LECTURE 1 OVERVIEW OF CELL MEMBRANE PERMEABILITY AND CARDIAC CONDUCTION.pptx

OVERVIEW OF CELL MEMBRANE PERMEABILITY AND CARDIAC CONDUCTION.pptx

1. OVERVIEW OF CELL MEMBRANE PERMEABILITY AND CARDIAC CONDUCTION SYSTEM LECTURE 1 1 PUAN NOOR AZIAH BINTI MUSTAN (SRN, CCN, SCM, BNSc , MNSc (UM)

2. Definition: Membrane permeability refers to the ability of molecules or ions to pass through the cell membrane . It regulates the movement of substances in and out of cells , crucial for cellular function and homeostasis. INTRODUCTION TO MEMBRANE PERMEABILITY 2

3. Phospholipid bilayer: Composed of hydrophilic heads and hydrophobic tails . Integral proteins: Including ion channels and transporters, facilitating the movement of ions across the membrane . Selective permeability: Allows certain substances to pass while restricting others. STRUCTURE OF THE CELL MEMBRANE 3

4. 1. Passive Transport : Diffusion : Movement of molecules from an area of high concentration to low concentration . Facilitated Diffusion : Assistance of carrier proteins to facilitate the movement of specific molecules. 2. Active Transport : Primary Active Transport : Utilizes ATP to move molecules against their concentration gradient. Secondary Active Transport : Uses the energy from the movement of one molecule down its gradient to transport another molecule against its gradient. TYPE OF MEMBRANE TRANSPORT 4

5. Ion Channels: Integral membrane proteins facilitating the selective passage of ions across the membrane . Types of Ion Channels : Voltage-Gated Channels: Open or close in response to changes in membrane potential. ION CHANNELS AND MEMBRANE POTENTIAL 5

6. Membrane Potential: Difference in electrical charge across the cell membrane . Resting Membrane Potential: Typically around -70 mV, maintained by the Na+/K+ pump . Action Potential: Brief reversal of membrane potential during cell excitation. ION CHANNELS AND MEMBRANE POTENTIAL 6

7. ION CHANNELS AND MEMBRANE POTENTIAL 7

8. Hyperkalemia : Elevated extracellular potassium affecting membrane potential. Hypokalemia : Low extracellular potassium leading to altered membrane excitability. 3.6-5.2 mmol /L* DISORDERS OF MEMBRANE PERMEABILITY 8

9. OVERVIEW OF CARDIAC CONDUCTION SYSTEM 9

10. Sinoatrial (SA) Node: Pacemaker of the heart, initiating electrical impulses . Atrioventricular (AV) Node: Delays impulse transmission to allow atrial contraction before ventricular contraction. Bundle of His: Conducts impulses from the AV node to the ventricles. Purkinje Fibers : Rapidly transmit impulses to the myocardium , leading to ventricular contraction. CARDIAC CONDUCTION SYSTEM 10

11. P Wave: Represents atrial depolarization . QRS Complex: Indicates ventricular depolarization . T Wave: Represents ventricular repolarization. ELECTRICAL EVENTS IN THE CARDIAC CYCLE 11

12. Bradycardia: Abnormally slow heart rate , often due to dysfunction in the conduction system. Tachycardia: Abnormally fast heart rate , disrupting normal conduction and rhythm. DISORDERS OF CARDIAC CONDUCTION 12

13. CONCLUSION Membrane permeability, ion channels and cardiac conduction system . Understanding these concept s helps in the diagnosis and management of cardiac disorders. 13

14. THANK YOU 14