Physiology notes
Planarian: gastrovascular system (digestion and circulation) with a
gastrovascular cavity
Insects: open circulation (tubular heart)
Earthworm: closed circulation with lateral hearts
Open circulatory system: no difference between blood and
extracellular fluid
Closed circulatory system (vertebrates):
o Transport: oxygen, nutrients, metabolic waste
o Regulation: hormones, temperature
o Immune system
Thought: open air system (false!) 130-200 AD
- No capillaries?
- Blood produced in liver and disappeared out of the body?
Low oxygen right ventricle and right atrium lungs high oxygen
left atrium and ventricle aorta organs.
Conduction system of the heart
1. SA node depolarizes
2. Electrical activity goes rapidly to AV node via internodal pathways
3. Depolarization spreads more slowly across atria. Conduction slows
through AV node
4. Depolarization moves rapidly through ventricular conducting system
to the apex of the heart.
5. Depolarization wave spreads upward form the apex.
Node = pacemaker
SA node = sinus node.
AV node = atrioventricular node.
P wave in ECG = represents what happens
in the atria.
QRS wave in ECG = represents what
happens in the ventricles.
Planarian: gastrovascular system (digestion and circulation) with a
gastrovascular cavity
Insects: open circulation (tubular heart)
Earthworm: closed circulation with lateral hearts
Open circulatory system: no difference between blood and
extracellular fluid
Closed circulatory system (vertebrates):
o Transport: oxygen, nutrients, metabolic waste
o Regulation: hormones, temperature
o Immune system
Thought: open air system (false!) 130-200 AD
- No capillaries?
- Blood produced in liver and disappeared out of the body?
Low oxygen right ventricle and right atrium lungs high oxygen
left atrium and ventricle aorta organs.
Conduction system of the heart
1. SA node depolarizes
2. Electrical activity goes rapidly to AV node via internodal pathways
3. Depolarization spreads more slowly across atria. Conduction slows
through AV node
4. Depolarization moves rapidly through ventricular conducting system
to the apex of the heart.
5. Depolarization wave spreads upward form the apex.
Node = pacemaker
SA node = sinus node.
AV node = atrioventricular node.
P wave in ECG = represents what happens
in the atria.
QRS wave in ECG = represents what
happens in the ventricles.
