chapter 21 Flashcards
two circuits
pulmonary and systemic
layers in order
fibrous pericardium, parietal pericardium, pericardial cavity, epicardium, myocardium, endocardium
pericardial sac
made of the parietal pericardium and fibrous pericardium
walls of the heart
epicardium, myocardium and endocardium (internal)
myocardium
muscle lining
-aerobic respiration
-intercalated discs that connect cardiocytes
epicardium
external surface
cardiocytes
contract without information from the CNS
-pace cells
-dont need brain
intercalated discs
-cell to cell junction
-desmosomes bind two sarcolemma
-discs bind myofibrils of adjecent cells
gap junctions
-bind cells to each other
-pores for ion movement
-ion movement allows the sarcomeres to contract as one
elastic sheath
wraps each cardiac cell
fibrous sheet
wraps each muscle layer
-separate superficial layer with the deep muscle layer
-encircle the base of the pulm trunk and ascending aorta
fibrous skeleton
-elastic sheath and fibrous sheet
-stabalize cardiac cells, heart valves, support nerves and vessels in myocardium, distribute contraction force, prevent overexpansion, recoils heart after contraction, isolate atrial cells from ventricular cells
oblique angle
heart sits at one
-inferior border= right ventricle
-right border= right atrium
-heart is also rotated slightly left
sternocostal surface
formed by the right atrium and right ventricle
posterioir surface
left atrium
sulci
are on the external structures of the four chambers
-interatrial, coronary, anterioir intercentricular and posterioir interventricular sulcus
interatrial sulcus
separate left and right atria
coronary sulcus
separate atria and the ventricles
anterioir interventricular sulcus
separatest the left and right ventricles
posterioir interventricular sulcus
spearates left and right ventricles
l and r atria
have walls, superior to the coronary sulcus, have auricles (extensions)
l and r ventricles
inferior to coronary sulcus, right ventricles forms diaphragmatic surface
interatrial septums
separate interatrial septum
what do the folds of the endocardium form>
atrioventricular valves
right atrium
deoxy from svc, ivc and coronary sinus
-has pectinate muscle and fossa ovalis
fossa ovalis
fetal remnant of the foramen ovale (atrium)
-let blood flow from right to left atria
right ventricle
deoxy from right atrium through tricuspid
muscles of valves
chordeae tendoneae connect to papillary muscles and they prevent valve inversion and backflow
right ventricle internal surface
-trabeculae carneae
-moderator band
-pulmonary valve
trabeculae carneae
meaty ridges in the wall the prevent suction during heart beat
moderator band
ONE IN THE RIGHT VENTRICLE
-muscular bands that come from the interventricular spetum to the ventricular wall
-part of the electrical system
-prevents overexpansion of thin walled right ventricle
left atriums
oxy blood from the pulm veins through bicuspid valve/ mitral valve
left ventricle
-thicket walls and highest pressure
-send blood through systemic circuit
-NO moderator bands
-av valve has the chorae tendineae with 2 cusps
lung pressure
very low (25) which is why right ventricle walls can be so thin
av valves
-have right connective tissue to connect heart tissue, cusps, chordae tendineae and papillary muscles
-open bc of pressure in atria
papillary muscles
relax
ventricular contraction
open semilunar valves
coronary vessels
supply heart with blood and branch of the ascending aorta near its base
-3 major are right coronary artery, left coronary artery and cardiac veins
coronary bloodflow
blood leaves left ventricle through aortic valves, blood surgest into aortic arch and rebounds backwards as the aortic valve shuts, rebound blood fills the coronary arties to supply walls of heart with oxy
right coronary artery
passes between the right auricle and pulm trunk
widow maker
left anterioir descending artery
branches of left coronary artery
-circumflex branch (form left marginal and posterioir left ventricle)
-anterioir interventricular branch (anterioir to posterioir branches. anastomoses)
Where does the great cardiac vein drain?
coronary sinus
cardiac cycles
-periods of relaxation and contraction
-systole= contract
-diastole= relax
diastole
chamber fills with blood
systole
blood into ventricles (atrial)
blood into pulmonary trunk and ascending aorta (ventricular)
conducting cells
-nodal cells and conducting fibers
nodal cells
pacemaker ells
-estabalish contraction rate
-membranes depolarize
conducting fiber
-send contractile stimulus to myocardium
-impulse from nodes to muscle
sinoatrial/ sa node
in posterior wall of right atrium
-determines rate
tachycardia
rapid rate
bradycardia
slow rate
internodal pathway
impulse travels to the av node
av node
in the floor of the right atriums
-impulse from av node to bundle that will divide into the right and left bundle branches tat wil send the impulse to purkinje fibers then to ventricular myocardium
first phase contraction
atriole systole not strong enough to open valve
heart rate
set by pace maker but controlled by sypathetic and parasympathetic nervous system
-autonomic nervous system changes pacemaker activity
ne
from sympathetic ns and causes increase heart rate and contraction force
acch
from parasympathetic ns, decreases heart rate and force of contractions
