SF3 1 General Flashcards
Tract of Thorel
Another name for Inferior Internodal Tract
Heat Stroke
Develops when body temperature rises beyond 105-108 F
Symptoms:
- Dizziness
- Abdominal distress
- Vomiting
- Delirium
- Loss of consciousness
- Circulatory shock (loss of fluids/electrolytes)
Mechanical connections between cardiac muscle cells
keep cells together during contraction. Have adherens junctions and desmosomes
Endothelial-derived Hyperpolarizing Factor (EDHF)
Vasodilator
Hyperpolarize smooth muscle, leading to relaxation
Mean Systemic Filling Pressure (PSF)
Equalized pressure throughout cardiovascular system if heart was hypothetically stopped. Dependent on Blood Volume and Vascular Compliance
(ECG) Hyperkalemia
Abnormality of Myocyte Repolarization.
- Tall, peaked T wave
Phases of Cardiac Cycle associated with Ventricular Diastole
Phase 5-7, 1
Foramen Secundum defect
(Atrial Septal Defect - ASD) Most common ASD. Large opening between the Right and Left Atria, as a result of…
1) Excessive resorption of Septum Primum OR
2) Insufficient development of Septum Secundum
Blood flows from L to R Atrium due to increase blood pressure in left atrium
Parasympathetics effect on Lungs
1) constrict respiratory passageways
2) vasodilation
3) increase mucous secretion
Left Coronary Artery
Origin is Aortic Sinus of Left Cusp of Aortic Valve.
Supplies:
1) Most of L Atrium
2) L Ventricle
3) Anterior 2/3 of Interventricular Septum
4) Atrioventricular Bundles
Pulse Pressure
Difference between systolic and diastolic pressure
PP = PS - PD = SV / C
Locations of Turbulent Flow
1) Distal to stenotic vessels/valves
2) Large arterial branch points
3) Ascending Aorta at high cardiac ejection velocities
Foramen Primum
Temporary space between free edge of growing septum primum and AV septum
Location of SA Node
In the wall of the Right Atrium, in superior part of Crista Terminalis
(Fast Response Action Potential Receptors) Phase 2
Calcium influx through L-type calcium channel. Some potassium efflux through slow delayed rectifier channel
“plateaued”
Branches of Aortic Arch (Right to Left)
1) Brachiocephalic Trunk (largest)
2) Left Common Carotid Artery
3) Left Subclavian Artery
Area where systolic blood restriction in Coronary Arteries is most pronounced
Left ventricle (higher contractility)
Limbus
thick upper margin of the Fossa Ovalis
Second Heart Sound (S2)
Closure of Semilunar Valves at end of Ventricular Systole.
Aortic Valve precedes Pulmonic valve. Sound combined into 1 during expiration. separates in inspiration “Physiological splitting of S2”.
(Cardiac Cycle) Phase 7: Reduced Filling (Diastasis)
Rate of passive fillings slows and plateaus. Ventricles become less compliant as they fill. Increase in ventricular volume causes a small and gradual increase in pressure.
Aortic/Pulmonary pressure drops as blood circulates
External Intercostal Muscle
Extends posterior from tubercle of rib to junction of rib with its costal cartilage. Moves rib superiorly (most active during inspiration)
Greater Splanchnic Nerves
Arise from 5-9/10 thoracic ganglia. Descend across vertebral bodies medially. Pass into abdomen through Crus of the Diaphragm.
End in Celiac Ganglion
Location of Cell Bodies of Parasympathetic Fibers affecting Heart
Dorsal Vagal Nucleus and Nucleus Ambiguus (medulla)
Cardiopulmonary Changes at Birth
1) Opening of pulmonary circulation
2) Closure of placental circulation
3) closure of ductus venosus
4) foramen ovale closes
5) closure of ductus arteriosus
Artery coursing with Phrenic Nerve to supply pericardium and diaphragm
Pericardiophrenic Artery (and accompanying vein)
Hydrothorax
Excessive serous fluid (Pleura). Result of cardiac failure and congestion of lungs.
Crista Terminalis
Vertical ridge dividing right atrium into two
Causes activation of Ryanodine Receptor (RYR)
Increase in intracellular Ca2+
Coronary Artery Bypass Graft
Occluded artery is replaced by a vein (usually Great Saphenous Vein). Grafted from Aorta to part of coronary artery not occluded.
Internal Thoracic Artery can be used to supply heart too. Stripped off Anterior Thoracic Wall but still attached to Subclavian Artery. Attach to non-occluded pt of artery
Meaning of QRS Complex
Ventricular depolarization
Joint between Sternal Body and Manubrium
Symphysis joint, allowing for little movement
σ = 0
Capillary freely permeable
Channel releasing Ca2+ from SR in smooth muscle
Inositol 1,4-5-Triphosphate Channel
Right Para-Tracheal Stripe
Thin white stripe at the right edge of the trachea. Created by air of low density on either side of the tracheal wall. Normally < 3mm thick, any thicker may be mass or enlarged lymph node.
Right side not well defined
Form Definitive Right Subclavian Artery
1) Right Aortic Arch 4
2) Right Dorsal Aorta
3) Right 7th Intersegmental Artery
Fenestrated Capillaries
Perforations in the endothelium. Found in: exocrine glands, renal glomeruli, and intestinal mucosa
Capillary Plasma Oncotic Pressure (πc)
Determined by proteins in capillary. Albumin generates about 70% of it. Rest is globulins and fibrinogen
Left Ventricle is lined by Trabeculae Carnae except..
Smooth-walled Aortic Vestibule under Aortic Orifice
Factors Affecting Afterload
1) Vascular Resistance to Blood Flow (small arteries/arterioles major source)
2) Decreased compliance of ventricles/great vessels
3) Pathological issues (ex: valvular stenosis)
4) drugs
Cycloxygenase Inhibitors
Include Aspirin and others.
Reduce fever by inhibiting Prostaglanding synthesis
Primary Neural Regulatory Areas of Cardiovascular Function
Reticular Formation of Ventrolateral Medulla and Lower Third of the Pons
Polycythemia
Elevated hematocrit
ABCDEF System
- Airway
- Bones and Soft Tissue
- Cardiac and Mediastinum
- Diaphragm
- Effusions
- Fields (Lungs)
Small Cardiac Vein
Tributary of Coronary Sinus. Right anterior-inferior margin of right ventricle.
Drains area supplied by Marginal Artery
Aortic Arches that degenerate
1, 2, and 5
Exception: 1 forms part of maxillary, 2 part of stapedial artery
Sensory fibers of heart (where do they enter CNS)
Enter spinal cord at T1-T4 on left side
Afterload
Resistance that ventricle must overcome to eject blood into vasculature.
Structures at level of Sternal Angle (7)
1) Costal Cartilage of Rib 2
2) Intervertebral Disc between T4-T5
3) Line between Superior and Inferior Mediastina
4) Superior extent of fibrous pericardium
5) Trachea division into Main Bronchi
6) Azygous Vein -> Superior Vena Cava
7) Bifurcation of Pulmonary Trunk into Right/Left Pulmonary Arteries
Anteroapical Myocardial Infarction (Leads and Typical Artery)
Leads V3-V5
Left Anterior Descending Coronary Artery (distal)
Electrical connections between cardiac muscle cells
Allow action potential propagation via gap junctions
β2-adrenoreceptors
Cause vasodilation of vessels
Brugada Syndrome
Characterized by right bundle branch block (RBBB) and ST segment elevation in right precordial leads. Majority fast sodium channel loss-of-function mutations.
Xiphoid Process
most inferior portion of sternum; first cartilagenous then becomes ossified in adults
Conditions causing hypoeffective heart
1) Decreased contractility
2) inefficient pumping (valvular disease or septal defect)
3) Reduced filling (ex: pericardial effusion and cardiac tamponade)
4) Increased afterload (ex: hypertension)
5) Cardiac Hypoxia
6) Abnormal heart rhythm
Subcostal Muscles
Fibers in same direction as Internal/Innermost Intercostal muscles. Span 1-2 intercostal spaces. More numerous in lower posterior thoracic wall
Structures Visible in Aortopulmonary Window Level
1) Aortopulmonary window
2) Ascending Aorta
3) Descending Aorta
4) Superior Vena Cava
5) (possibly) uppermost aspect of the L Pulmonary Artery
6) Trachea bifurcation
Tetralogy of Fallot
Four Defects (Mnemonic: “IHOP”)
1) Interventricular Septal Defect
2) Hypertrophy of R Ventricle (increased pressure on right)
3) Over-Riding Aorta (Large aorta arising above septal defect)
4) Pulmonary Stenosis
Result of unequal division of Bulbus Cordis by Aorticopulmonary Septum.
Presents with Cyanosis
Sustained Muscle Contraction (Skeletal Muscle Perfusion)
Mean flow decreases during this period. Afterwards, postcontraction hyperemic response
(ECG) Left Ventricular Hypertrophy
- Leads overlying L Ventricle (V5, V6, I, and aVL) show taller R waves
- Leads on other side (V1, V2) show deeper S waves than normal
Middle Cardiac Vein
Tributary of Coronary Sinus. In posterior part of Interventricular Sulcus.
Drains areas supplied by Posterior Interventricular Artery
(ECG) Junctional Escape Rhythm
Arise form AV Node or Proximal Bundle of His
- Normal QRS
- No P wave
- rate of 40-60 bpm
First Heart Sound (S1)
From closure of the AV valves. Mitral valve closes before tricuspid but it’s too quick to distinguish.
Persistent Truncus Arteriosus
Failure of development of Bulbar/Truncal Ridges. Presents as single arterial trunk giving rise to both Pulmonary Trunk and Ascending Aorta.
Usually accompanied by defect in IV Septum. No bulbar ridges to fuse with AV Septum.
Infant presents with Cyanosis
Native Pacemaker
SA Node. 60-100 bpm at rest
Starling Forces Governing Fluid Filtration/Reabsorption
1) Capillary Pressure (Pc)
2) Interstitial Fluid Pressure (Pi)
3) Capillary Plasma Colloid Osmotic Pressure (πc)
4) Interstitial Fluid Colloid Osmotic Pressure (πi)
Hemothorax
Blood in pleural cavity
(ECG) Second Degree AV Conduction System Block, Mobitz Type II
- Sudden, intermittent loss of AV conduction
- Block may persist for two or more beats
- Caused by conduction block BEYOND AV node (His/Purkinje)
- QRS often widened
- Indicates severe disease
Calculating Mean QRS Axis
1) If Lead I/II predominantly upright, you’re gucci. If not..
2) Inspect 6 LIMB LEADS for most isoelectric QRS. Mean axis is perpendicular to this lead
3) if perpendicular lead is primarily upward, it’s positive end. If downward, it’s the negative end
Common Atrium (Trilocular Biventriculare)
(Atrial Septal Defect - ASD) Total lack of development of Atrial Septum. Always alongside another serious heart defect
Fossa Ovalis
Thin-walled oval depression in posterior wall of right atrium. Successor of the Foramen Ovale in development.
Thick upper margin of fossa called Limbus
Postductal Coarctation of Aorta
Narrowing of the Aorta inferior to the entrance of the Ductus Arteriosus.
For blood to reach the structures supplied by the aorta inferior to narrowing, collateral (anastamoses) circulation develops at two locations:
1) Anterior Intercostal Branches of the Internal Thoracic Artery and the Posterior Intercostal Arteries of the Aorta
2) Superior Epigastric Artery and Inferior Epigastric Artery
Premature Closure of Foramen Ovale
(Atrial Septal Defect - ASD) Happens prenatally. Underdevelopment of the left side heart. Hypertrophy of right. Death shortly after birth
Components of Definitive Right Ventricle
1) Trabeculated Part (majority) - from Primitive Ventricle
2) Smooth Upper Part (Conus Arteriosus) drived from Bulbus Cordis
Anterior Mediastinum
Between the pericardium and sternum
Right Lymphatic Duct
Right side of root of neck. Drains into Right Brachiocephalic vein.
Receives:
1) Right Subclavian Lymph Trunk
2) Right Bronchomediastinal Lymph Trunk
3) Right Jugular Lymph Trunk
Drains:
1) Right side head/neck
2) right upper limb
3) right lung
4) skin of right thoracic wall
Reactive Hyperemia
Transient increase in organ blood flow after brief period of ischemia, usually produced by temporary arterial occlusion. During occlusion, tissue hypoxia and vasoactive metabolites dilate arterioles.
Currents of Injury Mechanism
Can produce deviation of ST segment. Believed to be caused by injured myocardial cells adjacent to infarct zone. Produce abnormal diastolic or systolic currents
Paired Lateral Splanchnic Arteries
form renal, suprarenal, and gonadal arteries
(ECG) Ventricular Escape Rhythm
Ventricles depolarized from distal point in conduction system
- Rate of 15-40 bpm
- Widened QRS complex
- No P Wave
- Have R’ second upward spike
Myogenic Regulatory Mechanism in small arteries/arterioles
Sudden expansion of vessel lumen leads to smooth muscle contraction. Reverse also true
Costodiaphragmatic Recess
Founds on both sides. Slit-like space of reflection of costal pleura onto diaphragmatic pleura. Lungs do not enter it with normal inspiration
Muscle layers where Intercostal Neurovascular Bundle found
In between Internal and Innermost Intercostal Muscle layers
Preganglionic Neuronal Bodies of Sympathetic Division (LocatioN)
Lateral horns of spinal gray matter T1-T12, L1-L3
False Ribs
Do not articulate with sternum. Ribs 8-12
(Cardiac Cycle) Phase 6: Rapid Filling
AV valve opens when pressure in relaxing ventricles falls below that of the atria. Rapid filling ensues because (a) venous return has filled Atrium and (b) AV valve resistance is very low.
Increase in ventricular volume.
Autoregulatory Range
Range of pressures over which vessel blood flow barely changes
Pulmonary Ligament
2 layers of pleura in contact with each other inferior to root of lung. No major structures in it.
Endothoracic Fascia
Separates parietal pleura from the ribs/intercostal muscles
Meaning of T Wave
Ventricular Repolarization
Left atrium entirely smooth-walled except..
Lining of Left Auricle (contains pectinate muscles)
Stimulates shivering
hypothalamus
Afterdepolarizations
First action potential leads to oscillations of membrane voltage
Normal response of Coronary Arteries to increase heart rate / metabolic consumption
Dilate. Vasodilator reserve becomes limited if they’re diseased however. This can lead to myocardial ischemia and anginal pain.
Radiological indication of Pneumothorax
Slight shift of the heart and mediastinum toward the left indicates a tension pneumothorax
(Jugular Venous Pulse Graph) X descent
downward component of an A Wave. Happens from pressure decline of atrial relaxation
Loss-of-Function Mutation
Results in reduced or abolished protein function
Myosin Isoform in Smooth Muscle
Slower ATPase activity than its counterpart in skeletal muscle
(Cardiac Cycle) Phase 1: Atrial Systole
Initialized by spread of depolarization in atrium. Causes transient rise in Left Atrial Pressure. At rest, contribution to ventricular filling only 10-15%. Greater contribution during strain (decreased interval from increased heart rate means less time for passive filling).
End of Atrial Systole coincides with end of Ventricular Diastole. End-Diastolic Volume (EDV).
Function of Transversus Thoracis
Depress costal cartilages
Hypertrophic Cardiomyopathy
One part of heart thicker than other parts. Most common monogenic cardiac disorder. Most cases genetic. It’s AUTOSOMAL DOMINANT.
Predominant mutations:
a) myosin heavy chain
b) myosin binding protein
Can result in myofibril disarray. Clinical symptoms range from asymptomatic to heart failure, exercise intolerance, and chest pain. Symptoms with aging due to loss of left ventricular function. Increased risk for sudden cardiac death because of arrhythmias.
Fibrous Skeleton of the Heart
Fibrous rings of connecting tissue.
On right-side, surrounds orifice of pulmonary trunk and R Atrioventricular orifice.
On left, orifice of ascending aorta and L Atrioventricular orifice
Methods to calculate Heart Rate from ECG
1) HR = 60/RR
2) “Count-Off” Method
3) Count # of complexes in 3 or 6 seconds
Ductus Venosus
Shunts placental blood directly to IVC
Lusitropy
Relaxation of myocardium
ST Segment
Isoelectric period and depolarized ventricles. End of S wave to beginning of T wave.
Dextrocardia
Heart located on right side of Thorax. Due to ventricle and bulbus cordis bending to wrong side. Relatively uncommon
Capillary-like vessels blood passes through in liver
Liver Sinusoids
Normal Duration of QT Interval
0.20-0.40 seconds
5-10 boxes
Anterior/Posterior Intercostal Arteries - which is larger
Posterior
(ECG) Ventricular Tachycardia
- Widened QRS complex (>0.12 s)
- Rate of 100-200 bpm (sometimes faster)
Two Types: Monomorphic and Polymorphic VT
Filtration Constant (Kf)
Permeability of capillary to fluid. Increased by histamine
Dromotropy
Conduction velocity
High Pulmonary Vasculature Resistance in Fetus
Only small amounts of Right Ventricular output enters pulmonary circulation. Lungs non-functional. Remainder crosses over to Descending Aorta in the Ductus Arteriosus
Caused by:
1) Collapsed Lung
2) Hypoxic Vasoconstriction
Bradykinin
Formed in the blood and tissue fluids of some organs. Released during tissue inflammation or similar physical/chemical effects. Role in blood flow regulation in skin and salivary and gastrointestinal glands.
Causes arteriolar dilation and increased capillary permeability.
Sources of blood drained through Azygous Vein
1) Right Thoracic Wall (Posterior Intercostal Veins)
2) Left Thoracic Wall (Hemiazygous/Accessory Hemiazygous Veins)
3) Esophagus (Esophageal Veins), Lung Tissue (Bronchial Veins), and Vetrebral Column (Vertebral Venous Plexus)
Coursing of Left Anterior Fascicle
Runs through Anterior, Superior, and Lateral Left Ventricle
Destination of Excitatory Interneurons from Nucleus Tractus Solitarus
Vagal Neurons in Dorsal Vagal Nucleus and Nucleus Ambiguus
Myocardium formation in development
Forms from Splanchnic mesoderm surrounding the single heart tube
Fick’s First Law of Diffusion
Js= (D)(A)(ΔC) / (ΔX)
Js: Flux (mol/s) D: Diffusion const. of barrier (substance-dependent) A: Surface Area ΔC: concentration gradient ΔX: diffusion distance
Lesser Splanchnic Nerves
Arise from 9/10 or 10/11 Thoracic Ganglia. End in Aorticorenal Ganglion
Continuous with Superior Mediastinum
Inferior Mediastinum
Pericardial Cavity
Potential space between serious parietal and visceral pericardia.
Vasodilatory Theory
Local regulatory theory.
Greater metabolic function leads to formation of vasodilatory substances. Blood flow increases to area of increased metabolism.
Firing Rate of Cells of Purkinje System
30-40 bpm
Capillary Recruitment
Increased recruitment of perfused capillaries during skeletal muscle contraction and Active Hyperemia
Ejection Fraction
Fraction of End-Diastolic Volume that is ejected from ventricle during systole. Normally greater than 55%
EF = (SV)/(EDV) * 100
(ECG) Hypocalcemia
Abnormality of Myocyte Repolarization.
- prolonged QT interval
Atrial Natriuretic Peptide (ANP)
Released from Cardiac Atrial Tissue in response to:
1) Atrial Distention
2) Sympathetic Stimulation
3) Increased Angiotensin II
4) Endothelin
Counter-regulatory mechanism for Renin-Angiotensin-Aldosterone system
Left Anterior Descending (or Anterior Interventricular Branch)
From Left Coronary Artery. Runs inferior to Anterior interventricular sulcus toward apex. Can continue into Posterior Interventricular Sulcus. May anastomose with Post. Interventricular Branch there.
Supplies:
1) Both Ventricles
2) Anterior 2/3 of Interventricular Septum
Artificial Pacemaker
Pacemaker attached to chest wall and an electrical lead is fed through the Cephalic or Subclavian Vein. Tip of lead implanted into Right Ventricle, allowing for synchronized contraction
Inferior (Diaphragmatic) Surface of Heart
Right and left ventricles
Sternal Angle (of Louis)
Joint between the sternal body and manubrium
Left Superior Vena Cava
Terminal part of left anterior cardinal vein that normally degenerates persists but terminal part of right anterior cardinal vein degenerates.
Gain-of-Function Mutation
Results in new or enhanced activity of a protein
Coronary Sinus
Large vein in posterior part of Atrioventricular Sulcus. Receives most of heart’s blood via tributaries. Opens into Right Atrium superior to IVC. Rudimentary, single cusp valve.
Three Tributaries: Great Cardiac Vein, Middle Cardiac Vein, and Small Cardiac Vein
Two layers of Serous Pericardium
Parietal and Visceral
Why are Ribs 11/12 not palpable?
Buried in abdominal wall musculature
Chordae Tendinae
Small, thin cords which attach to free margins of cusps to papillary muscles on ventricular walls.
Function: papillary muscles contract, keep Chordae Tendinae taut to prevent backflow
Azygous Vein
Anterior right side of Thoracic Vertebrae. Superior continuation of Right Ascending Lumbar Vein. Drains blood from the Right Posterolateral Abdominal Wall into Inferior Vena Cava. Enters Poster Mediastinum passing through Aortic Hiatus of Diaphragm. Drains into Super Vena Cava
Normal Range of Mean Electrical Axis
(-30) - (+90)
Contractility (Inotropy)
Intrinsic property of myocardium accounting for changes in contraction strength when Preload/Afterload are held constant
Angioplasty
Balloon catheter inserted into Ascending Aorta and into occluded coronary artery. Balloon expanded using dilute contrast media. Point is to widen them.
Pneumothorax
Air enters pleural cavity and collapses lung via external or internal sources
Vagus Nerve Effect on Heart
Parasympathetic. Decrease heart rate and force of beat. Constricts coronary arteries
Determinants of Blood Oxygen Content
1) PO2
2) amount of hemoglobin
3) hemoglobin binding affinity for oxygen
NDF < 0
Net Driving Force < 3
Indicates reabsorption
Jugular Venous Pulse Wave
There are no valves to impede flow between Right Internal Jugular Vein and the Right Atrium. Can learn about pressure in Right Atrium by examining vein’s distention. from retrograde blood flow.
Anulus Fibrosis
Ring of fibrous tissue surrounding right atrioventricular orifice. Serves as attachment site for cusps
Hematocrit
Percentage of RBC in blood by volume
Smooth and Cardiac Muscle T-Tubules
Smooth does not have them. Cardiac does.
α1-adrenoreceptors
Sympathetic adrenergic nerves found on smooth muscles and heart. Stimulation via norepinephrine causes constriction
Lingula
“tongue” of left superior lobe (lung), inferior to cardiac notch. Extends into Left Costomediastinal recess during inspiration
Specific Vasodilator Peptide Hormones released by Mucosa of Intestinal Tract
1) Cholecystokinin
2) Vasoactive Intestinal Peptide
3) Gastrin
4) Secretin
Transposition of the Great Arteries
Aorta from Right Ventricle and Pulmonary Artery from Left Ventricle. Failure of Aorticopulmonary Septum to spiral within Bulbus Cordis and Truncus Arteriosus. Abnormal migration of neural crest cells. Sometimes associated with a defect in the Membranous Part of Interventricular Septum. Usually accompanied by Patent Ductus Arteriosus (failure to close).
Infant presents with Cyanosis. Condition fatal without surgery
Firing Rate of AV Node / Bundle of His
50-60 bpm
(ECG) Severe Hyperkalemia
Abnormality of Myocyte Repolarization.
- Tall T-wave
- Flattened P wave
- Widened QRS
Structures visible in Five Vessel Level (CT)
- Great Vessels:
1) R Brachicephalic Vein
2) L Brachicephalic Vein
3) Brachiocephalic Trunk
4) Common Carotid
5) Left Subclavian - Trachea (black due to air)
- Esophagus (posterior to trachea; usually collapse may have some air)
Passive Filling of Ventricles
Phases 6 and 7 are passive. Atrial Systole (phase 1) is active
M2 Muscarinic Receptors in SA Node
1) Decrease rate of Phase 4 depolarization
2) Increase efflux of K+
Point of division of Brachiocephalic Trunk
Right sternoclavicular joint
Metaarterioles
Intermediate vessel between arterioles and capillaries
Regurgitation
Insufficiency. Backward flow of blood through a valve which fails to close properly
Loss-of-Function Mutations in Atrial Fibrillation
Centered around Voltage-Gated K+ Channel, Kv1.5
Involved in atrial repolarization in phases 1-3. Leads to decrease in efflux of K+. Longer to reploarize. Leads to longer action potential and possibly early afterdepolarizations.
Path for Bronchogenic Tumors to metastasize to Vertebral Column
Bronchial Veins -> Azygous Vein -> Posterior Intercostal Veins -> Intervertebral Veins -> Vertebral Venous Plexus
Echocardiography
Ultrasound imaging technique used to, among other things, measure cardiac output
Normal Duration of PR Interval
0.12 - 0.20 seconds
3-5 boxes
Cardiac and Pulmonary Branches of Vagus Nerve
Leave Vagus Nerve in Superior Mediastinum. Course to Cardiac and Pulmonary Plexuses
Blood Supply to Thymus
Branches of Internal Thoracic Artery and Inferior Thyroid Artery
Branches of the fuse single aorta
1) Paired Intersegental Arteries
2) Unpaired Vitelline Arteries
3) Paired Umbilical Arteries
4) Paired Lateral Splanchnic Arteries
Superior Mediastinum
Located above horizontal plane through sternal angle and T4-T5 intervertebral disc
(ECG) Ventricular Fibrillation
- Disordered, rapid stimulation of ventricles
- No coordinated contractions
- Cessation of C.O. and death if not quickly reversed
- Comes with severe heart disease (major cause of mortality in acute myocardial infarction)
- Often initiated by an episode of VT which degenerates by breakup of waves into wavelets
- NO QRS WAVES
Origin of Brachiocephalic Trunk
from part of the Aortic Sac
Transmural Pressure
Difference in pressure inside and outside a vessel
Bipolar Limb Leads
Leads I, II, and III
T Waves are Sensitive to…
1) Change in electrolytes
2) ischemia
3) las drogas
Interventricular Foramen
Between the AV Septum and free edge of (growing) Muscular Ventricular Septum
Intima
Innermost layer of vasculature. Single layer of thin endothelial cells. Separated from media (blood) by basal lamina
Formation of Single Heart Tube
Paired (endocardial heart) tubes are brought together in lateral folding of the embryo and fuse. Form single heart tube at midline - the endocardium
Location of valve for Foramen Ovale
Left Atrium
Three articulations between ribs and vertebral column (Ribs 2-9)
1) Head-Vertebral Body
2) Head-Above vertebral Body
3) Posterior Curve - Transverse Process of Vertebrae
Types of Ventricular Arrhythmias (Tachyarrhthmias)
1) Ventricular Premature Beats (VPB)
2) Ventricular Tachycardia
3) Ventricular Fibrillation
Root of Lung
Collection of neurovascular structures that supply the lung. Covered by pleura.
Change in pressure in pleural cavity during inspiration
decrease in pressure
Cholinesterase activity in heart
High cholinesterase concentration in/around SA and AV nodes is the reason ACh effects from parasympathetics decay rapidly.
Pleural Cavity
Potential space between parietal and visceral pleura under negative pressure. Contains a thin layer of serous fluid for lubrication
Postganglionic Neuronal Bodies of Sympathetic Division (Location)
Sympathetic Chain or Preaortic Ganglia
Floating Ribs
Not attached to sternum or adjacent ribs (Ribs 11-12)
Esophageal Atresia with Tracheoesophageal Fistula
Due to improper fusion of Tracheoesophageal folds. Results in ‘Polyhydramnios’ - amniotic fluid drank by fetus cannot enter stomach Surgical intervention required.
Hepatic Blood Flow sources
1) Portal Vein (75% by vol)
2) Hepatic Artery (75% of O2 supply)
Accessory Hemiazygous Vein
Drains middle left intercostal spaces. Crosses midline to drain into Azygous Vein
Smallest Cardiac Veins (or Venae Cordis Minimae)
Tiny vessels within heart wall opening directly into chambers of the heart
(ECG) Right Bundle Branch Block (RBBB)
- Normal depolarization of R Ventricle Interrupted
- Initial depolarization of Ventricular Septum unaffected (stimulated by L Bundle)
- Normal R wave in Lead VI and Small Q in V6 still recorded
- Slow cell-to-cell depolarization in R Ventricle
- Widened QRS complex
- Late depolarization in R Ventricle produces R’ wave in Lead V1
- Prominent Downward S wave in Lead V6 (not normally there)
Aorticopulmonary Septum
Formed from fused Bulbar and Truncal Ridges. Divides Bulbus Cordis and Truncus Arteriosus into Ascending Aorta and Pulmonary Trunk. Half of each structure contributes to half of each great vessel.
Fascicular Blocks
Also called Hemiblocks. Happen in Left Anterior/Posterior Fascicles of Left Ventricle. Do not result in widened QRS because Purkinje Fibers bridge the territories of each fascicle.
Most useful to analyze limb leads.
Posterior Descending Artery (or Posterior Interventricular Branch)
Located in the Posterior Interventricular Sulcus. Can anastomose with Anterior Interventricular Branch of Left Coronary Artery
Supplies:
1) Right Ventricle
2) Left Ventricle
3) Posterior 1/3 of Interventricular Septum
Factors shifting Hemoglobin-Oxygen Dissociation Curve to the Right
1) Increase in Temperature
2) Increase in PCO2
3) Decrease in pH
Moderator Band or Septomarginal Trabecula
Single specialized trabeculum that forms bridge between lower portion of Interventricular Septum and Anterior wall at base of Anterior Papillary Muscle
Cardiopulmonary Receptors Reflex
Type of stretch receptor called “low-pressure receptors”. Located at Venoatrial Junctions of heart. Respond to atrial filling and contraction.
Activated by increased central venous pressure/volume, leading to a decrease in sympathetic activity.
Other types of cardiopulmonary receptors decreased ADH/Vasopression released from Posterior Pituitary. Decreased in blood volume and venous pressure
Factors affecting venous return to heart
1) R Atrial Pressure
2) Mean Systemic Filling Pressure
3) Resistance to flow btwn peripheral vessels and R Atrium
Meaning of P Wave
Atrial Depolarization
Vertical Lines on Lateral View (Anterior to Posterior)
1) Anterior Axillary Line
2) Midaxillary Line
3) Posterior Axillary Line
Umbilical Veins
1) Right umbilical vein degenerates
2) Left Umbilical vein: Postnatally, fibrotic and form Ligamentum Teres Hepatis (round ligament of liver)
Torsades de Pointes
Specific polymorphic VT with acute myocardial ischemia/infarction. Long QT syndrome.
Prevertebral Ganglia
Also called Preaortic
Anterior to lumbar vertebrae and abdominal aorta. Most of these associated with branches of abdominal aorta.
Right and Left Vitelline Veins
Drain primitive gut. Form:
1) Hepatic Sinusoids
2) Ductus Venosus
3) Remainder of L Vitelline degenerates
4) Right Vitelline vein (enlarges to form pt of IVC and hepatic portal system)
Atresia
Absence of normal lumen or opening (developmental)
(ECG) Left Bundle Branch Block (LBBB)
- Normal initial depolarization of left septum does not occur
- Right ventricular septum first to depolarize (move toward V6)
- Initial downward deflection recorded in Lead V1
- Absent small Q wave from Lead V6
- Slow left ventricular spread results in Wide QRS
- Abnormal second terminal upward deflection in leads over L Ventricle (V5, V6)
Heart Rate and Systole/Diastole Time Relation
At rest, more time is spent in diastole than systole. Increasing heart rate shortens both but more so diastole.
Rhythmic/Phasic Contraction (skeletal muscle perfusion)
Normal locomotory.
Mean flow is higher. However, it’s phasic so low flow during contraction (compressed vessels) and high at rest.
Mutations involved with Dilated Cardiomyopathy
Majority of the mutations are genes encoding proteins in sarcomere
1) titin (most common)
2) cardiac troponins T, C, and I
3) desmin
4) myosin heavy chain
Venous Return Formula
VR = (PSF - PRA) / RVP
VR: Venous Return
PRA: Right Atrial Pressure
RVR: Resistance to Venous Return
Role of Right Vagus on Heart
Primarily inhibits SA Node
Paired Umbilical Arteries
Form…
1) Internal Iliac Arteries
2) superior vesical artery
3) distally, fibrous cord - medial umbilical ligament
Fate of Caudal Part of Right Dorsal Aorta
degeneration
Umbilical Vein
Feeds fresh blood from placenta to fetus (80-90% O2 saturation)
Describe origin of Posterior Intercostal Arteries
Branch from the aorta.
Exception: 1st/2nd branch from Superior Intercostal Artery
Pectinate Muscles
form criss-crossing ridges of muscular anterior wall of right atrium
Frank-Starling Law
Stretching of the sarcomere increases cardiac contractility
All blood from gut, spleen, and pancreas immediately flows into Liver via…
Portal Vein
Chorionic Villi
Capillary network where nutrients/waste exchanged between maternal and fetal blood without mixing. Blood returned to fetus via Umbilical veins
Intervillous Space
Placental space which receives input and output of maternal blood for exchange with Chorionic Villi.
Increased morbidity/mortality in LQTS
if QTc > 500 msec
Gain-of-Function Mutations in Atrial Fibrillation
Channels:
1) Ks
2) Kr
Mutations in all 5 regulatory subunits of Ks channels. Leads to increase in efflux of K+ and thus increase in rate of phases 2/3. Reduction in duration of both AP and effective refractory period in atrial myocytes
Ways to Express Preload on Frank-Starling Curve
1) End Diastolic Volume
2) End Diastolic Pressure (most common clinically)
3) Right Atrial Pressure
Hemiazygous Vein
Left side of anterior vertebral column. Continuation of Left Ascending Lumbar Vein as it passes posterior to diaphragm. Drains Left Posterolateral Abdominal wall directly into Inferior Vena Cava before becoming Hemiazygous Vein. Enters thorax through Diaphragmatic Crura. Drains lower left intercostal spaces via Left Posterior Intercostal Veins.
Crosses midline to drain into Azygous Vein
Fate of Septum Primum
Upper part degenerates.
Lower part becomes the valve of Foramen Ovale
J Point (ECG)
Point at which ST Segment begins (end of S Wave)
Structures visible in Aortic Arch Level (CT)
- Aortic Arch
- Superior Vena Cava
- Arch of Azygous (emptying into the SVC)
Pulmonary Valve
Located at pulmonary orifice at superior end of Conus Arteriosus. Have three semilunar cusps. Cusps catch backflow from pulmonary trunk after systole and close off orifice
Rhythmicity
Regularity of pacemaking activity
Pleurisy
Inflammation of pleura. Can result in fibrous connective tissue adhesions between visceral and parietal pleura.
Antipyretics
Drugs that reduce fever
Right Coronary Artery
Arises from opening to right aortic sinus. Descends in Atrioventricular Sulcus
Supplies:
1) Right Atrium
2) Right Ventricle
3) Sinoatrial Node
4) Atrioventricular Node
5) Interatrial Septum
6) Posterior 1/3 of Interventricular Septum
Nucleus Tractus Solitaris
Area in medulla receiving sensory fibers from CN IX and X. Includes information from baroreceptors and chemoreceptors
(ECG) Third Degree AV Conduction System Block
- “complete heart block” (conduction failure)
- No relationship between P wave and QRS
- SA node depolarizes atria; ventricles rely on escape rhythm
- If escape from AV node - QRS normal (40-60 bpm)
- If escape from His-Purkinje - QRS widened and slower
(ECG “hints”) T Waves
Each T wave begins with a gradual rise, falling more abruptly distally. Sharp proximal rise in ST segment is SUSPICIOUS
Normal Cardiac Rhythm / Sinus Rhythm
Every P wave followed by QRS. Every QRS preceded by P wave.
Leads I, II, and III have UPRIGHT P
Compartments of the Thoracic Cavity
1) Right Pulmonary Cavity
2) Left Pulmonary Cavity
3) Central Mediastinum
Implication of shorter diastole during Tachycardia
Less time for venous return, decreases cardiac output. Most myocardium blood perfusion is during diastole so less effective perfusion via Coronary Arteries.
Beginning of Heart Development
Begins on Day 18 in Cardigenic Area of Splanchnic Mesoderm
Resistance/Flow and Stenosed Arteries
- Increased velocity in narrowed segment
- Some fluid energy is lost to KE. Less energy to pressure
- Decrease in pressure exacerbates tendency to close shut
Released from Gastrointestinal Glands during Active Absorption of Nutrients. Vasodilator
Bradykinin
Terminal Ganglia
Parasympathetic ganglia located adjacent to or within the walls of organs
Oxygen Lack Theory
Local regulatory theory
Oxygen is needed for vascular muscle contraction. If there’s an absence, smooth muscle relaxes (vessel dilates). So decreased oxygen leads to increase in blood flow
Renin released by kidneys in response to…
1) Sympathetic stimulation
2) hypotension
3) decreased sodium in distal tubules
Key CT Scan Levels (windowing view) (Superior to Inferior)
1) Five-Vessel Level
2) Aortic Arch Level
3) Aortopulmonary Window Level
4) Main Pulmonary Artery Level
5) High Cardiac Level
6) Low Cardiac Level
Net Systemic Effects of Angiotensin II
Increase:
1) Blood volume
2) venous pressure
3) arterial pressure
Structures in Aortic Hiatus
1) Descending Aorta
2) Thoracic Duct
3) Azygous Vein
Least Splanchnic Nerves
Arise from 12th Thoracic Ganglion. End in Renal Plexus
Histamine
Released in response to tissue damage, inflammation, or allergic reaction. Mostly derived from mast cells in damaged tissue or basophils in blood.
It’s a vasodilator (arterioles) and increases capillary permeability
(ECG) Atrial Fibrillation
- Chaotic rhythm with very fast atrial rate (350-600 bpm)
- Multiple Wandering Reentrant Circuits in Atria
- No P waves or fine, high frequency, low voltage “noise”
- QRS-T normal but irregular timing
- many impulses encounter refractory AV node
- untreated AF has 140-160 bpm rate
(ECG) Acute ST Segment Elevation Myocardial Infarction (Acute STEMI)
Temporal sequence of ST Segment and T wave abnormalities. (gonna have to look at this one)
1) Acute: ST elevation
2) Hours: ST elevated, lowered R wave, appearance of Q wave
3) Day 1-2: T wave inverts, deeper Q
4) Days: ST normalizes, T still inverted
5) Weeks: ST + T normalized. Q wave persists
What are pain fibers in the heart sensitive to?
Metabolic products from ischemia in myocardium
Tricuspid Valve
Prevent blood flow back to right atrium following ventricular contraction.
Three Cusps:
1) Anterior Cusp (anterior wall of ventricle)
2) Posterior Cusp (inferior to anterior cusp)
3) Septal Cusp (posterior on Interventricular septal wall)
Discontinuous Capillaries
Large intercellular gaps. Gaps in basement membrane. Found in: Liber, spleen, and bone marrow
Things which can force constriction of esophagus
Esophagus forced to constrict when filled/constricted
1) Pharynx narrowing
2) Arch of Aorta
3) Left Main Bronchus
4) Diaphragm
Effect of Phosphorylating Light Chains of Myosin (MLC)
Increase Myosin ATPase Activity
Three methods of removing Ca2+ during smooth muscle relaxation
1) SR Ca2+-ATPase (SERCA)
2) Plasma Membrane Ca2+ Pump
3) Na+-Ca2+ Exchanger (plasma membrane)
Only way to rid body heat if Ambient Temp> Skin Temp
Evaporation (sweating)
Origin of Internal Thoracic Artery
Subclavian Artery
Function of Intercostal Muscles
support thoracic wall and change volume during breathing
Checking for Effusion on X-ray
Costophrenic angles should be sharp. A blunted angle may indicate small effusion
Thoracic Splanchnic Nerves
Originate from Lower 7 Ganglia in Sympathetic Trunks. Mainly preganglionic sympathetic fibers, also containing visceral afferent fibers.
Form three nerves:
1) Greater Splanchnic Nerves
2) Lesser Splanchnic Nerves
3) Least Splanchnic Nerves
Cardiac Index
Cardiac output per m^2 body surface (usually 2.6-4.2 L/min/m^2)
Oxygenated Blood Supply to Non-Respiratory Tissue of Lungs
Branchial Arteries. Supply root, supporting lung tissue and visceral pleura.
Right Lung: 1 branched from either Aorta of 3rd posterior intercostal artery
Left Lung: 2 branched directly from Aorta
0 < σ < 1
Capillary partially permeable
Fate of Right and Left Anterior Cardinal Veins
- Both contribute to Internal Jugular Vein. Become connected by “Oblique Anastomosis” which becomes left brachiocephalic vein
- Right Anterior Cardinal Vein contributes to Right Brachioephalic
- Terminal part of Right Anterior Cardinal V and Right Common Cardinal form Superior Vena Canva
- Posterior Cardinal veins degenerate
(ECG) Second Degree AV Conduction System Block, Mobitz Type I
- Progressive increase in PR interval from one beat to next
- Eventually, you miss a QRS complex
- After, PR interval resets to initial length and cycle repeats
usually benign
Vertical Lines on Anterior View
1) Anterior Median (Mediasternal) Line
2) Midclavicular Line
Left Coronary Artery Divides into..
1) Left Anterior Descending (LAD) or Anterior Interventricular Branch
2) Circumflex Branch (artery)
Thermoreceptors of the Skin
Cold receptors most abundant. Also warm ones.
Reflex effects when chilled:
1) Shivering / increasing heat
2) Inhibition of sweating
3) Vasoconstriction
Fate of Distal Part of Aortic Arch 6
Degenerates on the right but on the left it persists as the Ductus Arteriosus
(Cardiac Cycle) Phase 4: Reduced Ejection
Ventricular repolarization. Atrial volume and pressure continue to rise (venous return). Tension in ventricular muscle begins to decrease, along with intraventricular pressure and the ejection rate of blood. 30% of blood ejected in this phase.
Aortic pressure begins to decrease because resistance to flow of peripheral vessels begins to overtake ventricular output.
Slowed output through semilunar valves means reverse flow begins. Valves close, marking the beginning of diastole.
Reynold’s Number (Re)
Used to predict turbulence under ideal conditions
see formula sheet for actual formula
Active Hyperemia
Increased in blood flow associated with metabolic activity of tissue/organ
Anterior and Posterior Sulcus (Heart)
Separate right/left ventricles
(ECG) Ventricular Premature Beats (VPB)
- Arises when ectopic ventricular focus fires AP
- Widened QRS complex (depolarization via slow cell-to-cell transmission)
- unrelated preceding P wave
- T wave in opposite direction of QRS
Repeating Patterns:
1) Every beat
2) Bigeminy - every alternate
3) Trigeminy - two normal, one VPB
4) Couplets - two in a row
5) triplets - three in a row
Roughened parts of Right Atrium
Right Auricle and Anterior Wall
Enhanced Automaticity of Latent Pacemakers
Mechanism of Tachycardia. Latent pacemarker’s rate > SA node rate. Ectopic beat / Ectopic rhythm – premature to normal rhythm
Several Circumstances:
1) High catecholamine concentration can enhance automaticity
2) Hypoxemia, Ischemia, Electrolyte Disturbances, and drug toxicities
Mechanical Efficiency of the Heart
Also called Cardiac Efficiency. Typically around 25%
= PVA/MVO2 = work/total energy use
Long QT Syndrome (LQTS)
Longer cardiac repolarization and refractory period. Genetic defects in cardiac voltage-activated sodium and potassium channels. Loss of function mutations
Male QT interval (.35-.45 s), Female QT (.36-.46 s)
Physical and emotional stress triggers syncope or sudden death.
Fibrous Pericardium, Embyrological Origin
Body Wall (Somatic) Mesoderm of lateral plate
Costal Margin
Formed by costal cartilages of Ribs 7-10 rising up to the sternum
Sources of Thoracic Duct Drainage
1) All lymph below diaphragm
2) L Side Thoracic Cavity
3) L Side Head/Neck
4) L Upper Extremity
Dilations of the Heart Tube (Rostral/Arterial to Caudal/Venous)
Occurs by Day 23.
1) Truncus Arteriosus
2) Bulbus Cordis
3) Primitive Ventricle
4) Primitive Atrium
5) Sinus Venosus
(ECG “hints”) Leads V1-V6
Amplitude of R wave normally increases until it reaches a Equiphasic RS complex at V3.
Continues to rise through V6
Superior Aspect of the Manubrium
Jugular (or Suprasternal) Notch
Murmurs
Heart sounds generated by turbulent bloodflow
Endothelin-1 (ET-1)
Vasoconstrictor
From intracellular precursor, Big Endothelin-1. Synthesized by Endothelin-Converting Eznyme (ECE) on Endothelial membrane
Two factors determining blood flow (generally)
1) Pressure Difference (Perfusion Pressure)
2) Resistance
Umbilical Arteries
Fetus to placenta flow. 3/5 of Descending Aorta blood in fetus directed to placenta this way.
Parts combining to form Definitive Left Atrium
1) Primitive Left Atrium which forms Definitive Left Auricle
2) Pulmonary Vein and its smooth-walled lumen incorporated as smooth-walled part
Tumor of Liver / Right Atrium Collaterals
Tumor of liver can destruct Inverior Vena Cava. Collateral pathway through SVC
Lumbar veins-> R/L Ascending Lumbar Vein -> Hemiazygous Vein - Azygous Vein -> SVC
Foramen Primum Defect
Partial fusion of endocardial cushions, leads to a gap in the inferior part of the Atrial Septum. Ventricular septum intact. Endocardial cushions fuse enough to form membranous part of IV Septum, just not enough to join septum primum
Terminal Branches of Internal Thoracic Artery
Musculophrenic and Superior Epigastric Arteries
Function of Aldosterone
Increase renal Na reabsorption
Body Heat / Epinephrine+NE
Affect rate of metabolism with 40-50% increase. Boost body heat
Ventricular Escape
Escape Rhythm from distal points of the conduction system. Very strong parasympathetic activity can surpass the SA and AV nodes. Purkinje fibers doing the pacemaking
Left Atrium and Esophagus
Hypertrophy of the Left Atrium can cause compression and displacement of posteriorly-located esophagus
Unpaired Branches to Viscera from Descending Aorta
1) Left Bronchial Arteries (2)
2) Esophageal Arteries (2-5)
3) Mediastinal Arteries
4) Pericardial Arteries
Collateralization
In heart/coronary artery network, increased number of parallel vessels can reduce resistance
What are actin filaments in Smooth Muscle missing
no troponin
Triggered Activity
Mechanism of Tachycardia. Action potentials under certain conditions can trigger extra heart beats or rapid arrhythmias.
1) Early Afterdepolarizations
2) Delayed Afterdepolarizations
Compliance
“Distensibility”
Ability of hollow organ to distend and increase in volume in response to increased pressure
Patent Ductus Arteriosus (PDA)
Failure to close results in persistent Descending Aorta - Pulmonary Artery shunt. Blood flows.
Volume overloading of Pulmonary Circulation, L Atrium, and L Ventricle.
Left Ventricular Dilation and Left-Sided Heart Failure
Primary Capacitance Vessels of the Body
Venules and Veins
Pleural Friction Rub
Sound during breathing with Pleurisy (inflammation of pleura).
Posterior Myocardial Infarction (Leads and Typical Artery)
Leads V1-V2 (remember this is the weird, odd-ball case)
Right Coronary Artery
Order of Functional Potency of Adrenergic Receptors (Heart)
Beta-1, Beta-2, Alpha-1
Types of External Intermittent Compression on Lymphatic Vessels
1) Contraction of skeletal muscle
2) movement of body
3) Pulsation of adjacent arteries
4) Compression of tissues by objects outside body
Coursing of Left Posterior Fascicle
Runs through Posterior, Inferior, and Medial Left Ventricle
Branches of Left Bundle Branch
1) Left Anterior Fascicle
2) Left Posterior Fascicle
Septum Transversum
Future central tendon of the diaphragm. Veins must pass through it first to reach Sinus Venosus
Arch of the Azygous Vein
Arches superior to root of right lung before draining into SVC
Innermost Intercostal Muscles
Oriented in same direction and act with Internal Intercostal Muscles. Found in lateral most portion of Thoracic Wall
Released from Adrenal Medulla
Epinephrine and Norepinephrine
Innervation of Intercostal Muscles
Intercostal Nerves (from Ventral Rami of Thoracic Spinal Nerves)
Functions of Angiotensin II (7)
1) Aldosterone Release
2) Direct stimulation of Renal Na reabsorption
3) Stimulate thirst
4) Stimulate released of ADH
5) Systemic Vasoconstriction
6) Activate Sympathetics
7) Cardiac/Vascular Smooth Muscle Hypertrophy
Origin of Superior Intercostal Artery
Costocervical trunk of subclavian artery
Paired dorsal aortae (caudal to heart) fuse to form…
single aorta
Muscular Ventricular Septum
Forms in midling of floor of ventricle; grows toward AV Septum
Landmark for start of Descending/Thoracic Aorta
Continuation of Aortic Arch inferior to level of sternal angle
Paired Parietal Branches of the Descending Aorta
1) Posterior Intercostal Arteries (9 pair - Intercostal spaces 3-11)
2) Subcostal Artery (1 pair) - supplies below rib 12
Overall Vascular Compliance dependent on…
Venous compliance (15x more blood)
Aortic Arches in Development
- Originate from rostral end of Truncus Arteriosus.
- Supply Pharyngeal Arches
- Connected to Paired Dorsal Aortae
Subregions of Pericardial Cavity
1) Transverse Pericardial Sinus
2) Oblique Pericardial Sinus
Exceptions to Sympathetic/Parasympathic Dual Innervation to Same Organ
1) Sweat Glands
2) Adrenal Medulla
3) Arrector Pili Muscles
Causes of Edema
1) Increased Capillary Pressure
2) Increased capillary permeability
3) Decreased plasma oncotic pressure
4) Lymphatic blockage (Lymphedema)
Corrected QT Interval
Allows for comparison of QT interval, corrected for different heart rates.
= QT / sqrt(RR)
Normal value <= 0.44 seconds
Conduction Blocks
Bradycardic. Impulse encounters unexcitable region. Can be transient/permanent, unidirectional or bidirectional.
Caused by:
1) Ischemia
2) Fibrosis
3) Inflammation
4) drugs
5) etc..
(ECG “hints”) Lead V1
- Small initial R wave (sometimes not able to see)
- Deep(er) S Wave
- T wave maybe positive, biphasic, or negative
Membranous Ventricular Septum
Closed Interventricular Foramen. Formed by fusion of three structures:
1) Right Bulbar Ridge
2) Left Bulbar Ridge
3) Atrioventricular Septum
Right Axis Deviation
Mean Electrical Axis of greater than +90
Preload
Stretch of Ventricular muscle fibers before contraction.
End Diastolic Volume and End Diastolic Pressure are good measures of Preload.
PR Interval
Atrial Depolarization and AV Delay. P wave to start of QRS.
(Cardiac Cycle) Phase 5: Isovolumetric Relaxation
Ventricles continue to relax. Decline in pressure. Decline in Aortic Pressure is not abrupt (smaller arteries resist flow but elastic recoil of vessels maintains pressure).
End Systolic Volume
Peripheral Venous Pool
Blood contained within veins of systemic organs
(ECG) Atrial Fluter
- Rapid, regular atrial activity at a rate of 180-350 bpm
- Usually caused by Large Anatomically-Fixed Circuit
- Impulses reach AV node during refraction (often do not conduct; 2+ beats of atria per ventricle beat)
- Asymptomatic under 100 bpm
- > 100 bpm: palpitations, dyspnea, or weakness
(ECG “hints”) Lead aVR
All complexes (P-QRS-T) normally negative
Central Venous Pool
Smaller reservoir of blood in Great Veins of Thorax and Right Atrium
(ECG) Hypercalcemia
Abnormality of Myocyte Repolarization.
- Shortened QT interval
Drainage of Branchial Veins
Right: Azygous Vein
Left: Accessory Hemiazygous or Left Superior Intercostal Vein
Right and Left Brachiocephalic Veins
Union of Internal Jugular and Subclavian Veins. Begins posterior to Sternoclavicular Joints.
Parts of the Sternum
1) Manubrium
2) Body
3) Xiphoid Process
(Fast Response Action Potential Receptors) Phase 3
Repolarization by Potassium efflux through delayed rectifier channels. Slow activating current first, followed by fast activating current.
Posterior Mediastinum
Between pericardium and lower 8 thoracic vertebrae. Contains tubular structures (esophagus, aorta, etc…)
Dicrotic Notch
Closure of Aortic Valve during Phase 4 of Cardiac Cycle (Reduced Ejection) momentarily interrupts the decline in Aortic pressure
Deviation in Left Posterior Fascicle Block
Right Axis Deviation
Higher Bloodflow Velocity? Semilunar or AV Valves?
Semilunar Valves have smaller openings, therefore faster velocity.
Bruit
Sound generated by turbulent blood flow in vessel
Contents of Lung Hilum
1) Bronchi (posterior)
2) Pulmonary Artery (Anterior/Superior)
3) Pulmonary Vein (Anterior/Inferior)
4) Bronchial Arteries/Veins
Superior Vena Cava
Union of Right and Left Brachiocephalic Veins. Extends from Costal Cartilage levels 1-3. Recieves Azygous Vein @ level of Sternal Angle before entering the Right Atrium
Deoxygenated blood from all structures above the diaphragm
(ECG “hints”) Lead II
All complexes (P-QRS-T) normally positive
Escape Rhythm
Surpressed SA Node allows a latent pacemaker to fire an impulse (escape beat). A continued series is called an Escape Rhythm
Central Venous Pressure
Blood pressure in Thoracic Vena Cava near R Atrium. good approximation of right atrial pressure.
Fixed Conduction Block
Area unexcitable because of barrier imposed by fibrosis or scarring that replaces myocytes
Anterior (Sternocostal) Surface of Heart
Mostly right ventricle, some right atrium
Bypassed in fetal circulation
Liver and Lungs
Make-up of Capillaries
Composed of just endothelial cells and a basal lamina
Mechanisms of Exchange Through Capillary Endothelia
1) Diffusion
2) Bulk Flow
3) Vesicular Transport
4) Active Transport
Tissue (Interstitial) Hydrostatic Pressure
ΔPi = ΔVi / C
ΔPi : Δ interstitial fluid pressure
ΔVi: Δ interstitial fluid volume
C: Interstitial Compliance
Trachea
Begins in neck below Larynx (C6). Contains cartilagenous rings. Anterior and to the right of Esophagus. Divides into Principal Bronchi at level of sternal angle. Principal bronchi within the Middle Mediastinum
Vertebral Level: Aortic Hiatus
T12
Flow Capacity (Vasodilator Reserve)
Difference between basal and maximal flow to organs
Muscular Part of Interventricular Septum
Thick, forms most of septum
Opening of Pulmonary Circulation Afterbirth
Lungs expand and open up. Increased PO2 from breathing leads to pulmonary vasodilation
Net Driving Force Equation
NDF = (Pc-Pi) - σ(πc-πi)
Division of Primitive Atrium
Accomplished by fusion of Septum Primum and Septum Secundum. These also fuse to Endocardial Cushions
(Cardiac Cycle) Phase 2: Isovolumetric Contraction
Spread of action potential through ventricles. Rapid increase in intraventricular pressure. Closure of Atrioventricular (Tricuspid/Mitral) Valves.
Volume is constant since AV and Semilunar valves are closed
Clinical concern with Costodiaphragmatic Recess
Fluids can accumulate (blood, lymph) in disease states (visualized on x-ray)
Naming of Intercostal Spaces
Named for rib ABOVE
Structures Visible in Low Cardiac Level
1) L/R Atria
2) L/R Ventricles
3) Interventricular Septum
4) Descending Aorta
5) Pericardium
Function of Vasopressin/ADH
Primary function is to increase water retention. Leads to increase in blood volume and arterial pressure.
Secondary function - direct vasoconstrictor actions at high levels
(ECG) Sinus Tachycardia
- Elevated SA node discharge rate > 100 bpm
- Normal P Waves and QRS
- Occurs most often from increased sympathetics or decreased vagal tone
- Appropriate response to exercise
Pathological Causes (all sympathetic):
1) fever
2) hypoxemia
3) hyperthyroidism
4) hypovolemia
5) anemia
Total Energy (Heart)
Energy = External Work + Elastic Potential Energy
True Ribs
Directly attach to sternum. Ribs 1-7
Effect of Temperature on SA Node
Increasing temperature increasing discharge frequency. May contribute to Tachycardia from fever.
Sympathetics effect on Lungs
1) dilate respiratory passageways (Bronchodilation)
2) vasoconstriction
3) decrease mucous secretion
Visceral Pleura
Covers lungs
Vasodilatory Substances
Adenosine, CO2, K+, H+
Issue with Left Dominant Heart
Entire Interventricular Septum supplied by Left Coronary Artery. Occlusive blockage will result in ischemia. Decreased survival from blockage
Venous Drainage of Posterior Intercostal Veins
- Right Side: Azygous Vein
* Left Side: Accessory Hemiazygous and Hemiazygous Veins
Costomediastinal Recess
Formed by costal and mediastinal pleura. Anterior margins of lung pass into this space during inspiration. Prominent on the left side.
LQT1
Type of Long QT Syndrome.
Mutations lead to defective Ks channel (current reduced). Symptoms triggered by emotional or physical stress.
Exercise more likely to trigger cardiac event than in either LQT2 or LQT3
Name for area connecting rib and costal cartilage
Costochondral Junction
Vertebral Levels from which Splanchnic Nerves Emanate
T5-L2
Driving Force for Venous Return
Difference between Right Atrial Pressure and Mean Systemic Filling Pressure (PSF)
Location of Deep Body (Thermal) Receptors
1) Spinal Cord
2) Abdominal Viscera
3) In/Around Great Veins of Upper Abdomen/Thorax
Insertion of Transversus Thoracis
Lower border of costal cartilages of Ribs 3-6. Fibers cross 1-2 intercostal space
M2 Muscarinic Receptors in Heart
Bind ACh. Dramatic negative chronotropic and dromotopic effects. Modest inotropic effect primarily on the atria.
Conditions causing hypereffective heart
1) Sympathetic Stimulation
2) Trained Athletes (increased cardiac mass / contractile strength)
Cardiac Output
Volume of blood ejected by ventricle per minute
CO = SV * HR
Parts of Interventricular Spetum
1) Muscular Part
2) Membranous Part
Closure of Foramen Ovale Afterbirth
Left atrial pressure becomes higher than right.
1) Functional closure in 18-24 hrs via smooth muscle, drop in circulating PGE2, and pressure of lumen in ductus
2) anatomical occlusion over the next few days via endothelial and fibrous tissue proliferation
Preload
Stretch of cardiac muscle before contraction. Cardiac muscle normally at less than max preload, allowing it to meet increased demand.
Endothelial-Derived Factors
Vascular endothelium has important paracrine role in regulating smooth muscle tone and blood flow.
Release Stimulated by:
a) Endocrine / Paracrine Hormones
b) Shearing Forces
c) Hypoxia
d) Drugs
_____
Factors:
1) Nitric Oxide
2) Endothelial-Derived Hyperpolarizing Factor (EDHF)
3) Endothelin-1 (ET-1)
4) Prostacyclin (PGI2)
5) Thromboxane
6) Leukotrienes
Somatomotor Central Command Center
Area in cerebral cortex which recruits muscles needed for specific activity. Functions as a “Feed-Forward” center sending signals to regulatory areas of meddula to activate respiratory/cardiovacular regulators
Meaning of U Wave (if present in EKG)
Follows T Wave; terminal stages of ventricular repolarization, possibly Purkinje Network
Path out of liver for blood
Leaves via Hepatic Veins then goes to Inferior Vena Cava
Atrivoentricular Block
Blocked/Unexcitable Atrioventricular connections removes normal Overdrive Suppression keeping His-Purkinje system in check.
Emergences of escape beats/rhythms
Hilum of Lung
Area where nerves and vessels enter and leave lung.
Middle Mediastinum
Contains heart, pericardium surrounding heart
Bulbar and Truncal Ridges
Ridges formed by Neural Crest Cells that grow longitudinally and spiral down Bulbus Cordis and Truncus Arteriosus. Fuse to form Aorticopulomary Septum
SR Ca2+-ATPase (SERCA)
pumps Ca2+ back into SR during muscle relaxation
Structures Visible in High Cardiac Level
1) L/R Atria
2) L/R VentricleS
3) Ascending/Descending Aorta
Adventitia
Outermost layer of vasculature. Contains…
1) Collagen
2) fibroblasts
3) blood vessels (Vasa Vasorum)
4) Autonomic nerves (mainly sympathetic)
Atrioventricular Reentrant Tachycardias (AVRT)
Presence of abnormal, Accessory Pathway, ideal condition for reentry. Refractory period different. Conduction usually faster through accessory pathway than AV Node.
(Cardiac Cycle) Phase 3: Rapid Ejection
Aortic and Pulmonary Valves open when left/right ventricular pressure exceeds that of the exiting vessel. Ventricle muscle shortens, leading to decrease in ventricular volume. Period of peak flow from ventricles to Aorta/Pulmonary Artery. Atrial volume increasing because the AV valves are closed and venous return ongoing.
70% of stroke volume ejected in this phase
Fetal Hemoglobin
Higher oxygen affinity than adult hemoglobin
Count-Off Method (Calculating Heart Rate)
Memorize: Start-300-__-100-75-60-50 (each 1 box)
Count # of large boxes between 2 beats. estimation of heart rate
Normal Duration of QRS Complex
0.06-0.10 seconds
~1-2.5 boxes
Effect of Thyroid Hormone on Cardiovascular System
Excess thyroid hormone leads to increase in Heart Rate, Stroke Volume, Contractility, and Cardiac Output.
(Jugular Venous Pulse Graph) Y Descent
Rapid flow of blood into the right ventricle. Opening of the Tricuspid Valve at end of Isovolumetric relaxation phase
Anterior Cardiac Veins
2-4 draining directly into the Right Atrium
Pressure Volume Area (PVA)
Represents total mechanical energy generated by single beat of the heart.
PVA = SW + PE
Determinants of Resistance in a Vessel
1) Vessel Length
2) Blood Viscosity
3) Radius
Structures in Caval Opening
1) Inferior Vena Cava
2) Right Phrenic Nerve
Nitric Oxide (dilate/constrict?)
Vasodilator
Fick Principle
Xtc = Q[X]a - Q [X]v = Q([X]a - [X]v)
Xtc = Substance consumed by organ Q[X]a = Substance entering during given time Q[X]v = Substance exiting during given time Q = flow rate
External Intercostal Membrane
Thin aponeurosis replacing external intercostal muscles in ANTERIOR part of each intercostal space
Most likely to be damaged if upper intercostal space perforated/puncture
Intercostal Nerve
(ECG) Digoxin Therapy
Abnormality of Myocyte Repolarization.
- “Scooped” ST depression
- Mildly lengthened PR Interval
Paired Intersegmental Arteries
Form definitive…
- Posterior Intercostal and Lumbar Arteries
- Arteries to upper extremity (part/all of R/L subclavian arteries)
- Arteries to Lower Extremity (Common Iliac Arteries)
Causes of Right Axis Deviation
1) Right Ventricular Hypertrophy
2) Acute Right Heart Strain (e.g. massive pulmonary embolism)
3) Left Posterior Fascicular Block
Forms epicardium of heart
Visceral Layer of Serous Pericardium
Atrioventricular Sulcus
Separates the atria from ventricles. Also called Coronary sulcus
Alpha-2 Adrenergic Receptors
Norepinephrine receptors on sympathetic nerves which acts as a negative feedback loop. Inhibits further release of Norepinephrine
Effects of Increase Intracranial Pressure (cerebral perfusion)
1) Collapsed Veins
2) Reduced effective blood flow
Vagal Trunks
Pass through Diaphragm with Esophagus.
Left Vagal Trunk = Anterior Esophagus
Right Vagal Trunk = Posterior Esophagus
Fourth Heart Sound (S4)
Coincides with Atrial Contraction during late ventricular diastole. Commonly associated with resistance to filling (impaired relaxation)
Sign of diastolic heart failure
Fistula
Abnormal channel between two structures
Neural center for sweating
Anterior Hypothalamus (Preoptic Area). Sweat glands are sympathetically innervated by cholinergic fibers
Easy way to tell if Mean QRS Axis is normal
Lead I/II predominantly upright
Carina
Internal keel at division of trachea into main bronchi. Landmark visible with bronchoscope.
Rib 1
Immediately inferior to the clavicle; Has an abnormally flattened shape
Collateral Pathway to Right Atrium
Azygous Vein and Ascending Lumbar veins are collateral pathways to Right Atrium if Superior or Inferior Vena Cava are blocked
Types of Smooth Muscle
1) Single-Unit / Visceral
2) Multi-Unit
Determinants of Mean Arterial Pressure
1) Cardiac Output
2) Systemic Vascular Resistance
3) Central Venous Pressure
Origin of Phrenic Nerve
Ventral/Anterior Rami of C3-C5
Muscular Interventricular Septal Defect
Less common VSD. Spontaneously closes/resolves during childhood
Systolic Pressure
Pressure at top of pulse
(ECG) Orthodromic AVRT
- Most common PSVT for WPW patients
- NO DELTA WAVE
- Retrograde (not hidden) P wave via Accessory Pathway (occur after QRS)
- QRS width normal
- ventricles exclusively depolarized via normal pathway
Pregangliongic Cell Bodies of Parasympathetic Division (Location)
- CN Nuclei III, VII, IX, X
* Gray Matter of Spinal Cord S2-S4
(Jugular Venous Pulse Graph) C Wave
Interrupts X descent on an A wave.
Produced when Tricuspid Valve closes and bulges into atrium during onset of Isovolumetric Ventricular Contraction
Ribs articulating with sternum via costal cartilages
Ribs 1-7
Transersus Thoracis
Course obliquely, deep to Internal Thoracic vessels. Originate from posterior aspect of xiphoid process. Fibers cross 1-2 intercostal spaces.
(ECG) Polymorphic Ventricular Tachycardia
- Wide QRS continually changing
- Irregular rate
- Cause: Multiple ectopic foci or continually changing reentry circuit
Impalpable Ribs
1, 11, 12
Formed from Proximal Part of Aortic Arch 6
Left and right pulmonary arteries
Effects of Sympathetic Stimulation in Heart
Positive chronotrophy, dromotropy, and inotropy.
Phospholambin
Protein found in Sarcoplasmic Reticulum Membrane. When unphosphorylated, it inhibits Calcium uptake by SERCA. Phosphorylation increases Ca uptake.
(ECG) Acute Non-ST Segment Elevation Myocardial Infarction (non-STEMI)
Not all myocardial infarctions result in ST elevate and Q waves. These are a result of acute partially occlusive coronary thrombus. Only subendocardial layers of myocardium damaged
- ST segment depression AND/OR
- T wave inversion
Atrioventricular Canal
Junction between Primitive Atrium and Primitive Ventricle. Later divided by Dorsal and Ventral Endocardial Cushions fusing into AV Septum. This forms Right and Left AV Canals
(ECG) Transient Myocardial Ischemia
Among most important ST Segment / T Wave abnormalities. Usually Coronary Artery Disease -related.
- Transient ST Segment depression
- T Wave flattening or inversion
A normal T wave should be…
Positive in all three bipolar limb leads
Plasticity of smooth muscle
maximum tension variable for a given length
Maximum Lymph Flow Rate
Rising interstitial pressure will at some point compress lymphatic vessels, impeding flow.
Otherwise normally, increased interstitial pressure increases lymph flow
Sweating and Heat Acclimatization
Basically, you end up secreting Aldosterone and your sweat is more dilute champ
Leukotrienes
Vasoconstrictor
Stimulate Release of Vasopressin/ADH
1) Angiotensin II
2) Hyperosmolarity
3) Decreased atrial firing (usually from hypovolemia)
4) Sympathetic activation
Insensible Water Loss
Fluid lost daily via lungs, skin, and respiratory tract, as well as feces
Development origin of Superior Vena Cava
Terminal part of Right Anterior Cardinal vein and Right Common Cardinal vein form Superior Vena Cava
Stroke Volume (SV)
Volume of blood ejected from ventricles during single contraction
SV = EDV - ESV
Cardiac muscle nuclei
usually one one per cells; maybe 2
Effects of Acute Ischemia on Action Potentials
1) Reduce resting membrane potential
2) shorten duration of AP
3) decreased rate of rise and amplitude of Phase 0
Thermodilation Method
Clinical Technique to Measure Cardiac Output
Specialized catheter (Swanz-Ganz Catheter) with multiple lumens and balloon tip inserted into systemic vein (Internal Jugular or Subclavian).
Threaded through the right side of the heart, with its tip lying in the pulmonary artery. A cold saline solution of known temp/vol injected into R atrium to decrease blood temp. Magnitude of temperature change determines blood mixing. Computer calculates Right Ventricular Cardiac Output
External Work (EW)
Area circumscribed by PV-Loop
Sinus Venarum
Smooth-walled part of Right Atrium. Origin is the right horn of sinus venosus.
Effect of Infrathoracic Pressure on Cardiac Function
Inspiration increases the pressure gradient for venous return to the Right Atrium. Expiration does the opposite.
Net Effect: Increase in Venous Return
Three Cardinal Veins function in early embryo
Anterior and Posterior Cardinal veins drain cephalic and caudal parts of early embryo. Both empty into Common Cardinal Vein which drains into Sinus Venosus
Ejection Murmur
Abnormal sound created by opening of Semilunar Valves during systole. Caused by Stentotic Valve
(Fast Response Action Potential Receptors) Phase 1
Partial repolarization by potassium efflux, through voltage-gated potassium channels
Pulmonic Valvular Incompetence
Valve doesn’t close properly due to thickened/inflexible free margins of cusps. Blood flows back into right ventricle from pulmonary trunk.
Heard as a heart murmur
LQT2
Type of Long QT Syndrome.
Mutations lead to defective Kr channel (current reduced). Symptoms triggered by stress and rest. Arrhythmic events more likely to be triggered by sudden loud noises.
Diastolic Pressure
Pressure at lowest point of each pulse
(Jugular Venous Pulse Graph) V Wave
Upward inflection caused by filling of R Atrium. Venous collection with a closed Tricuspid Valve
Coarctation of Aorta
Narrowing of the Aorta superior (Preductal Coarctation) or inferior (Postductal Coarctation) to the entrance of the Ductus Arteriosus
Paired Endocardial Heart Tubes
Form from Splanchnic Mesoderm. They later come dorsal to the pericardial coelom as a result of head folding of the embryo
Sinus Bradycardia
Decreased firing of the SA node (below 60 BPM) results in slowing of normal heart rhythm. Normal P wave and QRS complexes, however. Normal benign in many at rest or during sleep.
Pathologically can result from:
- Intrinsic: Aging, Ischemic Heart Diseases, Cardiomyopathy
- Extrinsic: Drugs (beta-blockers) and metabolic causes (hypothyroidism)
Pronounced reduction: fatigue, light-headedness, confusion, and syncope
Radioactive Labeling to determine Cardiac Output
Blood (either RBCs or albumin) labeled with radionuclides, such as technetium-99. Detected by a camera. Volume is estimated by the intensity of radioactivity. Radioactivity of ESV and EDV compared.
Overdrive Suppression
Suppression of pacemaker activity in secondary pacemakers.
Ectopic pacemakers hyperpolarized when heart rate is greater than intrinsic rate. Higher frequency APs stimulate activity of Na+/K+-ATPase. High sodium concentration from the APs increases pump activity -> hyperpolarizing current
Decreases rate of spontaneous depolarization
Chronotropy
Cardiac rate
(ECG) Atrial Premature Beats (APB)
- Pacemaking originates from atrial focus outside of the SA node
- asymptomatic; may cause palpitations
- early-than-expected P Wave with abnormal shape
- Normal QRS
- can happen in healthy people
Unpaired Vitelline Arteries
To yolk sac derivatives…
1) Esophageal Arteries
2) Bronchial Arteries
3) Celiac, Superior, and Inferior Mesentary Arteries
Ganglion from which Splanchnic Nerves Emanate
Pre-Aortic Ganglion
Pulmonary Stenosis
Narrowing of pulmonary orifice due to fusion of free margins of cusps by disease processes. Result is right ventricular hypertrophy, as it must work harder to pump blood to lungs
Media
Middle layer of vasculature. Ratio of contents determines properties.
Contains…
1) Smooth Muscle Cells
2) Matrix of collagen
3) Elastin
4) Various glycoproteins
Thoracostomy
Draining fluid/air from pleural cavity surrounding lungs. Chest tube is placed immediately above a rib to avoid damage to neurovasculature
Done at Midaxillary Line of 5th intercostal space
Ductus Arteriosus
Wide muscular vessel connecting pulmonary arterial trunk to descending aorta. Under circulating influence of prostaglandin E2 (helps keep it open)
Atrioventricular Bundle
Pierces the fibrous rings separating atria from ventricles. Passes through membranous part of Interventricular Septum. Divides into Right and Left AV Bundles, coursing along muscular part of interventricular septum
Factors Affecting Body Heat Production
1) Basal Metabolic Rate
2) Muscular Activity
3) Hormones
4) Thermic Effect of Food
Vertebral Level: Esophageal Hiatus
T10
Circumflex Branch of Left Coronary Artery
Courses in Left Atrioventricular Sulcus. Can anastomose with termination of R Coronary Artery on Posterior Heart.
Supplies Left Heart
Actively Developed Pressure
Difference between Diastolic and Systolic Pressure at any point of a pressure-volume plot
Role of Left Vagus on Heart
Primarily inhibits AV Conduction
Midclavicular Line
Passes through midpoint of each clavicle
(ECG “hints”) Lead V6
QRS complex typically begins with narrow Q wave followed by large R wave
Infundibulum (Conus Arteriosus)
Superior, cone-shaped, smooth-walled part of Right ventricle. Inferior to the Orifice of the Pulmonary Trunk
Dilated Cardiomyopathy (DCM)
Most common cardiomyopathy. Symptoms include: shortness of breath, swelling of feet/ankles, and fatigue.
Left ventricular enlargement and reduced ejection fraction.
Mutations negatively affect ability of L Ventricle to contract. Muscles stretch and become thinner. Heart weakness can cause heart failure over time,
Describe origin of Anterior Intercostal Arteries
- Upper 6: Internal Thoracic Artery
- 7-9: Musculophrenic Artery
- 10-11: none
Contents of Intercostal Spaces
Intercostal muscles and neurovascular bundle
Primary Regulation of Coronary Flow
Changes in tissue metabolism.
- Adenosine - dilates during hypoxia or elevated metabolic rate
- Nitric Oxide - flow-dependent vasodilation
Location of Atrioventricular Node
Inferior part of Interatrial septum, superior to orifice of Coronary Sinus
σ = 1
Capillary completely impermeable
Posterior Part of Right Atrium
Smooth-walled. Receives the two Vena Cavae and Coronary Sinus. Contains the fossa ovalis
Persistent Atrioventricular Canal
Failure of endocardial cushion fusion. Defects in the Atrial and Ventricular Septa. Single Atrioventricular orifice
Early Afterdepolarizations
Type of triggered activity leading to tachycardia. Positive change in membrane potential interrupts normal repolarization. More likely in conditions prolonging action potential duration
Triggered action potentials can be self-perpetuating and lead to tachyarrhythmia
Sympathetic Chain Ganglia
Also called Paravertebral
Located in Sympathetic Trunk. Adjacent to vertebral column from C1-Coccyx
Innervation types in Intercostal Nerves
1) Somatic Motor
2) Somatic Sensory
3) Postganglionic Sympathetic Fibers
Chylothorax
Lymph and chyle (milky fluid) from intestines in pleural cavity. Happens from a tear in Thoracic Duct
Counting complexes in time (Calculating Heart Rate)
Often 3 second or 6 second markers on ECG.
Count number of QRS complexes. If in 3 second, multiply by 20. If 6 second, multiply by 10.
Bachmann Bundle
Branch of Anterior Internodal Tract connecting right and left atria electrically
Pericardium
Membranous sac composed of outer fibrous membrane and inner serous membrane. Covers heart
Causes of Murmurs
1) Stenosis of valve
2) Regurgitation
3) ejection of blood into dilated chamber
4) Increased blood flow in normal structures (bruit)
5) abnormal shunting
6) Valve disease
(ECG) Right Ventricular Hypertrophy
- Chest Leads V1 and V2 (overlying R Ventricle) record larger upward deflection.
- R wave becomes taller than S wave
- Mean axis shift right.
Pathway to Formation of Angiotensin II
1) Renin released by Kidney
2) Renin acts on Angiotension, synthesizing Angiotensin I
3) Angiotensin I converted to Angiotensin II by Angiotensin-Converting Enzyme (ACE)
(ECG) Hypokalemia
Abnormality of Myocyte Repolarization.
- ST Depression
- Flattened T
- PROMINENT U WAVE
Types of Supraventricular Arrhythmias (Tachyarrhythmia)
1) Sinus Tachycardia
2) Atrial Premature Beats (APB)
3) Atrial Flutter
4) Atrial Fibrillation
5) Paroxysmal Supraventricular Tachycardias (PSVTs)
Esophagus
Extends from pharynx through super and posterior mediastina. Ends at stomach. Courses between trachea and vertebral column, then through the Esophageal Hiatus in Diaphragm
Abnormal Automaticity
Mechanism of Tachycardia. Cardiac tissue injury induces myocardial cells outside specialized conduction system to acquire automaticity. Ectopic beat/rhythm.
Possible Mechanisms:
1) Leaky membrane after myocyte injury; resting potential less negative
2) membrane potential > -60 mV, gradual Phase 4 depolarization possible
Chemical Thermogenesis
Uncoupling of Oxidative Phosphorylation in brown fat. Increased metabolic rate produces heat.
Acute from: Catecholamine Release
Chronic: Hyperthyroid function
Steps of Cross-Bridge Cycling in Smooth Muscle
1) ATPase on globular head of myosin hydrolyzes ATP -> ADP + Pi
2) Myosin head binds actin
3) Release of ADP+Pi causes head to turn; “ratchet movement”
4) Actin released when ATP binds myosin
Manners of body heat loss
1) Radiation (Major)
2) Conduction (to objects/with air)
3) Convection
4) Evaporation
Great Cardiac Vein
Tributary of Coronary Sinus. Begins in anterior part of Interventricular Sulcus. Courses posteriorly intro Atriventricular Sinus (continues as Coronary Sinus).
Drains area supplied by Left Coronary Artery
Phases of Cardiac Cycle associated with Ventricular Systole
Phase 2-4
White Ramus Communicans
Neural structure in which Sympathetic Preganglionic Axons leave Ventral Rami destined for Sympathetic Chain or Pre-Aortic Ganglia
Closed Pneumothorax
Rupture of superficial air sacs in lungs. Tearing of visceral pleura. Air within respiratory passages (high pressure) can now enter pleural cavity (low pressure)
Short QT Syndrome (SQTS)
Accelerated cardiac repolarization and shorter refractory period. Shoter QTc than normal (<= .33 sec males, <= .34 females)
Causes:
1) Gain-of-Function mutations in Kr, Ks, and K1 (inward rectifying) channels
2) Increased efflux of potassium during repolarization phase
Symptoms:
1) Dizziness
2) atrial or ventricular fibrillation
3) sudden death
Pleural Recess
Narrow region of Pleural Cavity where parietal pleura folds and contacts parietal pleura from another region
Myocardial Infarctions and the Q Wave
Q Wave:
- More prominent (activation of healthy opposite unopposed)
- Width >= 1
- Depth of >25% total QRS height
- Develops in leads overlying infarction (must be in group of leads, not just one)
Required for sustained contraction of smooth muscle
extracellular calcium
Elastic Potential Energy
Area to left side of PV-Loop, bracketed by ESPVR and EDPVR
Atrial Septum (origin)
Fusion of Septum Secundum and (lower part) Septum Primum
Span of Intercostal Muscles
Rib above to rib below (one)
Net Flux Across Capillaries
J = Kf * (A)(NDF)
J: net fluid flux
Kf: Filtration constant
A: Surface area for exchange
NDF: net driving force
Pericardiocentesis
Procedure to alleviate Pericardial Effusion. Two methods
1) Needle inserted parasternally in left 4th/5th intercostal space
2) Needle inserted left of xiphoid processed, angled posterior/superiorly 45 degrees
Located smooth muscle primarily found
hollow organs and tubes
Sources of blood for Splanchnic Circulation
1) Celiac Artery
2) Superior Mesenteric Artery
3) Inferior Mesenteric Atery
Superior to Inferior Order of Intercostal Neurovascular Bundles
Vein, (posterior) Artery, Nerve (Mnemonic: VAN)
Mechanisms increasing Stroke Volume
1) Sympathetic Stimulation of heart (enhanced atrial and ventricular contractility)
2) Venous return increase via skeletal muscle contraction and respiration
3) Enhanced venous constriction
4) Increased Rate of Lusitropy (cardiac muscle relaxation)
Eustachian Valve
Tissue flap at Inferior Vena Cava and Right Atrium Junction. Directs blood through Foramen Ovale to Left Atrium.
Function of Subcostal Muscles
depress Ribs
Structures in Esophageal Hiatus
1) Esophagus
2) Right and Left Vagal Nerve Trunks
LQT3
Defective fast inactivating Na channel. Inward sodium current increased. Syncope of cardiac arrest more likely to happen during sleep or inactivity
Sources of blood to Sinus Venosus
1) Paired umbilical veins (placenta)
2) Paired Vitelline Veins (yolk sac - future gut)
3) Paired Common Cardinal Veins (from remainder of embryo)
Functions of Atrial Natriuretic Peptide (ANP)
Decreases…
1) renin
2) angiotensin II
3) aldosterone
4) blood volume
5) central venous pressure
6) arterial pressure
Primary Resistance Vessels
Primary Resistance vessels regulating arterial blood pressure and flow within organs are smaller arteries and arterioles
Types of Capillaries (sorted by bulk flow properties from least to greatest permeability)
1) Continuous Capillaries
2) Fenestrated Capillaries
3) Discontinuous Capillaries
Torsade de Pointes
Ventricular tachycardia characterized by a change in amplitude and the twisting of QRS Complexes
Double Aortic Arch
Develops in addition to normal left aortic arch. Due to persistence of Distal pt of R Dorsal Aorta. Forms a vascular ring around trachea/esophagus and causes difficulty in swallowing/breathing.
Augmented Unipolar Leads
Two limbs connected to a (-) terminal. third to a positive.
Leads aVR, aVL, aVF
Innervation of Right Phrenic Nerve
1) Muscles of Right Dome of Diaphragm
2) Central part of Diaphragmatic Pleura/Peritoneum
Hypothermia
Results in general slowing of metabolism and of cardio/neuronal excitability
- Temperature hits 94F - thermoregulation impaired
- Temperature below 85 - thermoregulation lost
- Temperature ~77 - Death due to heart standstill or fibrillation
Delayed Afterdepolarizations
Type of triggered activity leading to tachycardia. May appear shortly after repolarization complete. Most common in states of increased intracellular Calcium. Also can be self-perpetuating and lead to tachyarrhythmia
NDF > 0
Net Driving Force > 0
Indicates filtration
Proteins in myofilament sarcomere
1) actin
2) myosin
3) tropomyosin
4) troponins
5) titin
Conditions DIRECTLY altering (shifting) venous return curves
1) change in blood volume
2) change in venous tone
3) resistance to venous return
Junctional Escape
Escape Rhythm arising from AV node or Proximal Bundle of His. Can happen under moderate parasympathetic stim.
Atrial Internodal Tracts
Specialized myocytes serving as conduction pathways between SA node and AV node.
1) Anterior Internodal Tract
2) Middle Internodal Tract
3) Posterior Internodal Tract
Plurae
continuous layer covering lungs, air tubes, and bloodvessels to lungs and thoracic wall
Thromboxane
Vasoconstrictor
Effect of Sympathetics on Cerebral Circulation
Has little effect actually. Autoregulation due to changes in arterial pressure is the dominant force. Very highly regulated, I might add. Gotta keep a tight hold on these things in the brain cuz
(ECG) Ventricular Pre-Excitation Syndrome
- aka Wolff-Parkinson-White Syndrome (WPW)
- predisposition to PSVTs (accessory pathway can become loop)
- Atrial impulse can move to ventricle both via AV node and Accessory Pathway (faster)
- Ventricles stimulated earlier than normal
- short PR Interval (<0.12 seconds)
- QRS complex “slurred” – called a Delta Wave
- QRS widened
Cisterna Chyli
Dilated lymph sac inferior to diaphragm. Drains into Thoracic Duct
Cardio-Thoracic Ratio
Widest diameter of the heart compared to the widest internal diameter of the Thoracic Cage. Normal CTR is <50% in normal adults
Dextrocardia with Situs Inversus
Dextrocardia with inversion of other viscera
Components of Definitive Ventricular Septum
1) Muscular Ventricular Septum
2) Membranous Ventricular Septum
Superior Vena Cava Syndrome
Bronchogenic tumor of R Lung compresses Superior Vena Cava.
Venous blood from head/neck/upper limbs difficulty returning. Bulged Internal/External Jugular Veins and tributaries of Subclavian in upper R limb.
Venous blood bypasses SVC traveling inferiorly to Azygous Vein.
Azygous Vein -> Ascending Lumbar Vein -> Lumbar Vein > IVC
Chemoreceptor Reflexes
Result of activity of arterial chemoreceptors, located in Carotid Arteries and Aortic Arch. There are also ‘Central Chemoreceptors’ in the CNS.
Respond to decreased PO2, decreased pH, and/or increased PCO2 in arterial blood.
Response: increase breathing and mean arterial pressure
Continuous Capillaries
Tight endothelium and continuous basement membrane. Least permeable type.
Inferior Mediastinum
Located between body and xiphoid process of sternum (anteriorly) - and lower 8 thoracic vertebrae (posteriorly)
Lymph Trunks draining into Thoracic Duct from upper body
1) Left Jugular
2) Left Subclavian
3) Left Bronchomediastinal
Aortic Sinus
Space between each cusp and wall of ascending aorta. Openings to R/L coronary arteries lead from same-named cusps/sinuses.
Fill with blood during diastole when there’s flowback from Ascending Aorta. Cusps close valve and blood enters coronary arteries.
Silhoutte Sign
Elimination of the silhouette or loss of lung/soft tissue interface caused by a mass or fluid in the normally air-filled lung
Aortic Valve
Similar to pulmonary valve. Three semilunar cusps (Posterior/Non-coronary, right, and left). Has the Aortic Sinus
Anatomical Reentry
Unidirectional block and reentry occurring over anatomically-fixed path. Usually appears as monomorphic tachycardia on ECG.
Examples:
- AV Nodal Reentrant Tachycardia (AVNRT)
- Atrioventricular Reentrant Tachycardias (AVRT)
- Atrial Flutter
Functional Conduction Block
Area unexcitable because cardiac cell still refractory.
Ex: Antiarrhythmic drugs induce this condition by prolonging APs
Membranous Interventricular Septal Defect
Failure of fusion of 3 structures forming the Membranous Interventricular Septum. Blood flows from L to R Ventricle. Shunt increases pulmonary blood flow and causes severe pulmonary disease
Cardiac Notch
Indentation in anterior border of left superior lobe of lungs. Due to deviation of hearts apex to left side.
(ECG) Atrioventricular Nodal Reentrant Tachycardia (AVNRT)
- Most common form of PSVTs in adults
- normal QRS complex
- P wave hidden in QRS (retrograde atrial depolarization happens simultaneously with ventricles)
Functional Reentry
Unidirectional block and reentry not requiring fixed path and occurring in electrically heterogeneous myocardium. Waves continually change direction (Spiral Waves)
Examples:
- Polymorphic Ventricular Tachycardia
- Atrial Fibrillation
- Ventricular Fibirilation
Sternopericardial Ligaments
Teather anterior surface of pericardium to sternum
Sympathetic Nerves Effect on Heart
Increased heart rate. Increased contractility. Dilates coronary arteries.
Open Pneumothorax
Happens from a penetrating wound to Thoracic Wall. Air enters pleural cavity since atmospheric pressure > intrathoracic pressure
(ECG) Monomorphic Ventricular Tachycardia
- Wide QRS Complex
- Rate 100-200 bpm
- QRS complexes identical and rate is regular
- Reentry circuit, often from myocardial scar or cardiomyopathy
Left Axis Deviation
Mean Electrical Axis of less than -30
Anteroseptal Myocardial Infarction (Leads and Typical Artery)
Leads V1-V2
Left Anterior Descending Coronary Artery
Bicuspid (Mitral) Valve
Guards left Atrioventricular orifice in the Left Ventricle. Composed of Anterior and Posterior Cusps.
Cusps commonly affected by Ca deposits in Rheumatic Fever. Stick together and lead to valve incompetency and a heart murmur.
Allows placental venous flow to bypass Hepatic Circulation
Ductus Venosus (enters Inferior Vena Cava with deoxygenated blood)
Normal Duration of P Wave
0.08-.10 seconds
2-2.5 boxes
Inferior Myocardial Infarction (Leads and Typical Artery)
Leads II, III, aVF
Right Coronary Artery
Posterior (Base) Surface of Heart
Mostly left atrium
Echocardiography
Measures changes in volume of heart chambers
Internal Intercostal Membrane
Thin aponeurosis replacing internal intercostal muscles in POSTERIOR part of each intercostal space.
Gap in Diaphragm where Superior Epigastric Artery Passes
Sternocostal Hiatus
Coronary Arterial Dominance
Relates to source of Posterior Interventricular Artery. Either from Right or Left Coronary Artery.
From R: Branch of R Coronary Artery (67% pop.)
From L: Branch of Circumflex Branch
Tract of Wenckebach
Another name for Middle Internodal Tract
Sweat
You know what it is bro.
Osmolar concentration below plasma. Made up of NaCL mainly. Trace amounts of potassium, urea, and lactate.
Ways to Express Ventricular Performance on Frank-Starling Curve
1) Stroke Volume
2) Cardiac Output
Stroke Work
Work done by ventricle to eject a volume of blood.
Estimated by:
L Ventricle - SW = SV * Mean Aortic Pressure
R Ventricle - SW = SV * Mean Pulmonary Artery Pressure
Types of Mutations in Long QT Syndrome
1) LQT1 (defective Ks channel)
2) LQT2 (defective Kr channel)
3) LQT3 (defective fast inactivating Na Channel)
Innervation of Parietal Pleura
1) Intercostal Nerves (Costal Pleura and peripheral pt of diaphragmatic pleura)
2) Phrenic Nerve (mediastinal pleura and central part of diaphragmatic pleura)
Automaticity
Ability of heart to initiate own beat
Origin of Intercostal Nerves
Ventral Rami of T1-T11
Third Heart Sound (S3)
Occurs in early diastole during passive ventricular filling. May be normal (if present) in young people but it’s a sign of heart failure in adults > 40
Caused by blood hitting the Ventricular Wall
Innervation of Post-Ganglionic Adrenergic Nerves from the Rostral Ventrolateral Medulla (RVLM)
1) SA + AV Nodes
2) Conduction Pathways
3) Myocardium
Effect: Vasoconstriction / Tachycardia
Causes of Left Axis Deviation
1) Inferior Wall Myocardial Infarction
2) Left Anterior Fascicular Block
3) Left Ventricular Hypertrophy (sometimes)
Vertebral Level: Caval Opening
T8
Specialized epithelium found in plurae, peritoneum, and pericardium
mesothelium
Parasternal Hernia (Foramen of Morgagni)
Abdominal viscera herniated through Sternocostal Hiatus surrounding the Superior Epigastric Artery. Hiatus abnormally enlarged due to developmental issues of small part of muscles of diaphragm. Rare.
Anterior Median (Midsternal) Line
Passes through the center of the sternum. Intersects median plan with Anterior Thoracic Wall.
Sternal Puncture (what is it and where is it done)
Body of the Sternum. Done to obtain bone marrow sample.
Activated byCa2+-Calmodulin complex in smooth muscle
Myosin Light Chain Kinase (MLCK)
(ECG) Antidromic AVRT
- Wide QRS complex
- retrograde P Wave (via AV node)
- Complete anterograde conduction happens via Accessory Pathway
Internal Intercostal Muscle
Arranged at 90 degree angle to External Intercostal layer. Most active during expiration.
Forms Left Subclavian Artery
ONLY Left 7th Intersegmental Artery
Double Superior Vena Cava
Terminal part of left anterior cardinal vein that normally degenerates persists
Parietal Pleura
Outer wall of cavity
Neural Areas Regulating Cardiovascular Function
1) Medulla (Reticular formation of ventrolateral medulla and lower 1/3 pons)
2) Hypothalamus
3) Cerebral Cortex
Congenital Diaphragmatic Hernia (Foramen of Bochdalek)
Herniation of abdominal organs into pleural cavity, due to a defect in diaphragm. Failure of Pleuroperitoneal Membrane to form or fuse properly with other contributors to diaphragm.
Compression of lungs if defect is large. Lungs are hypoplastic (underdeveloped) and dysfunctional. High mortality rate
Phases of Cardiac Cycle
1) Atrial Systole
2) Isovolumetric Contraction
3) Rapid Ejection
4) Reduced Ejection
5) Isovolumetric Relaxation
6) Rapid Filling
7) Reduced Filling (Diastasis)
Blood supply to Anterior Abdominal Wall
Superior Epigastric Artery
Aortic Arch 3
Proximal pt: Forms Common Carotid Artery
Distal pt:
1) Internal Carotid Artery (along with pt of Dorsal Aorta)
2) External Carotid Arteries
Location of division of Internal Thoracic Artery into terminal branches
level of 6th intercostal space
Branches of Right Coronary Artery (Proximal to Distal)
1) Sinu-Atrial Nodal Branch
2) Marginal Artery
3) AV Nodal Artery
4) Posterior Descending Artery (Posterior Interventricular Branch)
Types of Ribs
1) True Ribs
2) False Ribs
3) Floating Ribs
Factors Affecting Preload
1) Total Blood Volume
2) Venous Tone (alters amount of blood in veins)
3) Atrial Contraction (increases amount of blood in ventricle)
4) Intrathoracic Pressure
5) Body Position
6) Skeletal Muscle Pump
7) Intrapericardial Pressure (build-up of fluid limits cardiac filling)
EKG Chest Leads
V1 - 4th ICS, 2 cm R of Sternum V2 - 4th ICS, 2 cm L of Sternum V3 - Midway between V2 + V4 V4 - 5th ICS, L Midclavicular Line V5 - 5th ICS, L Anterior Axillary Line V6 - 5th ICS, L Midaxillary Line
Thyroxine
Effect on all cells to increase local metabolic rate upto 100% of basal. Heating effect on body
Layers of (large) blood vessels (superficial to deep)
1) Intima
2) Media
3) Adventitia
β2-Adrenergic Receptors and Epinephrine levels
Arterioles in specific organs have β2 receptors mediating vasodilation. They are more sensitive to epinephrine than α1 receptors.
Moderate levels of epinephrine: vasodilation (β2)
Higher Levels: vasoconstriction (α1)
Everything is negative in this lead
aVR
Structures Visible in Main Pulmonary Artery Level
1) Pulmonary Trunk
2) R/L Pulmonary Arteries
3) R/L Main Bronchi
4) Superior Vena Cava
5) Ascending Aorta
6) Descending Aorta
Sympathetic Nervous Control: Coronary Arteries
Leads to transient vasoconstriction but then unlike other vessels, dilation. Increased heart rate and inotropy leads to production of vasodilator metabolites.
“Functional Sympatholysis”
Postganglionic Cell Bodies of Parasympathetic Division (Location)
Terminal Ganglia
Baroreceptor Reflex
Powered by stretch receptors in the walls of the heart/vessels. Stimulated by distention. Found in abundance in Carotid Sinus (via: CN IX) and Aortic Arch (via: CN X). Monitor arterial pressure.
Tonically active at normal pressure. Firing rate increases with pressure.
Net Effect: Vasodilation of peripheral vessels and decreased rate of cardiac contraction
Paroxysmal Supraventricular Tachycardias (PSVTs)
Sudden onset and termination. Atrial rates 140-250 bpm. Mechanism most often re-entry involving AV node, Atrium or accessory pathway between atrium/ventricle.
Most common form is Atrioventricular Nodal Reentrant Tachycardia (AVNRT)
Special Case: Posterior Wall Myocardial Infarction and ECG
- No pathological W wave because no electrode in place to identify it.
- Leads V1 and V2 record opposite of what hypothetical properly-placed lead would
- Taller than normal R waves in V1, V2
- Distinguish from Right Ventricular Hypertrophy (also large R wave in V1, V2) because RVH causes Right Axis Deviation, this does not!
QT Interval
Action potential duration. Length of depolarization and repolarization. Beginning of QRS to end of T.
Reason for increased risk of sudden death in Long QT Syndrome
Ventricular Fibrillation
Subregions of Parietal Pleura
1) Diaphragmatic Part
2) Costal Part
3) Mediastinal Part
4) Cervical Part
Treatment for Patent Ductus Arteriosus
Postaglandin Synthesis Inhibitors to promote closure
Components of Cardiac Conduction System
1) SA Node
2) AV Node
3) Bundle of His
4) Left/Right Bundle Branches
5) Purkinje Fibers
Membranous Part of Interventricular Septum
Thin; located in upper septum, inferior to right + posterior cusps of Aortic valve
site of congenital Ventricular Septal Defects (VSD)
Esophageal Hiatal Hernia
Stomach herniated through an enlarged Esophageal Hiatus of the Diaphragm. Stomach contents reflux into the esophagus. Esophageo-Gastric sphincter is nonfunctonal. Infants present with vomiting when laid on back
Mean Electrical Axis
Average of all of the instantaneous mean electrical vectors occurring during ventricular depolarization
Nerve innervating same dermatome as heart
Intercostobrachial Nerve (T2)
Fate of Left Horn of Sinus Venosus
Forms the Coronary Sinus
Autoregulation (Vessels)
Intrinsic ability of organ to maintain constant blood flow despite change in perfusion pressure
Prostacyclin (PGI2)
Vasodilator
Right Aortic Arch
Can pass anterior or posterior to esophagus/trachea. Difficulties swallowing/breathing.
Due to persistence of entire right dorsal aorta and degeneration of distal part of left dorsal aorta
Arachidonic Acid Metabolites
Released as Endothelial-Derived Factors
1) Prostacyclin (PGI2)
2) Thromboxane
3) Leukotrienes
(ECG) First Degree AV Conduction System Block
- PR interval is lengthened ( >0.2 seconds)
* benign, asymptomatic
Pyothorax
pus in pleural cavity
Capillary Hydrostatic Pressure (Pc)
Determined by arterial/venous pressures and by precapillary/postcapillary resistance
Increased by:
- Increase in arterial/venous pressure
- Increase in venular resistance
Decreased by:
* Increase in arteriolar resistance
Intercalated Discs
Junctions between cardiac muscle cells with Mechanical and Electrical connections.
Trabeculae Carnae
Irregular ridges of muscle that line the Ventricular Lumen
Anterolateral Myocardial Infarction (Leads and Typical Artery)
Leads V5-V6, I, aVL
Left Circumflex Coronary Artery
Pyrogens
Substances causing hypothalamic set point to rise (fever?)
ex: Proteins, breakdown products of proteins, lipopolysaccharide toxins
Heat Exhaustion
Occurs after excessive loss of salt and water due to sweating and/or venous return being compromised by heavy exertion and maximum cutaneous vasodilation.
Body temp may still be normal
Innervation of Left Phrenic Nerve
Muscles and central part of diaphragmatic pleura/peritoneum
Mean Arterial Pressure
Blood pressure averaged out by time.
Approximation: MAP = P(diastolic) + [P(systolic) - P(diastolic)] / 3
Destination of Inhibitory Interneuron from Nucleus Tractus Solitarus
Sympathetics in Rostral Ventrolateral Medulla (RVLM)
Abnormal Right Subclavian Artery
Branch of the aortic arch and passes posterior to esophagus. (Starts to left of esophagus instead of on right like normal) Can result in kinking of the esophagus. Dysphagia. Result of..
1) Obliteration of R 4th Aortic Arch and adjacent part of R Dorsal Aorta
2) Abnromal R Subclavian forms from right 7th intersegmental artery and persistence of distal part of R Dorsal Aorta (normally degenerates)
Diurnal Variation
Core temperature minimal ini the morning and peaks in the late afternoon
(Jugular Venous Pulse Graph) A Wave
Upward wave coinciding with Atrial Systole
Structures that pierce Crura of Muscular Diaphragm
1) Greater, Lesser, and Least Splanchnic Nerves
2) Hemiazygous Vein
Thymus Gland
Bilobed lymphoid organ of immune system, located in Superior and Anterior (Inferior) Mediastinum. Becomes fatty remnant in puberty.
Pericardial Effusion
Fluid (blood) can build up in pericardial sac due to external fluid pressure on heart. Can cause Cardiac Tamponade (compression by fluid)
Deviation in Left Anterior Fascicle Block
Left Axis Deviation
Stenosis of Aortic Orifice
Narrowing due to adherence of free margins of cusps
Function(s) of Fibrous Skeleton of Heart
1) Attachment site for valves (Anulus fibrosis)
2) Attachment site for cardiac fibers
3) Separates atrial from ventricular cardiac muscle at Atrioventricular Orifice
4) Gives rigidity to orifices
Components of Definitive Left Ventricle
1) Trabeculated Part from Primitive Ventricle
2) Smooth Upper Part (Aortic Vestibule) from Bulbus Cordis
Spine Sign
Density of vertebral column (check lateral view) gradually decreases down the spine (becomes darker). Absence of the decrease in density may indicated a mass overlying the vertebrae
Form Definitive Arch of Aorta
1) Left Aortic Arch 4
2) Aortic Sac
3) Left Dorsal Aorta
(Fast Response Action Potential Receptors) Phase 0
Depolarization by Sodium influx through fast channel Nav1.5
Bronchopulmonary Segment
a function surgical/functional unit of lung
Aortic Arch 4
- Left Aortic Arch 4: Arch of the Aorta (along w/ aortic sac and left dorsal aorta)
- Right Aortic Arch 4: pt of Right Subclavian Artery
