Mediastinum and Heart Flashcards Preview

S1 Anatomy > Mediastinum and Heart > Flashcards

Flashcards in Mediastinum and Heart Deck (42):
1

mediastinum
-where is it/what is it
-limited by

central compartment of thoracic cavity
limited by
-connective walls that separate this central region from the pleural cavities on either side

2

mediastinum
-continuous anteriorly/posteriorly with...
-continuous superiorly with...
-attached inferiorly to...

A/P
-sternum
-costal cartilages to the bodies of the vertebrae
superiorly
-thoracic aperture
inferiorly
-diaphragm

3

mediastinum divisions

superior
inferior
-anterior
-middle
-posterior

4

inferior divisions of mediastinum separated by...

pericardium (CT)

5

what are the thoracic viscera located within the mediastinal regions?

esophagus
trachea and bifurcation to primary bronchii
heart
origin of great vessels

6

pericardium
-location
-composed of...

location
-middle region of inferior part of mediastinum
consists of a CT sac that is made up of 2 layers
-tough outer layer of dense irregular CT
-inner serous layer of simple squamous epithelium (mesothelium)

7

fibrous pericardium continuous with...

tunica adventitia of great vessels
cervical fascia

8

inner layer (mesothelium) of pericardium
-called...
-reflected onto heart as...

called parietal epicardium
reflected onto heart as visceral epicardium or outermost layer of heart

9

visceral epicardium adheres to...

muscular myocardium (heart muscle)

10

3 layers of heart tissue
-continuous with...

visceral epicardium
-outermost
myocardium
-cardiac branched striated muscle
endocardium
three layers continuous with three tunics of the vasculature

11

myocardium
-sarcomere arrangement

branched striated, similar to that of a skeletal muscle

12

why are differences in the type of muscle between the heart and muscles important

sarcomere contractions

13

how do sarcomeres in the heart connect?
-why is this important

via modified z-lines (intercalated discs)
ensures contraction occurs in a widespread fashion rather than a strict linear fashion as seen in skeletal muscle

14

why are branched sarcomeres of the heart connected by gap junctions

allow direct sharing of cytoplasmic signals
in the heart, the sharing is of Ca++ to assure contraction

15

where in the heart is there a gross difference of appearance in terms to muscle (sarcomeres)
-is the myocardium different in these areas?

between atrium and ventricular walls
pectinate and trabeculae carneae
branched striated myocardium is similar

16

fibrous skeleton of heart
-histological composition
-function

composition
-dense collagen
supports integrity of
-cusps of the valves
-opening of each transition from chamber to vessel and between chambers
"insulator" of electrical activity limiting the spread of contraction from the atria to the ventricles, directing the depolarizing wave to the atrioventricular node

17

heart conductive system function

designed to spread a depolarizing wave across the atria and ventricles

18

from sinoatrial node, wave goes to...

goes through both atria myogenically (through the muscle)

19

myogenic spread of signal through atria limited to atria by...

fibrous skeleton

20

wave from SA node converges at...
-what is activated here

atrioventricular node
activates AV bundle (bundle of His)

21

AV bundle
-location
-function

location
-located in interventricular septum
-branches near apex of heart to spread through a right and left bundle branch
function
-right bundle branch supplies right ventricle
-left bundle branch supplies left ventricle

22

bundle branches end in...
-function of these

end in purkinje fibers
spread depolarization across walls of ventricles

23

function of papillary muscles from a timing standpoint

contract first in order to stabilize the two AV valves to resist prolapse and regurgitation of blood back into the atria

24

atrial and ventricular walls
-marked by
-these are not found...

marked by multiple muscular fiber ridges
ridges not present on interatrial or interventricular septa

25

atrial and ventricular ridges
-function

assist in complete contraction of the walls of the chambers

26

markings of thin vs. thick walled atria

thin
-pectinate muscles
thick
-trabeculae carneae

27

chordae tendineae
-what are they

strong connective tissue attachments between papillary muscles of the ventricular system and the connective tissue edges of the cusps of the AV valves

28

myocardium perfused by...

two coronary arteries and their branches

29

where are the openings of the coronary arteries

behind the left and right cusps of the aortic valve

30

left coronary artery primary branches

anterior interventricular artery (LCA; left anterior descending)
circumflex of the LCA

31

right coronary artery branches

marginal branch that travels along right ventricule
terminal posterior interventricular branch

32

posterior interventricular branch of right coronary artery
-has a...

capillary bed that overlaps the circumflex branch of the LCA

33

LAD
-termed the...
-also known as

widow maker
also known as L interventricular artery

34

venous drainage relation to arterial supply in heart

parallels it

35

veins of the heart

great cardiac vein
middle cardiac vein
small cardiac vein

36

where do the great cardiac vein and the middle cardiac vein lie

interventricular groove anterior and posterior, respectively

37

small cardiac vein parallels...

marginal branch of RCA

38

veins of the heart drain into...

cardiac sinus that lies in the right atrioventricular sulcus posteriorly
this drains into the right atrium

39

when are the coronary arteries covered

during systolic time frame of cardiac cycle

40

what happens to the coronary arteries at the beginning of diastole

ventricles begin to relax
elasticity of the aorta pushes blood back toward aortic valve

41

what occurs when the elasticity of the aorta pushes blood back toward the aortic valve

it mechanically closes the cusps of the valve
blood pools in the aortic sinuses of the left and right aortic cusps

42

function of elastic pressure of aorta during diastole

perfuses arterial blood into the coronary vessels