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
