Chapter 10Muscular

Tissue

Lecture slides prepared by Curtis DeFriez, Weber State University

• Like nervous tissue, muscles are excitable or "irritable”

they have the ability to respond to a stimulus• Unlike nerves, however, muscles are also:

Contractible (they can shorten in length)Extensible (they can extend or stretch)Elastic (they can return to their original shape)

Functions of Muscular Tissue

• Muscle makes up a large percentage of the body’s weight

• Their main functions are to:

Create motion – muscles work with nerves, bones, and joints

to produce body movements

Stabilize body positions and maintain posture

Store substances within the body using sphincters

Move substances by peristaltic contractions

Generate heat through thermogenesis

Functions of Muscular Tissue

Location Function Appearance Control

Skeletal

skeletonmovement,

heat, posture

striated, multi-nucleated

(eccentric), fibers parallel

voluntary

Cardiacheart

pump blood continuously

striated, one central nucleus

involuntary

Visceral(smooth muscle)

G.I. tract, uterus, eye,

blood vessels

Peristalsis, blood

pressure, pupil size,

erects hairs

no striations, one central

nucleus

involuntary

Three Types of Muscular Tissue

(b) Cardiac muscle (c) Visceral smooth muscle

(a) Skeletal muscle

Three Types of Muscular Tissue

Location Function Appearance Control

Skeletal

skeletonmovement,

heat, posture

striated, multi-nucleated

(eccentric), fibers parallel

voluntary

Cardiacheart

pump blood continuously

striated, one central nucleus

involuntary

Visceral(smooth muscle)

G.I. tract, uterus, eye,

blood vessels

Peristalsis, blood

pressure, pupil size,

erects hairs

no striations, one central

nucleus

involuntary

Skeletal Muscle

Skeletal Muscle

Skeletal muscle fibers are very long “cells” - next to neurons (which can be over a meter long), perhaps the longest in the bodyThe Sartorious muscle contains single fibers that are at least 30 cm long

A single skeletal muscle fiber

Skeletal Muscle

Sarcolemma

Motor neuron

Skeletal MuscleThe terminal processes of a

motor neuron in close proximity to the sarcolemma of a skeletal

muscle fiber

The epimysium, perimysium, and endomysium all are continuous with the connective tissues that form tendons and ligaments (attach skeletal muscle to bone) and muscle

fascia (connect muscles to other muscles to form groups of muscles)

Organization of Muscle Tissue

Organization of Muscle Tissue

Organization of a single muscle belly

Epimysium

Perimysium

Organization of a fasciculus

Organization of Muscle Tissue

Organization of a muscle fiber

Organization of Muscle Tissue

A muscle, a fasciculus, and a fiber all visualized

Organization of Muscle Tissue

• In groups of muscles the

epimysium continues to

become thicker, forming

fascia which covers many

muscles

• This graphic shows the

fascia lata enveloping the

entire group of quadriceps

and hamstring muscles in

the thing

Organization of Muscle Tissue

Organization of Muscle

Tissue• Many large muscle

groups are encased in both a superficial and a deep fascia

Real Anatomy, John Wiley and Sons