anat

sinoatrial (SA) node

to start each heartbeat and set the rhythm for the heart

atrioventricular (AV) node

to delay and move electrical signals from the atria to the ventricles

atrioventricular (AV) bundle

The AV bundle conducts the impulse from the AV node to the ventricles and is located in the interventricular septum.

Purkinje fibers

to move electrical signals from the base of the ventricles toward the top of the heart

AV valves

AV valves (tricuspid and mitral) prevent backflow of blood into the atria during ventricular contraction. They are open during heart relaxation (diastole) and closed during ventricular contraction (systole).

semilunar valves

Semilunar valves (pulmonary and aortic) prevent blood from flowing back into the ventricles after contraction. They are closed during diastole and open during ventricular contraction (systole).

cerebral cortex

control voluntary skeletal muscle, intellectual and emotional processing

thalamus

relays impulses to cerebral cortex

hypothalamus

regulation of autonomic nervous functions, regulates temp, water balance, food

limbic system

mediates emotional response

medulla oblongata

relays sensory input, controls HR, respiratory rate

cerebellum

smooths skeletal muscle movements, regulates balance and posture

calcium

activates binding sites on actin filament

myosin

protein with head that attaches to actin and performs power stroke (thick filament)

actin

protein that myosin head pulls in power stroke, causing muscle to shorten (thin filament)

sarcomere

basic unit of muscle contraction, shortens as actin filaments are pulled toward center

pulmonary v. systemic circulation

• Pulmonary circulation carries blood to the lungs for oxygenation 

• Systemic circulation delivers oxygenated blood to the body. 

• The right side of the heart drives pulmonary circulation 

• The left side drives systemic circulation.