Mediastinum & Heart

Question 1

pericardium

Answer 1

double walled fibrous membrane that encloses the heart (pericardial sac/fibrous pericardium AND visceral layer of serous pericardium)

Question 2

pericardial sac/fibrous pericardium

Answer 2

• external fibrous layer of dense connective tissue
• fused with tunica advent of greater vessels & entering and leaving the heart
• prevents heart from overfilling
• comparable to spinal dura in toughness

Question 3

visceral layer of serous pericardium

Answer 3

aka epicardium

• lines surface of the heart
• contains serous fluid
• can’t dissect it off

Question 4

parietal layer of serous pericardium

Answer 4

• lines inner surface of fibrous pericardium
• continuous with visceral serous pericardium around great vessels & along lines of attachment between them
• fluid between the parietal and visceral layers allow for rubbing on a low friction surface
  (liquid created by both layers)

Question 5

recesses in pericardium

Answer 5

places where parietal & visceral layers come together & allow for structures to enter

• oblique sinus
• transverse sinus

Question 6

oblique sinus

Answer 6

between posterior surface of the heart and pericardial sac –> where SVC, IVC and pulmonary veins enter the heart

Question 7

transverse sinus

Answer 7

between aorta & pulmonary trunk - in front of SVC and left atrium
–> where aorta & pulmonary trunk leave the heart

Question 8

Atrial supply to the pericardium

Answer 8

PRIMARY- from the pericardiacophrenic artery from the internal thoracic artery
SECONDARY- from the musculophrenic artery from the internal thoracic artery

• bronchial, esophageal & superior phrenic arteries from the thoracic aorta

Question 9

venous drainage of pericardium

Answer 9

pericardiophrenic veins & azygos venous system

Question 10

Nerve to pericardium

Answer 10

Phrenic nerve – C3, C4, C5 – vital for survival, innervates diaphragm…

• goes through the root of lung & descends past the parietal sac into the pleura
• sensory fibers: cause “referred pain”

Question 11

Referred pain

Answer 11

visceral pain but the original presentation of this pain is to the cuteaneous areas of skin

ex: pain in left arm with a heart attack
- this is because dermatomes are located there - C3, C4, C5 (phrenic nerve) - provides pain from pericardium and refers it out to upper extremity
- referred pain eventually will become visceral pain

Question 12

diastole

Answer 12

period of ventricular elongating & filling

Question 13

systole

Answer 13

period of ventricular shortening and emptying

Question 14

lub

Answer 14

blood is sucked from atria to ventricle

Question 15

dub

Answer 15

ventricular contraction and expulsion of blood from the heart

Question 16

epicardium

Answer 16

thin external layer of heart formed from the visceral layer of the serous pericardium

Question 17

myocardium

Answer 17

thick, middle layer of heart composed of cardiac muscles

Question 18

endocardium

Answer 18

thin internal layer of the heart – covers heart valves

• holds the orifices in place
• forms our fibrous skeleton wall

Question 19

MV prolapse

Answer 19

btwn left AV orifice is mitral valve

- condition occurs if we didn’t get full closure of the valve and the blood pushes back into the atrium

Question 20

fibrous skeleton of heart

Answer 20

• anchors muscle fibers
• forms 4 fibrous rings to surround orifices of valves & surround R & L trigones

FUNCTION-

• keeps orifices of the AV & semilunar valves patent & from being overly distended
• provides attachment for leaflets & cusps of valves
• provides attachment for myocardium
• forms an electrical insulator
• provides passage for initial part of AV bundle

Question 21

Apex of heart

Answer 21

inferior point

• directly anterior & to left - is formed by the inferolateral part of the left ventricle
• located posterior to the left of the 5th intercostal space 9 cm from midline
• where sound of mitral valve closing is maximal
• underlies the site where the heartbeat may be osculated on the thoracic wall

Question 22

Base of Heart

Answer 22

• heart’s posterior aspect
• formed mainly by the left atrium, some of right atrium
• faces posteriorly - towards bodies of T6-T9
• extends superiorly to the bifurcation of the pulmonary trunk & inferiorly to the coronary groove
• receives pulmonary veins on the right and left sides of its left atrial portion & the SVC & IVC at the right atrial portion

Question 23

right border

Answer 23

• formed by the right atrium between SVC & IVC

Question 24

inferior border

Answer 24

• formed mainly by right ventricle and slightly by left ventricle

Question 25

left border

Answer 25

• formed mainly by left ventricle and slightly by left auricle

Question 26

superior border

Answer 26

• formed by left & right atria & auricles in the anterior view
• aorta and pulmonary trunk emerge from here
• SVC enters on right side

Question 27

right auricle

Answer 27

exterior surface of heart

• muscular patch projecting from right atrium
• primordial atrium

Question 28

coronary sinus

Answer 28

exterior surface of heart

• posterior part of coronary groove
• receives blood from cardiac veins
• collecting blood from veins that goes around the heart
• ———> dumps into right atrium

Question 29

sinus venarum

Answer 29

exterior & interior surface of heart

• smooth wall of adult rt atrium
• need smooth wall where structures are entering or leaving the heart
• site for SVC & IVC to enter heart

Question 30

sulcus terminalis

Answer 30

external area of separation between primordial atrium (auricle) & sinus venarum

Question 31

crista terminalis

Answer 31

interior area of separation between the primordial atrium (auricle) and sinus venarum