BIO 211 Greenville Tech Chapter 19: Cardiovascular System – Heart
Study Guide, Notes & Practice Questions (2026 Updated)
Cardiovascular System components - ANS ✔✔blood vessels, blood, heart
Intercalated Discs - ANS ✔✔connect adjacent muscle cells
Desmosomes - ANS ✔✔anchoring protein filaments
Gap Junctions - ANS ✔✔- protein channels
- allow passage for nutrients
- allow action potential to take place and move down the sarcolemma
Metabolism of Cardiac Muscle - ANS ✔✔1.) requires extensive blood supply for energy
- numerous mitochondria for energy
- extensive supply of proteins (myoglobins)
2.) ability to use different fuel types
- glucose, lactic acid, fatty acid, amino acids
3.) rely on aerobic cellular respiration
- requires oxygen
Cardiac Muscle Contraction - ANS ✔✔*Atrial Contraction*
- atrial walls compress and move blood to ventricles
*Ventricular Contraction*
- "wringing of the mop"
- begins at the apex and moves upwards (compresses superiorly)
- moves blood out of heart (aortic and pulmonary semilunar valves)
, Heart Conduction System - ANS ✔✔1.) Sinoatrial (SA) Node initiates contraction
2.) Action potential is conducted through the atria
3.) Action potential spread down sarcolemma of cardiac muscle cells - first in atria and then in
ventricles
4.) Thin and thick filaments form crossbridge, then muscle contracts
Sinoatrial (SA) Node - ANS ✔✔"pacemaker"
- located in posterior wall of right atrium
- establishes a pattern
Atrioventricular (AV) Node - ANS ✔✔- located on floor of right atrium, adjacent to opening of
coronary sinus
Atrioventricular Bundle - ANS ✔✔- bundle of nerves
- extends from the AV node through AV septum and then splits into the right/left AV bundles
Purkinje Fibers - ANS ✔✔- extend from the AV bundles and travel up the heart walls
Sympathetic Innervation of the Heart - ANS ✔✔cardioacceleratory center >> sends nerve
signals to sympathetic nerves >> increases heart rate and force of contraction
Parasympathetic Innervation of the Heart - ANS ✔✔cardioinhibitory center >> sends nerve
signals to vagus nerve >> decrease in heart rate and force of contraction
Cardiac Center - ANS ✔✔- located in the medulla oblongata
- contains both the cardioacceleratory center and the cardioinhibitory center
Study Guide, Notes & Practice Questions (2026 Updated)
Cardiovascular System components - ANS ✔✔blood vessels, blood, heart
Intercalated Discs - ANS ✔✔connect adjacent muscle cells
Desmosomes - ANS ✔✔anchoring protein filaments
Gap Junctions - ANS ✔✔- protein channels
- allow passage for nutrients
- allow action potential to take place and move down the sarcolemma
Metabolism of Cardiac Muscle - ANS ✔✔1.) requires extensive blood supply for energy
- numerous mitochondria for energy
- extensive supply of proteins (myoglobins)
2.) ability to use different fuel types
- glucose, lactic acid, fatty acid, amino acids
3.) rely on aerobic cellular respiration
- requires oxygen
Cardiac Muscle Contraction - ANS ✔✔*Atrial Contraction*
- atrial walls compress and move blood to ventricles
*Ventricular Contraction*
- "wringing of the mop"
- begins at the apex and moves upwards (compresses superiorly)
- moves blood out of heart (aortic and pulmonary semilunar valves)
, Heart Conduction System - ANS ✔✔1.) Sinoatrial (SA) Node initiates contraction
2.) Action potential is conducted through the atria
3.) Action potential spread down sarcolemma of cardiac muscle cells - first in atria and then in
ventricles
4.) Thin and thick filaments form crossbridge, then muscle contracts
Sinoatrial (SA) Node - ANS ✔✔"pacemaker"
- located in posterior wall of right atrium
- establishes a pattern
Atrioventricular (AV) Node - ANS ✔✔- located on floor of right atrium, adjacent to opening of
coronary sinus
Atrioventricular Bundle - ANS ✔✔- bundle of nerves
- extends from the AV node through AV septum and then splits into the right/left AV bundles
Purkinje Fibers - ANS ✔✔- extend from the AV bundles and travel up the heart walls
Sympathetic Innervation of the Heart - ANS ✔✔cardioacceleratory center >> sends nerve
signals to sympathetic nerves >> increases heart rate and force of contraction
Parasympathetic Innervation of the Heart - ANS ✔✔cardioinhibitory center >> sends nerve
signals to vagus nerve >> decrease in heart rate and force of contraction
Cardiac Center - ANS ✔✔- located in the medulla oblongata
- contains both the cardioacceleratory center and the cardioinhibitory center
