7.01 - Intro to Muscular System

Intro to muscles!

Properties, Functions, and

Types

Introduction

• There are over 600 muscles in the human body

Introduction

• Muscles make up approximately 45% of the body weight of an adult

Introduction

• Muscles are made up of bundles of fibers (long, slender cells) that are held together by connective tissue

Introduction

• When fibers are stimulated by nerves they contract (become short and thick) which causes
movement

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Behavioral Characteristics of muscles

• Irritability: the ability to receive and respond to a stimulus and the ability to respond by generating and transmitting an electrical current (action Potential)

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Behavioral Characteristics of muscles

• Contractility: ability to shorten forcefully

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Behavioral Characteristics of muscles

• Extensibility: ability to be stretched

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Behavioral Characteristics of muscles

• Elasticity: ability to resume resting length after being stretched

Functions of

muscles

1.

Movement

2.

Maintain posture

3.

Stabilize joints

4.

Generation of heat and
regulation of body temperature
(homeostasis)

5.

Protection of internal organs

Types of Muscles

• Skeletal Muscle

– Striated, multinucleated, voluntary muscle

Types of Muscles

• Cardiac Muscle

– Striated, uninucleated, involuntary muscle

Types of Muscles

• Smooth Muscle

– Non-striated, uninucleated, involuntary muscle

Skeletal Muscles

• Approximately 40% of your body

Skeletal Muscles

• Have the longest fibers of all your muscle cells.

Skeletal Muscles

• Contracts rapidly, tires easily, has great power, and is adaptable

Skeletal Muscles

• Causes movement controlled by somatic nervous system

Skeletal Muscle

Attachments

• Indirect attachments

• Tendons

Skeletal Muscle

Attachments

• Indirect attachments

• Fascia

Skeletal Muscle

Attachments

• Indirect attachments

• Aponeurosis

Cardiac Muscles

• Forms the walls of the heart

Cardiac Muscles

• Branched cells that are connected by intercalated discs

Cardiac Muscles

• Contracts at a steady rate (except for brief bursts of
rapid activity) and is
controlled through the
autonomic nervous system

Visceral (Smooth) Muscles

• Forms the walls of your hollow, visceral organs

Visceral (Smooth) Muscles

• Movement is called peristalsis: smooth wave-like contraction

Visceral (Smooth) Muscles

• Controlled by the autonomic nervous system