Muscles & Muscular Tissues 12 Feb. 2013Musc-tissue-lab.ppt1

Muscles & Muscular Tissues

12 Feb. 2013 Musc-tissue-lab.ppt 1


MUSCLE TISSUE

• Abundant, dense tissue– 40-50% of body weight

• High metabolic activity– high energy use/output;

– O2 consumption;

– CO2 production


Characteristics of Muscle Tissue

• Contractility– Muscle tissue shortens producing force.– “Muscles can only contract!”

• Excitability– Responds to nerve impulses by contracting.

• Extensibility– Can be stretched by outside force (such as by

another muscle).

• Elasticity– Recoils after being stretched


Functions of Muscle Tissue

• Produce movement by contracting– Locomotion & manipulation– Movement of blood, food, urine, etc. through

hollow organs

• Maintenance of posture• Stabilize joints

– so that other muscles can produce movement or maintain posture

• Heat production– Maintenance of body temperature.


Gross structure of a skeletal muscle: • Tendons connect muscle

to bone, transmit force.

• Origin = attachment to more stationary (proximal) bone

• Insertion = attachment to more mobile (distal) bone

• Belly = muscular tissue

• Head = one of multiple origins (-ceps)


Naming of muscles • Shape, arrangement of

fibers – Deltoid, orbicularis oris

• Location, origins/insertions– Pectoralis major

• Size– Latissimus dorsi

• Action – Flexor carpi ulnaris


Muscle Groups

• Agonist (prime mover) vs. AntagonistMuscles can only CONTRACT !!Muscle must be stretched by antagonist(s) before it can

contract again.

• Synergist(s) = muscle(s) that works with prime mover.

• Fixator(s) = muscle(s) that stabilizes body part.– Prevents one kind of motion so another can happen.


Three Kinds of Muscle Tissue

• Skeletal muscle: – Striated, usu. voluntary, attached to skeleton

• Cardiac muscle: – Striated, involuntary, walls of heart

• Smooth muscle: – Non-striated, involuntary, wrapping of hollow organs

– Stomach, intestines, arteries, bladder, vas deferens, uterus, etc.


Skeletal Muscle:

• Long, cylindrical cells,• Multinucleate (nuclei peripheral),• Covered by plasma membrane (sarcolemma),• Striated.


Cardiac Muscle• Branched cells• Striated• Intercalated discs


Smooth Muscle• Non-striated• Thin cells pointed at ends• wrapping of hollow organs

Documents

Muscles & Muscular Tissues 12 Feb. 2013Musc-tissue-lab.ppt1