Muscle ICS Course Overview

Muscle ICS Objectives

• The objectives of the Muscle ICS course include understanding the types, functions, and characteristics of muscle tissue.
• This will involve studying histological organization and connective tissue components.
• The course will also cover muscle organization and contractile units.

Function of Muscles

• Muscles have three primary functions: movement, posture, and generating heat.
• The different types of muscles (skeletal, cardiac, smooth) are illustrated to demonstrate their specific roles.

Skeletal Muscle

• Skeletal muscle tissue is examined microscopically.
• The images display the structure of skeletal muscle on a tissue level.
• Images of skeletal muscle microstructure are presented.

Cardiac Muscle

• Microscopically, cardiac muscle shows branching cells.
• The structure of cardiac muscle tissue is visualised.
• Images of cardiac muscle microstructure are presented.

Smooth Muscle

• Smooth muscle cells are elongated, spindle-shaped cells.
• Visual images of longitudinal and cross-sectional views of smooth muscle microstructure are available.
• Information about smooth muscle microstructure is presented.

Organization of Skeletal Muscle

• Skeletal muscle consists of bundles of fibers (fascicles).
• Connective Tissue is organized to form different layers (epimysium, perimysium, endomysium).
• Each layer has different functions in supporting and organizing muscle fibres for efficient movement.

Primary Proteins in Muscle

• Essential muscle proteins like troponin complex (TnC, TnT, TnI), tropomyosin, and actin are detailed.
• These proteins play crucial roles in muscle contraction.
• Images show the arrangement of these proteins within the sarcomere.

Sliding Filament Theory

• The sliding filament theory describes how muscles contract.
• The process involves the sliding of actin and myosin filaments past each other.
• The micrographs demonstrate the structural changes during contraction.

The Sliding Filament Theory- Further Detail

• The myosin head binds to the actin filament.
• ATP hydrolysis facilitates the power stroke.
• ATP binding detaches the myosin head.
• The cycle repeats for continued contraction.
• Illustrations and micrographs show the mechanics.

Triad System

• The triad system consists of T-tubules and the sarcoplasmic reticulum, releasing calcium for muscle contractions.
• A critical component for muscle function.

Skeletal Muscle Triad/Fiber

• Diagrams showcase the arrangement of the triad (terminal cisternae of the sarcoplasmic reticulum and T tubules) around myofibrils in a skeletal muscle fiber.
• The arrangement of these structures in a muscle fiber and their roles in transmitting signals are emphasized.

Neuromuscular Junction

• The neuromuscular junction details are illustrated and explained.
• The process of nerve impulse transmission between a motor neuron and the muscle fibers.

Motor Endplates of Skeletal Muscle

• Diagrammatic representations of the motor endplate structure of the skeletal muscle and the relevant components involved in muscle contraction.
• Visual images emphasize the importance of this area, and its components in muscle function.

Myocardial Infarction

• Myocardial infarction is cardiac muscle injury/death caused by tissue blockage.
• This leads to repair through fibrous tissue.
• The process and markers are described.

Actin and Myosin Arrangement

• Muscle images show actin and myosin arrangement is different in smooth muscle.
• This is also shown in different muscle types.

Smooth Muscle

• Features of smooth muscle like caveolae, dense bodies, and gap junctions are detailed in microscope images.
• Diagrammatic representation of smooth muscle and its structural components and functions are illustrated.

Chronic Asthma

• Respiratory airways are hypersensitive in chronic asthma.
• This causes constriction from smooth muscle constrictions in airways, leading to edema, mucus, and inflammation.
• Pathologic alterations in smooth muscle are outlined.

Cardiac vs. Skeletal Muscle

• The key differences between cardiac and skeletal muscle structures and functions are compared.
• The organization and microscopic image details regarding cardiac muscle are given.

Three Types of Cell Junctions

• Three types of cell junctions in cardiac muscle (fascia adherens, desmosomes, gap junctions) that contribute to the functional properties of cardiac cells.
• Visual representation of the interconnectedness of cardiac muscle.

Terms to know

• Autoimmune diseases (e.g., myasthenia gravis) involve the immune system attacking the body's own tissues.
• Caveolae are small invaginations of the smooth muscle cell membrane.
• Dystrophin is crucial for linking the contractile proteins of muscle cells to the surrounding structural proteins.
• Fibrosis is the formation of excessive fibrous tissue in place of normal tissue.
• The synaptic cleft is the space between the nerve ending and the muscle cell.