between the aortic valve and mitral valve leaflets
Pulmonic valve is not part of the fibrous skeleton of the heart???
SA node is on the epicardial surface of the heart
Mitral Valve Prolapse – trabeculae become thinned and can cause the two valves to be misaligned
Echocardiograms
Echocardiograms look at heart upsidedown from the apex
Dots are 1 cm apart
The MHz of the echocardiogram need to be different depending on where you stick the probe
○ Transesophageal echocardiogram uses 7.5 MHz
In Doppler echocardiograms you can transform the velocity information into pressure info via P=4V2
Transesophageal Echo – has multiple potential views (trans-atrial, trans-gastric, epiaortic)
Pathology
Tumor on valves can break off tiny pieces and cause strokes and such
Aortic stenosis – can see because aorta doesn‘t move
Thickening of aorta – can see because of dots on the image
Contraindications – esophageal or pharyngeal problems, can‘t bend neck, pediatric size issues
Complications – hoarseness is actually a significant problem, etc.
If used during an operation it will often help and change the operation
Enhances preop diagnostic accuracy, well suited for evaluating great vessels, serves to guide volume &
contractility so medicines can be altered?, improves evaluation of operation, reduces morbidity and mortality of
cardiac surgery
Development of the Cardiovascular System ○ Objectives
Compare and contrast vasculogenesis and angiogenesis. List/describe the derivatives of the aortic arches. Diagram the sequential changes that lead tthe development of the definitive aortic arch and its branches. Describe the development errors that result in aortic arch abnormalities. Describe the developmental relationships of the recurrent laryngeal nerves.
Define and describe: cardinal veins (anterior, posterior, common), subcardinal veins, supracardinal veins. Describe the formation of the left brachiocephalic vein, and the ductus arteriosus Describe the development errors that result in venous system abnormalities.
○ Development of Blood and Blood Vessels
Blood Islands – develop in the mesodermal wall of yolk sac into vessels
Hemangioblasts help form primordial blood island
Hemocytoblasts – form blood inside blood islands
Angioblasts – endothelial cells that line the blood island to make a primitive vessel
Vasculogenesis – fusion of locally formed endothelial vesicles (tubelike free-floating vesicles made out of
angioblasts) to form extensions of blood vessels
A developmental process
Angiogenesis – outgrowth or branching of preformed vessels
Happens throughout life
In early embryo there are no blood vessels, then the extraembryonic vascular channels develop, then the
intraembryonic vascular network develops
Differentiation process - Vascular networks develop into vessels and which type of vessel is made is
determined by the amount of pressure it is exposed to?
Development of Veins – the embryo‘s venous system develops out of a very irregular network of capillaries
○ Thus the venous system is not very uniform and there are more variants in venous than arterial system
vascular wall (angiopoietin), differentiation into artery (mesenchyme migrates and TGF-β helps out)
○ Development of Circulatory System
Primordial Heart
Aortic Sac – has aortic arches sprouting off of it, primitive arterial circulation
○ Helps give rise to the arterial system (see below)
Sinus venosus – primitive atrium, has three veins
sprouting off of it, primitive venous circulation
○ Cardinal Veins – form the basis for the
intraembryonic venous circulatory system
anterior cardinal veins (superior) – drain blood
from the head via the left & right common
cardinal vein
posterior cardinal veins (inferior) – drain blood
from the lower half of the body into the two
common cardinal veins
During development of this system vessels
dissolve and reappear to form the final result,
the details aren‘t important
Superior vena cava formed by cardinal system
○ Umbilical System – bring nutrient and oxygen rich
blood from the placental villi via the umbilical cord
to the embryo
Is an unpaired umbilical vein
Connected to two intraembryonic umbilical veins
The umbilical veins become included
in the developing liver
Development
○ Note that the right umbilical vein disappears and that a connection between the sinus venosus and the
left umbilical vein develops through the liver and this is called the ductus venosus
The ductus venosus allows embryo to control the pressure of blood coming in from maternal area
○ Omphalomesenteric (Vitelline) System – for yolk sac
Closely associated with development of duodenum and liver
○ Portal vein, superior mesenteric vein and splenic vein all form from vitelline
Drains the blood of the umbilical vesicle
Pulmonary Veins – not associated with any of the three
systems because they develop independently
○ Don‘t really know how they develop
Aterial System
○ Ventral Aorta – sprouts off the aortic arches
○ Heart starts turning
○ Heart starts forming in the neck, then the neck grows (or
the heart moves down??) and attachments stretch
○ Aortic Arches
Within each arch there is an artery, a nerve, and
cartilage
Organized similar to aquatic vertebrates
Right and left dorsal aorta becomes single dorsal aorta
Appear and disappear in a cranial → caudal fashion
Derivatives of Aortic Arches
○ Note - 1,2 and 3 are all related to the head
Original 'Arch' End Structure
1 Most regresses, the rest forms maxillary artery
2 Most regresses, the rest forms stapedial artery
3 Forms common and internal carotid arteries
Right 4
Left 4
Forms proximal right subclavian artery
Forms arch of aorta
5 Never develops
Right 6
Left 6
Forms part of right pulmonary artery
Forms part of left pulmonary artery and ductus arteriousus
Not real arches
Right 7th
segmental artery
Left 7th
segmental artery
Forms part of the right subclavian artery
Forms entire left subclavian artery
Right Dorsal Aorta
Left Dorsal Aorta
Regresses forms the middle of the right subclavian artery
Forms descending thoracic aorta
Aortic Sac Forms ascending aorta and the brachiocephalic artery
○ Ductus Arteriosus – communication from pulmonary trunk to aortic arch
Blood sent to aortic arch instead of lungs before birth since lungs aren‘t needed then
Neural Crest Cells – help form aortic arches and heart
○ DiGeorge Syndrome – genetic problem that causes neural crest cells to be messed up and results in a
bunch of abnormalities in different systems
Note – arterial system develops in lots of places simultaneously then hooks up to stuff resulting from
aortic arches??
○ Aortic Arch Anomalies
Right Aortic Arch
○ Results from
obliteration of the left 4th branchial arch artery
regression of the left dorsal aorta
○ Aortic arch instead is constructed from equivalent vessels on the right side
○ To reach aortic arch, the ductus venosus must go around the esophagus and
can cause constriction
Double Aortic Arch
○ Two arches surrounding the esophagus and trachea
forming a vascular ring
○ Can cause dysphasia and respiratory distress
○ Results from - a failure of regression of the section of right dorsal aorta between the 7th intersegmental
artery and the junction of the left dorsal aorta
Interrupted Aortic Arch
○ Results from - the obliteration of the left 4th brachial arch artery
The proximal part of the aortic arch still forms the three branches, but after
that it stops
○ The ductus arteriosus persists and becomes greatly dilated, but doesn‘t help
anything because it is connected to pulmonary trunk
Right Subclavian Artery Anomaly
○ Results from regression of the right 4th
branchial arch artery
○ Causes the right subclavian artery to arise from aortic arch distal to the left subclavian
artery
Right subclavian then goes behind esophagus and trachea to produce a vascular ring
○ Recurrent Laryngeal Nerve
Branch of the vagus nerve that supplies motor function and sensation to the larynx
Arises from the 4th and 6
th aortic arches??
During development the right and left laryngeal nerves go down and wrap around the blood vessels in the
6th arch
○ Then the right 6th arch disappears and the only thing the right laryngeal wraps around is right
subclavian artery, while the left still wraps around the aortic arch
Circulatory System ○ Objectives
Identify the twmajor components of the circulatory system and their functions. Identify the components of the cardiovascular and lymphatic systems and integrate the structure with the function of each component.
Describe the three layers of blood vessels and integrate their structural components tspecific functions. (Tunica intima, media, & adventitia) Compare and contrast the structural and functional differences between the various types of vessels, arterial and venous as well as microcirculation. Integrate the structure of the three types of capillaries with their functional capacities and locations. Integrate the structural components of an arteriovenous anastomosis and the microcirculatory bed ttheir functions. Relate the microscope structure of the heart tits gross anatomy. Identify and describe the layers of the pericardial sac and heart wall. Be able trelate them tthe function of the heart. Describe the structural components and functions of the cardiac skeleton. Describe the structural components cardiac conduction system and relate them ttheir function.
Locate and describe the function of the carotid sinus and aortic bodies. Integrate the lymphatic system circulation intthe cardiovascular system both structurally and functionally. Relate how the following diseases affect the cardiovascular system: varicose veins, Marfan's syndrome, Ehler-Danlos syndrome, atherosclerosis, &
aneurysm.
○ Circulatory System
Closed system
Heart
Basic Anatomy
○ Cardiac muscle lined by endothelium
○ Has endocardium, myocardium and epicardium
○ Pericardial Sac
Fibrous Pericardium – outer wall, fibroelastic CT
Parietal Serous Pericardium – inner portion of pericardium
○ Instead of tunica media there are occasional pericytes
○ Greatest concentration in myocardium
○ Capillaries also make and excrete stuff
○ Best way to distinguish subtypes is by which tissue they are in
○ Types
Continuous Capillary – basal lamina is continuous with no pores or fenestrations
Found in muscle, CT and gut
Fenestrated Capillary – basal lamina is continuous but the endothelial cells have fenestrations
(holes through the cytoplasm)
Found in endocrine glands, intestinal villi, exocrine pancreas
Discontinuous Capillary (Sinusoids) – basal lamina is discontinuous (does not cross gaps
between cells)
Large gaps between cells (allows easy transport), irregular shape
Found in spleen, liver, bone marrow, lymph nodes
○ Methods of transport across epithelium
Diffusion
Transcytosis – pinocytotic vesicles form, are non-selective
Receptor-mediated transport – also into vesicles, is selective
Direct channels from fused vesicles
○ Secretions of Capillary Endothelial Cells
Help form basal lamina (secretes stuff for that)
Produces signals for extravasation and diapedesis (p-selectin, PAF, CAMs)
Releases substances that affect vascular tone
Vasoconstrictors – endothelin I
Vasodilators – nitrous oxide, etc.
Produces clotting factors
Von Willebrand Factor – a glycoprotein used in coagulation of platelets
Von Willebrand’s Disease – lack of the factor, genetic, prolonged coagulation
○ Lymphatic System
Function – removes excess interstitial fluid from extracellular space, filters it then returns it to cardiovascular
Second system of circulatory system
Ducts
Thoracic duct collects lower and left part of body
○ Cisterna chyli – beginning of thoracic duct, starting at diaphragm
○ Drains into left subclavian vein merging with left internal jugular vein
Right lymphatic duct – drains right, upper quarter of body
○ Drains into right subclavian vein
Vessels start as blind ended lymphatic capillaries → Drain into larger vessels with valves → into lymph nodes →
return to blood vascular system
Can differentiate from blood vessels because
○ No blood in lumen
○ Incomplete basal lamina
○ Thin wall and anchoring filaments (may be visible)
Cardiac Development
○ Objectives Define and describe endocardial tube, myoepicardial mantle and derivatives, cardiac jelly, endocardial cushions. Describe formation of the mesodermal germ layer, cardiogenic plate and embryonic foldings. Describe early development of the primitive heart tube. Describe and discuss the relationship between sinus venosus, primitive atrium, primitive ventricle, bulbus cordis, and truncus arteriosus.
Define aortic sac and explain its relationship tthe truncus arteriosus and aortic arches. Explain the process of looping of the heart. Describe partitioning of the atrioventricular canal, primordial atrium and ventricle. Describe partitioning of the bulbus cordis and truncus arteriosus. Describe development of the cardiac valves and conducting system of the heart. Describe the normal fetus blood circulation and the changes that occur when a newborn switches from fetal tadult-type blood circulation.
○ Basic Steps of Cardiogenesis
Bilateral Heart Primordia
Primitive Heart Tube
Heart Looping
Atrial and Ventricular Septation
Outflow Tract Septation – this part requires neural crest cells, all others only require splanchnic mesoderm (which
Compare the structural differences between the somatic and the autonomic components of the peripheral nervous system. Compare the sympathetic and parasympathetic divisions of the ANS. How are these twsimilar? How are they different? Be able tdiagram a ―typical‖ visceral efferent path for both the sympathetic and parasympathetic division of the ANS. List four possible terminations for the preganglionic sympathetic fiber. What is a pelvic splanchnic nerve? Describe the course and termination for a pelvic splanchnic.
○ Somatic parts of the CNS are derived from somites
○ Somatic afferent – receives information
○ Somatic efferent – sends information
○ Autonomic Nervous System – controls activity of involuntary muscle (smooth muscle, cardiac muscle, glands)
Also called visceral or splanchnic
Visceral afferent – sensory, receives information from organs
Same pathway, but travels in an interganglionic segment and does not synapse in a paravertebral ganglia until
it travels to the vertebrae that it will exit from
T1-T4 ascend, T11-L2 descend
This means that white rami are only associated with T1-L2 (14), while grey rami are associated with every
vertebral level
○ Paravertebral Ganglia
There are only 22 of them
Cervical Ganglia – superior, middle and inferior
Thoracic, lumbar and sacral ganglia
○ In the sacral ganglia, there is the ganglion impar which is where the two sympathetic chains meet
○ Getting from Paravertebral Ganglia to the Effectors
Thoracic Viscera – Comes from T1-T4
○ Splanchnic nerve comes directly from paravertebral ganglion (where a synapse occurs) to effector
Abdominal and Pelvic Viscera – comes from T5-L2
○ Splanchnic nerve comes from paravertebral ganglion, but does not synapse there. Instead it synapses in a
prevertebral ganglia located near the abdominal portion of the aorta
○ After the prevertebral ganglia the nerve travels with blood vessels to the effector
Adrenal Medulla ○ Goes through both the paravertebral ganglia and the prevertebral ganglia and does not synapse there,
instead it synapses in the adrenal medulla
○ This makes sense because the adrenal medulla is neurosecretory and secretes norepinephrine, just like a
postganglionic sympathetic neuron and creates a systemic sympathetic response
○ Splanchnic Nerve – portion of ANS between the paravertebral ganglion and the prevertebral ganglion or the
effector
Parasympathetic Division
○ CN X uses terminal ganglia on organs of thorax and upper abdomen
Travels directly from brain to terminal ganglia
○ Lateral Horn S2-S4 uses terminal ganglia on organs of lower abdomen and pelvis
Travels through ventral ramus via pelvic splanchnic nerve to terminal ganglia
○ Terminal Ganglia – either in or on the wall of the organ
If used, this is where the postganglionic nerve starts
Remember that sympathetics also go through the dorsal and ventral rami to innervate the skin
Lymphatic System ○ Objectives
Be able tidentify the tissues and cells of the lymphoid system. Know the functions of the various cells of the lymphoid system. Be able ttrace cells of the lymphoid system within the body. Know the functions of the tissues of the lymphoid system. Be able tdistinguish cellular from humoral immunity. Be able tdescribe basic immune responses. Compare and contrast structure-function relationships between the lymphoid organs.
Natural Killer Cells (10-15%) – kill things and do not need specific activation
T-Cells (65-75%) – cell mediated response
○ Subtypes
Helper T-Cells – identified by CD4, makes B-cells and cytotoxic T cells active
○ Destroyed by AIDS
Supressor T Cells – don‘t memorize
Cytotoxic T Cells – identified by CD8, kills stuff
B-Cells (5-10%)
○ Type for each antigen
○ Expresses IgM on surface – a receptor used to identify an antigen
○ When activated they become plasma cells (which make the antibodies)
Maturation of T and B Cells
Both come from stem cells in the bone marrow, but T-cells mature in the thymus (this is where they get their
surface proteins (CD4 and CD8))
○ Encapsulated Lymphatic Structures
Surrounded by CT
Stroma – framework of tissue made of reticular connective tissue
Parenchyma – cells exist in spaces between reticular fibers (lymphocyes, macrophages, plasma cells, etc)
Thymus
Bi-lobed organ in thymus that becomes fatty with age (but not completely useless)
Here T-Cells become immunocompetent, express surface proteins, recognize self from non-self, proliferate
Gets rid of T-cells that recognize self
Capsule and trabeculae divide it into lobules containing cortex and medulla
○ Cortex – tightly packed lymphocytes and macrophages, more dense than medulla, where self-recognizing
T-cells are killed
Is isolated from body
Type I Epithelial Reticular Cells (ERC) – isolate cortex from body
Type II ERC – divide cortex into lymphocyte-filled pockets; forms most of cortex
Type III ERC – isolates cortex from medulla
Type II and III ERC are antigen presenting cells?
○ Medulla – less tightly packed, only T-cells that don‘t recognize self get through and are eventually released
from here
Type IV ERC – isolates cortex from medulla on medullary side
Type V ERC – forms most of medulla
Type VI ERC – unknown function, big cells
Tolerance
○ Tolerance – ability to recognize self from non-self, established in the Thymus
○ Occurs via anergy (disabling) or via killing immunocompetent cells (which occurs in cortex of thymus)
○ Requires that immune cells recognize MHC and don’t recognize self-peptides
1. MHC Recognition (must occur)
○ Antigen presenting cells display MHC
CD4 cells recognize MHC-II
CD8 cells recognize MHC-I
If they can‘t then they are killed
2. Self-Recognition (must not occur)
○ Antigen presenting cells display self antigen → if T-Cell Receptor binds to self-peptide then it is
killed
Lymph Nodes
Only structures that filters lymph
Concentrated near mammary glands, axilla, groin, midline and neck
Stroma (capsule) made of trabeculae & reticular fibers
Parenchyma consists of cortex and medulla
○ Cortex
Outer Cortex - B-Cell Domain
○ Has nodules containing active B-cells (plasma cells) called germinal centers
Inner Cortex - T-Cell Domain/paracortex
High endothelial venules – specialized capillaries for the lymph nodes
○ Lymphocytes enter lymph node through these
Follow the Lymph Flow
○ Lymph enters through afferent lymph vessels → goes through subcapsular sinus → to medullary sinus →
exits through efferent lymph vessel
○ During this course it leaves the sinuses and gets filtered by cells in the lymph node (esp. cortex)
Spleen
Filters all of the blood to:
○ Remove old blood cells
○ Mount an immune response in the blood
Note – lymph does not enter spleen
Between stomach and diaphragm
Stroma made of capsule, trabeculae, fibers, fibroblasts
Parenchyma made of white pulp and red pulp
○ White Pulp – lymphatic tissue containing lymphcytes and macrophages around branches of splenic artery
Peri-arteriolar lymphatic sheath (PALS) - T-cell domain, a bunch of T-cells that surround central
arteries in the spleen
Marginal Zone Sinuses - B-cell domain, peripheral to the PALS, here B-cells form germinal centers
○ Red Pulp – splenic cords and meshwork of venous sinuses filled with blood
Near end of central artery penicillar arterioles branch off into either closed circulation (where the
arteriole ends in a sinusoid) or open circulation (where the arteriole just spits out blood)
○ Either way the blood passes through a sheath (a ring of macrophages that eats old RBCs) before
Follow the Blood
○ Trabecular artery → central artery → passes through white pulp → ends in red pulp
○ Diffuse Lymphoid Tissue – Lymph Nodes
Concentrations of lymphatic tissue not surrounded by a capsule scattered throughout CT and mucus membranes
Mucosa Associated Lymphoid Tissue (MALT) – for antigen presentation and phagocytosis
○ In gastrointestinal tract (GALT) – trachea, tonsils, Peyer‘s patch (in lumen of GI), appendix
Peyer’s Patch – one of the only MALTs with a definitive structure and T & B cell domains
○ Antigen presenting cell (M Cell) on gut lumen can move into Peyer‘s patch and help mount immune
response
○ In bronchus (BALT)
○ Lymph Circulation
Lymph flows in closed-ended tubes
There are no lymph pump or lymph-associated muscles. Lymph propelled in vessels by surrounding skeletal
muscle
Empties into subclavian veins (only direct connection of lymph to blood)
Cross-Sections Thoracic Imaging ○ Objectives
Identify Structures
○ Heart Shadow – can‘t see RV or LA
Can see superior vena cava, aortic knob
○ Cross Sections – it is like you are looking at the patient from their feet while they are laying down,
Thus right is on the left side of the image
○ T3 – Right brachiocephalic, Left brachiocephalic, Brachiocephalic trunk, left common carotid, left subclavian,
esophagus, trachea
○ T4-T5 – Superior vena cava, aortic arch, arch of azygos, trachea begins to bifurcate, esophagus
○ T5-T6 – Superior vena cava, ascending aorta, pulmonary trunk, right and left pulmonary arteries, right and left main
bronchus, esophagus, azygos, descending aorta
○ T6 – superior vena cava, right auricle/atrium, right ventricle, aorta, left atrium, esophagus, azygos, descending aorta
This one is tricky
○ T7-T8 – right atrium, right ventricle, beginning of ascending aorta, IV septum, interatrial septum, left atrium, a piece
of the mitral valve, wall of left ventricle, esophagus, azygos, descending aorta
○ T8-T9 – right dome of the diaphragm, liver, RA, tricuspid, RV, IV septum, LV, coronary sinus!, azygos, descending
aorta
Congential Heart Defects ○ Objectives
List the most commonly encountered congenital cardiac malformations. Classify the congenital cardiac malformations according tstructural anomalies.
Describe the development errors that take place in the heart resulting in left-to-right shunt. Describe the development errors that take place in the heart resulting in right-to-left shunt. Describe the development errors that take place in the heart causing anomalies of the outflow tract. Describe and compare the clinical consequences of:
Patent Ductus Arteriosus
Coarctation of Aorta
Transposition of Great Arteries
Atrial Septal Defect
Ventricular Septal Defect
Tetralogy of Fallot
Persistent Truncus Arteriosus
○ Congentical heart defects don‘t have to result in alteration of heart function
○ Caused by genes, environmental factors, maternal ingestion of toxins, viruses (Rubella)
○ Ventricular septal defect is the most common one
○ Cyanosis – when circulating blood has a lot of reduced hemoglobin
○ Starling law? – if excess pressure in one chamber of the heart then eventually all will get higher pressure
If constriction ahead then you will have hypertrophy behind
If leaky valve ahead then you will have dilation behind?
○ Abbott Classification
Acyanotic – does not have an abnormal communication between the 2 circulations
Cyanotic – permanent R→L shunt (deoxygenated blood gets into body circulation)
Cyanotic Tardive – initial L→R shunt with late reversal of flow to R→L
Only Tetralogy of Fallot
○ Shunt Classification
Initial L→R Shunt – VSD, ASD, PDA, PTA
R→L Shunt – Tetralogy of Fallot
No Shunt – TGV, CoA (sometimes)
Note – pure TGV is incompatible with life, only another defect will save them
○ Ventricular Septal Defect Most common congenital heart defect
Types
Membranous VSD – most common, membranous septum doesn‘t fully form
Muscular VSD – part of muscular septum disappears
Symptoms
Small VSD – may remain asymptomatic
Larve VSD – can develop congestive heart failure due to left heart volume overload
Holosystolic mumur
The lungs are the main problem because too much blood goes to RV and it is sent to the lungs
L→R shunt causes too much blood in lungs, but no cyanosis
X-Rays
Enlarged pulmonary vessels
LA so large you can see it in heart shadow
Pulmonary trunk visible in heart shadow
○ Atrial Septal Defect Types
Ostium secundum defect - excessive resorption around the foramen segundum
Ostium primum defect – ostium primum doesn‘t close
Sinus Venosus defect – blood goes through ostium primum and segundum at top
Can also be caused by hypoplastic (too little) growth of the septum segundum?
More common in females
Symptoms
Most infants are asymptomatic, often detected as murmur at school age
Adults can develop palpitations. This is because part of conduction system is in
interatrial septum and it is missing
L→R shunt causes too much blood in lungs, but no cyanosis
X-Rays
Heart shadow shows large pulmonary trunk and small aortic notch
Pulmonary arteries can get big too
○ Patent Ductus Arteriosus Can be life-threatening or life-saving
More common in females
Higher risk – premature infants, maternal rubella
Symptoms
If small – asymptomatic
If large – gets symptoms of congestive heart failure
○ Cyanosis of the feet
○ no cyanosis in upper extremities
Continuous murmur
L→R shunt that causes cyanosis in lower extremities
X-Ray – can have hypoplasia of the aorta
How Ductus Arteriosus Closes
Fetal Circulation – prostaglandins and low O2 keep ductus arteriosus open
Neonatal Circulation – high O2 prompts bradykinin to be released and this constricts ductus arteriosus
If ductus is only thing keeping baby alive then give prostaglandins to keep it open
If ductus doesn‘t close when it should then give indomethicin (a prostaglandin
antagonist)
○ Coarctation of the Aorta Hypertension in the upper body
Blood flow to lower extremities may be diminished
Types
Preductal Coarctation ○ If ductus arteriosus closes then congestive heart failure shortly after birth
○ If ductus arteriosus remains open
Shunt is R→L
Upper half of body will be perfused with oxygen
○ Will have high pressure here
Lower half of body will be cyanotic (because it will get must of its blood from pulmonary trunk via
ductus arteriosus
○ Will have low pressure here
Postductal Coarctation
○ If small then not much problem
○ If big then newborn will develop congestive heart failure from pressure overload and die
○ If ductus arteriosus closes then no cyanosis
No shunt
Upper half of body will have high pressure and left internal thoracic will enlarge, intercostal arteries will
cause rib notching because they get bigger and beat away at the bones
○ If ductus arteriosus remains open then:
L→R shunt
??
Causes
Preductal – anomaly resulting in hypoplastic development of aorta
Postductal – muscular ductal tissue gets into aorta during fetal life, when ductus closes, so does that part of
aorta
○ Tetralogy of Fallot Rightward displacement of the infundibular septum (pulmonary exit) resulting in
unequal division of pulmonary and aortic outflow
For anatomical anomalies
Ventricular septal defect due to septum misalignment
Subvalvular pulmonic stenosis because of obstruction of the conus arteriosus (path
from RV to pulmonary artery)
○ Makes the shunt R→L
Aorta is moved to the right so that it receives blood from both ventricles
Acquired anomaly - Right ventricular hypertrophy due to high pressure load of
pulmonic stenosis
Symptoms
Dyspnea or ‗spells‘ (getting cyanotic) on exertion (crying, feeding, etc)
Convulsions due to cerebral hypoxemia
Often a little cyanotic
Systolic murmur
Cyanosis can be alleviated by ‗squatting‘
○ Venous system → trap blood in legs → ↓ blood return to RA → ↓ blood to RV → ↓ deoxy blood to R→