1AA3 - WEEK 1

Functions of the Cardiovascular System

* transportation
* immunity
* tissue repair
* body temperature

Components of the Cardiovascular System

* heart
* blood vessels
* blood

Apex

* anterior-inferior
* towards left

Base

* posterior-superior
* towards right

Functions of the Heart

* generate blood pressure
* route blood
* ensure one-way flow
* regulate blood supply

Layers of Heart Wall

* fibrous pericardium
* serous pericardium (parietal and visceral)
* epicardium
* myocardium
* endocardium

Atria

* two
* have auricles (raised tissue pockets)

Coronary Sulci

* encircles heart
* boundary between atria and ventricles

Interventricular Sulci

* anterior + posterior
* boundary between ventricles

Ventricles

* three lower

Sulcus

* groove on surface
* with blood vessels and fat

Arteries in Coronary Circulation

right coronary

* right marginal: to lateral wall of RV
* posterior interventricular: to posterior and inferior heart

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left coronary

* anterior interventricular: to LV
* circumflex: to posterior heart
* left marginal: to lateral wall of LV

Veins in Coronary Circulation

great cardiac: drains left side of heart

small cardiac: drains right margin

middle cardiac: dramas area supplied by posterior interventricular artery

coronary sinus: large venous cavity / dumps blood into right atrium

Heart Chambers

* right atrium
* right ventricle
* left atrium
* left ventricle
* aorta

Trabeculae Carnae

raised cardiac tissue

Papillary Muscles

cone shaped cardiac tissue / contract with ventricles

Chordae Tendinae

attaches onto valves

Atrioventricular (AV) Valve

* leaf like
* attached to papillary muscles by chord tendinae
* tricuspid and bicuspid/mitral

Semi-Lunar Valve

* right (coronary) and left (aortic)
* filled cusp = closed valve

Skeleton of Heart

* plate of fibrous CTT
* rings around valves
* for support, electrical insulation, muscle attachment

Relaxed and Contracted Heart Valves

relaxed

* cardiac muscle and papillary relaxed
* low tenineae tension
* high atrial pressure
* high aortic pressure

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contracted

* atria contracts before ventricles
* tendineae contract → hold valve → stop back flow

Structure of Cardiac Muscle Tissue

* elongated
* branches
* connect in series
* 1-2 central nuclei
* lots of mitochondria

Intercalated Disks

where specialized cells connect

Desmosomes

plasma membrane holding cells together during contraction / “staples”

Gap Junction

* for electrical synapses
* physical connection
* ion directly to neighbour

T-Tubles in Muscle Tissue

* where z-disk is location
* decreased sarcoplasmic reticulum organization and decreased t-tubule contact

Conducting System of the Heart

* SA node
* AV node
* AV bundle
* right and left bundle branches
* purkinje fibres

Cardiac Muscle Action Potential

depolarization: Na+ in

plateau: Ca2+ in and K+ out

repolarization: K+ out

refraction: longer than contraction

SA Node Action Potential

* self generated AP
* regular time intervals
* has specialized Na+ channels

Electrocardiogram

p wave: depolarization of atria

qrs complex: depolarization of ventricles

t wave: repolarization of ventricles

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pq interval: atrial excitation start - ventricle excitation start

st interval: ventricular depolarization end - ventricular repolarization

qt interval: ventricular depolarization start - ventricular repolarization

Systole

* chamber contracts
* ejection of blood

Diastole

* chamber fills with blood

Phases of the Cardiac Cycle

* atrial contraction
* isovolumetric contraction
* ventricular ejection
* isovolumetric relaxation
* passive ventricular filling

Dicrotic Notch

blip in aortic pressure

AV Valve Opening

atrial pressure > ventricular pressure

Semilunar Valve Opening

ventricular pressure > aortic pressure

End Diastolic Volume

max volume that could be pushed out of heart / after relaxation

End Systolic Volume

min volume / after contraction

Stroke Volume

volume of blood pumped per beat

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SV = EDV - ESV

Heart Sounds

lubb: AV valves and surrounding fluid vibrations / as valves close at beginning of ventricular systole

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dupp: closure of semilunar valves / at beginning of ventricular diastole

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third: turbulent flow into ventricles / deflected near end of first 1/3 of diastole or atrial systole