Page 153 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)
2. Ca2+ entry ➔ stimulates the release of more Ca2+ from intracellular stores in sarcoplasmic reticulum (SR)   intracellular
Ca2+ Conc.
3. Ca2+ binds to troponin C ➔ causing actin & myosin binding and sliding of the thick & thin filaments over each other 
Myocardial cell contracts.
4. Relaxation occurs when  Ca2+ is return to the SR by an active Ca2+ pump.
Definition Change of cardiac Muscle contractility / effect of drug on contractility

Inotropism Positive Inotropic effect Negative Inotropic effect
Types
Increase in Contractility Decrease in Contractility

Regulation of cardiac activity

1) Autonomic Nervous System

Sympathetic Nerve supplies Parasympathetic (vagal) nerve supplies
All cardiac tissue including the ventricles Atria & SA node & AV node but not the ventricle
Sympathetic Parasympathetic

Effect Receptor Effect Receptor

Heart Hate  β1  M2
Conduction velocity (AV  β1
 M2
node)

Contractility  β1  (Atria only)
M2

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