Bio Option D4: The Heart

Actin and Myosin proteins in Sacromeres, similar.

Contains sarcomeres, remain single cell, joined by intercalated discs. 

Disc-shaped areas: gap junctions, allow quick passage of electrical signals.

Intercalated discs from fibrous units, branch repeatedly. 

Dense muscle tissue, large mitochondria.

Highly vascular.

Needs to work as units.

The events happening from the beginning of one heartbeat to the beginning of the next.

Heart rate = frequency of cardiac cycle (beats/min)

Systole= Chamber contraction, after recieving electrical signal.

Diastole= relaxation of the heart.

Atria contract, ventricles contract together after atrial systole.

Keeps blood moving in same direction. (No backflow)

Atrioventricular and Semilunar valves. "Lub Dub" sound

No vavles where blood enters the atria.

Internal, passive flap valves: Vena Cava & Pulmonary Veins.

Atrial Systole, less pressure.

controls frequency and internal timing of cardiac cycle.

SA- Node= Pacemaker.

Action potential from SA- node results in atrial systole, signal reaches AV- node.

AV sends out action potential, conducting fibres in septum & up on sides of the ventricles out to Purkinje fibres, causing contraction of ventricles.

Graph plotted.  Electrical activity from SA and AV nodes, plotted on X & Y axis.

P wave: voltage give off by SA- node, atrial systole.

Point Q: when AV - node sends impulse.

QRS complex: impulse from AV node  spreas down conducting fibres, out to the Purkinje Fibres.

T wave: repolariziing of AV node.

SA node repolarization hidden behind QRS complex. Delay btw SA & AV node firing.

Systolic/ Diastolic. 

Systolic pressure: in arteries when heartbeats ( heart muscle contraction) 

Diastolic pressure: in arteries, heart muscle rests and refilling blood.

Normal. Less than 120/ less than 80.

Slow, fast, irregular heart rates, and other problems.

Battery- operated devices implanted under skin, upper chest.

Small electric shocks , regular intervals, triggers a cardiac cycle.

Battery life, 7 years.

Cardiac arrest = heart has stopped

Arrhytmnia= Heart not in sequence with the normal set of electrical impulses.

Device used to deliver electric shock to the heart.

- resets electrical signals, starting with SA- node.

Automated External Defibrillators (AED) portable defibrilators. 

Condition where clot (thrombos) forms within blood vessels.

Deep vein thrombosis. (DVT) in one of larger veins, usually leg- sitting a long time in plane or car.

All portion can break loose, travel to smaller vein, block it.

Treated with, anticoagulants.

Coronary Thrombosis= Plaque in coronary artery or arteries. 

. If thrombus detaches and lodges in the reduced lumen -------- > Myocardial infarction (heart attack)

Excessively high blood pressure.

Develops over years. Need to monitor over time, to know what's higher than normal.

Narrower arteries, more pressure, higher blood pressure. 

Loss of elasticity & plaque,  builds up primary contributors to hypertension.

Slow plaque build up- Up in arteries & corresponding problems that can result.

Two factors, determine plaque build up.

Avoidable factors: overweight, sedentary (stillasittande), lifestyle, smoking, stress. etc.

Unavoidable factors: genetics.

Slow plaque build up- Up in arteries & corresponding problems that can result.

Two factors, determine plaque build up.

Avoidable factors: overweight, sedentary (stillasittande), lifestyle, smoking, stress. etc.

Unavoidable factors: genetics.

Slow plaque build up- Up in arteries & corresponding problems that can result.

Two factors, determine plaque build up.

Avoidable factors: overweight, sedentary (stillasittande), lifestyle, smoking, stress. etc.

Unavoidable factors: genetics.

Slow plaque build up- Up in arteries & corresponding problems that can result.

Two factors, determine plaque build up.

Avoidable factors: overweight, sedentary (stillasittande), lifestyle, smoking, stress. etc.

Unavoidable factors: genetics.

Slow plaque build up- Up in arteries & corresponding problems that can result.

Two factors, determine plaque build up.

Avoidable factors: overweight, sedentary (stillasittande), lifestyle, smoking, stress. etc.

Unavoidable factors: genetics.

Slow plaque build up- Up in arteries & corresponding problems that can result.

Two factors, determine plaque build up.

Avoidable factors: overweight, sedentary (stillasittande), lifestyle, smoking, stress. etc.

Unavoidable factors: genetics.