Development and Anatomy of Heart

Question 1

During development, how many blood vessels fuse together to form the heart? What does the sinus venosus, bulbus cordis, and truncus arteriosus develop into?

Answer 1

2 blood vessels form heart

sinus venosus - absorbed into atrium
bulbus cordis - absorbed into ventricle
truncus arteriosus - part of the bulbus cordis that develops into the pulmonary trunk and aorta

Question 2

Where is the heart located? Describe what is in the middle, superior, anterior, and posterior mediastinum

Answer 2

heart is located in middle mediastinum

superior - thymus (child), trachea, esophagus, aortic catch, superior vena cava, vagus and phrenic nerves

anterior - thymus (remnants in adult)

posterior - thoracic aorta, esophagus, vagus and phrenic nerves

Question 3

Describe what these borders and surfaces of the heart mean:
anterior surface
inferior border
posterior surface

Answer 3

anterior surface - most of right ventricle
inferior border - right ventricle
posterior surface - left atrium and most of left ventricle

Question 4

Describe what these borders and surfaces of the heart mean:
anterior surface
inferior border
posterior surface

Answer 4

anterior surface - most of right ventricle
inferior border - right ventricle
posterior surface - left atrium and most of left ventricle

Question 5

What does the pericardial cavity contain? Where does the heart sit in respect to it?

Answer 5

pericardial cavity only contains serous fluid that acts as lubricant for heart movement
- encases heart with double layers
- heart is not IN pericardial cavity - SURROUNDED by it

Question 6

Describe the following layers of the heart wall:
epicardium, myocardium, endocardium

Answer 6

epicardium - visceral serous pericardium
- most superficial layer
- SS epithelium with layer of loose CT and adipose tissue

myocardium - cardiac muscle
- involuntary, striated, single nucleus, branching
- CT - fibrous skeleton of the heart

endocardium - lining of the heart
- continuous with endothelium of the blood vessels
- SS epithelium + loose CT
- attached to myocardium via loose/dense irregular CT
- contains autorhythmic cells in sub endothelial tissue

Question 7

What are the layers of the pericardial cavity?

Answer 7

parietal fibrous pericardium - outer most layer of pericardial cavity
- prevents stretching, protects heart, anchors to mediastinal space
- tough, dense irregular CT

parietal serous pericardium - SSET + loose CT
- continuous with visceral serous pericardium
- attached and forms inner lining for fibrous pericardium

visceral serous pericardium - epicardium - SSET + loose CT
- serous membrane - secretes watery fluid into pericardial cavity
- attached directly to myocardium

Question 8

What is pericarditis?

Answer 8

increased fluid or irritation/inflammation of the pericardial cavity

Question 9

What is a cardiac tamponade?

Answer 9

too much fluid in pericardial cavity - limits expansion of the chambers when filling with blood
- heart beats faster to try and compensate for decreased volume output
- can be caused by pericarditis

Question 10

Describe the muscle cell structure of the myocardium

Answer 10

short, flat, branches cells joined by intercalated discs
- intercalated discs - formed by desmosomes and gap junctions
- striations due to sarcomeres
- many mitochondria

Question 11

Describe the difference between the R and L atrium

Answer 11

Right - received deoxygenated blood from:
- superior vena cava - chest, upper extremities, neck, head
- inferior vena cava - abdomen, lower extremities
- coronary sinus - venous drainage from the heart
CONTAINS THE REGULATORY STRUCTURES
- sinoatrial node
- atrioventricular node
fossa ovalis more pronounced on R side

Left - receives oxygenated blood from the pulmonary veins of R and L lung
- NO REGULATORY STRUCTURES

Question 12

Describe the following features found in the ventricles: trabeculae carnae, papillary muscles, and chordae tendinae

Answer 12

trabeculae carnae - ridges of cardiac muscle that line the ventricle walls

papillary muscles - from ventricular wall, attached to AV valves via chordae tendinae
- prevents AV valves from turning inside out

chordae tendinae - connective tissue cords that attach to the AV value and papillary muscles
- prevents AV valves from turning inside out

Question 13

Describe auricles. Where are they found?

Answer 13

made of ridges of cardiac muscle called pectinate muscle
- only found in atria

Question 14

Describe the L and R AV valve. What are the other names for the valves?

Answer 14

Right atrioventricular valve - tricuspid valve - 3 leaflets

left atrioventricular valve - bicuspid valve - mitral valve

Question 15

Describe the L and R AV valve. What are the other names for the valves? What do they look like at rest?

Answer 15

Right atrioventricular valve - tricuspid valve - 3 leaflets

left atrioventricular valve - bicuspid valve - mitral valve

both are open at rest bc P atrium > P ventricles when heart is not contracting
- when ventricles contract - leaflets close

Question 16

Describe the R and the L ventricle. What is a moderator band? What do the s

Answer 16

Right ventricle - received deoxygenated blood from R atrium
- empties into the pulmonary trunk via pulmonary semilunar valve
- contains moderator band

Left ventricle - receives deoxygenated blood from the L atrium
- empties into the ascending aorta via aortic semilunar valve

Question 16

Describe the R and the L ventricle. What is a moderator band? What do the semilunar valves look like a rest?

Answer 16

Right ventricle - received deoxygenated blood from R atrium
- empties into the pulmonary trunk via pulmonary semilunar valve
- contains moderator band

Left ventricle - receives oxygenated blood from the L atrium
- empties into the ascending aorta via aortic semilunar valve

moderator band - specialized muscle cells that are not contractile
- carry electric current from SA to AV node across and down AV septum

Question 17

The aortic semilunar valves have special openings. What are they for?

Answer 17

aortic semilunar valves have openings for the R and L coronary arteries
- oxygenated blood goes to heart before rest of the body
- heart only gets blood when the valve is closed/heart relaxed

Question 18

What is the pulmonary circuit and the systemic circuit? Describe the flow of blood through the heart

Answer 18

pulmonary - venous system
- R side of heart to lungs, back to L side heart
- low pressure

systemic - arterial system,
- L side of heart to body ad back to R side of heart
- high pressure

Superior VC - R atrium - R AV valve - R ventricle - pulmonary semilunar valve - pulmonary trunk and arteries
LUNGS
pulmonary veins - L atrium - L AV valve - L ventricle - aortic semilunar - ascending aorta

Question 18

What is the pulmonary circuit and the systemic circuit? Describe the flow of blood through the heart

Answer 18

pulmonary - venous system
- R side of heart to lungs, back to L side heart
- low pressure

systemic - arterial system,
- L side of heart to body ad back to R side of heart
- high pressure

Superior VC - R atrium - R AV valve - R ventricle - pulmonary semilunar valve - pulmonary trunk and arteries
LUNGS
pulmonary veins - L atrium - L AV valve - L ventricle - aortic semilunar - ascending aorta

Question 19

What is congestive heart failure? What’s the different in CHF in the L and R side?

Answer 19

myocardium of the ventricles becoming stiff or weakened - unable to move blood out of the ventricle at same rate that it is entering the atria

R CHF - unable to keep up with amount from body - blood backs up into body
- systemic (pitting) edema

L CHF - blood backs up into lungs
- pulmonary edema - leakage of fluid out of pulmonary capillaries of alveoli

Question 20

What is mitral valve stenosis?

Answer 20

thickening/stiffening of L atrioventricular valve
- narrows opening between L atrium andL ventricle
- decreased volume of blood that passes thru

Question 21

What is mitral valve prolapse?

Answer 21

L atrioventricular valve flaps move into L atrium during ventricular contraction
- allows blood from L ventricle to flow back into L atrium instead of all to aorta
- associated with murmurs, enlargement of L side of heart

Question 22

What is patent foramen ovale?

Answer 22

when foramen oval does not close shortly after birth to form the fossa ovalis
- typically closes within 6-12 months after birth
- known unless they get blood clots - then stroke

Question 23

What is a ventricular septal defect?

Answer 23

opening in the inter ventricular septum
- major mixing of blood
- murmurs, infant blue when crying

Question 24

What is the transposition of the great vessels?

Answer 24

R ventricle receives deoxygenated blood and pumps it though the aorta to the systemic circulation
L ventricle receives oxygenated blood from lungs and pumps through pulmonary trunk back to lungs

needs surgery immediately, unless:
- associated with intraventricular septum - allows oxygenated blood to mix and allows time for baby to get stronger before surgery

Question 25

What is the tetralogy of fallot?

Answer 25

4 defects:
1. pulmonary stenosis - reduced blood flow to lungs

2. R ventricular hypertrophy - increased R ventricular contractile work, increased muscle cell size, stiffening and failure of heart muscle
3. ventricular septum defect - deoxygenated and oxygenated blood mixed btw both ventricles
4. over-riding aorta - aorta receives blood from both ventricles

oxygen poor blood enters aorta
- cyanosis, easy fatigue, heart murmur, prolonged crying, difficulty in weight gain

Question 26

What are the first branches off of the ascending aorta? What arteries do they become?

Answer 26

Coronary arteries

R coronary artery
- marginal artery: supplies lateral part of R atrium and R ventricle
- posterior inter ventricular: supplies posterior wall of L and R ventricle

L coronary
- circumflex artery (posterior aspect of heart): L atrium and L/posterior walls of L ventricle
- anterior inter ventricular: inter ventricular septum and anterior walls of L and R atrium

Question 27

Describe venous blood flow. What drains into the coronary sinus, and what arteries are associated with those veins?

Answer 27

venous blood flows towards the back of the heart

coronary sinus receives blood from:
- great cardiac vein: associated with anterior IV, circumflex artery
- middle cardiac vein: associated with posterior IV artery
- small: associated with marginal and R coronary artery

Question 28

Where do the anterior cardiac veins drain into?

Answer 28

drains directly into the R atrium