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165 Cards in this Set
- Front
- Back
What are the two layers of the pericardium?
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1. Fibrous pericardium
2. Serous pericardium |
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Where is the fibrous pericardium attached?
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Anteriorly to the sternum, posteriorly to structures in the posterior mediastinum, inferiorly to the diaphragm
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What layer is the fibrous pericardium?
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Outer layer
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What are the two layers of the serous pericardium?
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Parietal: lines the inside of the pericardium
Visceral: covers the heart, also called epicardium |
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What is the pericardial cavity?
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The space between the two layers of serous pericardium
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What are the two pericardial reflections?
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1. Transverse sinus
2. Oblique sinus |
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Where is the transverse sinus?
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Posterior to the ascending aorta and pulmonary trunk, and anterior to the superior vena cava, separates venous from artery
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Where is the oblique sinus?
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A recess posterior to the heart, blocked by the serous pericardium
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Pericardial effusions?
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fluid from pericardial capillaries collecting in the pericardial cavity
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Cardiac Tamponade?
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Excessive fluid accumulation that exerts pressure in the heart and affects action of the heart
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What is the base of heart?
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It is where all the vessels attach
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What is the apex of the heart?
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Inferior most portion of the heart. It is pointy
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What does the coronary sulcus do?
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Separates atria from ventricles
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What is a sulcus?
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A depression or groove
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What does the anterior interventricular sulcus separate?
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Left ventricle from the right ventricle
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Position of the right atrium?
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Right most
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Position of the left ventricle?
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Left most
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Position of the right ventricle?
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Anterior most
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Position of the left atrium?
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Posterior most
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What is a coronary artery?
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Artery delivering blood to the heart
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What branches from the right coronary artery?
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1. Sinoatrial nodal a.
2. Marginal a. 3. Posterior interventricular artery 4. Atrioventricular node artery |
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What arises from the left coronary artery?
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1. Anterior interventricular a.
2. Circumflex a. |
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Where does the rt and lt coronary arteries come from?
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rt and lt aortic sinus
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What is a left coronary-artery dominant heart?
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Left gives rise to the posterior interventricular artery (15% of time, rt=67%, balanced=18%)
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What are the 3 cardiac veins and what do they drain?
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GMS:
Great cardiac v. = drains the apex, anterior interventricular sulcus to the left side of the coronary sulcus Middle cardiac v.= drains the apex, posterior interventricular sulcus to the right side of the coronary sinus Small cardiac v.= travels with marginal artery |
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What drains the cardiac veins?
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Coronary sinus
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What plane of the heart would you take to see all 4 chambers
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Slightly angled transverse plane
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What forms the endocardial tubes and in what week do they appear?
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The tubes are formed by angioblastic cords in splanchnic mesoderm during the 4th week
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What are the three layers of the endocardial tubes?
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1. endocardium- future internal endothelial lining of heart
2. Myocardium- muscular wall of the heart 3. Epicardium- Becomes the visceral pericardium |
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What separates the myocardium from the endocardium?
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Cardiac jelly
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What are epicardium cells derived from?
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Mesothelial cells
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What does lateral folding of the embryo cause?
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endocardial tube fusing, craniocaudally
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What does headfolding of the embryo cause?
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The heart and pericardial cavity to lie ventral to the foregut, and caudal to the oropharyngeal membrane
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How is the endocardial tube formed?
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Endocardial cells grow and make a column, then apoptosis hollows out the inside to form a tube
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What does the dorsal mesocardium do?
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suspends the developing heart from the pericardial cavity
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When is the dorsal mesocardium degraded?
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Week 4
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What does the primitive atria give rise to?
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Auricle
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What does the endocardial tube elongate to form?
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ATABS(V)V
A: Primitive Atria (gives rise to auricle) T: truncus arteriosus: Located cranially A: Atrioventricular canal: separates primitive atria from primitive ventricle B: Bulbus cordis: just caudal to truncus arteriosus S(V): Sinus venosus: Located caudally, receives the umbilical, vitelline, and common cardinal veins V: Ventricles |
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What causes shifting of the endocardial tube?
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Different rates of growth
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How is heart bending accomplished?
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Ventricle and bulbous cordis grow more rapidly causes the tube to bend, leads to atrium and sinus venosus moving cranially, the ventricle moves caudally, bulbous cordis shifts to the right
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What are the final heart positions after bending?
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Atrium: dorsocranial location, widens laterally
Ventricle: caudal Bulbus cordis: right side |
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When do the four septations occur?
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concurrently
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When does septation begin and end?
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4th week to the 8th week
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What forms endocardial cusions which project into the lumen?
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Cell proliferation within the dorsal and ventral walls of the atrioventricular canal
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What creates the septum intermedium?
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Fused endocardial cushions
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What does the septum intermedium separate?
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The atrioventricular canal into left and right portions
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What is the sinus venarum?
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Smooth part of the posterior inner wall of the right atrium
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What is the auricle?
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Atrial appendage
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What muscle does the auricle contain and what is it a convenient site for?
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Pectinate mm which terminates on the crista terminalis... surgical access
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What opens into the right atria?
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VICTS:
Venae cordae minimae Inferior VC Coronary sinus Tricuspid valve (anterior posterior and septal cusp) Superior VC |
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What is an embryological remnant of the foramen ovale?
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Fossa ovale
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Where is the fossa ovalis located?
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Interatrial septum to of the right atrium. it is a shallow translucent oval depression
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What is an atrial septal defect?
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Failure of the fossa to close allowing oxygenated blood from the left atrium to enter the right atrium.
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How many openings does the left atrium have into the principal cavity?
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4. 2 superior, 2 inferior, left and right
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How many cusps does the mitral valve have?
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bicuspide, anterior and posterior cusps
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What separates the 2 forming atria?
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The septum primum ( thin crescent shaped membrane, grows from the roof of the atrium fuses with endocardial cushions)
Septum secondum- thick septum |
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What is the foramen primum?
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space between the septum primum and endocardial cushions, allows O2 blood to pass from rt to lt atrium
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What is the foramen secondum?
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Coalesced perforations in the septum primum as the foramen primum closes. Allows O2 to pass from the right atrium to left atrium
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Characteristics of the septum secondum?
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thick, originates from cranial wall of atrium
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What is the foramen ovale?
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Opening between free edge of septum secondum and septum primum.
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What drains into the sinus venosus horns?
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Common cardinal vitelline and umbilical veins
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What forms the coronary sinus?
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the shrunken left horn of the sinus venosus
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What do veins that drain to the right horn anastomose to become?
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Superior vena cava
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What does the right horn become?
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smooth walled portion of the right atrium
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What does the primitive right atrium become?
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right auricle and pectinate mm of the right atrium
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What forms the smooth walled portion of the left atrium?
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the root of the pulmonary vein
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Papillary mm, where do they arise, attach and anchor?
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Arise from the ventricular wall, attach to the leaflets of the tricuspid valve via chordae tendinae, anchor the cusps
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What is the trabeculae carnea?
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Irregular muscular elevations projecting from ventricular walls.
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What is the conus arteriosus (infundibulum)?
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Funnel shaped, smooth walled tube leading to the pulmonary trunk
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What does a valve cusp consist of?
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a nodule, lunule and sinus
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Where is the pulmonary vale located and how many semilunar cusps does it have?
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Apex of the conus arteriosus, 3 cusps
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Which ventricle has finer and more numberous trabeculae carnae?
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Left ventricle
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How do the ventricles and great vessels form?
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Bulbar and truncal ridges form on opposite internal walls of the bulbus cordis and truncus ateriosus, ridges proliferate in a spiral fashion, they meet at the midline to form the aorticopulmonary septum
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What does the aorticopulmonary septum create?
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Distinct aorta and pulmonary artery
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What does the bulbus cordis form in each ventricle?
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Conus arteriosus in the rt, aortic vestibule in the lt
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When does partitioning of the bulbus cordis and truncus arteriosus occur?
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at the 5th week
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When do the ventricles separate?
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4th week
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What does the muscular interventricular septum develop from?
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Base of the primitive ventricle
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What is the interventricular foramen?
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Space between the muscular interventricular septum and fused endocardial cushions
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Membranous interventricular septum forms from what three sources?
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Right bulbar ridge, the left bulbar ridge, and proliferation of the fused endocardial cushions
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What is Hemopoiesis?
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Development of blood
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What type of cells do blood cells develop from?
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Endothelial cells
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What are the 3 primary sites of hematopoieses and during what times?
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Yolk sac (3rd week - 2nd month)
Liver (starts 5th week, primary site 3-6 months) Bone marrow (begins in 4th month and is primary from 7th month till birth) |
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Where does primitive blood circulation occur?
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Yolk sac, chorion, embryo
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What are the 3 major pairs of fetal arteries?
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DUV:
Dorsal aortae (O2 to embryo) Umbilical (Carry Deox blood from embryo to placenta) Vitelline- O2 blood to the yolk Sac |
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What enlarges to form the aortic sac?
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Cranial truncus arteriosus
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How many aortic arches are there and what do they connect?
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6 pairs, connect aortic sac to the dorsal aortae
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Which aortic arch pairs degenerate?
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1, 2, 5
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What does the 3rd aortic arch become?
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Proximal- common carotid arteries
Distal + Dorsal Aorta - Internal carotid arteries |
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What does the 4th aortic arch become?
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Left- arch of the aorta
Right- proximal part of right sublcavian artery |
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What does the 6th aortic arch become?
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Right of 6th degrades, Proximal- pulmonary arteries
Distal left- Ductus arteriosus |
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What does the ductus arteriosus do?
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Allows blood between the aorta and pulmonary trunk, should become ligamentum arteriosum
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What is the reason for the superior location of the right laryngeal nerve?
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Degeneration of the 6th right arch allows the nerve to move superiorly in the body
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What does the aortic sac become?
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Arch of the aorta & Brachiocephalic artery
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What are the 3 pairs of embryo veins?
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Cardinal (from embryo), vitelline (from yolk sac), umbilical (carries O2 blood to embryo from placenta)
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What forms the superior vena cava?
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The right anterior cardinal and right common cardinal veins
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What doe the following cardinal veins drain?
Anterior Posterior Common |
Anterior- cranial
Posterior- caudal Common- drains anterior and posterior |
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What does the Vitelline vein form in the:
duodenum? Liver? Cranial to liver, rt vitelline vein remains what? |
Duodenum- portal vein
liver- hepatic vein cranial to liver- hepatic inferior vena cava |
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What happens to the umbilical left and right?
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Right degenerates,
left degnerates in region of liver and cranial to liver, Caudal to liver it enlarges to carry all blood from the placenta |
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What is the ligamentum teres?
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What the left umbilical becomes after birth
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What is the ductus venosus, and what does it become after birth?
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The ductus venosus is a shunt between the umbilical vein and IVC. It becomes the ligamentum venosum
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What is the path of blood through the heart?
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SVC & IVC -> rt atrium -> rt ventricle -> pulmonary trunk -> pulmonary veins -> lt atria -> lt ventricle -> Aorta
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What is the fetal circulation?
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Most: umbilical -> ductus venosus -> SVC & IVC -> rt atrium -> foramen ovale -> lt atrium and on
Some rt atrium -> rt ventricle -> pulmonary trunk -> ductus arteriosus and into the aorta (90%) or into pulmonary circulation (10%) |
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What is the ductus arteriosus?
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Shunt from the pulmonary trunk to the aortic arch
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After birth what two things happen in circulation due to pressure changes in the chest due to breathing?
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Foramen ovale closes (becomes the fossal ovalis) and the ductus arteriosus constricts (bradycinine) and eventually atrophies to ligamentum arteriosum
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Adult circulation with valves?
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Rt atrium -> tricuspid -> rt ventricle -> pulmonary valve -> arteries to veins to lt atrium -> mitral valve -> lt ventricle -> aortic valve
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Sympathetic innervation of the heart?
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Preganglion in T1-5 in the IMLCC
Postganglion from superior, middle and inferior cervical ganglia |
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Parasympathetic innervation of the heart?
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Preganglionic fibers in vagus (CN X)
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SA location and what does it receive innervation from?
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SA node (wall of rt atrium) receives symp & parasym innervation from cardiac plexus
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Pathway electrical signal follows
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SA node to AV to bundle branches to muscles
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AV node location, bundle and branches
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In the interatrial septum, AV bundle or bundle of HIS then the Right and left branches finally to the terminal subendocardial network
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What is an atrial septal defect (ASD)? cyanotic?
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Functioning opening between right and left atria, results in blood flow from left to right - due to failure of the septum primum to press against septum secondum - acyanotic
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What are 2 causes of Atrial septal defects?
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Abnormal resorption of septum primum
Inadequate development of septum secondum |
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What is a ventricular septal defect (VSD)? cyanotic?
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Functional opening between the ventricles, most common cardiac defect- acyanotic
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What is more common, membranous VSD or muscular VSD?
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Membranous VSD
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How does blood flow in VSD and the ASD? What does these do to infants?
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from left to right - fatigue easier
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What is the reason for VSD?
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failure of tissue from endocardial cushions to fuse with aorticopulmonary septum
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What are the four features of the tetralogy of Fallot?
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PARV
Pulmonary stenosis: obstruction of right ventricle outflow Aorta overrides VSD Right ventricular hypertrophy Ventricular septal defects |
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How does blood flow in the tetralogy and what does this lead to? And what is the shape of the heart in CXR?
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Blood flow is from right to left, infant is cyanotic... Boot shaped appearance due to right ventricle hypertrophy
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What is an explanation of tetralogy of Fallot?
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Unequal division of the bulbus cordis by aorticopulmonary septum (gives large aorta and small pulmonary trunk)
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What is persistent truncus ateriosus?
What defect is it accompanied by? |
blood flow from both ventricles leaves by the same vessel i.e. pulmonary artery and aorta are not separated. Always accompanied by VSD
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What is the embryological explanation for persistent truncus arteriosus?
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Failure of truncal and bulbar ridges to develop hence:
1. no division of vessel 2. No membranous interventricular septum |
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What is transposition of the great vessels?
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Aorta arises from right ventricle, pulmonary trunk arises from the left ventricle. Blood flows from system to right side to system. or pulmonary vessels lt heart to pulmonary vessels
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Transposition of Great Vessels:
Baby cyanotic? What is necessary for survival? Embryological explanation? |
Yes
Mixing blood through: 1: Patent ductus arteriosus 2. Open foramen ovale 3. VSD Aorticoplulmonary septum does not spiral |
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What happens to the ductus arteriosus after birth?
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1. Lungs are aerated
2. muscle in wall of ductus contracts 3. ductus arteriosus closes Physiologically in a few hours Anatomically at 3 months 4. Forms ligamentum arteriosum |
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Why would the ductus arteriosus remain open?
Symptoms? |
Muscle does not contract properly
Symptoms: 1. Machine murmur 2. Hypertrophy of left ventricle 3. No cyanosis 4. Growth retardation |
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What is detrocardia, and when is it a high risk condition?
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Heart is on the rt side. High risk is when it occurs without sinus inversus
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What is sinus inversus?
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All organs are reversed
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What is coarctation of the aorta? and where/why does it occur?
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A constriction of the aorta, distal to the origin of the left subclavian (around entrance of ductus arteriosus) due to presence of ductus arteriosus tissue in the region of the arch of the aorta
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What are signs of coarctation of the aorta?
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High BP in upper extremities, low BP in lower extremities, rib notching b/c of large intercostal artery size
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What is angina pectoris?
What is it described as? |
Chest pain due to myocardial ischemia. Due to progressive occlusion of coronary arteries by arterioschlerosis.
Crushing or heavy pain substernally or left side brought on by exercise |
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What is a myocardial infarction?
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heart attack: when ischemia progresses to a point where heart muscles have been perfused by too little blood for too long and dies
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What are women more likely to have with MIs instead of coronary artery disease?
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Abnormalities of coronary endothelial tissue
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What doe women present with when they have a heart attack?
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shortness of breath, nausea, vomiting, sleeplessness, back or jaw pain, fatigue
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How many cell layers is diffusion sufficient for?
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7
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What are the three layers of the heart wall?
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Endocardium, pericardium, epicardium
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What cell type and Connective Tissue (CT)? is endocardium?
Myocardium? Epicardium? |
Endo: simple squamous epith., think layer of CT
Myo: Spiral, multilayered Epi: Squamous epith. w/in CT is adipocytes, nerve bundles, and coronary arteries that penetrated the myocardium |
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What is a modified myofiber in the heart? How does it look different?
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Purkinje fiber, larger not striated more gap junctions, stains paler
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What are cardiac valves composed of, and what are they lined with?
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Composed of dense central core of collagen and elastic fibers, lined with squamous epithelium
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What are the layers of a artery?
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Intima, media, externa
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What does the artery intima consist of?
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layer of endothelial cells with a thin subendothelial layer of loose CT followed by an internal elastic membrane
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What does the artery media consist of?
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Concentric layers of smooth muscle cells with elastic fibers, collagen III fibers, glycoproteins and proteoglycans. The outermost layer is the external elastic membrane
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What does the artery externa consist of?
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Collagen (I) and elastic fibers. This layer becomes continuous with CT of the organ
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What is a vasa vasorum?
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The blood vessels in the externa of large vessels
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What are distinguishing features of elastic arteries? What is a prominent elastic artery?
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1. Large with a lot of elastic fibers in the tunica media
2. Intima is relatively thick and the internal elastic membrane is difficult to distinguish 3. Elastic fibers in the media allow the artery to expand during systole Aorta |
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What are the distinguishing features of muscular arteries (4)?
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1. Layers of smooth muscle in the media
2. Intima has a thin subendothelial layer 3. 30-40 layers of smooth muscle in large arteries with elastic and reticular fibers intermixed 4. Innervated by sympathetic postganglionic axons to control blood flow |
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Features of arterioles?
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1. 1-2 layers of smooth muscle
2. Subendothelial layer is thin, the elastic laminae are absent, |
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What is an anteriovenous anastomoses?
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Allows flow from arterioles to venules bypassing the capillaries
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What is the difference between tunica adventitia and tunica externa?
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Externa is the generic name, and adventitia is the name when in a defined tissue
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Feature of capillaries?
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1. Permit metabolite exchange between blood and tissue
2. single layer of endothelial cells ~ 50 microns long 3. Diameter = diameter of RBC 4. Slow flow rate |
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What are the three types of capillaries?
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1. continuous
2. fenestrated 3. sinusoid |
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What are features of continuous capillaries?
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Occluding junctions between cells, material moved both ways in pinocytotic vesicles. e.g. CNS
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What are features of fenestrated capillaries?
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Thin patches of fenestrae which are covered with proteoglycans, no plasma membrane but the basal lamina is continuous. found in tissues where more rapid exchange is needed (intestine kidney)
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What are features of sinusoid capillaries?
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Large fenestrae without diaphragms, large spaces between cells and basal lamina is non-continuous, cells macromolecules etc are free to move in and out e.g. spleen
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Locations of sinusoidal capilary?
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bone marrow and spleen
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How does venous blood return to heart? 2 ways
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Via contractions of media but mostly compression from surrounding muscles and tissues
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3 layers of large veins?
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Well developed intima, a thin media, a relatively large externa
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What is a vein valve a projection of?
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tunica intima
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What is the lymphatic system?
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A system of thin walled endothelial lined channels that collect excess interstitial fluid and eventually return it to the venous system
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What do lymphatic capillaries begin as?
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closed ended vessels of a single layer of endothelium and incomplete basal lamina
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What do veins and lymphatics have a lot of to prevent backflow?
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valves
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What is the chief propulsive force in lymphatics?
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Muscle contractions
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What is found in the largest lymph vessels?
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Muscle in the middle that runs both longitudinally and circularly, also has vasa vasorum and a neural network
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Thrombus vs embolus?
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Thrombus - a solid mass of platelets and/or fibrin that forms in a vessel
Embolus - a piece of a thrombus that has broken free and is carried toward the brain by the blood stream |
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Cause of an aneurysm?
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Hardening of arteries, age
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