mod 5

• Attachment is a strong reciprocal emotional bond between an infant and a primary caregiver

  
• Schaffer and Emerson's 1964 study on attachment:

  • Aim: identify stages of attachment / find a pattern in the development of an attachment between infants and parents
  • Participants: 60 babies from Glasgow
  • Procedure: analysed interactions between infants and carers
  • Findings: babies of parents/carers with 'sensitive responsiveness' were more likely to have formed an attachment
• Freud's superego is the moral component of the psyche, representing internalized societal values and standards
• Muscle tissue is the fourth basic tissue type, composed of cells that optimize the universal cell property of contractility and is of mesodermal origin

  
• Functions of muscle tissue include movement of the body, maintenance of posture, respiration, production of body heat, communication, constriction of organs and vessels, and contraction of the heart
• Properties of muscle tissue:

  • Contractility: ability to shorten forcefully
  • Excitability: capacity to respond to a stimulus
  • Extensibility: can be stretched beyond its normal resting length and still contract
  • Elasticity: ability to recoil to its original resting length after being stretched
• Three major types of muscle tissue:

  • Skeletal (Striated) Muscle
  • Cardiac Muscle
  • Smooth (Visceral) Muscle
• Muscle fiber is a single cylindrical cell with either single or numerous nuclei, with sarcoplasm as the cytoplasm and sarcolemma as the plasma membrane and external lamina

  
• Skeletal muscle is striated muscle with long, cylindrical, multinucleated fibers, and myoblasts align and fuse together to form myotubes, which differentiate into muscle fibers
• Satellite cells are reserve progenitor cells important for muscle repair and regeneration, found on the external surface of muscle fibers inside the developing external lamina
• Organization within muscle fibers includes:

  • Myofibrils: threadlike structures composed of protein filaments within the sarcoplasm
  • Sarcomeres: highly ordered units formed by actin and myosin myofilaments, extending from one Z disk to an adjacent Z disk
• Freud's superego represents internalized societal values and standards
• Nervous tissue is involved in muscle contraction through electrical signals from the brain or spinal cord

  
• Module 5 in Human Histology covers Muscle and Nervous Tissue

  
• Development of skeletal muscle:

  • Starts with myoblasts
  • Myoblasts activate, proliferate, fuse to form myotubes
  • Myotubes differentiate into muscle fibers
  • Satellite cells important for muscle repair and regeneration

  
• In Module 5.1, focusing on Muscle Tissue, students learn about the functions, types, and organization of muscle tissues
• Diagram of the organization of skeletal muscle

  
• Muscle tissue is the fourth basic tissue type, composed of cells that optimize the universal cell property of contractility and is of mesodermal origin
• Skeletal muscle fiber:

  • Panel (a): shows myofibril with A band, I band, N line (Z disk), F line
  • Panel (b): enlargement showing repeating sarcomeres
  • Panel (c): electron micrograph showing thick (myosin) and thin (actin) filaments

  
• Functions of muscle tissue include movement of the body, maintenance of posture, respiration, production of body heat, communication, constriction of organs and vessels, and contraction of the heart
• Thin filament in skeletal muscle contains regulatory proteins like tropomyosin and troponin
• Properties of muscle tissue include contractility, excitability, extensibility, and elasticity
• Accessory proteins in skeletal muscle include titin and nebulin
• There are three major types of muscle tissue: Skeletal (Striated) Muscle, Cardiac Muscle, and Smooth (Visceral) Muscle
• Sarcoplasmic reticulum in skeletal muscle contains pumps for Ca2+ sequestration
• A muscle fiber is a single cylindrical cell with either single or numerous nuclei, with components like sarcoplasm, sarcolemma, and sarcoplasmic reticulum
• Skeletal muscle is striated muscle composed of long, cylindrical, multinucleated cells with specific characteristics like elongated nuclei found peripherally just under the sarcolemma
• Muscle fibers are electrically excitable and have a resting membrane potential
• In skeletal muscle, myoblasts align and fuse together to form longer multinucleated tubes called myotubes, which synthesize proteins for myofilaments and show cross-striations
• Action potentials in muscle fibers involve depolarization and repolarization phases
• The organization of skeletal muscle includes external sheaths like epimysium, perimysium, and endomysium, each serving specific functions in muscle structure
• Nerve supply to muscle fibers occurs through axons of neurons that innervate muscle fibers at neuromuscular junctions
• Myofibrils within muscle fibers are threadlike structures composed of protein filaments, consisting of sarcomeres with actin (thin) and myosin (thick) myofilaments
• Neuromuscular junctions involve the release of acetylcholine (ACh) to trigger muscle fiber contraction
• A sarcomere is the highly ordered unit formed by actin and myosin myofilaments, extending from one Z disk to an adjacent Z disk, with specific bands like A band, I band, H zone, and M line
• Muscle contraction is powered by energy sources like creatine phosphate, anaerobic, and aerobic respiration
• The thick filament in muscle fibers consists of myosin with a tail and head structure, where the head binds both actin and ATP, essential for muscle contraction
• Globular actin (G actin) monomers in thin filaments have binding sites for myosin, crucial for muscle contraction
• TEM image showing a contractile unit (sarcomere) in muscle fibers, illustrating the detailed structure of myofibrils and sarcomeres

  
• The TEM image highlights the A band, H zone, I band, Z disc, and other components within the muscle fiber, essential for understanding muscle contraction