module 3 - 8.5 the heart Flashcards
what is the heart?
a muscular organ that pumps blood through the circulatory system by increasing blood pressure relative to lowest blood pressure in blood vessels - difference in pressure causes blood to flow
what 3 layers is the wall of the heart made up of?
- epicardium - outer layer of the heart wall and inner pericardial membrane
- myocardium - cardiac muscle
- endocardium - lines the chambers and covers the heart valves, joins with endothelium that lines blood vessels
what is the heart enclosed by and why?
- enclosed by pericardium for protection of the heart
- fluid between inner and outer pericardial membranes lubricates movement of the heart
what is the pericardium?
double walled sac for protection of the heart
why does blood not separate when pumped?
due to hydrogen bonds between water molecules in blood
where is the heart beat initiated?
right atrium
where does the tricuspid valve prevent backflow of blood?
from right ventricle to right atrium
which pressure increases during ventricular systole in a mammalian heart?
ventricular pressure
when listening to the heart on a stethoscope, what contributes to the first ‘lub’ sound?
closing of the bicuspid valve
when listening to the heart on a stethoscope, what contributes to the second ‘dub’ sound?
closing of semi lunar valves
what are the 3 types of vertebrate muscle?
skeletal , cardiac, smooth
what are cadriac muscles made from?
cardiomyoctyes joined together by intercalated discs
why do cardiomyocytes need to contract in coordination with its neighboring cells?
to efficiently pump blood from the heart, if this coordination breaks down, the heart may not pump blood
what are intercalated discs?
a type of cell junction/cytoplasm bridge
what do intercalated discs allow?
allows cardiomyocytes to contract in coordinated manner
what are the 4 valves in the heart?
bicuspid
tricuspid
pulmonary
aortic
what are the main pumping chambers?
ventricles
what is the flow of blood and blood type on the right side of the heart?
- deoxygenated blood
- travels to lungs from the rest of the body
what is the blood flow and blood type on the left side of the heart?
- oxygenated blood
- travels from lungs to the rest of the body
what is the role of cardiac fat around the heart?
- food supply
- protection
what are papillary muscles?
they prevent heart valves from folding too far back during heart contraction
what are chordae tendineae?
connect papillary muscles to the cusps of atrio-ventricular valves
what are trabeculae carneae/’meaty ridges’?
rough lining of inside of ventricles, help papillary muscles to prevent folding of atrio-ventricular valves
- keep heart strings tight
what is the pericardium?
a double-walled sac containing the heart and roots of the great vessels
what are the 2 layers of the pericardium?
- fibrous pericardium - outer layer made of strong connective tissue, mostly fixed shape
- serious pericardium - inner layer made of serous membrane, smooth to allow sliding motion
what does the pericardium do?
encloses pericardial cavity which contains pericardial fluid
what does pericardial fluid do?
heart movements
