Cardiac muscles. Features and functions. General Anatomy laik hussain. Lecture no 16.
Subscribe to my YouTube channel drtouseef1. In this video you'll learn about Cardiac muscles. Lecture no 1 • General Anatomy by laiq Hussain | cha... Lecture no 2 • Planes and positions of the body. Gen... Lecture no 3 • Types of body movements. || General A... Lecture no 4 • Anatomy and physiology of bone. Gener... Lecture no 5 • Distribution and classification of bo... Lecture no 6 • Gross anatomy of typical long bone. G... Lecture no 7 • What is cartilage? || It's types and ... Lecture no 8 • Part 01. What are joints. It's classi... Lecture no 9 • Part 02. What are synarthrosis joints... Lecture no 10 • Part 03. What are diarthrosis joints.... Lecture no 11 • Synovial joints. Classifications of s... Lecture no 12 • Part 2. Classification of synovial jo... Lecture no 13 • What are the muscles?. General Anatom... Lecture no 14 • Types of muscles. Skeletal muscles. g... Lecture no 15 • Smooth muscles. Characteristics and f... Cardiac Muscles Cardiac muscles are involuntary, striated muscles found exclusively in the walls of the heart (myocardium). They are responsible for pumping blood throughout the body and are controlled by the autonomic nervous system. --- 1. Structure of Cardiac Muscles Cells (Cardiomyocytes): Short, branched, and cylindrical. Usually uninucleated (sometimes binucleated). Surrounded by a sarcolemma and contains sarcoplasm rich in mitochondria. Myofibrils: Contain sarcomeres, giving them a striated appearance similar to skeletal muscles. Composed of actin (thin) and myosin (thick) filaments. Intercalated Discs: Specialized junctions connecting cardiomyocytes. Contain: Gap Junctions: Allow rapid transmission of electrical impulses for synchronized contraction. Desmosomes: Provide mechanical strength by anchoring cells together. --- 2. Functions of Cardiac Muscles Pumping Blood: Continuous rhythmic contractions maintain blood circulation. Automaticity: Can generate impulses independently (via pacemaker cells). Synchronous Contraction: Intercalated discs ensure coordinated contraction of the heart muscle. --- 3. Properties of Cardiac Muscles Involuntary Control: Regulated by the autonomic nervous system (sympathetic and parasympathetic). Rich Blood Supply: High oxygen demand due to continuous activity. Mitochondria Abundance: High ATP production to meet energy requirements. Self-Excitation: Can generate its own action potentials (autorhythmicity). --- 4. Mechanism of Contraction (Similar to Skeletal Muscle): Follows the Sliding Filament Theory: Calcium ions (Ca²⁺) released from the sarcoplasmic reticulum (SR) and extracellular fluid. Calcium binds to troponin, causing tropomyosin to shift and expose binding sites on actin. Myosin heads bind to actin, creating a cross-bridge. ATP hydrolysis allows the myosin heads to pull the actin filaments, shortening the sarcomere. --- 5. Differences Between Cardiac and Skeletal Muscles --- 6. Blood Supply and Nerve Supply Blood Supply: Highly vascularized through coronary arteries. Nerve Supply: Controlled by sympathetic (increases rate & force) and parasympathetic (decreases rate) nervous systems. ---