Intro/Heart Failure Flashcards
What is the function of the heart?
So tissues receive adequate nutrients & oxygen, & waste products are removed
What is the first organ to form in the embryo?
heart
What chambers does the heart consist of in mammals and birds?
4 chambers (2 atria & 2 ventricles)
What are the 4 cardiac valves?
- Right atrio-ventricular (tricuspid)
- L atrio-ventricular (bicuspid or mitral)
- Aortic (semi-lunar)
- Pulmonic
Which ventricle is thicker in the adult animal?
L ventricle
Systemic circulation returns…
… non-oxygenated blood from the body to the R atrium via the vena cava
From R atrium blood passes through…
…right AV valve into right ventricle
From R ventricle blood is pumped ….
…into lungs via pulmonary (pulmonic) arteries
Blood passes from L atrium to….
…L ventricle through mitral valve
From lung…
… oxygenated blood returns to the L atrium via pulmonary veins
What are the 3 layers of the heart?
- pericardium (epicardium)
- myocardium (heart muscle)
- endocardium (atria, ventricles, & valves
What needs to be removed from heart to expose epicardium (is continuous with it)?
Pericardium
What is pericardium?
Double-layered serosal mb that covers heart & proximal part of great vessels
What is the parietal pericardium?
most external & thicker layer of pericardial sac
What is the visceral pericardium?
(aka epicardium); most internal & thinnest layer of pericardial sac that intimately covers myocardium
What are 2 serosal mbs of the pericardium composed of?
thin layer of mesothelium & CT which supports blood vessels, lymphatic vessels, nerves, & adipose tissue
What does the epicardial fat generally follow?
Coronary grooves
What is the pericardial space & what does it contain?
Present btwn epicardium & pericardium. Contains small amounts of clear lubricating fluid
What is the myocardium?
Muscle of the heart
How does the heart pump blood to the lungs & systemic circulation?
through contraction (systole) & relaxation (diastole)
How does the myocardial muscle compare to skeletal muscle?
they are histologically similar but not identical
What kind of muscle is the myocardium?
involuntary, striated muscle w/ branched fibres that connect to each other through intercalated disks. these fibres contain abundant mitochondria (only seen by electron microscopy).
What is the endocardium?
thin layer lining internal surface of heart
endocardium of heart is equivalent to what in blood vessels?
tunica intima
Endocardium is in close contact w/?
blood
Endocardium is microscopically composed of these 3 layers:
- endothelium (superficial)
- basal lamina
- sub-endothelial CT (elastin & collagen)
Part of the conductive system & Purkinje fibres are contained in which heart layer?
endocardium
What are Purkinje Fibers?
Specialized myocardial cells that are responsible for electrical impulse conduction (not to be confused w/ Purkinje cells in cerebellum)
What do heart valves allow for?
Unidirectional blood flow