Mediastinum & Circulatory System

Question 1

where is the mediastinum?

Answer 1

central area of thorax between the two pleural cavities

Question 2

where does mediastinum extend?

Answer 2

superiorly to thoracic outlet and root of neck, inferiorly to diaphragm, anteriorly to sternum, posteriorly to thoracic verterbrae

Question 3

what is contained within the mediastinum?

Answer 3

thymus, heart and large blood vessels, trachea and oesophagus, thoracic duct and lymph nodes, vagus and phrenic nerves, sympathetic trunks

Question 4

how are the viscera of the mediastinum connected?

Answer 4

by loose connective tissue and fat, surrounded by blood vessels and nerves

Question 5

what is mediastinum divided into?

Answer 5

superior and inferior compartments

Question 6

what is the transverse thoracic plane?

Answer 6

horizontal plane from sternal angle to T4/T5 intervertebral disc separating mediastinum

Question 7

superior mediastinum structures, anterior to posterior?

Answer 7

thymus, large veins, large arteries, trachea, oesophagus and thoracic duct, sympathetic trunks

Question 8

inferior mediastinum structures, anterior to posterior?

Answer 8

thymus, heart within pericardium with phrenic nerves either side, oesophagus and thoracic duct, descending aorta, sympathetic trunks

Question 9

superior boundary of the superior mediastinum?

Answer 9

thoracic inlet

Question 10

inferior boundary of the superior mediastinum?

Answer 10

continuous with inferior mediastinum at level of sternal angle

Question 11

anterior boundary of superior mediastinum?

Answer 11

manubrium of sternum

Question 12

posterior boundary of superior mediastinum?

Answer 12

vertebral bodies of T1-4

Question 13

lateral boundary of superior mediastinum?

Answer 13

pleurae of lungs

Question 14

structures contained within the superior mediastinum?

Answer 14

aortic arch, superior vena cava, vagus nerve, phrenic nerves, cardiac nerves, sympathetic trunk, thymus, trachea, oesophagus, thoracic ducts and lympathic vessels, muscles

Question 15

muscles in superior mediastinum?

Answer 15

sternohyoid, sternothyroid, inferior longus colli muscle

Question 16

where is the inferior mediastinum?

Answer 16

between transverse thoracic plane and diaphragm

Question 17

boundaries of inferior mediastinum?

Answer 17

sternum and lower 8 thoracic vertebrae

Question 18

what divides the anterior and posterior mediastinum?

Answer 18

the fibrous pericardium

Question 19

pericardial sac further subdivides the inferior mediastinum into…

Answer 19

anterior, middle and posterior mediastinum

Question 20

anterior mediastinum?

Answer 20

space between fibrous pericardium and sternum

Question 21

middle mediastinum?

Answer 21

pericardium and heart

Question 22

posterior mediastinum?

Answer 22

between fibrous pericardium and vertbral column at T5-12 vertebrae

Question 23

middle mediastinum contains?

Answer 23

pericardium, heart, origins of great vessels, various nerves, smaller vessels, lymphatics, tracheal bifurcation

Question 24

posterior mediastinum contains?

Answer 24

thoracic aorta (descending), oesophagus, thoracic duct, azygous system of veins, sympathetic trunks

Question 25

what is the pericardium?

Answer 25

fibro serous sac surrounding the heart and roots of the great vessels. consists of fibrous and serous pericardium

Question 26

what is fibrous pericardium?

Answer 26

tough connective tissue outer layer, defines boundaries of middle mediastinum

Question 27

what is the serous pericardium?

Answer 27

thin, consists of the parietal and visceral layers

Question 28

what is the parietal layer of the serous pericardium?

Answer 28

lines inner surface of fibrous

Question 29

what is the visceral layer of the serous pericardium?

Answer 29

aka epicardium, adheres to heart forming its outer covering

Question 30

where are the parietal and visceral layers of the serous pericardium continuous?

Answer 30

at the roots of the great vessels anteriorly at arteries and posteriorly at veins

Question 31

what is the pericardial cavity and what is its function?

Answer 31

narrow space between parietal and visceral serous pericardium layers, contains fluid, allows potential space for movement of heart

Question 32

what is the oblique pericardial sinus?

Answer 32

J shaped cul-de-sac zone of reflection surrounding veins

Question 33

what is the transverse pericardial sinus?

Answer 33

the passage between the two sites of reflected serous pericardium

Question 34

where does the transverse pericardial sinus lie?

Answer 34

anterior to superior vena cava, posterior to aorta and pulmonary trunk, superior to left atrium

Question 35

fibrous pericardium base attachment?

Answer 35

to central tendon of diaphragm and on left side of diaphragm

Question 36

fibrous pericardium apex attachment?

Answer 36

continuous with the adventitia of the great vessels

Question 37

anterior attachments of fibrous pericardium?

Answer 37

posterior sternum by sternopericardial ligaments; retain heart position and limits distension

Question 38

which nerves pass through the fibrous pericardium?

Answer 38

phrenic (C3, 4 ,5- innervate diaphragm)

Question 39

which vessels are located within and supply the fibrous pericardium?

Answer 39

pericardiacophrenic vessels

Question 40

what arteries supply the pericardium?

Answer 40

branches of the internal thoracic, pericardiacophrenic, musculophrenic, inferior phrenic arteries and thoracic aorta

Question 41

what are the veins draining the pericardium?

Answer 41

enter the azygous system of veins and the internal thoracic and superior phrenic veins

Question 42

what nerves supply the pericardium?

Answer 42

arise from the vagus (X) nerve, sympathetic trunks and phrenic nerves

Question 43

why does pain from parietal pericardium often get referred to as from the supraclavicular region?

Answer 43

somatic (pain) sensation is carried by somatic afferent fibres in phrenic nerves

Question 44

what systems is the blood vascular system split into?

Answer 44

pulmonary circulation and systemic circulation

Question 45

how much blood does the average adult contain?

Answer 45

5 litres

Question 46

why is the blood system "closed"?

Answer 46

blood never leaves the system

Question 47

what is the valve between the right atrium and right ventricle?

Answer 47

tricuspid valve

Question 48

what valve is between the right ventricle and the pulmonary trunk?

Answer 48

the semilunar valve

Question 49

where does the pulmonary trunk bifurcate?

Answer 49

at level of sternal angle

Question 50

what branches are given off before the blood vessels enter the lung?

Answer 50

the lobar branch to supply the superior lobe

Question 51

what do lobar branches give rise to and what do they supply?

Answer 51

to segmental branches, supplying the bronchopulmonary segments

Question 52

what organ/tissue is NOT supplied by the systemic circulation?

Answer 52

the parenchyma of the lungs, supplied by the pulmonary circulation

Question 53

valve between left atria and left ventricle?

Answer 53

mitral valve (bicuspid)

Question 54

valve between left ventricle and aorta?

Answer 54

aortic valve

Question 55

what does aortic artery branch into after the diaphragm?

Answer 55

iliac, renal and suprarenal arteries

Question 56

how are portal veins different? eg?

Answer 56

eg hepatic portal vein, combines with capillaries of liver rather than leading directly back to the heart

Question 57

where do the right and left coronary arteries begin?

Answer 57

near the origin of the aorta

Question 58

where does blood from the coronary veins return?

Answer 58

into the coronary sinus, then into the right atrium

Question 59

what valve prevents backfloow of blood during atrial systole?

Answer 59

thebasian valve

Question 60

where do the smallest cardiac veins drain into?

Answer 60

directly into the chambers

Question 61

where does the anterior brain circulation arises? what does it supply?

Answer 61

arises from the internal carotid arteries and supplied front of the brain

Question 62

where does the posterior brain circulation arise? what does it supply?

Answer 62

arises from the vertebral arteries, supplies back of brain and brainstem

Question 63

what % of the cardiac output does the renal circulation receive?

Answer 63

20%

Question 64

where does the renal circulation branch from?

Answer 64

from the abdominal aorta

Question 65

how does blood return to heart from renal circulation?

Answer 65

via the ascending vena cava

Question 66

which is the first branch off the aortic arch?

Answer 66

the brachiocephalic artery/trunk

Question 67

what does the brachiocephalic bifurcate into?

Answer 67

the right common carotid and the right subclavian artery

Question 68

what is the 2nd branch off the aortic arch?

Answer 68

left common carotid artery

Question 69

what is the 3rd branch off the aortic arch?

Answer 69

left subclavian artery

Question 70

where do the carotid arteries bifurcate and what into?

Answer 70

divide in the neck, into internal and external carotid arteries

Question 71

when does the subclavian artery become the axillary artery?

Answer 71

at the 1st rib