Superior, Posterior, Anterior Mediastinum

Question 1

what space is the superior mediastinum?

Answer 1

between thoracic inlet and level of sternal angle (T4-5)

Question 2

what are the subspaces of the inferior mediastinum?

Answer 2

anterior, posterior

Question 3

what space is the anterior mediastinum?

Answer 3

between sternum/transversus thoracis muscles and pericardial sac

Question 4

what occupies the anterior mediastinum in early childhood?

Answer 4

thymus gland

Question 5

the anterior mediastinum is filled with what structures?

Answer 5

loose connective tissue, fat

Question 6

what vessels branch from the arch of the aorta?

Answer 6

brachiocephalic trunk, left common carotid artery, left subclavian artery

Question 7

the superior mediastinum is filled with what structures?

Answer 7

thymus, great vessels, nerves, trachea, esophagus, thoracic duct, prevertebral muscles

Question 8

what two vessels drain blood into the superior vena cava?

Answer 8

left brachiocephalic vein, right brachiocephalic vein

Question 9

what nerves are found in the superior mediastinum?

Answer 9

phrenic nerve, left vagus nerve, right vagus nerve, cardiac plexus

Question 10

what are the branches of the right and left vagus nerve in the superior mediastinum?

Answer 10

right and left recurrent laryngeal nerves

Question 11

what structures are in the posterior mediastinum?

Answer 11

thoracic aorta, thoracic duct, lymph nodes, esophagus, esophageal plexus, trachea

Question 12

what level does the trachea bifurcate at?

Answer 12

sternal angle

Question 13

what are branches of the thoracic aorta?

Answer 13

costocervical trunk, coronary artery, bronchial artery, esophageal artery, posterior intercostal artery, subcostal artery, pericardial artery, mediastinal artery

Question 14

what are two branches of the costocervical trunk?

Answer 14

deep cervical artery, superior intercostal artery

Question 15

what nerves are found in the posterior mediastinum?

Answer 15

thoracic sympathetic trunk, lower thoracic splanchnic nerves

Question 16

what is unique about the lower thoracic splanchnic nerves?

Answer 16

all are sympathetic preganglionic fibers to abdomen

Question 17

what are the three components of the thoracic sympathetic trunk?

Answer 17

sympathetic ganglion, white ramus communicans, gray ramus communicans

Question 18

what component of the nerve fiber is in the sympathetic ganglion?

Answer 18

postganglionic (postsynaptic) neuron cell bodies

Question 19

what nerve fibers are in the white ramus communicans?

Answer 19

preganglionic fibers entering the chain/trunk

Question 20

what nerve fibers are in the gray ramus communicans?

Answer 20

postganglionic fibers exiting the chain/trunk

Question 21

what vein handles venous drainage for the posterior mediastinum?

Answer 21

azygos vein

Question 22

what are the veins that drain into the azygos vein

Answer 22

posterior intercostal vein, mediastinal vein esophageal vein, bronchial vein, hemiazygos vein, accessory hemiazygos vein (can accept blood from left superior intercostal vein)

Question 23

what do tissues need for perfusion?

Answer 23

oxygen, carbon dioxide removal, substrates (lipids, glucose, amino acids), ions, hormones

Question 24

acute blood flow control occurs through which processes?

Answer 24

vasodilation, vasoconstriction

Question 25

long term blood flow control occurs through what structures and processes?

Answer 25

change in vessel size, anastomosis, angiogenesis

Question 26

what system causes vasoconstriction of arterioles and large veins?

Answer 26

sympathetic nervous system

Question 27

what effects does the sympathetic nervous system have on the heart?

Answer 27

increase heart rate, increase contractility

Question 28

resting rate of sympathetic nervous system stimulation causes what?

Answer 28

vasomotor "tone"

Question 29

what is the transmitter substance of the sympathetic nervous system?

Answer 29

norepinephrine

Question 30

sympathetic nervous system is more effective in which organs? it is less effective in which organs?

Answer 30

more - kidney, intestines, spleen, skin less - skeletal muscle, brain

Question 31

how many liters of fluid is in the intracellular compartment?

Answer 31

28 L

Question 32

how many liters of fluid is in the extracellular compartment?

Answer 32

14 L

Question 33

what is another name for the extracellular compartment?

Answer 33

interstitium (cells depend on substances here)

Question 34

how many liters of fluid is in blood plasma?

Answer 34

3 L

Question 35

how many liters of fluid is in interstitial fluid?

Answer 35

11 L

Question 36

what fluid makes up the extracellular compartment?

Answer 36

blood plasma, interstitial fluid, transcellular fluid

Question 37

where is transcellular fluid found?

Answer 37

synovial, pericardial, peritoneal, and intraocular spaces

Question 38

what makes up blood?

Answer 38

hematocrit, blood plasma

Question 39

where is interstitial fluid found? it is the same composition as what other substance, just with less proteins?

Answer 39

in the space between cells plasma

Question 40

what is the interstitium filled with?

Answer 40

fluid, fine web/net-like filaments

Question 41

how does 'free' fluid pass through interstitium?

Answer 41

small channels

Question 42

what does most extracellular fluid diffuse through in the interstituium?

Answer 42

'gel'

Question 43

lymph vessels attach to tissues via what?

Answer 43

anchoring filaments

Question 44

lymph vessels have valves - what vessel does this mirror?

Answer 44

veins

Question 45

what causes fluid from the interstitial space to enter lymph vessels?

Answer 45

anchoring filaments pull on endothelial cells

Question 46

body fluid compartments are separated by cell membranes that have what feature?

Answer 46

semi-permeable

Question 47

equilibrium of fluid and substances is maintained by what processes and mechanical factors?

Answer 47

diffusion, osmosis, capillary filtration, negative pressure in most interstitial spaces

Question 48

the body is 'held together' by what, especially in the superficial fascia layer?

Answer 48

negative pressures

Question 49

what substances easily pass through membranes because they are lipid soluble?

Answer 49

oxygen, carbon dioxide

Question 50

what substances easily pass through pores/gated channels in membranes because they are water soluble?

Answer 50

water, electrolytes, glucose

Question 51

what substances do not easily pass through membranes because they are large molecules?

Answer 51

proteins

Question 52

what is the transfer of substances across capillary membranes due to thermal motion water molecules and dissolved substances?

Answer 52

diffusion

Question 53

what is the movement of water across membranes in response to concentration of solutes?

Answer 53

osmosis

Question 54

what causes water to flow into capillaries?

Answer 54

plasma proteins

Question 55

what causes negative pressure in most interstitial spaces?

Answer 55

fluid is trapped in 'gel' layer of connective tissue, lymph vessels automatically contract to pump fluid out of space

Question 56

higher pressures/arterial end forces fluid where? lower pressures/venous end forces fluid where?

Answer 56

higher - interstitium lower- vein

Question 57

what supports the lymphatic 'pump?'

Answer 57

low tissue compliance, increased lymphatic flow

Question 58

"wash out" of proteins with increased lymphatic flow in interstitial space reduces what?

Answer 58

osmosis, capillary filtration rate

Question 59

what does increased lymphatic flow prevent?

Answer 59

positive pressures in interstitial space (can increase 10-50x normal rate)

Question 60

what limits the free flow of fluid?

Answer 60

gel-like matrix of tissues (cytoplasm)

Question 61

why does low tissue compliance support the lymphatic pump?

Answer 61

small changes in extracellular fluid volume associated with large changes in interstitial pressure which limits capillary filtration rate

Question 62

what is excess fluid in body tissues?

Answer 62

edema

Question 63

what causes intracellular edema?

Answer 63

ischemia, inflammation, metabolic conditions

Question 64

what leads to increased intracellular concentrations, change in osmotic pressure, and swelling?

Answer 64

loss of sodium ion pump in cell membrane

Question 65

what causes extracellular edema?

Answer 65

loss of negative pressure in interstitial space

Question 66

what causes increased capillary filtration rates, leading to extracellular edema?

Answer 66

kidney disease, heart failure, venous obstruction or failure of venous pump, decreased plasma proteins, inflammation

Question 67

what can lead to kidney disease?

Answer 67

retention of salt and water

Question 68

what is the difference between right and left sided heart failure?

Answer 68

right - generalized left - pulmonary

Question 69

what is an example of venous obstruction or failure of venous pump that would cause extracellular edema?

Answer 69

paralysis

Question 70

what is an example of decreased plasma proteins that would cause extracellular edema?

Answer 70

burns, wounds

Question 71

what is an example of inflammation that would cause extracellular edema?

Answer 71

release of histamines

Question 72

what causes impaired lymphatic function (lymphedema)?

Answer 72

removal of lymph nodes, cancer, congenital absence of lymph vessels/nodes

Question 73

edema is largely what type of fluid?

Answer 73

'free'

Question 74

'free fluid' edema is the basis for what condition?

Answer 74

pitting edema

Question 75

edema is dependent on what factor, causing fluid to accumulate in inferior spaces like ankles/feet?

Answer 75

gravity

Question 76

what is edema in the potential spaces?

Answer 76

effusion

Question 77

where is effusion common in the body?

Answer 77

pericardium, peritoneum, synovial joint

Question 78

normal interstitial fluid pressures are positive or negative?

Answer 78

negative

Question 79

what is the normal interstitial fluid pressure in the pleural cavity?

Answer 79

7-8 mg Hg

Question 80

what is the normal interstitial fluid pressure in the joint spaces?

Answer 80

3-5 mg Hg

Question 81

what is the normal interstitial fluid pressure in the pericardium?

Answer 81

5-6 mg Hg

Question 82

what can block lymphatic drainage, leading to positive pressures in the interstitium and causing effusion due to a loss of negative pressure 'suction?'

Answer 82

injury, infection