WEEK 3: The Heart

Question 1

Deoxygenated blood is depicted in what colour?

Answer 1

Blue

Question 2

Where is the heart? Name 4 different ways to describe its position

Answer 2

1. In the thoracic cavity
2. Inferior mediastinum
3. posterior to the sternum
4. Inferior to the sternal angle

Question 3

what is a mediastinum

Answer 3

The area between the lungs

Question 4

Where is the heart situated then, according to mediastinum

Answer 4

Middle mediastinum

Question 5

Where is the sternal angle?

Answer 5

Manubrial sternal joint

Question 6

Name 3 more ways to describe where the heart is

Answer 6

• Inside of the pericardial cavity
  -Anterior to the esophagus
  -superior to the diaphragm

Question 7

how many layers of pericardium exist? name them

Answer 7

2. parietal pericardium and visceral pericardium (epicardium)

Question 8

why does the pericardium exist?

Answer 8

the pericardium consists of fluid that lubricates the heart - easier for heart to pump and reduce rubbing that could cause inflammation + seperates heart from lung & no opportunity for adhesion/scars

Question 9

What other components make up the heart wall?

Answer 9

• mycocardium (heart muscle cells)
• endocardium (innermost)

Question 10

what is cardiac tamponade?

Answer 10

if the heart wall ruptures, the pericardial sac can fill up with too much blood, and pressure becomes so high that the atria cannot be filled anymore - compression of the heart chambers can cause one to die

Question 11

How many chambers in the heart?

Answer 11

4

Question 12

How many atria and ventricles in the heart respectively?

Answer 12

2 & 2

Question 13

What are the valves between the atria and ventricles called?

Answer 13

atrioventricular valves

Question 14

What are the valves between ventricles and aorta & pulmonary trunk called?

Answer 14

semilunar valves

Question 15

the right heart is equal to?

Answer 15

right atrium and right ventricle - receives deoxygenated blood from the body and pumps it towards the lungs

Question 16

the left heart is equal to?

Answer 16

left atrium and left ventricle. receives oxygenated blood from the lungs and pumps it into the body

Question 17

What are the 3 different surfaces of the heart called

Answer 17

• sternocostal (anterior)
• diaphgramatic (inferior)
• pulmonary (left/right)

Question 18

Where is the apex?

Answer 18

towards the bottom of the heart
5th ICS, midclavicular, left ventricle

Question 19

what is the rough part of the right atrium called?

Answer 19

pectinate muscles

Question 20

what is the smooth part of the right atrium called?

Answer 20

sinus venarum

Question 21

What are the other sections of the right atrium?

Answer 21

• auricle
  -crista terminalis
  -fossa ovalis
  -opening coronary sinus
  -superior vena cava
  -inferior vena cava

Question 22

What are the parts of the right ventricle

Answer 22

• tricuspid valve
  -papillary muscles
• tendinous cords
• conus arteriosus
• pulmonary valve
• interventricular septum
  -trabeculae carnae

Question 23

What important function does the tricuspid valve have?

Answer 23

The sails of the tricuspid valve flap and align into the papillary muscles and tendinous cords to avoid regurgitation of blood going back into right atrium

Question 24

What two parts are the interventricular septum made out of?

Answer 24

• muscular part
  -membranous part

Question 25

what are the components of the left atrium

Answer 25

- 4 pulmonary veins - left auricle - floor oval fossa

Question 26

what are the components of the left ventricle?

Answer 26

ventricular walls bicuspid valve aortic vestibule (smooth) aortic valve papillary muscles trabeculae carnae (finer/delicate)

Question 27

What is the most posterior part of the heart?

Answer 27

left atrium

Question 28

What is the most anterior part of the heart

Answer 28

right ventricle (otherwise known as directly posterior to the sternum)

Question 29

What is the function of the skeleton of the heart?

Answer 29

- electrical insulation -support of leaflets and cusps - 4 fibrous rings

Question 30

How many coronary arteries are there?

Answer 30

2, the left coronary artery (LCA) and right coronary artery (RCA)

Question 31

What kind of fat are the coronary arteries surrounded by?

Answer 31

epicardial fat

Question 32

Where do coronary arteries originate from

Answer 32

the aorta, superior to the aortic valves

Question 33

What does functional endarteries mean and why are coronary arteries known as this?

Answer 33

When there is a limited blood supply, these dense connections between cappilarries, hence this part of the heart will become ischaemic- they cannot compensate

Question 34

difference between left coronary and right coronary artery?

Answer 34

LCA- more the anterior part, septum and left side RCA- more posterior and diaphragmatic and conduction system

Question 35

coronary arteries are perfused with blood mainly during???

Answer 35

diastole

Question 36

Define the heart

Answer 36

A muscular pump with 4 chambers, 2 receiving and 2 pumping, that distribute blood to 2 vascular circuits

Question 37

Main vessels attached to the heart?

Answer 37

inferior cava/superior vena cava (return blood to heart) aorta and pulmonary trunk (take blood to rest of body)

Question 38

Main chambers of the heart

Answer 38

right atrium, left atrium, right ventricle, left ventricle

Question 39

what are the three layers of the heart wall called?

Answer 39

1. endocardium 2. myocardium 3. epicardium/ visceral pericardium

Question 40

Wall thickness varies according to?

Answer 40

chamber type as thickness relates to workload done by walls

Question 41

the entire heart is enclosed within the?

Answer 41

pericardial sac

Question 42

what is the endocardium?

Answer 42

inner layer of wall that lines chambers

Question 43

what is the myocardium

Answer 43

middle thickest layer

Question 44

what is the epicardium

Answer 44

outer layer of wall in contact with pericardial cavity

Question 45

the wall of the pericardial sac can be divided into what two sublayers?

Answer 45

- serious pericardium (parietal layer of the pericardium) - fibrous outer pericardial layer

Question 46

T or F: atrial walls are thinner than ventricular walls

Answer 46

T

Question 47

right ventricle wall is thinner than?

Answer 47

left ventricle wall

Question 48

parietal pericardium is seperated from the heart by the? why?

Answer 48

pericardial activity - keeps heart in place and lubricates + protects the heart against infection and injury + prevents overexpansion

Question 49

what is the histological composition of the pericardial sac?

Answer 49

- mesothelium (simple squamous epithelium) which covers the surface facing the pericardial cavity -fibrous/dense connective tissue which anchors into surrounding CT structures

Question 50

the makeup of the epicardium is?

Answer 50

- mesothelium which secretes lubricating pericardial fluid to prevent friction as heart beats - underneath mesothelium: underlying connective tissue - connective tissue contains adipocytes, nerves -coronary vessels that send branches into myocardium

Question 51

what is the makeup of the myocardium

Answer 51

-composed of cardiac muscle fibers in concentric layers - superficial layers of ventricular muscle wrap around both ventricles -muscle arrangement allows heart to pump blood more effectively -vascular connective tissue between muscle fibres

Question 52

what is the tissue composition of myocardial layer?

Answer 52

-> layer contains: - loose connective tissue: endomysium surrounds fibres -abundant blood capillaries in the endomysium tissues: reflects high oxygen demand of the muscle fibres -small nerves

Question 53

cardiac muscle is a type of muscle that is?

Answer 53

striated

Question 54

cardiac muscle consists of

Answer 54

branched fibres, central nuclei, direct cell-cell communication via intercalated discs, abundant mitrochondria (25%), large energy stores in the form of glycogen

Question 55

mitochondria and glycogen in the cardiac muscle reflect its high?

Answer 55

energy demand and constant supply of ATP needed due to the aerobic respiration of these fibres

Question 56

why are largest diameter fibres in the left ventricle?

Answer 56

because the workload is greatest

Question 57

endocardium layer varies in thicknes: T or F

Answer 57

T thickest in atria, thinnest in ventricles

Question 58

what are the 3 sublayers of endocardium?

Answer 58

endothelium- in contact with blood subendothelial CT layer- dense and regularly arranged collagen & elastin fibres deep connective tissue layer- more irregular & loose arrangement of collagen

Question 59

what is the main subendocardial structure?

Answer 59

modified cardiac muscle conducting fibres - purkinje fibres, nerves and blood cells

Question 60

characteristics of purkinje fibres?

Answer 60

- specialized fibres for rapid transmission of signals -allow for coordinated/unified contraction of heart muscle -larger cells, pale staining than contractile cardiac muscle cells (less myofibils) -contain large stores of glycogen

Question 61

what is the cardiac skeleton?

Answer 61

a region of fibro collagenous tissue located at the level of heart valves- and anchors valves and chambers together