Cardiovascular System Notes

Cardiovascular System Notes in Physiology

Notes on the Cardiovascular System:

Veins and arteries differ in structure

• Left ventricle is thickest because it squeezes the hardest to get blood thoughout the body.

2 types of circulation:

• Pulmonary circulation (involves lung only)
• Systemic circulation (blood leaving the LV dispersed throughout body, and comes back to RA)

Systole-when ventricles are contracted, and atria relaxed and filling with blood (duration is 0.3 second)
Diastole—when ventricles are relaxing and filling, atria are contracting. (duration is 0.5 seconds)

Each complete heartbeat is less than one second (because normal resting is 70bpm)

Three different kinds of heart cells

• Pacemaker cells
  • Autorhythmic myocardia (cause excitation/contraction rhythmically)
  • Found in various heart regions, but typically in the nodes of the heart
    • Sinoatrial node SA node—roof of right atrium
    • Atrioventricular AV node—found at floor of right atrium
      •  (node is cluster of pacemaker cells)
  • Set the pace in terms of heartbeat. SA node starts the signal, sending to AV node, which sends to conduction myofiber

• Conduction myofibers
  • Found in Atrioventricular bundle (Bundle of His) fibers run down between right and left ventricles and throughout the ventricles. Now these fibers are called Purkinje fibers. Purkinje fibers allows signals to be spread/conducted to various parts of the heart

• Contractile Myocardium
  • Actual contractile cells. Millions of cells in the ventricles and atrial walls that contract at same time to perform a heartbeat.

Heart EKG Technique


Three applications of Calmodulin:

1. Calcium calmodulin—promotes Exocytosis
2. Calcium calmodulin in smooth muscle--Activates myosin light chain kinases
1. Small protein associated with myosin head
3. Calcium calmodulin in growth hormone—activates phosphodiesterase
1. Turns cyclic amp (cAMP) into AMP.
2.  GH opposes glucagon because decrease in cAMP decreases glucagon.

Cardiac Output

Cardio Output = Heart Rate x Stroke Volume

• The amount of blood the heart pumps in a minute.
• Can vary dramatically depending on activity level.
• At resting 5L per min.
• After exercise (close to aerobic capacity) can be 25 Liters/min.

  Heart Rate: Number of beats per minute.
  
  
  
  Stroke Volume: The amount of blood pumped per heart beat.
  

Brief notes on Venous Return

Cardiac Blood Flow

Definition of high blood pressure (hypertension)

What is hypotension?

 

Other Cardiovascular System Topics

Atheriosclerosis

What is Ischemia?

What is Syncope?

Cause of Edema