Muscle Tissue Chapter 10

Functions of Muscular Tissue Properties of Muscular Tissue Producing body movements Stabilizing body positions Storing and movement of substances in the body Producing heat Properties of Muscular Tissue Excitability Contractility Extensibility Elasticity

Types of Muscle Skeletal Muscle Cardiac Muscle Smooth Muscle

Types of Muscle

Connective Tissue Components

Muscle Attachments Attachment - connective tissue layers extend to attach to bone (tendon or aponeurosis) Insertion - attachment to a movable bone Origin - attachment to stationary bone

Anatomy of a Muscle Fiber

Anatomy of a Muscle Fiber

Myofibril and Sarcomere

Sarcomere Dark(A) & light(I) bands visible with an electron microscope

Sarcomere

Thick and Thin Filaments

Skeletal Muscle Fiber Proteins

Sliding Filament Mechanism

The Contraction Cycle

Excitation - Contraction Coupling

Neuromuscular Junction

Summary

Contraction of a Skeletal Muscle Motor Unit: A motor neuron and all the muscle fibers it innervates.

Contraction of a Skeletal Muscle Muscle Twitch: Response of a muscle to a single stimulus

Contraction of a Skeletal Muscle Graded Muscle Responses Graded - variation in degree of contraction 1. Frequency of stimulation Wave summation and Tetanus 2. Strength of the stimulus Motor Unit Recruitment More motor units stimulated which leads to more muscle fibers responding.

Wave Summation and Tetanus

Muscle Tone Involuntary contraction of a small number of motor units which leads to partial state of contraction of relaxed muscles Keeps muscles firm even though relaxed Essential for maintaining posture

Isotonic and Isometric Contractions Isometric - muscle applies tension but does not move the load Isotonic - muscle changes length load is moved

Muscle Metabolism

Muscle Fatigue Inability to contract after prolonged activity central fatigue is feeling of tiredness and a desire to stop (protective mechanism) depletion of creatine phosphate decline of Ca2+ within the sarcoplasm Factors that contribute to muscle fatigue insufficient oxygen or glycogen buildup of lactic acid and ADP insufficient release of acetylcholine from motor neurons

Types of Skeletal Muscle Fibers

Types of Smooth Muscle

Microscopic Anatomy