ANATOMY OF THE HEART

Question 1

pulmonary vs systemic circulation?

Answer 1

• pulmonary = heart –> lung –> heart
• systemic = heart –> throughout body –> heart

Question 2

what are the 3 general principles for organisation of the cardiovascular system?

Answer 2

• supply side
• exchange network
• drainage

Question 3

TRUE/FALSE? arteries are the only supply path

Answer 3

true

Question 4

where is major arteries located and how it reflects the characteristic?

Answer 4

• 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

Question 5

how many sources would important structures often receive supply from?

Answer 5

2

Question 6

the various degrees of permeability in capillaries?

Answer 6

• continuous
• fenestrated
• sinusoidal

Question 7

the 3 pathways of drainage?

Answer 7

• deep veins
• superficial veins
• lymphatics

Question 8

why is the cross-sectional area of veins is at least twice that of arteries

Answer 8

• 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

Question 9

what is the shape of the heart?

Answer 9

blunt, cone shaped

Question 10

where is the apex and where is the base of the heart?

Answer 10

• base = broad end, align around 2nd-3rd rib
• apex = pointed end, at midclavicular around 5th and 6th ribs

Question 11

what is the PMI?

Answer 11

• point of maximal impulse
• where apex push hard against chest wall –> where we can listen to heart pound

Question 12

how does the heart situated within the thoracic cavity and what does that helps with the body function?

Answer 12

• 2/3 heart sit to left of midline
• apex point anteriorly
• this helps heart beats to chest wall instead of diaphragm

Question 13

simply describe small circulation of blood?

Answer 13

• 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

Question 14

why does atria of the heart has thin wall?

Answer 14

receiving chambers –> not too much work or pushing blood to the circulation pathways –> not need too much muscle

Question 15

what 3 veins bring deoxygenated blood to right atrium?

Answer 15

• superior vena cava
• inferior vena cava
• coronary sinus

Question 16

left atrium receives oxygenated blood from:

Answer 16

4 pulmonary veins

Question 17

what are the layers of the heart wall from innermost to outermost?

Answer 17

• endocardium
• myocardium
• epicardium
• pericardium

Question 18

what is the thickest layer of the heart wall?

Answer 18

myocardium

Question 19

what is the overall function of pericardium?

Answer 19

• provide lubricated sac –> not damage own heart when beating
• protect heart against injury and abrasion

Question 20

what is the type of epithelial sound at endocardium?

Answer 20

• squamous –> endothelium
• loose irregular FCT

Question 21

what is endothelium?

Answer 21

• lines the cardiovascular system and prevent blood clottage
• barrier between blood and wall of system

Question 22

what size of blood vessel at endocardium?

Answer 22

small

Question 23

what is a specialised type of tissue that you can find in endocardium and what is it for?

Answer 23

purkinje fibre –> carry electrical conduction eventhough not nervous tissue

Question 24

why is there a difference between thickness of the myocardium layer between left and right side of the heart?

Answer 24

• 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

Question 25

what type of muscle is myocardium?

Answer 25

cardiac muscle

Question 26

what can you find in epicardium ?

Answer 26

- blood vessels - loose irregular FCT - adipose - visceral pericardium

Question 27

which part of the epicardium fuses with pericardium?

Answer 27

visceral pericardium

Question 28

describe structure of the pericardium?

Answer 28

- 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

Question 29

what is AV valve?

Answer 29

- atrioventricular valve - between atrial and ventricle of the heart

Question 30

function of the av valve?

Answer 30

prevents blood returning to atria during ventricular contraction

Question 31

compare between the left and right side av valves

Answer 31

- left side: biscuspid (2 leaflets) valve - right side: triscuspid valve

Question 32

briefly compare diastole and systole phase of the heart, then relates it to the operation of av valve?

Answer 32

- 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

Question 33

what is the function of semilunar valves?

Answer 33

prevent blood returning to ventricles during diastole: - pushed open as blood flows out of heart - close as blood starts to backflow

Question 34

compare the right and left side of the semilunar valve

Answer 34

- right side: pulmonary valve, 3 cusps - left side: aortic valve, 3 cusps

Question 35

**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**

Question 36

what is chordae tendineae?

Answer 36

- heartstring - strong tender attach to av leaflet to keep it open/close when there is large pressure

Question 37

what does chordae tendineae also being referred as?

Answer 37

parachut cord

Question 38

what is papillary muscle?

Answer 38

- attach to chordae tendineae and the wall of the heart - contract to close the valve in a gentle way, not to pull

Question 39

what are the names of the vessels that is associated with blood circulation and supply/drainage of the heart?

Answer 39

- coronary artery - circumflex artery - coronary sinus - great and small cardiac vein

Question 40

what is the function of cardiac muscle?

Answer 40

beating off the heart (approximately 3 billions beats throughout a human's lifetime)

Question 41

describe the cardiac muscle cell structure

Answer 41

- striated - short, branched cells - 1-occasionally 2 nuclei/cell - central nucleus - cytoplasmic organelles packed at poles of nucles

Question 42

how does cardiac muscle cells interconnected with the neiboring ones?

Answer 42

- via intercalated disks (ICDs)

Question 43

____(1)____: connects actin - actin _____(2)______: connects cytokeratin with each other ___(3)____ is the electro chemical communication

Answer 43

(1): adhesion belts (2): desmosomes (3): gap junction

Question 44

what cell structure is abundant in cardiac muscles?

Answer 44

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)

Question 45

what is the conduction system of the heart responsible for?

Answer 45

the co-ordination of heart contraction and of atrioventricular valve action

Question 46

_______________ alter the rate of conduction impulse generation

Answer 46

sympathetic and parasympathetic of autonomic nerves

Question 47

describe structure of the conduction cells?

Answer 47

- 'bloated' appearance - peripheral myofibrils - central nucleus - mitochondria, glycogen - lots of gap junctions - some desmosomes and few adhesion belts

Question 48

conduction cells makes up ____ of the cardiac cells

Answer 48

1%

Question 49

why doesn't conduction cells need intercalated discs but abundant of gap junctions

Answer 49

because no need for contracting

Question 50

in autonomic nerves: - _____(1)_____ decrease heart rate - _____(2)_____ increase heart rate

Answer 50

(1): vagus - parasympathetic (2): T1-4 spinal nerves - sympathetic