*Cardiovascular system Flashcards
how many chambers does the heart have?
4 chambers
what are the 5 blood vessels?
- arteries
- arterioles
- capillaries
- venules
- veins
where is the heart found?
lies in mediastinum (space between lungs)
how large and what shape is the heart?
- fist sized
- coned shaped
what is the base of the heart? where is it found?
- top of the heart
- rib 2
what is the apex of the heart? where is it found?
- lowest corner
- 5th intercostal space, medial /inf to nipple
what is the heart position? (superiorly, inferiorly, anteriorly, medial, posteriorly)
- Superior to the diaphragm
- Inferior to the major blood vessels; superior vena cava, pulmonary arteries, ascending aorta pulmonary veins
- Anterior to the oesophagus, trachea, bronchi, descending aorta, inferior vena cava
- Medial to left and right lungs (left side overlaps)
- Posterior to the thymus, sternum, ribs & intercostal muscles
what are the 3 layers of the heart wall?
3 layers (outer to inner):
- Pericardium
- Myocardium
- Endocardium
what are the 2 sacs of the pericardium?
- fibrous pericardium
- serous pericardium
what are the characteristics of the fibrous pericardium?
inelastic, prevents over-distension
what are the characteristics of the serous pericardium?
Continuous double layer:
- Parietal pericardium
- Visceral pericardium
Pericardial fluid between them to minimise friction = pericardial cavity
what is the myocardium made up of?
Specialised cardiac muscle – striated involuntary
where is the myocardium the thickest in the heart?
at the apex
what allows rapid transmission of nerve impulses through the myocardium?
Intercalated discs allow rapid transmission of nerve impulse through sheet of muscle so myocardium contracts in co-ordinated way.
how and what are the hormones secreted from the myocardium?
Atrial natriuretic peptide (ANP) secreted by specialised muscle cells in atria (act on kidneys) in hypervolaemia (high blood volume)
