Cardio

Anatomy of the heart

Electrical conduction

The cardiac cycle

Define

Structural differences

End-diastolic volume

End-systolic volume

Heart rate

Preload

Stroke volume

Venous return

cardiac output

After load

volume of blood ejected by a single ventricle in 1 minute
calculated by multiplying heart rate times stroke volume

amount of blood pumped out during ventricular contraction
volume of blood ejected during 1 beat ( 70 mL)

Number of beats per minute, stimulates SA node to change its firing rate or AV node to alter amount of delay

labeled in phase 2, volume of blood within the end of diastole, ventricular filling is complete upon termination of atrial contraction and ventricles now hold their max blood volume

labeled in phase 2 blood remaining in a ventricle at the
end of systole, subtracting SV from EDV (130-70=60)

volume of blood returned to heart via great veins directly related to stroke volume. Determines amount of blood in ventricles at the end of rest immediately prior to contraction

stretch of the heart wall due to the load,
cardiac muscle is subjected before shortening

resistance in arteries to the ejection of blood by ventricles, pressure that must be exceeded before blood is ejected from chamber

Frank-Starling law

volume of blood entering heart increases; greater stretch of the heart wall; greater overlap of thick and thin filaments in the sarcomeres of the cardiac muscle cells composing the myocardium; allows formation of greater numbers of cross bridges. More forceful ventricular constriction is generated and stroke volume increases

Arterioles

Capillaries

Arteries

Veins

Carries oxygenated blood away from the heart

Venules

Septum

interatrial

interventricular

Valves

aortic semilunar

pulmonary semilunar

Coronary Vessels

Artery

Vein

small cardiac vein

coronary sinus

middle cardiac vein

great cardiac vein

right marginal artery

circumflex artery

interventricular artery (anterior & posterior)

coronary artery (right & left)

end artery

functional end arteries

Chambers

Right Ventricle

Right Atrium

Left Ventricle

Left Atrium

trabeculae carneae

tendinous cords/chorae tendineae

papillary muscles

fossa ovalis

foramen ovale

pectinate muscles

papillary muscles

tendinous cords

Inferior/Superior Vena Cava

Aorta

Pulmonary Trunk

ascending aorta

descending aorta

aortic arch

Left/Right Atrium

right/left pulmonary veins

right/left pulmonary artery

tricuspid

bicuspid

Pericardial Cavity

pericardia sac

AV Bundle

AV Node

Ventricular Myocardium

SA Node

beginning/ spread by gap junction, instantaneous excitation of all muscle cell in atrial walls results in cardiac muscle cells in bottom of atria to contract at the same time

delays action potential for the ventricles to contract

passage way from AV Node to Purkinje Fibers

gap junction spreads action potential between cardiac muscle cells through out ventricles

Purkinjie Fibers

extend from left and right bundles beginning at apex of heart and then continue through the walls of the ventricles

Ventricular Depolarization- QRS COMPLEX

Ventricular Plateau- QT INTERVAL

Arterial Plateau- P-Q SEGMENT

Ventricular Repolarization-

Atrial Depolarization- P WAVE

Atrial relaxation and ventricle filling

atrial & ventricles relaxed, atrial & arterial trunk pressure is more, AV valve is opened and Semilunar Valve is closed

Arterial contraction & ventricle filling

Atria contracts/ventricles relax, arterial & arterial trunk pressure is more, AV Valve is opened & Semilunar Valve is closed

Isovolumatric contraction/ Atria is repolarizing

Atria relaxes/Ventricles contract, atrial pressure is less & arterial trunk is greater, AV Valve & Semilunar Valve is closed

Ventricular Ejection

atria relaxes/ ventricles contract, atria & arterial trunk pressure is less, AV Valve is closed & Semilunar Valve is opened

Isovolumetric Relaxation

atria & ventricles relax, atrial pressure is less & arterial pressure is more, AV Valve & Semilunar Valve are closed

Cardiac Muscle Contraction

Drains blood from capillaries and returns deoxygenated blood to heart

Transport between arteries and veins

Regulate distribution of blood through vasoconstriction and vasodilation

Receives blood from capillaries

Lumen is narrower, wall is thicker, more elastic and collagen fibers in tunics, higher BP (100 mm Hg in larger & 40 mm Hg in smaller) than in veins; systemic arteries carry blood high in O2 and pulmonary arteries carry blood low in O2; shape retained without blood in vessels

Lumen is wider, walls are thinner, less elastic and collagen fibers in tunics, Lower BP (20mm Hg to 00 mm Hg) than in arteries; valves in most; systemic veins carry blood low in O2 and pulmonary veins carry blood high in O2; collapse without blood in vessels

Smallest arterioles 3 mm to 10 micrometers, only have thin layer of epithelium and 1 layer of smooth muscle; larger have 3 tunics

Smallest veins 8 to 100 micrometers; Smallest are postcapillary and larger have all 3 tunics

exchange substance between blood and tissue

Elastic

Muscular

Length 1 mm, diameter 8-10 micrometers; endothelial layer at basement membrane

Continuous

Fenestrated

Sinusoid

Sodium entering cell , stimulates the release of calcium from sarcoplasm reticulum, calcium binds to filaments troponin and tropomyosin, myosin is free to bind to action

nerve impulse enters T tubles and sarcoplasmic
reticulum stimulating the release of calcium ions

calcium ions combine with troponin and
expsing the myosin binding sites on the actin

acetylecholine causes impulse to spread
across the surface of the sarcolemma

ATP breaks down ADP + releasing energy activates the myosin cross bridges and results in the sliding of thin actin myofilament past the thick myosin myofilaments

nerve impulse travels down and axon
and causes the release of acetylcholine

sliding of myofilaments draws the z lines towards each other and the sarcomere shortens and the muscle fibers contract therefore muscle contracts

ACh is inactivated by acetylcholinesterase inhibiting
the nerve impulse conduction across the sarcolemma

nerve impulse is inhibited and calcium ions are actively transported back into the sarcoplasmic reticulum using the energy from the break down of ATP

low calcium concentration causes the myosin cross bridges to separate from the thick actin myofilaments and the actin myofilaments return to their relaxed position

sarcomeres return to their resting lengths and muscle fibers relax and the muscle relaxes

Skeletal Muscle

Cardiac Muscle

Stimulated by nervous system

Stimulated by electrical impulses

shorter refractory period

shorter contraction