ANATOMY OF THE HEART Flashcards
pulmonary vs systemic circulation?
- pulmonary = heart –> lung –> heart
- systemic = heart –> throughout body –> heart
what are the 3 general principles for organisation of the cardiovascular system?
- supply side
- exchange network
- drainage
TRUE/FALSE? arteries are the only supply path
true
where is major arteries located and how it reflects the characteristic?
- situated to avoid damage e.g. deep in the trunk or on flexor aspects of limbs
- supply path blood having high velocity so need protection
how many sources would important structures often receive supply from?
2
the various degrees of permeability in capillaries?
- continuous
- fenestrated
- sinusoidal
the 3 pathways of drainage?
- deep veins
- superficial veins
- lymphatics
why is the cross-sectional area of veins is at least twice that of arteries
- to shift the same volume of blood/second
- due to different physiology: pressure decrease –> velocity decrease for good exchange –> increase cross sectional area of drainage to balance the difference between in and out
what is the shape of the heart?
blunt, cone shaped
where is the apex and where is the base of the heart?
- base = broad end, align around 2nd-3rd rib
- apex = pointed end, at midclavicular around 5th and 6th ribs
what is the PMI?
- point of maximal impulse
- where apex push hard against chest wall –> where we can listen to heart pound
how does the heart situated within the thoracic cavity and what does that helps with the body function?
- 2/3 heart sit to left of midline
- apex point anteriorly
- this helps heart beats to chest wall instead of diaphragm
simply describe small circulation of blood?
- blood goes to right atrium (receive from systemic)
- blood then drains to the right ventricle (deoxygenated blood)
- after being pushed out to the lungs for reoxygenate, blood goes back into left atrium
- then blood drains down to left ventricle and being driven to the systemic circulation
why does atria of the heart has thin wall?
receiving chambers –> not too much work or pushing blood to the circulation pathways –> not need too much muscle
what 3 veins bring deoxygenated blood to right atrium?
- superior vena cava
- inferior vena cava
- coronary sinus
left atrium receives oxygenated blood from:
4 pulmonary veins
what are the layers of the heart wall from innermost to outermost?
- endocardium
- myocardium
- epicardium
- pericardium
what is the thickest layer of the heart wall?
myocardium
what is the overall function of pericardium?
- provide lubricated sac –> not damage own heart when beating
- protect heart against injury and abrasion
what is the type of epithelial sound at endocardium?
- squamous –> endothelium
- loose irregular FCT
what is endothelium?
- lines the cardiovascular system and prevent blood clottage
- barrier between blood and wall of system
what size of blood vessel at endocardium?
small
what is a specialised type of tissue that you can find in endocardium and what is it for?
purkinje fibre –> carry electrical conduction eventhough not nervous tissue
why is there a difference between thickness of the myocardium layer between left and right side of the heart?
- left around 0.5cm, right around 1.5cm
- need to pump the same volume but left side has a short journey (pulmonary circulation) meanwhile right side has a long journey (systemic circulation)
- right side needs to generate more force and bigger pressure
what type of muscle is myocardium?
cardiac muscle
what can you find in epicardium ?
- blood vessels
- loose irregular FCT
- adipose
- visceral pericardium
which part of the epicardium fuses with pericardium?
visceral pericardium
describe structure of the pericardium?
- a leathery bag of fibrous pericardium - thin but very strong at the outermost
- a parietal layer of serous pericardium which adhere with fibrous pericardium and part of visceral serous pericardium
- pericardial cavity which contains the serous fluid
what is AV valve?
- atrioventricular valve
- between atrial and ventricle of the heart
function of the av valve?
prevents blood returning to atria during ventricular contraction
compare between the left and right side av valves
- left side: biscuspid (2 leaflets) valve
- right side: triscuspid valve
briefly compare diastole and systole phase of the heart, then relates it to the operation of av valve?
- diastole = filling phase (blood flows from atrium to ventricle) –> av valve opens
- systole = contracting phase (ventricle contracts to push blood through the circulations) –> av valve
what is the function of semilunar valves?
prevent blood returning to ventricles during diastole:
- pushed open as blood flows out of heart
- close as blood starts to backflow
compare the right and left side of the semilunar valve
- right side: pulmonary valve, 3 cusps
- left side: aortic valve, 3 cusps
this is a reminder to put everything in to a circulation and figure out how the valve coordinates with the heart pumping blood around the 2 systems
what is chordae tendineae?
- heartstring
- strong tender attach to av leaflet to keep it open/close when there is large pressure
what does chordae tendineae also being referred as?
parachut cord
what is papillary muscle?
- attach to chordae tendineae and the wall of the heart
- contract to close the valve in a gentle way, not to pull
what are the names of the vessels that is associated with blood circulation and supply/drainage of the heart?
- coronary artery
- circumflex artery
- coronary sinus
- great and small cardiac vein
what is the function of cardiac muscle?
beating off the heart (approximately 3 billions beats throughout a human’s lifetime)
describe the cardiac muscle cell structure
- striated
- short, branched cells
- 1-occasionally 2 nuclei/cell
- central nucleus
- cytoplasmic organelles packed at poles of nucles
how does cardiac muscle cells interconnected with the neiboring ones?
- via intercalated disks (ICDs)
____(1)____: connects actin - actin
_____(2)______: connects cytokeratin with each other
___(3)____ is the electro chemical communication
(1): adhesion belts
(2): desmosomes
(3): gap junction
what cell structure is abundant in cardiac muscles?
mitochondria: 20% of cell because oxygen-supplied dependent metabolism –> allow to burn any fuel source –> operate the heart
(whereas mitochondria only 2% of skeletal muscles)
what is the conduction system of the heart responsible for?
the co-ordination of heart contraction and of atrioventricular valve action
_______________ alter the rate of conduction impulse generation
sympathetic and parasympathetic of autonomic nerves
describe structure of the conduction cells?
- ‘bloated’ appearance
- peripheral myofibrils
- central nucleus
- mitochondria, glycogen
- lots of gap junctions
- some desmosomes and few adhesion belts
conduction cells makes up ____ of the cardiac cells
1%
why doesn’t conduction cells need intercalated discs but abundant of gap junctions
because no need for contracting
in autonomic nerves:
- _____(1)_____ decrease heart rate
- _____(2)_____ increase heart rate
(1): vagus - parasympathetic
(2): T1-4 spinal nerves - sympathetic
