Anatomy and Physiology: Chapter 5-The Muscular System, Lesson 1-Muscle Tissue Categories and Functions (5.1)

Muscle Tissue

One of the four types of tissue in the body that enables movement through contraction.

Types of Muscle Fibers

Three major categories: Skeletal, Smooth, and Cardiac.

Skeletal Muscle Fibers

Attached to bones, voluntary, striated muscle fibers.

Smooth Muscle Fibers

Found in hollow organs, involuntary, non-striated muscle fibers.

Cardiac Muscle Fibers

Found in the heart, involuntary, striated muscle fibers.

Striated

Visible stripes or striations under a microscope typical of skeletal and cardiac muscles.

Voluntary Muscle

Muscles that can be controlled consciously.

Involuntary Muscle

Muscles that are not under conscious control.

Skeletal Muscle Fiber Structure

Composed of sarcolemma, cytoplasm, organelles, and endomysium.

Fascicle

A bundle of muscle fibers wrapped in a layer of connective tissue.

Paramycin

A strong, fibrous membrane that wraps around each fascicle.

Epomycin

A thick, tough connective tissue that encloses all the fascicles in a muscle.

Sarcolemma

The cell membrane surrounding a muscle fiber.

Tendon

A cord-like structure connecting muscle to bone.

Aponeurosis

A flat, sheet-like structure connecting muscle to bone.

Multiple Nuclei

Characteristic of skeletal muscle fibers, indicating that they have more than one nucleus.

Endomysium

A thin layer of connective tissue that wraps around each individual muscle fiber.

Cytoplasm

The jelly-like substance inside the cell membrane.

Organelles

Small structures within the cell performing specific functions.

Skeletal Muscle Characteristics

Striated, voluntary, and contains multiple nuclei.

Contract

The process through which muscle fibers shorten and generate movement.

Hollow organs

Organs such as the esophagus, stomach, and intestines where smooth muscle is found.

Muscle Fiber

A single muscle cell.

Bundles of Muscle Fibers

Groups of muscle fibers organized into fascicles.

Muscle Bundles

Multiple bundles of muscle fibers wrapped in connective tissue.

Connective Tissue Layers

Endomysium, paramycin, and epomycin that wrap around muscle fibers and bundles.

Analogies for Muscle Structure

A muscle fiber can be compared to a straw, with layers representing different connective tissues.

Functional Role of Skeletal Muscle

Allows for intentional movement and body function.

Cardiac Muscle Location

Found in the heart and responsible for involuntary contractions.

Skeletal Muscle Function

Facilitates movement by attaching to bones and contracting.

Smooth Muscle Function

Controls movements in hollow organs involuntarily.

Motor Control

The ability to consciously control voluntary muscle actions.

Muscle Tissue Examples

Includes skeletal, smooth, and cardiac muscle.

Nucleus in Muscle Fibers

Skeletal muscle fibers have multiple nuclei per fiber.

Straw and Muscle Fiber Analogy

The straw represents the muscle fiber, and the wrappers represent the sarcolemma and endomysium.

Muscle Movement Mechanism

Muscles contract to cause movement.

Connective Tissue Functions

Support and protect muscle fibers and bundles.

Skeletal Muscle Characteristics Summary

Striated, voluntary control, and attachment to skeleton.

Smooth Muscle Control

Not under conscious control, found in internal organs.

Fascicle Arrangement

Fascicles are wrapped in connective tissue to form a muscle.

Role of Tendons

Connect muscle to bone providing structure for movement.

Epomycin Function

Encloses all the fascicles in a muscle.

Importance of Muscle Tissue

Essential for bodily movement and organ function.

Defining Skeletal Muscle

Muscle fiber attached to the skeleton enabling voluntary movement.

Types of Contraction

Involuntary for smooth and cardiac, voluntary for skeletal muscle.

Muscle Function in Body

Enables the body to move and function efficiently.

Role of Endomysium

Surrounds individual muscle fibers to provide support.

Tendons vs Ligaments

Tendons connect muscle to bone; ligaments connect bone to bone.

Components of a Muscle Fiber

Includes sarcolemma, cytoplasm, organelles, and endomysium.

Connective Tissue Role in Muscles

Connective tissues protect and support muscle fibers.

Skeletal Muscle Examples

Muscles such as biceps and quadriceps that control voluntary movements.

Muscle Contraction

The process by which muscle fibers generate force and shorten.

Myofibrils

Thread-like structures making up muscle fibers, composed of sarcomeres.

Sarcomere

The basic functional unit of a muscle fiber, responsible for contraction.

Actin

A protein that forms thin filaments in muscle fibers.

Myosin

A protein that forms thick filaments and interacts with actin during contraction.

Neuromuscular Junction

The synapse between a motor neuron and a skeletal muscle fiber.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Muscle Fatigue

A decline in the ability of a muscle to generate force.

Isometric Contraction

Muscle contraction where tension develops but the muscle does not shorten.

Isotonic Contraction

Muscle contraction where the muscle changes length while maintaining tension.

Tropomyosin

A protein that blocks actin sites and inhibits contraction when muscle is relaxed.

Troponin

A protein complex that regulates muscle contraction by controlling the interaction between actin and myosin.

Eccentric Contraction

Lengthening of the muscle while it is under tension.

Concentric Contraction

Shortening of the muscle while it is under tension.

Lactic Acid

A byproduct of anaerobic respiration in muscles; builds up during intense exercise.

Capillary Density

The number of capillaries surrounding muscle fibers, important for oxygen delivery.

Hyperplasia

An increase in the number of muscle fibers.

Hypertrophy

An increase in the size of muscle fibers, typically in response to resistance training.

Muscle Tone

The continuous and passive partial contraction of muscles.

Satellite Cells

Stem cells located in muscle tissue that facilitate growth and repair.

Muscle Spindle

Sensory receptors located in muscles that sense stretch.

Golgi Tendon Organ

Receptors that prevent excessive force by inhibiting muscle contraction.

Type I Muscle Fibers

Slow-twitch fibers, fatigue-resistant, used for endurance activities.

Type II Muscle Fibers

Fast-twitch fibers, less resistant to fatigue, used for short bursts of power.

Skeletal Muscle Fibers

Also known as striated muscle fibers, controlled voluntarily and attached to bones.

Smooth Muscle Fibers

Found in the walls of hollow organs, these fibers are involuntary and non-striated.

Cardiac Muscle Fibers

Muscle fibers found in the heart, involuntary and striated.

Fascicle

A bundle of muscle fibers wrapped in a layer of connective tissue called paramycin.

Endomysium

A thin layer of connective tissue that wraps around each individual muscle fiber.

Paramycin

A strong, fibrous membrane that wraps around each fascicle of muscle fibers.

Epomycin

A thick, tough layer of connective tissue that encloses all the fascicles in a muscle.

Tendon

A cord-like structure that connects muscle to bone.

Aponeurosis

A flat, sheet-like structure that serves the same function as a tendon, but is flat rather than cord-like.