Cardiovascular pathology 1 Flashcards
Where does the heart develop from?
Splanchnic mesenchyme in the cardiogenic area
The embryological heart develops dilatations and constrictions which result in which 4 chambers?
- Sinus venosus
- Primordial atrium
- Primordial ventricle
- Bulbus cordis
How does the heart develop during cardiac looping?
The heart is converted from an elongated muscular tube into a C-shaped structure by a process termed looping
What are the precursors of the valve cusps called?
Endocardial cushions
Which two septum position the atria successively?
Septum primum
Septum secundum
The septum secundum is an incomplete partition and leaves …?
A foramen ovale
What is the role of the foramen ovale before birth?
Allows blood to pass from the right to the left atrium with reflux being prevented by a valve
What happens to the foramen ovale after birth?
Closes by fusion of the septum primum and septum secundum
The interventricular septum consists of which 3 parts?
- Muscular portion
- Membranous portion
- Conotruncal ridged
What do the 4th left and right aortic arches form?
Left - forms the proximal part of the arch of the aorta
Right - forms the proximal part of the right subclavian artery
Describe the flow of blood through fetal circulation starting at the umbilical veins
Umbilical veins => liver/ductus venosus => vena cava => right atrium => either through the foramen ovale to the left atrium and then aorta or to the right ventricle to the pulmonary artery, ductus arteriosus and then aorta => systemic arteries => umbilical arteries => placenta
Which 2 parts of foetal circulation are oxygen and nutrient rich?
Placenta
Umbilical veins
Which part of foetal circulation is oxygen and nutrient poor?
Umbilical arteries
Name and describe the sac surrounding the heart
Pericardium
- one layer of mesothelium with a central layer of connective tissue and adipose tissue
Name and describe the outer surface of the heart
Epicardium
- one layer of mesothelium and one connective tissue and adipose tissue
Name the muscle layer of the heart
Myocardium
What is the endothelium?
Identical to arterial endothelium with connective tissue and Purkinje fibres - lines the inner part of the heart
Describe the histological features of myocardium (cardiac muscle)
- Centrally placed nuclei
- Sarcomeric cross striations
- Ratio of muscle fibres to capillaries is 1:1
- Purkinje fibres arranged in bundles
- Connective tissue
Where are post-mortem clots seen in the heart and why do they occur?
Red clots in the atria, right ventricle, and large vessels at the base of the heart
- occur because the blood is static when circulation stops
How does rigor mortis affect the heart?
- Occurs in the left myocardium and produces contracted rigid ventricular walls
- Less pronounced in right side of heart
How will rigor mortis be different in the heart of animals with prolonged heart disease? Why is this?
- The ventricular chambers may fail to contract during rigor mortis: grossly soft muscles
- Occurs because there are inadequate glycogen reserves in cardiac myocytes
What are chicken fat clots?
- Sedimentation of erythrocytes
- Clots consist of colourless fibrin with no erythrocytes
What is haemoglobin imbibition?
Postmortem lysis of erythrocytes which produces a diffuse red staining of the endocardium